Megacystis in the first trimester of pregnancy: Prognostic factors and perinatal outcomes.

OBJECTIVE: To determine whether bladder size is associated with an unfavorable neonatal outcome, in the case of first-trimester megacystis.
MATERIALS AND METHODS: This was a retrospective observational study between 2009 and 2019 in two prenatal diagnosis centers. The inclusion criterion was an enlarged bladder (> 7 mm) diagnosed at the first ultrasound exam between 11 and 13+6 weeks of gestation. The main study endpoint was neonatal outcome based on bladder size. An adverse outcome was defined by the completion of a medical termination of pregnancy, the occurrence of in utero fetal death, or a neonatal death. Neonatal survival was considered as a favorable outcome and was defined by a live birth, with or without normal renal function, and with a normal karyotype.
RESULTS: Among 75 cases of first-trimester megacystis referred to prenatal diagnosis centers and included, there were 63 (84%) adverse outcomes and 12 (16%) live births. Fetuses with a bladder diameter of less than 12.5 mm may have a favorable outcome, with or without urological problems, with a high sensitivity (83.3%) and specificity (87.3%), area under the ROC curve = 0.93, 95% CI (0.86-0.99), p< 0.001. Fetal autopsy was performed in 52 (82.5%) cases of adverse outcome. In the 12 cases of favorable outcome, pediatric follow-up was normal and non-pathological in 8 (66.7%).
CONCLUSION: Bladder diameter appears to be a predictive marker for neonatal outcome. Fetuses with smaller megacystis (7-10 mm) have a significantly higher chance of progressing to a favorable outcome. Urethral stenosis and atresia are the main diagnoses made when first-trimester megacystis is observed. Karyotyping is important regardless of bladder diameter.

Introduction

First-trimester ultrasound is a fundamental element of screening policy. Over the past few decades, technical improvements in ultrasound equipment have ameliorated understanding and visualization of fetal anatomy in the first trimester. Thus, first-trimester ultrasound seems ready to evolve from a simple screening examination to a detailed anatomical examination traditionally performed in the second trimester of pregnancy [1-5].

Ultrasound, which is complementary to noninvasive prenatal testing [6], offers multiple advantages, including earlier and more precise diagnosis, despite an uncertain prognosis at this term of pregnancy [7-9].

Megacystis in the first trimester of pregnancy is usually defined by a bladder size > 7 mm between 11 and 13+6 weeks of gestation [10-12], after checking for bladder emptying during the exam [13]. It occurs in 1/1600 to 1/3000 pregnancies. The cause may be obstructive in 60% of cases (posterior urethral valves, urethral atresia or urethral stenosis, cloacal anomalies), non-obstructive in 30% of cases, mainly syndromic disease (megacystis-microcolon-intestinal hypoperistalsis syndrome, prune belly syndrome), and finally idiopathic or transient (10% of cases) [14].

Several authors have evaluated the prognostic factors and neonatal outcomes associated with megacystis, all terms of pregnancy combined [15-21], as well as the possibility of antenatal surgical intervention (vesicoamniotic shunt or ablation of the obstructive tissue through in utero cystoscopy) in obstructive megacystis [22-27]. However, few authors have specifically evaluated the prognosis associated with bladder size and etiology [12, 28–30], and in most cases these were limited series. The main objective of this work was to evaluate in first-trimester megacystis whether bladder size is associated with unfavorable outcome. The secondary endpoint was description of etiologies and evaluation of whether there was an association between bladder size and etiology.

Materials and methods

Data collection and population studied

This was a retrospective observational study performed between November 2009 and November 2019 in two prenatal diagnosis centers: the Cochin Hospital, Paris, France and the Timone Hospital, Marseille, France. All patients were informed during ultrasound examinations of the possible use of their data for scientific purposes and could at any time indicate their refusal. Written consent was given by adults as well as by parents for minors and by guardians for persons under guardianship. A request for processing of this data was made to the Committee of Patient Data Protection and was accepted (French PADS). All data have been fully anonymized.

