Pre-pregnancy exercise lowers risk for gestational diabetes

Women who exercise regularly before becoming pregnant are far less likely to develop gestational diabetes mellitus (GDM), according to a large prospective study.

Researchers from Harvard identified 1,428 cases of GDM among over 21,000 study participants. They found a significant inverse relationship between pre-pregnancy physical activity and risk for GDM that remained significant even after controlling for things like body mass, family history of diabetes, and parity.

Women who did the most vigorous exercise were 23% less likely to develop diabetes than those doing the least (RR 0.77 comparing highest and lowest quintiles, 95% CI; 0.69–0.94; P=0.002 for trend). Women who merely walked briskly versus at an easy pace were able to lower their risk as well (RR 0.66; 95% CI; 0.46–0.95). Conversely, women who spent 20 hours or more per week watching television and who did not exercise were almost two and a half times more likely to develop GDM than women who watched TV 2 hours or less per week and exercised.