Women with prepregnancy cardiovascular disease (CVD) risk factors have increasingly worse pregnancy outcomes, including a higher rate of maternal intensive care unit (ICU) admissions and fetal deaths, a new study suggests.
“With every additive cardiovascular risk factor — and it didn’t matter which risk factor — there was a graded and consistently higher risk for each of the pregnancy complications,” senior author Sadiya Khan, MD, Northwestern University Feinberg School of Medicine in Chicago, said in an interview with theheart.org | Medscape Cardiology.
Previous studies have shown that the presence of individual risk factors such as obesity and hypertension before pregnancy are associated with worse maternal and neonatal outcomes. Identifying the association with the total burden of prepregnancy CVD risk factors, however, may help guide comprehensive prevention strategies that look beyond targeting any one risk factor, the authors note.
The results were published online July 20 in the European Journal of Preventive Cardiology.
The researchers analyzed 18,646,512 pregnancies using maternal and fetal data drawn from the US National Center for Health Statistics and pooled individual-level data from births to women aged 15-44 years (mean, 28.6 years) from 2014 to 2018.
Women were categorized on the basis of having 0 to 4 prepregnancy CVD risk factors: hypertension, diabetes, self-reported smoking, and a BMI less than 18.5 kg/m2 or greater than 24.9 kg/m2. All analyses were adjusted for maternal age at delivery, race/ethnicity, education, receipt of prenatal care, parity, and birth plurality.
Over 60% of the women had one or more CVD risk factors, with 52.5% having one, 7.3% two, 0.3% three, and 0.02% four.
The association between CVD risk factors and all adverse pregnancy outcomes was dose-dependent. For instance, compared with women with no prepregnancy CVD risk factors, the risk ratios (95% CI) of maternal ICU admission were:
1.12 (1.09 – 1.15) for 1 risk factor
1.86 (1.78 – 1.94) for 2 risk factors
4.24 (3.85 – 4.68) for 3 risk factors
5.79 (4.07 – 8.23) for 4 risk factors
Compared with women without prepregnancy CVD risk factors, women with all four risk factors had significantly higher risk of all adverse outcomes:
Similar results were observed in an analysis of women having their first child.
“Pregnancy health and prenatal care begin before the first trimester. This is a challenge when pregnancies are unplanned but it speaks to the larger conversation, especially in the United States, about providing access to affordable healthcare for young adults,” Khan said.
“We’re noticing a rise in risk factors and a decreased awareness of personal cardiovascular risk, especially in this particular age group,” Nieca Goldberg, MD, medical director of the Joan H. Tisch Center for Women’s Health at NYU Langone Medical Center, New York City, said in an interview with theheart.org | Medscape Cardiology. She added that younger women may not believe that they could be at risk of CVD.
Additionally, many external factors may place some women at a higher risk of lacking access to needed care. Compared with women with no CVD risk factors, the study found that women with one or more risk factors had, on average:
Lower educational attainment (79.5% – 85.3% vs 88.7% graduated high school)
Lower likelihood of receiving prenatal care (97.8% – 98.5% vs 98.7%)
Higher prevalence of multiparity (64.4% – 69.3% vs 56.9%)
Higher prevalence of prior spontaneous or induced pregnancy loss (27.4% – 46.0% vs 23.4%)
Further analysis of how prepregnancy CVD risk factors affect various patient demographics is needed to address health inequities, Khan said.
“There are significant disparities in burden of cardiovascular risk factors, as well as access to care. And those may be factors that are contributing to stark disparities we observe in maternal morbidity and mortality, where African American and Indigenous women are more likely to experience not only severe complications but also maternal deaths,” she observed.
It will be important to “better characterize the root causes of the disparities in these cardiovascular risk factors that may be contributing to the high and increasing burden of maternal morbidity and mortality,” Khan said.
Both Khan and Goldberg emphasized that preconception care must be made a public health priority.
“A comprehensive cardiovascular assessment before pregnancy should be the standard and it currently isn’t,” Goldberg said. “In the future, I’d like to see an organized, cooperative approach between cardiologists and the gynecologist and obstetrician community to get young women evaluated for their risk factors.”
Limitations of the study are the potential for misclassification of prepregnancy risk factor status such as bias related to self-reported BMI; an inability to characterize risk factor control and its potential to modify associations with adverse pregnancy outcomes; a lack of available data on lifestyle factors; and the absence of linkage with maternal mortality, the study team notes.
Khan and Goldberg have disclosed no relevant financial relationships. The study was funded by research grants to Khan from the National Institutes of Health and the American Heart Association.
Eur J Prev Cardiol. Published online July 20, 2021. Full Text
Anna Goshua is a reporting intern with Medscape. She is a dual medical and journalism student who has previously written for STAT, Scientific American, Slate, and other outlets. She can be reached at [email protected] or @AnnaGoshua.