(VP129) VARIOUS COMBINATIONS OF GESTATIONAL DIABETES AND GESTATIONAL HYPERTENSION IN TWO PREGNANICES AND ASSOCIATIONS WITH CARDIOVASCULAR DISEASE

Background: Gestational diabetes (GDM) and gestational hypertension (GHTN) are established cardiovascular disease (CVD) risk indicators, but the nuances of patterns across pregnancies are uncertain. The current evidence forces ‘ever GDM/never GDM’ and ‘ever GH/never GH’ dichotomies when incorporating these into CVD risk assessment; however, it is unclear whether CVD risk increases with GDM/GHTN recurrence, with first time occurrence in a second pregnancy, or with first pregnancy occurrence followed by second pregnancy absence. We are examining GDM/GHTN history across two singleton pregnancies in relationship to the development of CVD.

METHODS AND RESULTS: We used Quebec healthcare administrative and vital statistics data for this retrospective cohort study. We considered women without prior CVD who had two singleton deliveries between 1990-2012 and defined 16 patterns of GDM/GHTN combinations across two pregnancies. The outcome was a CVD composite of myocardial infarction, stroke, and angina requiring hospitalization or resulting in death. We followed women from 12 weeks after the second delivery until the first of this outcome, death, or end of the study period (2019). We constructed Cox models to assess CVD hazard ratios of women with various GDM/GHTN combinations versus those without GDM and GHTN. In separate analyses, we recategorized GDM/GHTN as cumulative occurrence (zero, one, two, or three or more) across two pregnancies. Confidentiality rules in Quebec require rounded values for frequency measures with rounding at the unit level only at time of submission for final publication. We present here approximate values for frequencies and overall trends observed and wish to provide all 16 specific hazard ratios during the presentation.

Among over 430,000 mothers, more than 4,000 CVD events occurred during the 18-year median follow-up period. The highest hazards for CVD occurred in those with both GDM and GH in both pregnancies, with a hazard ratio of greater than 4. Various combinations of 3 diagnoses of GDM and/or GH across two pregnancies were associated with hazard ratios that ranged between 2.5-3.8. With two diagnoses of GDM and/or GH, there was an approximately a 2-fold increase in CVD hazards. With a single diagnosis of GDM or GH, the increase in hazards ranged between 40-60%.

Conclusion: Our findings indicate that the cumulative number of GDM and GH diagnoses across two singleton pregnancies can be used to provide more precise estimates of CVD hazards than simple dichotomies of ever/never GDM and ever/never GH; this must stimulate attentive surveillance and CVD prevention efforts by health care providers, mothers, and health systems.