Fetal megacystis was defined as a longitudinal bladder diameter ≥ 7 mm measured from the bladder dome to the bladder neck in the midsagittal plane on an ultrasound scan performed between 11 and 13+6 weeks of gestation and confirmed by an ultrasound specialist. We excluded any diagnosis of megacystis beyond this term.

Bladder diameter was investigated with respect to the likelihood of postnatal outcome (favorable with or without urological problems or adverse outcome), respectively. Sensitivity, specificity and area under the receiver operating characteristic (ROC) curve (AUC) were calculated.

Based on the ROC curve, two groups were compared: (i) bladder diameter under 12.5 mm; (ii) bladder diameter greater than 12.5 mm. Our primary study endpoint was neonatal outcome (adverse or favorable) based on bladder size. An adverse outcome was defined by the completion of a medical termination of pregnancy (TOP), the occurrence of in utero fetal death (IUFD), or a neonatal death (ND). In this work, neonatal survival was considered as a favorable outcome and was defined by a live birth, with or without normal renal function, and with a normal karyotype. Medical data for pediatric follow-up of liveborn children were checked during their first year of life.

Our secondary endpoint was description of etiologies and evaluation of whether there was an association between bladder size and the different etiologies of megacystis (fetal karyotyping and pathological examination of the fetus).

All patients underwent detailed sonographic examination twice: a first ultrasound examination and another ultrasound examination one week later, to assess progression. Patients were included when the longitudinal bladder diameter at the first ultrasound was ≥ 7 mm. When the parents wished to continue the pregnancy, close ultrasound follow-up was offered. Nuchal translucency, bladder diameter, appearance of kidneys (normal, hydronephrosis, abnormal renal cortical appearance), amount of amniotic fluid and presence of associated elements (ascites, pulmonary hypoplasia) were systematically reported whatever the pregnancy outcome. Fetal karyotyping by chorionic villus sampling was systematically offered to the patients after ultrasound diagnosis in the two prenatal diagnosis centers. In the case of TOP or intrauterine death, a fetal autopsy was suggested (vacuum system or vaginal delivery). Vaginal delivery was encouraged to facilitate the pathological examination.

The final (pathological) diagnosis was divided into two categories:

First, the obstructive causes (lower urinary tract obstruction diagnosis or LUTO diagnosis) encompassing the diagnosis of posterior urethral valve (PUV), urethral atresia, urethral stenosis, cloacal anomalies and ureterocele.

Second, “other diagnoses”, including syndromic disease (prune belly syndrome, megacystis-microcolon-intestinal hypoperistalsis syndrome) and other diagnoses not corresponding to obstructive causes. When pregnancy was continued, neonatal outcomes were obtained from medical records and pediatric care [31-34].

Statistical analysis

Statistical analyses were performed using IBM SPSS Statistics software, version 20.0 (SPSS Inc., IL, USA). Continuous variables are presented as a mean with standard deviation range. Categorical variables are presented as numbers and percentages. Antenatal characteristics and postnatal outcome were then compared according to bladder size at the first ultrasound. We used the Pearson’s X2 test for comparison of qualitative variables. The area under the ROC curve was used to define a cut-off value. The statistical significance was defined as p < 0.05.

Results

Analysis of the population studied

Seventy-five cases of first-trimester fetal megacystis at the first ultrasound were included in our study population. Sixty-three percent of patients opted for TOP (n = 47/75), 14.7% of fetuses died in utero (n = 11/75) and 6.7% postnatally (5/75). There were 16% live births (n = 12/75). Therefore, we report 63 adverse outcomes (84%) and 12 favorable outcomes (16%). (Fig 1).

Fig 1

Flow chart.

Population characteristics are detailed in Table 1. The median maternal age at diagnosis was 31 years (+/- 5.69). The median gestational age at diagnosis was 12.5 weeks of gestation (+/-1.79). The population consisted mainly of male fetuses (76%). Nuchal translucency was less than the 95th percentile in 69 cases (92%). During the first-trimester ultrasound examination, 64% of fetuses had kidneys of normal appearance (n = 48) and 90% had a normal amount of amniotic fluid (68%) (Table 1).

Table 1

Population studied.

