Fetal Malformations and the Pediatric Surgeon.

Subhasis Roy Choudhury

Despite the advances in fetal diagnosis, fetal surgery has remained a distant dream in India. Cost of establishment, training of personnel and most importantly, uncertainty about the outcome are the major reasons behind the impediment.

The prevalence of birth defects is in 3%–4% of neonates and birth defects cause 8%–15% of perinatal deaths.[1] The relative prevalence of birth defects is in the order of the central nervous system, genitourinary, gastrointestinal, cardiovascular, and thoracic anomalies. Understandingly, congenital anomalies impose a greater burden in developing countries due to late diagnosis and limited resources for their management. Fetal anomalies are associated with significant distress to the family, and major malformations have a mortality rate of above 50%.[2]

Encouragingly due to better awareness, pediatric surgeons are now increasingly involved in the decision-making process for the management of fetal malformations. The roles of pediatric surgeons are counseling, planning management, prevention, and continued postnatal care.

Counseling of the family regarding the possible outcome of antenatally detected anomalies is essential. This is currently best done by a team of experts involved in perinatal management. The role of antenatal counseling is to provide information to prospective parents regarding the fetal outcome, possible interventions, appropriate settings, time and route of delivery, and expected postnatal outcomes. The benefit not only includes care of the newborn in an appropriate center but also associated with a high level of family satisfaction.[3] The care of such patients should begin early and counseling should also include follow-up and planning of future pregnancies.

Antenatal counseling should be nondirective and follow certain guidelines.[4] For predicting realistic outcomes, appropriate knowledge about the evolution and progress of the disease is essential. Evidence based on the available data resources are useful; however, there are regional and racial variations of disease conditions which should be taken into account while counselling. Thus, the availability of a large regional database could form a useful source of information. There is a need for a countrywide database on fetal malformations for better understanding and management. Providing outcome information of a particular anomaly in one's setting will help both caregivers and parents to form realistic expectations regarding the prognosis of a particular anomaly under existing conditions.[2]

Late detection of anomalies poses a significant challenge in the management. In a study from SGPGI Lucknow, half of the malformations were diagnosed after 20 weeks of gestation, and only 1.6% of fetuses with malformations were picked up in the first-trimester scan.[5] This should aim at improving the sensitivity of two-dimensional ultrasound to around 50% at 11–14 weeks and to 90% with the additional second scan at 22–24 weeks. In India, Medical Termination of Pregnancy (MTP) act 1971 permits legal termination till 20 weeks of gestation, thus putting constraints by restricting termination of pregnancy in cases of late detection of major anomalies. Revision of the MTP act with the relaxation of timing for the termination in select situations is required. At the same time, one should be judicious in safeguarding the interest of the fetus and parents, especially in cases of minor and surgically correctable anomalies, thereby avoiding unnecessary terminations.

Pediatric surgeons should be cautious in interpreting the results of screening and images referred from elsewhere and should not hesitate to review them keeping in mind the possible evolution of the anomalies with time. As there are legal implications in the decision-making process, a jointly taken decision with the doctors and the family is desirable.

One should be familiar with the list of soft markers for aneuploidy and their relevance. While prognosticating, it is important to differentiate between an isolated versus multiple anomalies as outcomes are poor in the latter group. Appropriate genetic testing should be offered in suspected genetic syndromes for prognostication and management.[4]

The following scenarios may be followed in planning management of prenatally diagnosed anomalies.

Serious malformations; incompatible with postnatal life if detected early, the family has an option for termination

Correctable malformations are best managed by appropriate surgical therapy after delivery. Delivery at the appropriate time and center with timely interventions is associated with a good outcome

In utero intervention for a limited number of conditions with documented benefits

Preventable congenital malformations such as neural tube defects can be avoided with the use of periconceptional folic acid.

Preliminary results from analysis of the records of our patients registered in the fetal clinic and delivered in-house are encouraging. We recorded 70% overall survival for antenatally detected abdominal malformations with >90% survival for live-born babies with abdominal wall defect. The survival for antenatally diagnosed congenital pulmonary airway malformations with steroid therapy given to the mother between 24 and 28 weeks is 71% and nearing 100% in live-born babies. The overall survival for congenital diaphragmatic hernia (CDH) remained low at 44%. Antenatal assessment of observed versus expected lung to head ratio (o/e LHR) and cystic adenomatoid malformation volume ratio (CVR) are established parameters to prognosticate CDH and congenital cystic lung malformations. Out of the different renal pathologies that were diagnosed, survival was highest in the unilateral disease group. The factors associated with poor prognosis included bilateral disease, absence of amniotic fluid, and the presence of other associated malformations. Our study with fetal ventriculomegaly (VM) showed late referral pattern and poor outcome in cases with VM >15 mm and associated malformations.[6]

A significant number of fetal lesions, for example, cystic and vascular lesions have a tendency for spontaneous regression and can be managed with watchful expectancy. In cases of fetal loss, fetal autopsy, including photographs, X-rays, external and internal examination, and chromosome analysis should be done and recorded for future reference.

CURRENT ROLE OF FETAL SURGERY

In recent years, minimally invasive fetal interventions are replacing open fetal surgery. The current evidence supports superior results of fetal surgery for spina bifida (MOMS trial) although case selection bias needs to be addressed.[7] Similarly, the results of the PLUTO trial in cases with antenatally diagnosed lower urinary tract obstructions have shown that vesico-amniotic shunting improves perinatal survival, but the effect on long-term renal function is unclear.[8] Many of the results of fetal interventions are still awaited as they require a long time to unfold, for example, a multicenter randomized trial of fetal endoluminal tracheal occlusion versus nonintervention in CDH from Europe and America is currently underway, and the final results are still not available.

There are anecdotal reports from some Indian centers of fetal interventions in the form of aspiration of a large cyst, ex utero intrapartum treatment (EXIT), fetal reduction, administration of drugs, endoscopic ablation of posterior urethral valves, vesico- and pleuro-amniotic shunts, and LASER ablation of fetal abnormal blood vessels. There are centers also offering fetal interventions in the form of intrauterine transfusion, fetoscopic laser photocoagulation for twin-twin transfusion syndrome, radiofrequency ablation of complicated monochorionic pregnancies, fetal shunt placement, amniotic band resection, and the EXIT procedure. Only tertiary care centers with multidisciplinary team should be offering such fetal therapy and the patient referral system should be optimized accordingly.[910]

Pediatric surgeons should actively participate in antenatal counseling and planning management for the fetus with structural malformations, and this subject should be included in the curriculum of pediatric surgical residency training program. The involvement of pediatric surgeons in fetal management will expand their field of practice and open up a vast area for research.