The association between parity and birthweight in a longitudinal consecutive pregnancy cohort.
ISSN:- 0269-5022
- *Birth Weight
- *Parity
- *Weight Gain/ph [Physiology]
- Adolescent
- Adult
- Body Mass Index
- Female
- Gestational Age
- Humans
- Linear Models
- Longitudinal Studies
- Male
- Maternal Age
- Parity/ph [Physiology]
- Pregnancy
- Risk Factors
- MedStar Washington Hospital Center
- Obstetrics and Gynecology, Maternal-Fetal Medicine
- Comparative Study
- Journal Article
- Research Support, N.I.H., Intramural
Item type | Current library | Collection | Call number | Status | Date due | Barcode | |
---|---|---|---|---|---|---|---|
Journal Article | MedStar Authors Catalog | Article | Available | 24320682 |
BACKGROUND: Nulliparity is associated with lower birthweight, but few studies have examined how within-mother 141125s in risk factors impact this association.
CONCLUSIONS: The association between parity and birthweight was non-linear with the greatest increase observed between first- and second-born infants of the same mother. Adjustment for 141125s in weight or chronic diseases did not 141125 the relationship between parity and birthweight. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
METHODS: We used longitudinal electronic medical record data from a hospital-based cohort of consecutive singleton live births from 2002-2010 in Utah. To reduce bias from unobserved pregnancies, primary analyses were limited to 9484 women who entered nulliparous from 2002-2004, with 23,380 pregnancies up to parity 3. Unrestricted secondary analyses used 101,225 pregnancies from 45,212 women with pregnancies up to parity 7. We calculated gestational age and sex-specific birthweight z-scores with nulliparas as the reference. Using linear mixed models, we estimated birthweight z-score by parity adjusting for pregnancy-specific sociodemographics, smoking, alcohol, prepregnancy body mass index, gestational weight gain, and medical conditions.
RESULTS: Compared with nulliparas', infants of primiparas were larger by 0.20 unadjusted z-score units [95% confidence interval (CI) 0.18, 0.22]; the adjusted increase was similar at 0.18 z-score units [95% CI 0.15, 0.20]. Birthweight continued to increase up to parity 3, but with a smaller difference (parity 3 vs. 0 beta = 0.27 [95% CI 0.20, 0.34]). In the unrestricted secondary sample, there was significant departure in linearity from parity 1 to 7 (P < 0.001); birthweight increased only up to parity 4 (parity 4 vs. 0 beta = 0.34 [95% CI 0.31, 0.37]).
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