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

OBJECTIVE

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.