Bharti Garg1, Blair Darney2, Rachel A Pilliod3, Aaron B Caughey3. 1. Department oCf Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR. Electronic address: gargb@ohsu.edu. 2. Department oCf Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR; OHSU-Portland State University School of Public Health, Portland, OR; Instituto Nacional de Salud Publica, Centro de Investigacion en Salud Poblacional (CISP), Cuernavaca, Morelos, Mexico. 3. Department oCf Obstetrics & Gynecology, Oregon Health & Science University, Portland, OR.
Abstract
BACKGROUND: Severe maternal morbidity (SMM) is a composite variable that includes adverse maternal outcomes during pregnancy that are associated with maternal mortality. Previous literature has shown that inter-pregnancy interval (IPI) is associated with preterm birth, fetal growth restriction and low birth weight, but the association of IPI and composite SMM is not well studied. OBJECTIVE: We sought to determine the relationship between interpregnancy interval (IPI) stratified as <6 months, 6-11 months, 12-17 months, 18-23 months, 24-59 months and ≥60 months) and SMM, which we considered both with and without blood transfusion. STUDY DESIGN: This is a retrospective cohort study of multiparous women 15-54 years old with singleton, non-anomalous births between 23-42 weeks gestation in California (2007-2012). We defined SMM as the composite score of a published list of ICD-9 (International Classification of Diseases, 9th Revision) diagnoses and procedure codes, provided by Center for Disease Control and Prevention (CDC). We used chi-square tests for categorical variables and multivariable logistic regression models were utilized to determine the association of IPI (independent variable) with SMM (dependent variable), adjusted for maternal race/ethnicity, age, education, body mass index, insurance, prenatal care, smoking status and maternal co-morbidity index score. RESULTS: In this study, 1,669,912 women met inclusion criteria and of these, 0.87% (n=14,529) of women had SMM and 0.28% (n=4,712) had ntSMM. Multivariable logistic regression models showed that compared to women with 18-23 months IPI, women with IPI of less than 6 months (aOR=1.23; 95% CI: 1.14-1.34) and ≥60 months (aOR=1.11; 95% CI: 1.04-1.19) had significantly higher adjusted odds of SMM. Odds of ntSMM is higher in women with long IPI (≥60 months) after controlling for the same potential confounders (aOR=1.17, 95% CI: 1.04-1.31). We also found significantly higher odds of requiring ventilation (aOR=1.34; 95% CI: 1.03-1.75) and maternal sepsis (aOR=2.08; 95% CI: 1.31-3.31) in women with long IPI. CONCLUSION: Risk of SMM is higher in women with short IPI (<6 months) and long IPI (≥60 months) as compared to normal IPI (18-23 months). Risk of ntSMM is significantly higher in women with long IPI (≥60 months). IPI is a modifiable risk factor and counselling of women to have adequate gap between pregnancies may be an important to decrease the risk of SMM.
BACKGROUND: Severe maternal morbidity (SMM) is a composite variable that includes adverse maternal outcomes during pregnancy that are associated with maternal mortality. Previous literature has shown that inter-pregnancy interval (IPI) is associated with preterm birth, fetal growth restriction and low birth weight, but the association of IPI and composite SMM is not well studied. OBJECTIVE: We sought to determine the relationship between interpregnancy interval (IPI) stratified as <6 months, 6-11 months, 12-17 months, 18-23 months, 24-59 months and ≥60 months) and SMM, which we considered both with and without blood transfusion. STUDY DESIGN: This is a retrospective cohort study of multiparous women 15-54 years old with singleton, non-anomalous births between 23-42 weeks gestation in California (2007-2012). We defined SMM as the composite score of a published list of ICD-9 (International Classification of Diseases, 9th Revision) diagnoses and procedure codes, provided by Center for Disease Control and Prevention (CDC). We used chi-square tests for categorical variables and multivariable logistic regression models were utilized to determine the association of IPI (independent variable) with SMM (dependent variable), adjusted for maternal race/ethnicity, age, education, body mass index, insurance, prenatal care, smoking status and maternal co-morbidity index score. RESULTS: In this study, 1,669,912 women met inclusion criteria and of these, 0.87% (n=14,529) of women had SMM and 0.28% (n=4,712) had ntSMM. Multivariable logistic regression models showed that compared to women with 18-23 months IPI, women with IPI of less than 6 months (aOR=1.23; 95% CI: 1.14-1.34) and ≥60 months (aOR=1.11; 95% CI: 1.04-1.19) had significantly higher adjusted odds of SMM. Odds of ntSMM is higher in women with long IPI (≥60 months) after controlling for the same potential confounders (aOR=1.17, 95% CI: 1.04-1.31). We also found significantly higher odds of requiring ventilation (aOR=1.34; 95% CI: 1.03-1.75) and maternal sepsis (aOR=2.08; 95% CI: 1.31-3.31) in women with long IPI. CONCLUSION: Risk of SMM is higher in women with short IPI (<6 months) and long IPI (≥60 months) as compared to normal IPI (18-23 months). Risk of ntSMM is significantly higher in women with long IPI (≥60 months). IPI is a modifiable risk factor and counselling of women to have adequate gap between pregnancies may be an important to decrease the risk of SMM.
Authors: Maria I Rodriguez; Ann Martinez Acevedo; Jonas J Swartz; Aaron B Caughey; Amy Valent; K John McConnell Journal: JAMA Netw Open Date: 2022-04-01