Inadequate gestational weight gain contributes to increasing rates of low birth weight in Taiwan: 2011–2016 nationwide surveys

Objective: Low birth weight (LBW) is associated with adverse health outcomes. Incidence of LBW in Taiwan grew from 5% in 1997 to 8.4% in 2016. This study aims to identify the role of pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) in LBW rate changes during 2011–2016. Materials and methods: We analyzed 66 135 postpartum women from 6 cross-sectional national surveys. Data were collected through telephone interviews with randomly selected mothers. Logistic regression was applied to assess contribution of maternal characteristics to LBW time changes. Results: LBW increased from 5.3% to 7.0% during 2011–2016 (crude odds ratio (OR) = 1.04/year, p-value for trend = 0.001). Inadequate GWG increased from 27.9% to 41.5% (p-value for trend <0.001). Along with the increase in overweight (9.7%–11.1%) and obese (4.8%–7.4%), prevalence of underweight fluctuated between 16.0% and 17.8%. LBW increased in underweight group from 6.3% to 9.5% (crude OR = 1.09/year, p-value for trend<0.001). Adjustment for GWG attenuated odds ratio per year in total sample (adjusted OR = 1.03, p-value for trend = 0.04) and in underweight (adjusted OR = 1.08, p-value for trend = 0.002). Conclusions: Increasing percentage of women with inadequate GWG could contribute to LBW increase in Taiwan during 2011–2016, especially for the underweight. Prenatal advice on GWG should be individualized according to pre-pregnancy BMI.