title: Maternal weight change between 1 and 2 years postpartum: the importance of 1 year weight retention.
abstract: Pregnancy weight gain may lead to long-term increases in maternal BMI for some women. The objective of this study was to examine maternal body weight change 1y-2y postpartum, and to compare classifications of 2y weight retention with and without accounting for 1y-2y weight gain. Early pregnancy body weight (EPW, first trimester) was measured or imputed, and follow-up measures obtained before delivery, 1 year postpartum (1y) and 2 years postpartum (2y) in an observational cohort study of women seeking prenatal care in several counties in upstate New York (n = 413). Baseline height was measured; demographic and behavioral data were obtained from questionnaires and medical records. Associations of 1y-2y weight change (kg) and 1y-2y weight gain (≥2.25 kg) with anthropometric, socioeconomic, and behavioral variables were evaluated using linear and logistic regressions. While mean ± SE 1y-2y weight change was 0.009 ± 4.6 kg, 1y-2y weight gain (≥2.25 kg) was common (n = 108, 26%). Odds of weight gain 1y-2y were higher for overweight (OR(adj) = 2.63, CI(95%) = 1.43-4.82) and obese (OR(adj) = 2.93, CI(95%) = 1.62-5.27) women than for women with BMI <25. Two year weight retention (2y-EPW ≥2.25 kg) was misclassified in 38% (n = 37) of women when 1y-2y weight gain was ignored. One year weight retention (1YWR) (1y-EPW) was negatively related to 1y-2y weight change (β(adj) ± SE = -0.28 ± 0.04, P < 0.001) and weight gain (≥2.25 kg) (OR(adj) = 0.91, CI(95%) = 0.87-0.95). Relations between 1y weight retention and 1y-2y weight change were attenuated for women with higher early pregnancy BMI. Weight change 1y-2y was predicted primarily by an inverse relation with 1y weight retention. The high frequency of weight gain has important implications for classification of postpartum weight retention.
authors.affiliation: Division of Epidemiology, Statistics, and Prevention Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, USA. lipskylm@mail.nih.gov
authors.forename: Leah M
authors.initials: LM
authors.lastname: Lipsky
authors.forename: Myla S
authors.initials: MS
authors.lastname: Strawderman
authors.forename: Christine M
authors.initials: CM
authors.lastname: Olson
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001942:Breast Feeding / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D015438:Health Behavior; D006801:Humans; D007231:Infant, Newborn; D016014:Linear Models; D016015:Logistic Models; D009518:New York / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology* / Q000235:genetics / Q000517:prevention & control; D049590:Postpartum Period; D011247:Pregnancy; D011446:Prospective Studies; D012907:Smoking / Q000453:epidemiology*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D013997:Time Factors; D015430:Weight Gain; D015431:Weight Loss