Population characteristics (n = 75)
Median maternal age (years)	31
Median gestational age at diagnosis (WG)	12.5
First ultrasound
Nuchal translucency
< 95th percentile	70 (93.3%)
>95th percentile	5 (6.7%)
Bladder size
< 12.5 mm	14 (18.6%)
>12.5 mm	61 (81.4%)
Kidneys
Normal appearance	48 (64%)
Abnormal renal cortical appearance	11 (14.7%)
Hydronephrosis	21 (28%)
Amount of amniotic fluid
Normal quantity	70 (93.3%)
Oligohydramnios	5 (6.7%)
Fetal gender
Male	57 (76%)
Female	18 (24%)
Outcome
Favorable	12 (16%)
Adverse	63 (84%)

Fetal outcome according to bladder size

A ROC curve of bladder diameter was used to identify the optimal “cut-off” for prediction of neonatal outcome of megacystis in the first trimester (AUC = 0.93, [95% CI 0,86–0.99], p< 0.001). Based on the ROC curve analysis, the optimal “cut-off” bladder diameter was 12.5 mm. Under this cut-off, the probability of a favorable outcome was 91%, with 83.3% sensitivity (95% CI 33.3–91.7) and 87.3% specificity (95% CI 75–99.9) (Fig 2).

Fig 2

Prediction of neonatal outcome: Performance of bladder diameter in the prediction of favorable or adverse outcome of megacystis in the first trimester.

Fetal characteristics according to bladder size

For this analysis, patients were allocated to two groups, according to the size of the fetal bladder determined by the ROC curve: 14 fetuses (18.6%) had a bladder size under 12.5 mm mm, 61 fetuses (81.4%) had a bladder size greater than 15 mm. Fetal characteristics for each group are detailed in Table 2.

Table 2

Univariate analysis: Analysis of US antenatal characteristics and neonatal outcomes according to bladder size.

Antenatal characteristics and postnatal outcome	Bladder size		p
	< 12.5 mm	>12.5 mm
	n = 14 (18.6%)	n = 61 (81.4%)
Age (years)
< 30	5 (35.7)	21 (33.4)	0.81
31–40	9 (64.3)	32 (52.4)
>40	0	8 (13.1)
Nuchal translucency
< 1.5	8 (57.1)	25 (40.9)	0.17
1.5–3	6 (42.8)	31 (50.8)
>3	0	5 (8.3)
Kidney appearance (FU)
Normal appearance	11 (78.5)	32 (52.4)	0.02
Hydronephrosis	3 (21.4)	18 (29.5)	0.01
Abnormal cortical appearance	0	11 (18)	0.26
Amount of amniotic fluid (FU)
Normal	11 (78.5)	56 (91.8)	0.93
Oligohydramnios/anhydramnios	3 (21.4)	5 (8.2)	0.71
Kidney Appearance (SU)
Normal aspect	8 (57.1)	4 (6.5)	0.09
Hydronephrosis	3 (21.4)	33 (54.1)	0.01
Abnormal cortical aspect	1 (7.1)	40 (65.6)	0.01
Amount of amniotic fluid (SU)
Normal	12 (85.7)	19 (31.1)	0,12
Oligohydramnios/anhydramnios	2 (14.3)	42 (68.8)	<0.001
Fetal gender
Female (XX)	4 (28.5)	14 (22.9)	0.47
Male (XY)	10 (71.4)	47 (77.1)
Outcome (TOP excluded)
Favorable outcome	12 (100)	0	< 0.001
IUFD	0	11
ND	0	5
Outcome (TOP included)
IUFD	0	11 (18)	< 0.001
ND	0	5
TOP	2 (14.2)	50 (82)
Favorable outcome	12 (85.8)	0

(FU: first ultrasound; SU: second ultrasound; TOP: termination of pregnancy; IUFD: in utero fetal death; ND: neonatal death). The Chi-square test was used for statistical analysis.

There was no statistical difference between the groups concerning the mother’s age, nuchal translucency or fetal gender.

