Study Shows Strong Relationship Between Women’s Heart Health And Pregnancy Outcomes

A study of over 18 million pregnancies showed a strong and gradual relationship between women’s heart health and pregnancy outcome. The research is published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).

Researchers looked at the presence of four risk factors for cardiovascular disease in women before pregnancy: unhealthy body weight, smoking, high blood pressure, and diabetes. The likelihood of key pregnancy complications – admission to a maternal intensive care unit (ICU), premature birth, low birth weight, and fetal death – gradually increased with the number of cardiovascular risk factors prior to pregnancy.

Individual cardiovascular risk factors, such as obesity and hypertension, present before pregnancy have been associated with poor outcomes for mother and baby. Our study now shows a dose-dependent relationship between the number of risk factors and several complications. These data underscore that improving overall heart health before pregnancy must be a priority. “

Dr Sadiya Khan, study author, Northwestern University Feinberg School of Medicine, Chicago, USA

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 aggregated from births to women aged 15 to 44 from 2014 to 2018.

Information has been gathered on the presence or absence of four pre-pregnancy cardiovascular risk factors: body mass index (BMI; less than 18.5 kg / m² or more than 24.9 kg / m²), smoking, hypertension and diabetes. Women were classified as having 0, 1, 2, 3 or 4 risk factors. The researchers estimated the relative risks of admitting the mother to an intensive care unit, preterm delivery (before 37 weeks), low birth weight (less than 2,500 g) and fetal death associated with risk factors (1, 2, 3 or 4) versus no risk factors (0). All analyzes were adjusted for mother’s age at childbirth, race / ethnicity, education, receipt of antenatal care, parity and plurality of births.

A total of 18,646,512 pregnancies were included in the analysis. The mother’s average age was 28.6 years. More than 60% of women had one or more cardiovascular risk factors before pregnancy, 52.5%, 7.3%, 0.3% and 0.02% having 1, 2, 3 and 4 risk factors respectively.

Compared with women without pre-pregnancy risk factors, those with all four risk factors (3,242 women) had an approximately 5.8 times higher risk of ICU admission, a 3.9 times higher risk of premature delivery, a 2.8 times higher risk of low birth weight, and an 8.7 times higher risk of fetal death.

There were graduated associations between an increasing number of pre-pregnancy risk factors and a higher likelihood of adverse outcomes. For example, compared to women without risk factors, the relative risk of maternal admission to the intensive care unit was 1.12 for one risk factor, 1.86 for two risk factors, 4.24 for three risk factors and 5.79 for four risk factors.

The analysis was repeated in women with their first baby (women who had previous pregnancies were excluded) – with consistent results. “We performed this analysis because women with complicated first pregnancies are more likely to have complications in subsequent pregnancies,” said Dr Khan. “Additionally, gestational weight gain may lead to a higher BMI in the next pregnancy. We have seen very similar results, which strengthens the results for the full cohort.”

She continued, “Levels of obesity and high blood pressure before pregnancy are increasing and it appears that women acquire cardiovascular risk factors at an earlier age than before. Additionally, pregnancies occur later in life. life, which gives risk factors more time to build up. Taken together, this has created a perfect storm of additional risk factors, earlier onset and later pregnancies. “

Dr Khan concluded: “The results support a more comprehensive pre-pregnancy cardiovascular assessment rather than focusing on individual risk factors, such as BMI or blood pressure, in isolation. In reality, not all pregnancies are planned, but ideally we would assess women well. before getting pregnant, it is therefore time to optimize their health. We also need to focus on prioritizing and promoting women’s health as a society – so instead of just identifying hypertension, we are preventing blood pressure from rising. “