Impact of pregnancy on the trajectories of cardiovascular risk factors in women with and without gestational diabetes.

Abstract

The elevated lifetime risk of cardiovascular disease in women who develop gestational diabetes mellitus (GDM) has been attributed to adverse life-course trajectories of cardiovascular risk factors that arise before pregnancy and continue thereafter. We hypothesized that pregnancy may differentially affect these trajectories in women who develop GDM and those who do not. With population-based administrative databases, we identified all nulliparous women in Ontario, Canada, who had singleton pregnancies between January 2011 and December 2016 and ≥2 measurements of the following analytes both before and after pregnancy: glycated haemoglobin (HbA1c), glucose, lipids and transaminases. In total, 39 581 women (4373 with GDM) had 3.9 ± 3.4 tests before and 4.6 ± 5.4 tests after pregnancy. Both before and after pregnancy, women who developed GDM had higher HbA1c, fasting glucose, low-density lipoprotein (LDL)-cholesterol and triglycerides than their peers, with lower high-density lipoprotein (HDL)-cholesterol (all p < .0001). Before pregnancy, women who went on to GDM had higher annual increases than their peers did in HbA1c, fasting glucose and triglycerides (all p ≤ .01); lesser annual decrease in LDL (p=.0003); and greater annual decrease in HDL (p=.0006). Compared with pre-pregnancy, the postpartum differences in annual rates of change in HbA1c and fasting glucose were 6.9- and 3.3-fold higher, respectively, in women with GDM. Conversely, the respective postpartum differences in annual rates of change in triglycerides, LDL and HDL were 1.2, 1.6 and 0.3 times lower than before pregnancy. After pregnancy, differences in pregravid trajectories of glycaemic measures are amplified between women with GDM and their peers. In contrast, pregravid differences in lipid measures persist but do not differentially worsen after pregnancy.