In groups of fetuses with bladder size > 12.5 mm, the rate of hydronephrosis and oligohydramnios at the first-trimester ultrasound was significantly higher (p = 0.01). The rate of oligohydramnios was significantly higher too in fetuses with a bladder size > 12.5 mm (p<0.001), compared to fetuses with smaller bladder size.

Neonatal outcomes are described in Table 2. The rate of IUFD or ND was significantly higher in fetuses with a larger bladder diameter, whether or not TOP is taken into account in the statistical analysis.

Antenatal and postnatal characteristics of fetuses according to neonatal outcome

All infants with a favorable outcome (n = 12) had a normal bladder size at ultrasound at one-week control (spontaneous regression of megacystis). Spontaneous regression was observed in all cases when bladder size was < 12.5 mm at the first-trimester ultrasound scan. Renal appearance was normal, as was the amount of amniotic fluid in the ultrasound control one week later and on all other ultrasound scans during pregnancy. In the case of spontaneous regression, there was a favorable outcome without urological disease at one year.

Of the 12 children with a favorable outcome, 8 (66.7%) had normal renal function and non-pathological pediatric follow-up. Three children had transitory kidney disease (abnormal transitory renal function) and urinary disorders and needed pediatric urological monitoring. One child had an end-stage kidney disease at birth (abnormal renal function) that required a kidney transplant (Fig 1). Of the 4 favorable outcomes with urological problems at birth, isolated hydronephrosis was found in one case, an abnormal renal cortical appearance in two cases, and, in the last case, hydronephrosis and an abnormal renal cortical appearance associated with oligohydramnios in late pregnancy was found at the end of the ultrasound monitoring of each pregnancy.

Concerning adverse outcome, of the 11 cases of IUFD, 8 had an abnormal kidney ultrasound appearance. Of the 50 TOP, 43 (86%) had an abnormal renal appearance on ultrasound. Of the 5 ND, all cases had an abnormal renal appearance.

Seventy-three karyotypes were determined (in 2 cases the parents refused) and nine of them (12.3%) were abnormal. No statistical association was found between bladder size and the risk of chromosomal abnormality.

In the 63 cases of adverse outcomes, the parents refused pathological examination of the fetus in 11 (17%) cases (9 because the karyotype was abnormal and 2 because the parents refused). Of the 52 (82.5%) cases where pathological examination was performed, 17 (32.7%) were not informative (11 by vacuum system and 6 by vaginal delivery). Finally, 35 were informative (67.3%) and megacystis was obstructive in 31 of these cases (88.5%), the majority of which (n = 19 or 54%) involved urethral stenosis or atresia, followed by posterior urethral valve, cloacal anomalies, and finally obstructive ureterocele. The origin of megacystis was non-obstructive in only 4 cases (11.4%). Details of fetal karyotypes and pathological characteristics are reported in Table 3.

Table 3

Antenatal and postnatal characteristics of fetuses according to neonatal outcome.

COMPLEMENTARY EXAMS	All cases of megacystis	Bladder size
		< 12.5 mm	>12.5 mm
	n = 75 (100%)	n = 14	n = 61
Karyotype
Normal	64 (87.6)	13 (10.9)	44 (43.8)
Abnormal	9 (12.3)	1 (1.3)	8 (8.2)
Trisomy 13	2 (2.7)	0	2 (2.7)
Trisomy 18	5 (6.8)	1 (1.3)	4 (2.7)
Trisomy 21	1 (1.3)	0	1 (1.3)
Other	1 (1.3)	0	1 (1.3)
Not wanted	2 (2.7)	1 (1.3)	1 (1.3)
Pathological diagnosis	52 (82)	Not done	52 (65.4)
Informative	35 (67.3)		35 (44.2)
LUTO	31 (88.5)
Posterior urethral valves	6 (17.1)		7 (9.6)
Urethral stenosis/urethral atresia	19 (54)		17 (23.1)
Obstructing ureterocele	2 (5.7)		3 (3.8)
Cloacal anomalies	4 (11.4)		4 (3.8)
Cause non-obstructive	4 (11.4)
Prune-Belly syndrome	3 (8.6)		3 (1.9)
Other	1 (2.8)		1 (1.9)
Not wanted	11 (17.4)		11 (9.5)
Uninformative	17 (32.7)		17 (21.1)

(LUTO: lower urinary tract obstruction).

