PHOENIX – according to results from a multinational cohort study.
“Over the past 10 years, cardiovascular health [CVH] has been characterized across most of the life course and is associated with a variety of health outcomes, but CVH as a whole has not been well studied during pregnancy,”, said at the Epidemiology and Prevention/Lifestyle and Cardiometabolic Health meeting.
In an effort to examine the associations of maternal gestational CVH with adverse maternal and newborn outcomes, Dr. Perak of the departments of pediatrics and preventive medicine at Northwestern University and Lurie Children’s Hospital, both in Chicago, and colleagues drew from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study, which examined pregnant women at a target of 28 weeks’ gestation and assessed the associations of glycemia with pregnancy outcomes. The researchers analyzed data from an ancillary study of 2,230 mother-child dyads to characterize clinical gestational CVH with use of five metrics: body mass index, blood pressure, cholesterol, glucose, and smoking. The study excluded women with prepregnancy diabetes, preterm births, and cases of fetal death/major malformations.
Each maternal CVH metric was classified as ideal, intermediate, or poor according to modified definitions based on pregnancy guidelines. “For lipids, it’s known that levels change substantially during pregnancy, but there are no pregnancy guidelines,” Dr. Perak said. “We and others have also shown that higher triglycerides in pregnancy are associated with adverse pregnancy outcomes. We selected thresholds of less than 250 mg/dL for ideal and at least 500 mg/dL for poor, based on triglyceride distribution and clinical relevance.”
Total CVH was scored by assigning 2 points for ideal, 1 for intermediate, and 0 for each poor metric, for a total possible 10 points, with 10 being most favorable. They also created four CVH categories, ranging from all ideal to two or more poor metrics. Maternal adverse pregnancy outcomes included preeclampsia and unplanned primary cesarean section. Newborn adverse pregnancy outcomes included birth weight above the 90th percentile and a cord blood insulin sensitivity index lower than the 10th percentile.
The researchers used logistic and multinomial logistic regression of pregnancy outcomes on maternal gestational CVH in two adjusted models. Secondarily, they examined associations of individual CVH metrics with outcomes, with adjustment for the other metrics.
The cohort comprised mother-child dyads from nine field centers in six countries: the United States (25%), Barbados (23%), United Kingdom (21%), China (18%), Thailand (7%), and Canada (7%). The mothers’ mean age was 30 years, and the mean gestational age was 28 weeks. The mean gestational CVH score was 8.8 out of 10. Nearly half of mothers (42%) had ideal metrics, while 4% had two or more poor metrics. Delivery occurred at a mean of 39.8 weeks, and adverse pregnancy outcomes occurred in 4.7%-17.9% of pregnancies.
In the fully adjusted model, which accounted for maternal age, height, alcohol use, gestational age at pregnancy exam, maternal parity, and newborn sex and race/ethnicity, odds ratios per 1-point higher (better) CVH score were 0.61 (95% confidence interval, 0.53-0.70) for preeclampsia, 0.85 (95% CI, 0.76-0.95) for unplanned primary cesarean section (among primiparous mothers), 0.83 (95% CI, 0.77-0.91) for large for gestational age infant, and 0.79 (95% CI, 0.72-0.87) for infant insulin sensitivity index below the 10th percentile. CVH categories were also associated with outcomes. For example, odds ratios for preeclampsia were 4.61 (95% CI, 2.13-11.14) for mothers with one or more intermediate metrics, 7.62 (95% CI, 3.60-18.13) for mothers with one poor metric, and 12.02 (95% CI, 4.70-32.50) for mothers with two or more poor metrics, compared with mothers with all metrics ideal.
“Except for smoking, each CVH metric was independently associated with adverse outcomes,” Dr. Perak said. “However, total CVH was associated with a wider range of outcomes than any single metric. This suggests that CVH provides health insights beyond single risk factors.”
Strengths of the study, she continued, included geographic and racial diversity of participants and high-quality research measurements of CVH. Limitations were that the cohort excluded prepregnancy diabetes and preterm births. “Diet and exercise data were not available, and CVH was measured once at 28 weeks,” she said. “Further study is needed across pregnancy and in other settings, but this study provides the first data on the relevance of gestational CVH for pregnancy outcomes.”
In an interview,, who directs the Center for Public Health Genomics at the University of Virginia, said that the data “provide strong epidemiologic support to focus on the full range of cardiovascular health. In my view, the primary limitation of the study is that there may be significant differences in how one achieves ideal CHV across a single country, not to mention across the world, particularly in absence of a highly controlled, research environment. It is not clear that the approach used in this study at nine selected sites in six relatively highly developed countries could be translated into primary care – particularly in the U.S. with different regulatory and reimbursement plans and payers. Nonetheless, the evidence suggests a way to reduce adverse outcomes in pregnancy and the area deserves greater research.”
According to Dr. Perak, gestational diabetes is associated with a twofold higher maternal risk for cardiovascular disease (), while diabetes is also associated with higher offspring risk for CVD ( ). However, a paucity of data exists on gestational CVH. In one report, better gestational CVH was associated with less subclinical CVD for the mother 10 years later (J Am Heart Assoc. 2019 Jul 23. ). In , Dr. Perak and her colleagues found that better gestational CVH was associated with better offspring CVH in childhood. “Unfortunately, we also reported that, among pregnant women in the United States, fewer than 1 in 10 had high CVH,” she said (J Am Heart Assoc. 2020 Feb 17. ). “However, the relevance of gestational CVH for pregnancy outcomes is unknown, but a it’s key question when considering CVH monitoring in prenatal care.”
Dr. Perak reported having received grant support from the National Heart, Lung, and Blood Institute, the American Heart Association, and Northwestern University. The HAPO Study was supported by NHLBI and the National Institute of Diabetes and Digestive and Kidney Diseases.
The meeting was sponsored by the American Heart Association.
SOURCE: Perak A et al. Epi/Lifestyle 2020, .