Maternal obesity is not associated with increased crown-rump length in first-trimester ultrasounds of singleton gestations

AbstractObjective: To evaluate whether or not obesity affects fetal growth in the first trimester of pregnancy.Study design: A retrospective cohort study of obese versus non-obese women in our ultrasound database was performed to compare crown-rump length (CRL), a surrogate of fetal growth, at the first-trimester genetic screening.Results: A total of 50 obese and 50 non-obese women were included. CRL for both groups was performed at an average of 12wk5d ± 3 d. A linear regression analysis demonstrated that there was no difference between the cohorts in respect to CRL in the first trimester (p = .482). However, the estimated fetal weight at second-trimester anatomy ultrasound and the neonatal birth weight were increased in obese women (p < .001 for both analyses).Conclusion: Maternal obesity does not significantly alter the fetal CRL. However, maternal obesity appears to be associated with increased fetal growth as early as the second trimester.