35 Additive risk of chronic hypertension in women with pregestational diabetes


      Pregestational diabetes (PDM) often co-exists with chronic hypertension (cHTN), and both are associated with substantial risk for several adverse perinatal outcomes including fetal death. We sought to quantify the additive risk of a concurrent diagnosis of chronic hypertension and pregestational diabetes on pregnancy outcomes.

      Study Design

      This was a population based retrospective cohort study of all singleton births in the United States occurring >20 weeks’ gestation using national live birth and fetal death certificate data from 2018. Patients were grouped by presence of underlying cHTN, PDM, both or none. Baseline demographics and pregnancy outcomes were compared in a univariate analysis. Poisson regression with robust error variance was used to generate adjusted relative risks (aRR) and 95% confidence intervals (CI) for the studied outcome controlling for confounders.


      There were 3,590,179 women included in the analysis and 0.8% had PDM, 1.9% had cHTN and 0.2% had both. There were increased risks of all studied outcomes in women with PDM or cHTN compared to women without PDM or cHTN, but these risks were greatest when both co-morbidities were present (Table 1). Women with both conditions had significantly increased risks of both early (aRR 5.08, CI 3.95-6.53) and late (aRR 7.10, CI 5.74-8.77) fetal death (Figure 1). Large (LGA) and small for gestational age (SGA) birthweight was more common in women with only PDM and cHTN, respectively. However, women with both had reduced rates of LGA (25.9% vs 30.2%; p<.001) and increased rates of SGA (8.9% vs 6.3%; p<.001) when compared to PDM alone.


      Women with both PDM and cHTN have substantially increased risks for adverse perinatal outcomes that appear to be additive to having either condition alone. The fetal growth pattern seen in these patients may represent the combined effect of hyperglycemia and placental insufficiency, which could contribute to the increased rates of fetal death in this population.
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