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Gestational bodyweight gain among underweight Japanese women related to small-for-gestational-age birth
Journal of Obstetrics and Gynaecology Research, 05/09/2012
Harita N et al. – Underweight and poor GWG were associated with a higher incidence of SGA birth. However, the incidence of SGA birth among underweight women was not increased significantly if they had sufficient GWG.
Methods- They conducted a prospective cohort study of 1391 women who delivered full–term singleton babies.
- SGA was defined as below the 10th percentile of birthweight at each gestational age, baby sex, and parity.
- They calculated the 5th percentile of birthweight in the same way for another threshold for SGA.
- According to pre–pregnancy body mass index, they divided the participants into three groups: underweight (<18.5 kg/m2), normal weight (18.5–24.9 kg/m2), and overweight and obese (≤25.0 kg/m2).
- SGA birth was observed most frequently among the underweight group (13.8%).
- Underweight was associated with an increased risk of SGA birth.
- The multiple–adjusted odds ratio for underweight was 1.96 (95% confidence interval, 1.23–3.11) compared with normal weight.
- Sufficient GWG reduced the incidence and the multiple–adjusted odds ratio for 1–kg increase of GWG was 0.86 (0.81–0.92).
- The same tendency was observed for the delivery of infants below the 5th birthweight percentile.
- Women with underweight and normal weight who had 9.0 kg or less of GWG had a significantly higher risk of SGA birth than women with normal weight who had 9.1–11.0 kg of GWG.