Background: Data on the association of inappropriate gestational weight gain (GWG) and adverse outcomes in twin pregnancies are limited and inconsistent.
Objectives: To perform a systematic review and meta-analysis on the association between GWG and adverse outcomes in twin pregnancies.
Search strategy: Ovid, Medline, EMBASE and Cochrane Central databases from 1 January 1990 until 23 September 2020.
Selection criteria: Interventional and observational studies evaluating the association between GWG and adverse outcomes in twin pregnancies.
Data collection and analysis: Data were extracted by two independent reviewers. Summary odds ratios (OR) were calculated using a random-effects model in a subset of studies that analysed GWG as a categorical variable in relation to the Institute of Medicine (IOM) recommendations. The primary outcome was preterm birth.
Main results: From 277 citations, 19 studies involving 36 023 women with twin pregnancies were included in the qualitative analysis, of which 14 were included in the meta-analysis. Overall, 56.8% of women experienced inappropriate GWG: 35.4% (95% CI 30.0-41.0%) gained weight below and 21.4% (95% CI 14.2-29.5%) gained weight above IOM recommendations. Compared with GWG within IOM guidelines, GWG below IOM guidelines was associated with preterm birth before 32 weeks of gestation (OR 3.38; 95% CI 2.05-5.58), and a reduction in the risk of pre-eclampsia (OR 0.68; 95% CI 0.48-0.97). GWG above IOM guidelines was associated with an increased risk of pre-eclampsia that was consistent across all body mass index categories.
Conclusions: Inappropriate GWG affects over half of twin pregnancies, so is a common and potentially modifiable risk factor for preterm birth and pre-eclampsia.
Keywords: Multifetal; multiple; obesity; pre-eclampsia; preterm birth; weight gain.
© 2021 John Wiley & Sons Ltd.