A large US study looked at whether women who develop gestational diabetes during pregnancy are at a higher risk of cardiovascular disease later in life.
During pregnancy, some women develop problems controlling their blood glucose. This is known as gestational diabetes. Although the condition is not fully understood, it is known that in pregnant women the placenta produces hormones which decrease the mother’s sensitivity to insulin(the hormone which controls blood glucose). The pancreas, the organ which produces insulin, normally increases production to compensate.
In some women, however, this does not happen and their blood glucose levels rise.This can have health consequences for the mother (including high blood pressure and premature labor), and for the developing baby (including increased body size and prematurity). Gestational diabetes is common, occurring in about 6% of pregnancies in the USA. Maternity clinics carefully monitor pregnant women to check for signs of impaired blood glucose control.
In most women who develop gestational diabetes, blood glucose control returns to normal after delivery of the baby. However, these women appear to be at increased risk of health problems later in life, including type 2 diabetes or cardiovascular disease. Most studies investigating the relationship between gestational diabetes and cardiovascular disease have been retrospective. This type of study looks backward at conditions prior to an illness, and it may be difficult to eliminate factors which could bias the results. Researchers in the US wanted to evaluate the relationship between gestational diabetes and cardiovascular disease in a prospective study—following the health of women who had reported gestational diabetes—in order to better define the risks.The results of this study were recently published in JAMA Internal Medicine.
The Nurses’ Health Study is an ongoing study of over 116,000 female US nurses who were between the ages 26 and 44 years old at the start of the study in 1989. Health questionnaires are distributed every two years to collect extensive information on lifestyle and health. The researchers used data from these questionnaires to look at the relationship between gestational diabetes and cardiovascular disease later in life.Almost 90,000 women who reported at least one pregnancy were included in the study and women were followed up until May 2015. A total of 5,292 women reported gestational diabetes in at least one pregnancy (5.9%).
Women with prior gestational diabetes were found to have a 43% greater risk of cardiovascular disease (as evidenced either by a heart attack or stroke) compared with those without prior gestational diabetes. However, it is important to note that the absolute rate of cardiovascular disease in the overall group was low – perhaps due to their relatively young age.Looking in more detail at the gestational diabetes group, maintaining a healthy lifestyle (healthy diet, physically active, non-smoker, not overweight)reduced the modestly elevated risk in these women.
The researchers concluded that gestational diabetes is linked to a moderately increased risk of developing cardiovascular disease later in life. They suggest that this relationship might be partly caused by weight gain and a lack of healthy lifestyle, and the risk was reduced in women with healthy behaviors. Women who have gestational diabetes should be encouraged to maintain a healthy lifestyle.
Written by Julie McShane, Medical Writer
Tobias D, Stuart J, Li SS, et al. Association of history of gestational diabetes with long-term cardiovascular disease risk in a large prospective cohort of US women. JAMA Internal Medicine. Published online October 16, 2017. DOI: 10.1001/jamainternmed.2017.2790