Interrelationships between weight development and weight retention in subsequent pregnancies: the SPAWN study

Background Pregnancy is frequently associated with postdelivery weight retention in women. Most studies suggest weight retention associated with pregnancy of between 0.5 to 3.8 kg with up to 2.5 years of follow‐up. However, 73% of the female patients at our obesity clinic report that their pregnancies have been important trigger factors for marked weight gain and that they had gained more than 10 kg after each pregnancy. The aim of this study was to examine correlations in weight gain and weight retention after pregnancy in the long‐term perspective. Method and subjects. The SPAWN (Stockholm Pregnancy and Women's Nutrition) study is a long‐term follow‐up study of women who delivered children in 1984–85 in Stockholm (n = 2342). The participants filled out questionnaires about their eating and exercise habits, social condition, etc. before, during and up to 1 year after pregnancy. Antropometric data were also sampled. One thousand four hundred and twenty‐three women completed the study and filled out all questionnaires up to 1 year after pregnancy. Fifteen years later, these 1423 women were invited to the follow‐up study. Five hundred and sixty‐three women participated and filled out extended questionnaires, and antropometric data were also sampled. Data from the Swedish Medical Birth Register (MBR) about weight before and weight gain during pregnancy were collected. The sample was divided into groups regarding four critical time periods: (1) Time interval between first and second pregnancy, less and more than 2 years. (2) Overweight and normal weights before first pregnancy based on initial body mass index (BMI). (3) Low and high weight gainers during pregnancy by mean split. (4) Low and high weight retainers at 1 year after first pregnancy by mean split. Results. 1) There were no differences between those women who have more than 2 years between their pregnancies regarding weight gain during and weight retention after the first and second pregnancy. (2) Overweight women did not gain more weight during pregnancy or retain more weight at 1 year of follow‐up after the first and second pregnancy. (3) High weight gainers retained more weight at 1 year after both the first and second pregnancy. (4) High weight retainers had gained more during pregnancy and retained it into the second pregnancy, and also gained more during and retained more after the second pregnancy. Discussion. To our knowledge, the SPAWN study is the longest follow‐up study of factors affecti