Hyperemesis gravidarum and birth outcomes—a population-based cohort study of 2.2 million births in the Norwegian Birth Registry
Article first published online: 10 SEP 2013
© 2013 Royal College of Obstetricians and Gynaecologists
BJOG: An International Journal of Obstetrics & Gynaecology
Volume 120, Issue 13, pages 1654–1660, December 2013
How to Cite
Hyperemesis gravidarum and birth outcomes—a population-based cohort study of 2.2 million births in the Norwegian Birth Registry. BJOG 2013; DOI: 10.1111/1471-0528.12429., , , , , .
- Issue published online: 11 NOV 2013
- Article first published online: 10 SEP 2013
- Manuscript Accepted: 17 JUL 2013
- Norwegian Resource Centre for Women's Health
- birth outcomes;
To study associations between hyperemesis gravidarum (HG) and birth outcomes.
Population-based cohort study.
Singleton births in the Norwegian Birth Registry, 1967–2009 (n = 2 270 363).
Multiple logistic regression was applied to study associations between HG and dichotomous outcomes; multiple linear regression to study associations between HG, birthweight and gestational length. Generalised estimating equations were applied to obtain valid standard errors. Sub-analysis on data with available information on smoking was conducted (1999–2009).
Main outcome measures
Small and large for gestational age (SGA/LGA), Apgar score after 5 minutes, very preterm and preterm birth (VPTB/PTB), perinatal death, stillbirth, neonatal death, birthweight and gestational length.
No associations between HG and adverse pregnancy outcomes were observed in crude analyses, except for VPTB (odds ratio [OR] 0.79, 95% CI 0.67–0.93). In adjusted analysis, HG was associated with perinatal death (OR 1.27, 95% CI 1.08–1.48). Inverse associations were observed between HG and VPTB (OR 0.80, 95% CI 0.68–0.94) and LGA (OR 0.95, 95% CI 0.90–0.99). Sub-analyses showed no associations between HG and perinatal death (OR 1.29, 95% CI 0.91–1.83). The inverse associations between HG, VPTB and LGA were strengthened (OR 0.66, 95% CI, 0.48–0.91 and OR 0.86, 95% CI 0.79–0.93, respectively). Exposed babies had reduced birthweight and gestational length compared with unexposed, adjusted difference − 21.4 g and − 0.5 days, respectively. Adjustment for smoking slightly strengthened the impact of HG on birthweight.
Inverse associations for HG and VPTB and LGA were observed. HG was associated with slight reductions in birthweight and gestational age.