The Combined Influence of Maternal Medical Conditions on the Risk of Fetal Growth Restriction [34N

Abstract

INTRODUCTION: Common maternal medical co-morbidities such as hypertensive disorders, diabetes, tobacco use, and extremes of maternal age, BMI, and gestational weight gain (GWG), are known individually to impact fetal growth restriction (FGR) risk. We aim to examine the risk of FGR in women with multiple maternal medical co-morbidities to determine the cumulative risk imposed on pregnancy. METHODS: In this population-based retrospective cohort study we analyzed data from Ohio live birth records from 2006–2015 to estimate the influence of individual and combinations of maternal co-morbidities on rates of FGR (birthweight <10th percentile for gestational age) and severe FGR (<5th percentile). The exposures were individual and combinations of maternal medical conditions (chronic hypertension, gestational hypertension, pre-gestational diabetes, tobacco use, advanced maternal age, underweight, and insufficient GWG) and outcomes were rates and adjusted relative risk (aRR) of FGR. RESULTS: There were 1,463,506 live births in Ohio during the study period, of which 734,672 (50.2%) had one or more maternal medical condition. Pregnancies complicated by multiple co-morbidities had higher rates of FGR compared to those with a single medical condition. The rate and aRR range of FGR <10%ile and FGR <5%ile ranged from 8.8–18.4% (aRR 0.91–1.51) and 4.3–9.3% (aRR 0.84–2.22), respectively in pregnancies with single medical conditions, which increased to 10.4–57.9% (aRR 1.03–3.16) and 5.9–36.9% (aRR 1.11–7.03), respectively in pregnancies complicated by multiple medical co-morbidities. CONCLUSION: A greater number of maternal medical co-morbidities during pregnancy is associated with increasing cumulative risk of fetal growth restriction, which may be useful in patient counseling and screening for FGR.