Gestational weight gain and birth outcome in relation to prepregnancy body mass index and ethnicity.
OBJECTIVE
The obesity epidemic raises concerns about the impact of excessive and insufficient weight gain during pregnancy.


METHODS
We examined the association between gestational weight gain (GWG) and preterm birth, term small- and large-for-gestational-age (SGA and LGA), term birthweight, and term primary Cesarean delivery, considering prepregnancy body mass index (BMI) and ethnicity in a cohort of 33,872 New York City residents who gave birth between 1995 and 2003 and delivered in hospitals elsewhere in New York State.


RESULTS
Preterm birth (<37 weeks' gestation) showed a modest U-shaped relationship, with projected GWG of <10 kg and 20+ kg associated with odds ratios of 1.4 and 1.3, respectively, relative to 10 to 14 kg. The pattern was stronger for preterm birth <32 weeks' and for underweight women with low GWG and overweight/obese women with high GWG. Term SGA decreased and term LGA and birthweight increased monotonically with increasing GWG. Primary Cesarean delivery followed the same pattern as LGA, but less strongly.


CONCLUSIONS
Although the study is limited by potential selection bias and measurement error, our findings support the contention that GWG may be a modifiable predictor of pregnancy outcome that warrants further investigation, particularly randomized trials, to assess whether the relation is causal.
Savitz
David A
DA
Disease Prevention and Public Health Institute, Mount Sinai School of Medicine, New York, NY 10029, USA. david.savitz@mssm.edu
Stein
Cheryl R
CR
Siega-Riz
Anna Maria
AM
Herring
Amy H
AH
D000328:Adult; D015992:Body Mass Index; D002585:Cesarean Section; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D009518:New York / Q000453:epidemiology; D009519:New York City / Q000453:epidemiology; D009765:Obesity; D050177:Overweight; D011247:Pregnancy / Q000208:ethnology* / Q000502:physiology; D011248:Pregnancy Complications / Q000453:epidemiology; D047928:Premature Birth / Q000453:epidemiology; D015430:Weight Gain / Q000208:ethnology*