Discussion

In this observational study, our results show that fetuses with a bladder diameter of less than 12.5 mm can have a favorable outcome, with or without urological problems, with a high sensitivity and specificity (83.3 and 87.3%, respectively). Beyond this diameter, an adverse outcome is almost systematic.

With our results, 2 different situations can be highlighted. The first is where there is a high possibility of spontaneous regression when bladder size is less than 12.5 mm. A favorable outcome remains possible, albeit almost certainly with urological disease requiring short- or long-term care. In the case where diameter is greater than 12.5 mm, parents should be advised of certain adverse outcomes, like neonatal death or IUFD (Fig 3).

Fig 3

Decision analysis and prenatal counseling according to the bladder size “cut-off” determined by the area under the ROC curve.

(TOP: termination of pregnancy; IUFD: in utero fetal death; ND: neonatal death).

Our results are highly consistent with those of Kao et al, whose study was carried out at the same time as ours, showing that isolated megacystis < 12 mm is associated with a positive outcome [35]. Another strength of the current study is the size of the included population, which is one of the largest in the literature for a population concerning only megacystis in the first trimester of pregnancy, with evaluation of ultrasound characteristics and neonatal outcomes [12, 28–30, 35]. Furthermore, ultrasound was carried out by trained practitioners in two diagnosis centers, allowing a reliable diagnosis of megacystis. Moreover, we were able to collect all pathological findings desired by the parents, even if some of them were not informative. Indeed, macroscopic examination of lower urinary tract obstruction is technically difficult due to the term and the size of fetus, with dissection not always possible, even if it alone can identify the type of barrier [36, 37].

Our study has several limitations. No multivariate analysis was performed. However, our study was essentially descriptive, and multivariate analysis would not have justified the analysis of all data. Furthermore, concerning follow-up of liveborn infants, there is no certainty about their long-term state of health, even if the follow-up at one year is reassuring. Indeed, the perspective on the state of health is different because our data collection is spread over ten years. Finally, although it is known as a prognostic factor [20, 38], the evaluation of renal function in the antenatal period could not be done because this analysis was not performed at the two university hospitals.

In accordance with previously published studies, our study confirms that fetuses with a large megacystis more frequently have an adverse outcome [21, 39]. It is important to adjust prenatal counseling of the parents in the case of early diagnosis. In fact, the most important questions are the possibility of regression, and neonatal outcomes if pregnancy is continued. Bladder diameter seems to be a predictive marker of neonatal outcome.

Several authors have been interested in spontaneous megacystis regression. Iuculano et al [28, 40] consider that an ultrasound scan performed 2 weeks after the megacystis diagnosis can predict the outcome in fetuses with a longitudinal bladder diameter < 15 mm as early as the end of the first trimester. In their study, the outcome of euploid fetuses with a longitudinal bladder diameter < 15 mm was favorable in 58.3% of cases. Fontanella et al reported in 2017 [19] that diameter bladder is a predictor of spontaneous resolution if the diagnosis is made before 18 weeks (80% sensitivity and 79% specificity). They specified that spontaneous regression before 23 weeks is a marker of favorable neonatal outcome, without urological surgical intervention, which is consistent with the 2017 study by Girard et al. [29].

Bladder size was not linked with chromosomal abnormality. However, we consider that karyotyping should be offered to parents, since a chromosomal abnormality can be found regardless of the size of the megacystis. There is therefore no link between bladder size and chromosomal abnormality. Concerning the final diagnosis by pathological examination of the fetus, we observed some disagreement with the literature data [41, 42]. In our population, the main diagnosis was urethral stenosis or atresia compared to PUV, a diagnosis frequently reported as the most important cause of megacystis in the second and third trimesters of pregnancy [41]. Two possibilities could explain this discrepancy. Firstly, the technical difficulties of pathological examination of the fetus could lead to underdiagnosis of PUV at this term. Secondly, there may be a tendency to superimpose the etiological diagnoses of megacystis whatever the trimester of pregnancy. But, etiologies of complete and total urinary tract obstruction (urethral atresia, urethral stenosis, and some cases of completely obstructive PUV) explain the early and strong ultrasound and clinical expression. Indeed, technical improvements in ultrasound equipment have ameliorated visualization of fetal anatomy in the first trimester.

