A Korean study published in March 2018 looks at twin pregnancies, pregnant women’s pre-pregnancy BMI and the risk of preterm birth. The study was published in the Journal of Korean Medical Science. The retrospective cohort study included women pregnant with twins who gave birth at Seoul National University Hospital or Seoul Metropolitan Government-Seoul National University Boramae Medical Center between 2004 and 2014.
Among other things, the researchers looked at the women’s age, pre-pregnancy weight, how many children they’ve had and previous history of preterm birth. The participants were divided into three groups – underweight, normal and overweight/obese.
Weight loss helps to lower the risk of preterm birth.
A total of 1,959 women were included in the study. The researchers found that the risks of preterm birth in overweight women were higher than those in women with normal weight, even after adjusting for prior history of preterm birth, age, maternal height and in vitro fertilization. The percentage of preterm birth was 14.1 percent for the underweight group, 11.9 percent for the normal weight group and 16.3 percent for the overweight group. The researchers suggested, based on their findings, that adequate control or reduction of body weight before pregnancy could help overweight/obese women with twin pregnancies to lower the risk of spontaneous preterm birth.
See this twin pregnancy weight gain chart