In July 2019 researchers from The Netherlands, Spain, Portugal, Australia, Sweden, France, USA, Greece, UK, Canada, Norway, Italy, Germany, Poland, Finland, Ireland, Denmark, Slovak Republic and Ukraine published the results of their studies to assess the associations of maternal pre-pregnancy BMI and gestational weight gain with the risks of pregnancy complications. At total of 39 studies were analysed involving 265,270 births. Information was collected on maternal pre-pregnancy BMI, gestational weight gain, and pregnancy complications. Results showed that a higher maternal pre-pregnancy BMI and gestational weight gain were associated with an increased risk of gestational hypertensive disorders, gestational diabetes, and babies who were large for gestational age at birth. Both lower and higher BMI and weight gain was associated with an increased risk of preterm birth. Obese mothers with a high gestational weight gain appeared to have the highest risk of any pregnancy complication when compared with normal weight mothers with a medium gestational weight gain. The researchers estimated that 24% of any pregnancy complication was due to maternal overweight/obesity and that 32% of babies being born large for gestational age was due to excessive gestational weight gain.
Santos S et al. Impact of maternal body mass index and gestational weight gain on pregnancy complications: an individual participant data meta-analysis of European, North American and Australian cohorts. BJOG. 2019 Jul;126(8):984-995