Am J Obstet Gynecol MFM. 2022 Oct 20:100776. doi: 10.1016/j.ajogmf.2022.100776. Online ahead of print.
BACKGROUND: Patients with a hypertensive disorder of pregnancy are more likely to have underlying cardiovascular risk factors and are at increased risk of future cardiovascular disease. These patients are more likely to be diagnosed with new onset chronic hypertension and meet the criteria for Metabolic Syndrome postpartum. High-sensitivity C-reactive protein is a marker of general inflammation and may be used to identify increased risk for cardiovascular disease.
OBJECTIVE: This collaborative data sharing study between Yale University, United States (Yale Heart Moms study) and Queen’s University, Canada (Maternal Health Clinic) is to better study the utility of high-sensitivity C-reactive protein in postpartum cardiovascular risk screening, as determined by 30-year risk (Framingham) and Metabolic Syndrome 6-12 months postpartum.
STUDY DESIGN: Patients with a hypertensive disorder of pregnancy (n=478) or an uncomplicated, term pregnancy (n=90) had cardiovascular risk screening and risk scoring performed at 6-12 months postpartum. Patients were excluded if they had a multiple gestation or chronic hypertension, diabetes or cardiovascular disease diagnosed before pregnancy. Patients were categorized according to high-sensitivity C-reactive protein (mg/L) into Normal (<3.0), High (3.1 to <10.0), and Acute (≥10.0) groups. The primary outcome of the study is risk for future cardiovascular events, calculated through surrogate measures such as hypertension and cholesterol. Kruskal Wallis and Chi Square tests were used to compare groups, with post-hoc tests corrected using the Bonferroni method. Multivariable logistic regression was used to assess the association between high-sensitivity C-reactive protein and cardiovascular risk, adjusting for relevant medical and sociodemographic variables. Analysis was completed with IBM SPSS Statistics v27.
RESULTS: Patients in the High and Acute hsCRP groups were more likely to have a BMI≥30, have experienced a hypertensive disorder of pregnancy, have a lower household income, and to have not breastfed or breastfed <6 month, when compared to the Normal hsCRP group (all p<0.05). Patients in the High and Acute hsCRP groups had higher 30-year cardiovascular risk scores and were more likely to have Metabolic Syndrome, when compared to the Normal hsCRP group (all p<0.05). Patients with High hsCRP had a 2-fold odds of Metabolic Syndrome 6-12 months after delivery, compared to those in the Normal hsCRP group (aOR 2.85 (95% CI 1.66, 4.91)), adjusting for hypertensive disorder of pregnancy, body mass index, clinic site, breastfeeding, income, and family history of cardiovascular disease. Those with Acute hsCRP also appeared to have elevated odds of Metabolic Syndrome compared to the Normal hsCRP group (aOR 2.52 (95% CI 1.24, 5.12)). The odds of chronic hypertension were significantly higher (p<0.05) in the High hsCRP group [aOR 1.72 [95% CI 1.12, 2.65]] compared to the Normal group.
CONCLUSIONS: Individuals with elevated postpartum high-sensitivity C-reactive protein are at an increased risk of cardiovascular disease 6-12 months postpartum after a pregnancy complicated by a hypertensive disorder of pregnancy. Future research is critical to determine the most comprehensive and accurate method and timing of postpartum cardiovascular risk screening in order to decrease the incidence of preventable cardiovascular mortality among women.