Do you want to get pregnant? First check your risk of heart disease

A new Northwestern Medicine study reports that a woman’s heart health before becoming pregnant is strongly related to the likelihood of having complications during pregnancy or childbirth.

The study examined the presence of four cardiovascular risk factors in women before becoming pregnant: smoking, unhealthy body weight, hypertension and diabetes. With the presence of each additional risk factor, the likelihood that the woman will experience an adverse effect pregnancy the result increased more and more. These adverse outcomes include admission to the intensive care unit (ICU), premature birth, low birth weight and fetal death.

“We are not surprised that obesity or hypertension are associated with a higher risk of adverse pregnancy outcomes, but what is striking is that we found that, with each additional risk factor, the risk of an adverse pregnancy outcome increases successively, ”said corresponding author Sadiya Khan, adjunct professor of medicine and preventive medicine at Northwestern University Feinberg School of Medicine. “The sum of all the risk factors is greater than the individual parts.”

The study of more than 18 million pregnancies will be published on July 21 in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology.

The findings advocate a more comprehensive cardiovascular assessment before pregnancy rather than focusing on individual risk factors, such as body mass index or blood pressure in isolation, said Khan, also a cardiologist and epidemiologist of Northwestern Medicine.

“Actually, not all pregnancies are planned, but ideally we would evaluate women before they get pregnant, so there is time to optimize their health,” Khan said. “We also need to shift our focus to prioritizing and promoting women’s health as a society; therefore, instead of identifying hypertension, we are preventing blood pressure from rising in the first place.”

“There is a gap in understanding how these results affect the long-term health of women and their children,” said first author Michael Wang, a fourth-year medical student at Feinberg. “These data are exciting because we hope they will help in designing interventions and focus more attention on filling the care gap for these women.”

A “perfect storm” for pregnancy complications:

High levels of pre-pregnancy obesity blood pressure increase, Khan said, and there are some indications that women are acquiring cardiovascular risk factors at earlier ages than before. In addition, more women become pregnant later in life, which gives risk factors more time to build up.

“Taken together, this has created a perfect storm of more risk factors, early onset and subsequent pregnancies,” Khan said.

Breakdown of numbers:

The study was a cross-sectional analysis of maternal and fetal data from the U.S. National Center for Health Statistics (NCHS), which collects information on all live births and fetal deaths after 20 weeks of gestation. Data at the individual level were grouped from births to women aged 15 to 44 between 2014 and 2018.

A total of 18,646,512 pregnancies were included in the analysis. The mean maternal age was 28.6 years.

Scientists assigned women a risk factor score of 0-4 (0 for no risk factor or 4 for all four risk factors, for example). More than 60% of women had one or more pregnancies cardiovascular risk factors, with 52.5%, 7.3%, 0.3% and 0.02% with 1, 2, 3 and 4 risk factors, respectively.

The study found a graduated association between a higher number of risk factors and pregnancy complicated by any of the four adverse outcomes. For example, compared to women without risk factors, the proportion of risk of admission to the maternal ICU was 1.12 times more likely to be caused by a risk factor; 1.86 times more likely for two risk factors; 4.24 times more likely for three risk factors; and 5.79 times more likely for four risk factors.

All analyzes were adjusted for maternal age at birth, race / ethnicity, education, prenatal care, parity, and plurality of births.