The purpose of our study was mainly to improve prenatal counseling in the first trimester of pregnancy, by a response adapted to the first-trimester ultrasound findings. The proposal for a prognosis threshold based on neonatal outcome seems appropriate and necessary, in a society where end-of-life support is increasingly important.

Conclusion

Two different situations with different neonatal outcomes can be highlighted with megacystis in the first trimester of pregnancy. Fetuses with megacystis < 12.5 mm have a significantly higher chance of a favorable outcome compared to megacystis > 12.5 mm. Bladder diameter appears to be a predictive marker of neonatal outcome.

Similarly, it seems better to speak of low urinary tract obstacle rather than of PUV in cases of first-trimester megacystis. Urethral stenosis and urethral atresia are the commonest diagnoses. Regardless of bladder diameter, karyotyping remains important. Optimized first-trimester screening is now an integral part of our screening policy. Taken together, these investigations improve prenatal counseling by providing an adapted and adjusted response to the first-trimester ultrasound findings.

(XLSX)

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8 Feb 2021

PONE-D-20-39804

MEGACYSTIS IN THE FIRST TRIMESTER OF PREGNANCY: PROGNOSTIC FACTORS AND PERINATAL OUTCOMES

PLOS ONE

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Additional Editor Comments:

The authors included a large series of first trimester fetuses with megacystis and described the neonatal outcomes according to the bladder size.

I agree with one of the reviewers that this large series merits publication on this Journal but I also agree with the main criticism by the second reviewer that bladder size groups were arbitrarily selected and that fetal bladder size should be consider a continuous variable and therefore I strongly recommend to assess the clinical value of bladder size to predict neonatal outcome by a decision tree analysis, which allow an automatic classification using the predictive variable as a continuous variable allowing a sequential analysis to predict postnatal outcome. Since previous studies have demonstrated that the size of fetal bladder predicts adverse neonatal outcome, I think that assessing an automatic fetal bladder size cut-off may be of clinical interest and thus, deserving to be publish in this Journal

Please include the following references:

Fontanella et al. Antenatal Workup of Early Megacystis and Selection of Candidates for Fetal Therapy. Fetal Diagn Ther 2019;45(3):155-161.

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Reviewer #1: Yes

Reviewer #2: No

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Reviewer #1: Yes

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Reviewer #1: The authors report a multicenter cohort study, which evaluates the prognosis associated with the bladder size at 1st trimester in case of megacystis.

This large and interesting series deserve to be published. However it should be more focus on its originality that lies in the analysis of outcomes based on bladder size. Moreover, data on evolution during pregnancies and renal function should be provided.

INTRODUCTION

L66-68: The sentence is a bit unclear. Do the authors mean ‘after’ rather ‘with’ checking of bladder emptying during the exam’ ?

L73-78: The authors should rather justify the interest of the present study by describing the lack of data regarding the prognosis associated with bladder size, so as the etiology depending on the bladder size.

L78-80: The main objective should be rephrased to: ‘…in case of megacystis at first trimester, whether bladder size is associated to unfavorable outcome’

L80-83: I suggest to focus only on etiology based on bladder size (rather than to also aiming to describe the whole series as an objective)

METHODS

L95-100 : The authors should justify further the choice of these thresholds.

L103-105: It would be very important to identify cases with or without normal renal function among live births if there is a one-year follow-up+++ Dead/Alive is not appropriate for a study on megacystis and renal function is of interest.

L109: ‘all patients’ rather than ‘all fetuses’

L116: There was no karyotypes performed in one of the centers???

L112-115: Authors should precisely describe the parameters related to the inclusion criteria. How was measured the bladder? Which axis? What if the measurement is different at two different time points during the US examination or between 2 US?

