Childbearing is not associated with young women's long-term obesity risk.
OBJECTIVE
Contemporary childbearing is associated with greater gestational weight gain and postpartum weight retention than in previous decades, potentially leading to a more pronounced effect of childbearing on women's long-term obesity risk. Previous work on the association of childbearing with women's long-term obesity risk mostly examined births in the 1970s and 1980s and produced mixed results. The association of childbearing and obesity incidence in a diverse, contemporary sample of 2731 US women was estimated.


METHODS
Propensity-score (PS) matching was used for confounding control when estimating the effect of incident parity (1996-2001) on 7-year incident obesity (BMI≥30 kg/m(2) ) (2001-2008).


RESULTS
In the sample, 19.3% of parous women became obese, whereas 16.1% of unmatched nulliparous women did. After PS matching without and with replacement, the differences in obesity incidence were, respectively, 0.0 percentage points (ppts) (95% CI: -4.7 to 4.7) and 0.9 ppts (95% CI: -4.9 to 6.7). Results were similar in analyses of prevalent parity and obesity in 2008 (n = 6601) conducted to explore possible selection bias.


CONCLUSIONS
These results imply that, in contemporary US parous women in their late 20s and early 30s, childbearing may not increase obesity incidence.
Department of Epidemiology UNC Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA; Carolina Population Center, University of North Carolina, Chapel Hill, North Carolina, USA.
Whitney R
WR
Robinson
Mariah M
MM
Cheng
Katherine J
KJ
Hoggatt
Til
T
Stürmer
Anna M
AM
Siega-Riz
D000328:Adult; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008137:Longitudinal Studies; D009765:Obesity / Q000453:epidemiology* / Q000503:physiopathology*; D010298:Parity / Q000502:physiology*; D049590:Postpartum Period / Q000502:physiology; D057216:Propensity Score; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D015430:Weight Gain / Q000502:physiology