Improving cardiometabolic risk factors may lower adverse pregnancy outcomes

Key takeaways:

• Higher educational attainment was linked to increased birth weight and a protective association with all pregnancy outcomes.
• All cardiometabolic mediators were linked to at least one pregnancy outcome.

Intervening for type 2 diabetes, BMI, smoking, HDL cholesterol level and systolic blood pressure may reduce adverse pregnancy outcomes tied to lower educational levels, researchers reported in JAMA Network Open.

“Socioeconomic factors — educational attainment in particular — are associated with adverse pregnancy outcomes. However, it is challenging to modify an individual’s level of education, and opportunities to seek education are not equally distributed throughout the population,” Tormod Rogne, MD, PhD, of the department of chronic disease epidemiology and the Center for Perinatal, Pediatric and Environmental Epidemiology at Yale School of Public Health, and colleagues wrote. “It is therefore of great importance to identify modifiable risk factors through which the association with educational attainment is mediated.”

Rogne and colleagues conducted a Mendelian randomization cohort study with data from 3,037,499 women who had given birth. All women were of European ancestry mainly from Finland, Iceland, the U.K. or the U.S and had data on educational attainment. Researchers evaluated the association between educational attainment and pregnancy outcomes and what proportion of the association is mediated through modifiable cardiometabolic risk factors.

Researchers considered genetically estimated type 2 diabetes, BMI, smoking, HDL cholesterol level and systolic BP as mediators for the association between educational attainment and pregnancy outcomes.

The primary outcomes were ectopic pregnancy, hyperemesis gravidarum, gestational diabetes, preeclampsia, preterm birth and infant birth weight.

Every standard deviation increase in genetically estimated educational attainment was linked to an increased birth weight of 42 g and a protective association with all pregnancy outcomes ranging from an OR of 0.53 for ectopic pregnancy to 0.81 for preeclampsia.

All of the genetically estimated cardiometabolic mediators were associated with at least one pregnancy outcome with associations varying between different outcomes.

Type 2 diabetes was linked to increased gestational diabetes (OR = 1.66; 95% CI, 1.55-1.77), preeclampsia (OR = 1.15; 95% CI, 1.06-1.22), preterm birth (OR = 1.05; 95% CI, 1.02-1.09) and greater birth weight (9.41 g; 95% CI, 0.31-18.5) risk. Higher BMI was linked to increased ectopic pregnancy (OR = 1.13; 95% CI, 1.03-1.25), gestational diabetes (OR = 1.55; 95% CI, 1.42-1.69), preeclampsia (OR = 1.25; 95% CI, 1.12-1.4) and greater birth weight (38.34 g; 95% CI, 26.27-50.4) risk. Smoking was linked to an increased ectopic pregnancy risk (OR = 1.84; 95% CI, 1.4-2.41. Higher HDL cholesterol was linked to reduced ectopic pregnancy (OR = 0.92; 95% CI, 0.85-0.99), gestational diabetes (OR = 0.77; 95% CI, 0.73-0.82), preeclampsia (OR = 0.86; 95% CI, 0.78-0.94) and lower birth weight (–15.98 g; 95% CI, –26.86 to –5.5) risk. Higher systolic BP was linked to increased gestational diabetes (OR = 1.15; 95% CI, 1.01-1.3), preeclampsia (OR = 2.88; 95% CI, 2.36-3.52), preterm birth (OR = 1.16; 95% CI, 1.04-1.3) and lower birth weight (–141.07 g; 95% CI, –168.29-113.8) risk.

In addition, the combined proportion of the association mediated by the five chosen cardiometabolic risk factors ranged from –17% for hyperemesis gravidarum to 78% for preeclampsia.

Researchers observed similar findings in the sensitivity analysis.

“Except for preeclampsia, most of the association of genetically estimated educational attainment with the pregnancy outcomes considered was mediated through other pathways than these cardiometabolic risk factors, which warrants future studies on additional targetable mediators,” the researchers wrote.