RESULTS

Again, reporting renal function would be really important.

L176-177: Authors introduce here the evolution of US findings at second US. Is it second trimester US? It would be of interest indeed to have follow-up data but it should be more detailed (including bladder aspect, gestational age,…) in a specific table.

L184-186: Mixing data from both US is a bit confusing. If inclusion so as tables based on first US, it should be clearly stated in the methods section so as in the results section.

L191-216: This section is too long, a bit hard to understand, and not necessary. First information is already provided in Table 3 and above all the article should focus on the outcome based on the bladder size.

DISCUSSION

Discussion is interesting and figure 2 is appropriate.

Reviewer #2: This appears to be a rather large series of a rare fetal condition.

However, megacystis was only transient in a large proportion with good outcomes as expected

The authors arbitrarily grouped cases by bladder size. There is no rationale for this and bladder size should therefore be considered a continuous variable

There are no information on standardized care pathway or on indications for TOPs

The etiologies for LUTO in this series are similar to those reported in previous studies

The conclusions are trivial and not substantiated by the data, as explained above.

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18 Mar 2021

To Plos One Editorial

The 23rd of february 2021

Thank you very much for reviewing our manuscript “Megacystis in the first trimester of pregnancy: prognostic factors and perinatal outcomes”. We also greatly appreciate the reviewers for their complimentary comments and suggestions. We have carried out the experiments that the reviewers suggested and we revised the manuscript accordingly.

We hope that you find our responses satisfactory and that the manuscript meets Plos One publication criteria as it currently stands.

Sincerely,

Dr LESIEUR Emmanuelle

Submitted filename: Response to reviewer.docx

Click here for additional data file.

30 Mar 2021

PONE-D-20-39804R1

MEGACYSTIS IN THE FIRST TRIMESTER OF PREGNANCY: PROGNOSTIC FACTORS AND PERINATAL OUTCOMES

PLOS ONE

Dear Dr. Lesieur,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

The manuscript has been improved according to the reviewers' comments. However, a main concern persists throughout the manuscript, mainly due to the use of pre-defined bladder size groups instead to select an automatic bladder size cut-off to predict prognosis.

Please submit your revised manuscript by May 14 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Rogelio Cruz-Martinez, Ph.D.

Academic Editor

PLOS ONE

Editor comments:

The authors should grouped the prognostic category based in the analysis on bladder size and not in a pre-defined bladder size groups, i.e. to analyze bladder size as a continuous variable and selecting the best cut-off to predict adverse outcome. The mean bladder size was significantly higher in cases with adverse outcome, but it remains unknown which is the best cut-off to predict such adverse outcome.

[Note: HTML markup is below. Please do not edit.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

16 Apr 2021

Thank you very much for reviewing again our manuscript “Megacystis in the first trimester of pregnancy: prognostic factors and perinatal outcomes”. We also greatly appreciate the editor for his complimentary comment.

Editor comments :

The authors should grouped the prognostic category based in the analysis on bladder size and not in a pre-defined bladder size groups, i.e. to analyze bladder size as a continuous variable and selecting the best cut-off to predict adverse outcome. The mean bladder size was significantly higher in cases with adverse outcome, but it remains unknown which is the best cut-off to predict such adverse outcome.

Our response :

As recommended by this one, we carried out a new statistical analysis using a ROC curve to determine a “bladder diameter cut – off”, making it possible to determine a diameter for which we can predict the neonatal outcome with a high sensitivity and specificity.

Based on the ROC curve analysis, the optimal “cut-off” bladder diameter was 12,5 mm. Under this cut-off, the probability to have a favorable outcome was 91 %, with sensitivity 83,3 % CI 95 (33,3 – 91,7 %) and specificity was 87,3 % CI 95 (75 – 99,9)

Two groups were then compared : (i) bladder diameter under 12,5 mm; (ii) bladder diameter greater than 12,5 mm. Our population was distributed according to this cut off.

All tables and figures have been changed. A new figure, with the ROC curve was created.

Big changes have been made to the manuscript.

We hope that you find our responses satisfactory and that the manuscript meets Plos One publication criteria as it currently stands.

