Objective: To assess birth weight in relation to gestational weight gain (GWG) among women who were and were
not obese before pregnancy.
Methods: For a retrospective cohort study, data were obtained for women with a prepregnancy body mass index
(BMI, calculated as weight in kilograms divided by the square of height in meters) of at least 30 who had a singleton delivery at a center in Denmark in 2010–2011.
Data were also obtained for 455 non-obese women (BMI 20.0–24.9).GWG was expressed in absolute terms and relative to published recommendations(11–16 kg in non-obese women; 5–9 kg in obese women).
Results: A total of 231 obese women were included in analyses.
In non-obese and obese women, fetal weight was highest when GWG was above the recommended amount.
Among women who had a GWG in line with the recommendations, mean birth weight was
higher among those with a pre-pregnancy BMI of 35.0–39.9 (3758 ± 410 g) or at least 40 (3671 ± 374 g)
than among non-obese women (3394±453 g; P=0.0058). Conclusion: Birth weight is related to both maternal
BMI and GWG.
In obese women, adherence to GWG recommendations does not seem to prevent increased birth weights.