The relationship between being overweight and pregnancy complications has been suspected for years.  Today, it has been proven through a research study at Brigham and Women’s Hospital in Boston that weight gain between a woman’s first and second pregnancies can cause pregnancy and delivery complications.  This is both true of overweight women, and those who are not considered medically overweight. 

This study concludes that after a woman’s first pregnancy, she should exercise at least four hours or more a week and keep her weight down.  This will reduce her chances of future pregnancy complications as well as complications during delivery.  Furthermore, this exercise decreased women’s chances of future in-vitro fertilizations by 40%. 

During the study, body mass index (BMI) was calculated for 150,000 Swedish women between 1992 and 2001 for each pregnancy visit they had.  Women gaining 1-2 BMI units increased their risk of gestational diabetes, gestational hypertension or large-for-gestational age birth by an average of 20 percent to 40 percent.  A gain of 3+ BMI units resulted in a 63 percent greater chance of stillbirth compared to a gain of less than one BMI unit.  The BMI increase of 3 or more units also increased the risk of many other pregnancy complications. 

Surprisingly, even a small amount of weight gain between pregnancies caused problems for women.  This shows that women who are not considered overweight should exercise and keep weight down in-between each pregnancy as well as women considered to be overweight.