Submitted filename: Response to reviewer.docx

Click here for additional data file.

21 May 2021

PONE-D-20-39804R2

MEGACYSTIS IN THE FIRST TRIMESTER OF PREGNANCY: PROGNOSTIC FACTORS AND PERINATAL OUTCOMES

PLOS ONE

Dear Dr. Lesieur,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

The manuscript has been improved according to the editor and reviewer's suggestions but I still consider it is not suitable for publication in its current form.

Please submit your revised manuscript by Jul 05 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Rogelio Cruz-Martinez, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments (if provided):

The manuscript has been improved according to the editor and reviewer's suggestions and I consider it is now suitable for publication in its current form

Minor comments:

The manuscript still require a gramatical correction.

Please rephrase the following sentence in the abstract in order to clarify the meaning "Pathological examination of the fetus was performed in 52 (82.5%)".

Please define "neonatal outcome" in the Abstract.

In the Methods section, neonatal outcome has been defined as a live birth with or without normal renal function. Such outcome should be defined as "neonatal survival"

The clinical algorithm should include prediction of neonatal survival as a primary outcome and prediction of renal failure as a secondary outcome

Please clarify the meaning of the following sentence "In the case of TPO; pathological examination of the fetus was suggested". Does it mean fetal autopsy?

[Note: HTML markup is below. Please do not edit.]

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

25 May 2021

Dear Editor, Dear reviewers

I am pleased to submit again our revised manuscript “Megacystis in the first trimester of pregnancy : prognostic factors and perinatal outcomes” by E. Lesieur, MD, M. Barrois, MD, M. Bourdon, MD, J. Blanc, MD, L Loeuillet, MD, C. Delteil, MD, J. Torrents, MD, F. Bretelle, MD PhD, G. Grangé, MD, V. Tsatsaris, MD PhD, O. Anselem, MD

We also greatly appreciate the editor complimentary comments and journal requirements.

We revised the manuscript accordingly.

We hope that you find our responses satisfactory and that the manuscript meets Plos One publication criteria as it currently stands.

Sincerely,

Dr LESIEUR Emmanuelle

Submitted filename: Response to reviewer.docx

Click here for additional data file.

15 Jun 2021

PONE-D-20-39804R3

MEGACYSTIS IN THE FIRST TRIMESTER OF PREGNANCY: PROGNOSTIC FACTORS AND PERINATAL OUTCOMES

PLOS ONE

Dear Dr. Lesieur,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Jul 30 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Rogelio Cruz-Martinez, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments (if provided):

The manuscript has been improved accordingly. However, I strongly recommend to have a grammar correction by a native English speaker because there are still several typographical errors.

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

19 Jun 2021

Thank you very much for reviewing again our manuscript “Megacystis in the first trimester of pregnancy: prognostic factors and perinatal outcomes”. We also greatly appreciate the editor for his complimentary comment.

Journal requirements :

Please review your reference list to ensure that it is complete and correct.

All other references are correct and correspond to the manuscript. The reference list is complete.

Editor comments :

- The manuscript has been improved accordingly. However, I strongly recommend to have a grammar correction by a native English speaker because there are still several typographical errors.

We agree with the reviewer’s comment. Grammar correction has been made by a native English speaker.

We hope that you find our responses satisfactory and that the manuscript meets Plos One publication criteria as it currently stands.

Sincerely,

Dr LESIEUR Emmanuelle

Submitted filename: Response to reviewer.docx

Click here for additional data file.

27 Jul 2021

MEGACYSTIS IN THE FIRST TRIMESTER OF PREGNANCY: PROGNOSTIC FACTORS AND PERINATAL OUTCOMES

PONE-D-20-39804R4

Dear Dr. Lesieur,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Rogelio Cruz-Martinez, Ph.D.

Academic Editor

PLOS ONE

27 Aug 2021

PONE-D-20-39804R4

Megacystis in the first trimester of pregnancy: Prognostic factors and perinatal outcomes

Dear Dr. Lesieur:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr Rogelio Cruz-Martinez

Academic Editor

PLOS ONE