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Body Mass Index Change between Pregnancies and Risk of Spontaneous Preterm Birth.

CPQCC Publication
TitleBody Mass Index Change between Pregnancies and Risk of Spontaneous Preterm Birth.
Publication TypeJournal Article
Year of Publication2016
AuthorsRiley KL, Carmichael SL, Mayo JA, Shachar BZ, Girsen AI, Wallenstein MB, Gould JB, Stevenson DK, Shaw GM
JournalAm J Perinatol
Date Published2016 08
KeywordsAdult, Body Mass Index, California, Female, Gestational Age, Humans, Infant, Newborn, Obesity, Pregnancy, Premature Birth, Regression Analysis, Risk Factors, Weight Gain, Young Adult

Objective Studies have reported an increased risk of spontaneous preterm birth associated with elevated prepregnancy body mass index (BMI) among nulliparous but not multiparous women. We examined whether changes in BMI and weight between pregnancies contributed to risk of preterm birth among obese (BMI > 29 kg/m(2)) women. Study Design This study utilized maternally linked California birth records of sequential singleton births between 2007 and 2010. Preterm birth was defined as 20 to 31 or 32 to 36 weeks of gestation. BMI was examined as category change and by tertile of weight change. Primary analyses included women without diabetes or hypertensive disorders; these women were compared with those without prior preterm birth, women with preterm deliveries preceded by spontaneous preterm labor, and women without any exclusions (i.e., diabetes or hypertensive disorders). Results Analyses showed that obesity was not associated with increased risk of spontaneous preterm birth among multiparous women. Women whose BMI increased had a decreased risk of spontaneous preterm birth at 32 to 36 weeks. Change in BMI or weight between pregnancies did not substantively alter results. Conclusion Among multiparous women, obesity was associated with reduced risk of spontaneous preterm delivery. This observed association is complex and may be influenced by maternal age, gestational age, placental insufficiency, and altered immune response.

Alternate JournalAm J Perinatol
PubMed ID27128743
Grant ListUL1 TR001085 / TR / NCATS NIH HHS / United States