The impact of interpregnancy weight change on perinatal outcomes in women and their children: A systematic review and meta‐analysis

Prepregnancy overweight and obesity are associated with higher risk of perinatal complications. However, the effect of weight change prior to pregnancy on perinatal outcome is largely unknown. Therefore, it is aimed to examine the impact on perinatal outcomes of interpregnancy BMI change in women of different BMI categories. The MEDLINE, EMBASE, LILACS, and CINAHL databases were searched (1990‐August 2019). Observational studies on interpregnancy BMI change were selected. Outcomes evaluated were gestational diabetes mellitus (GDM), preeclampsia, gestational hypertension (GH), cesarean section, preterm birth, and newborns being large (LGA) or small (SGA) for gestational age. Meta‐analyses and meta‐regression analyses were executed. Thirty studies were included (n > 1 million). Interpregnancy BMI gain was associated with a higher risk of GDM (for BMI gain ≥3 kg/m²: OR 2.21; [95%CI 1.53‐3.19]), preeclampsia (1.77 [1.53‐2.04]), GH (1.78 [1.61‐1.97]), cesarean section (1.32 [1.24‐1.39]), and LGA (1.54 [1.28‐1.86]). The effects of BMI gain were most pronounced in women with BMI <25 kg/m² before the first pregnancy regarding GDM, GH, and cesarean section. Except for LGA, interpregnancy BMI loss did not result in a decreased risk of perinatal complications. In this study, women of normal weight who gain weight before pregnancy were identified as a high‐risk population for perinatal complications. This emphasizes that weight management is important for women of all BMI categories and a pregnancy wish.