Background: Obesity in pregnancy is associated with a number of adverse outcomes. The effects of central versus general obesity in pregnancy have not been well established.
Aim: To compare subcutaneous fat thickness (SFT) with body mass index (BMI) as a marker for pregnancy outcomes.
Methods: A stratified retrospective cohort study was performed on 1200 pregnancies, selected from a total of 4862 nulliparous, nonsmoking women between 2006 and 2010. SFT was measured on routine ultrasound at 18-22 weeks gestation. BMI and SFT measurements were compared for estimating risks for obesity-related pregnancy outcomes using logistic regression adjusted for maternal age.
Results: The median SFT was 18.2 mm (range 6.3-50.9 mm), the median BMI was 23.8 kg/m(2) (range 15.2-52.5), and the correlation between SFT and BMI was 0.53. For every 5 mm increase in SFT and every 5 kg/m(2) increase in BMI, the odds ratios for developing gestational diabetes mellitus were 1.40 (CI 1.22-1.61, P < 0.001) and 1.16 (CI 0.95-1.40, P = 0.1), for caesarean section 1.28 (CI 1.16-1.40, P < 0.001) and 1.16 (CI 1.05-1.28, P = 0.003), large for gestational age 1.28 (CI 1.16-1.47, P = 0.001) and 1.10 (CI 0.95-1.28, P = 0.16) and cumulative adverse obesity-related pregnancy outcomes 1.16 (CI 1.10-1.28, P = 0.002) and 1.05 (CI 0.95-1.16, P = 0.45), respectively.
Conclusion: SFT at 18-22 weeks gestation is better than BMI as a marker for obesity-related pregnancy outcomes. As SFT is considered a surrogate measure for visceral fat, these results suggest that central obesity is a stronger risk factor than general adiposity in pregnancy.
© 2012 The Authors ANZJOG © 2012 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.