Clinical and Ultrasonographic Predictors of Foetal Macrosomia

Abstract

BACKGROUND Foetal macrosomia is defined as foetal growth above the 90 th percentile for a given gestational age or as foetal weight >4000 gms. In India, a baby weighing more than 3.25 kg would be greater than the 90 th percentile and therefore by definition has macrosomia. Foetal macrosomia is associated with increased risk of maternal and foetal complications. The aim of the study is to study the predictive power of clinical parameters and ultrasound foetal measurements in macrosomia. MATERIALS AND METHODS A case-control study was conducted in the Department of Obstetrics and Gynaecology at the Institute of Maternal and Child Health, Government Medical College, Kozhikode, during the period March 2014-April 2015. A comparison between a group of women delivering liveborn babies between 37-40 weeks weighing more than 4 kg and another group with similar inclusion criteria with less than 4 kg is done. 110 cases constituted the macrosomic group and 440 cases constituted the non-macrosomic group. Singleton pregnancy with regular cycles, known LMP and obstetric ultrasonography before 20 weeks to confirm the gestational age more than 37 weeks and less than 40 weeks were taken as the criteria for inclusion into the study. Obstetric ultrasonography must have been performed 2 weeks before delivery. Multiple gestation, stillbirth, gross or chromosomal abnormalities, small for gestational age, oligohydramnios and pregnancy in advanced labour were excluded from the study. Detailed clinical history is taken. Foetal ultrasound parameters measured are Biparietal Diameter (BPD), Head Circumference (HC), Abdominal Circumference (AC), Femur Length (FL), Femur Length/Abdominal Circumference (FL/AC), Intrauterine Ponderal Index (IUPI) and Estimated Foetal Weight (EFW). Data are expressed in its frequency and percentage. To elucidate the association and comparisons, chi-square test was employed. Risk of each parameter was assessed using binary logistic regression analysis and odds ratio was found out. For statistical evaluation, a two-tailed probability value less than 0.05 was considered significant. RESULTS 87% of the study population were less than 30 years. More than half were multigravida. Among them, 24.5% had macrosomic babies while among the primigravida only 14% had macrosomic babies. About 30% had gestational diabetes mellitus. Previous history of macrosomic foetus was present in 18.44%. Among 110 macrosomic babies, 74 mothers of those babies had BMI more than 25. In ultrasonography, 45 babies had BPD more than 96 mm (90th percentile), 40 had HC more than 354 mm (90th percentile), 92 had AC more than 346 mm (90th percentile) and 85 had FL more than 74 mm (90th percentile). Estimated foetal weight was more than 4000 grams in 86 patients. CONCLUSION Foetal macrosomia is more common among multigravida. There is significant association between the incidence of macrosomia and gestational diabetes mellitus. Previous macrosomic birth and high body mass index have influence over macrosomia. Biparietal diameter and head circumference ...