Larger Babies, Higher Risk: Study Links Infant Birthweight to Maternal Cardiovascular Disease Mortality
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A new study reveals a complex relationship between infant birthweight and the risk of cardiovascular disease (CVD) mortality in mothers, especially those with preterm birth and hypertensive disorders of pregnancy (HDPs). Published in Pediatric and Perinatal Epidemiology, the research challenges previous assumptions about maternal risk following HDPs and highlights the critical need for improved cardiovascular screening and collaborative care for women after pregnancy.
The long-held belief that HDPs, while posing risks to the infant, automatically translate to increased maternal risk has been called into question. this data indicates a nuanced correlation, with a potential negative link between CVD trends and infant birthweight specifically among mothers experiencing preterm HDP.
Preterm HDP and Infant Size: A Risky Combination
Investigators suggest the findings point to a potentially distinct subtype of preeclampsia, particularly in mothers with preterm HDP delivering larger-than-average infants. This subtype may be closely linked to diabetes mellitus, warranting further investigation. “Our analysis shows that mothers with preterm HDP and large babies may have a clinically crucial subtype of preeclampsia that deserves further exploration, especially regarding the association with diabetes mellitus,” the researchers wrote.
Collaborative Care: A Vital Step Forward
Experts are emphasizing the importance of enhanced collaboration between cardiologists and obstetricians to proactively identify and manage long-term cardiovascular risks in women. Martha Gulati, MD, professor of cardiology at Cedars Sinai, highlighted the significance of addressing sex-specific risk factors for CVD, including age at menstruation onset, adverse pregnancy outcomes, and early menopause.
“Understanding the consequences long-term and how we can be more proactive, and more preventative, and knowing you’re at risk… can really go to save women’s lives, which is ultimately all our goals,” Gulati stated in an interview. She advocates for routine screening measures like blood pressure and cholesterol tests, coupled with increased awareness of these unique female-specific risk factors.
Study Details and Methodology
The complete study, conducted between 1967 and 2013, analyzed data from the Medical Birth Registry of Norway – a population-based database encompassing births, stillbirths, and abortions, along with detailed maternal and infant health information. A total of 1,034,792 mothers with at least seven years of follow-up data were included in the final analysis.
Researchers evaluated CVD risk based on HDP status, gestational age at delivery, and infant size for gestational age. HDP was categorized as eclampsia, preeclampsia, gestational hypertension, or hemolysis, elevated liver enzymes, and low platelets syndrome. Preterm birth was defined as delivery before 27 weeks’ gestation. Premature maternal death due to CVD was identified through linkage to the Norwegian Cause of Death Register.
The analysis revealed that 88.7% of mothers experienced a term normotensive first birth, while 5.2% had term HDP and 1% had preterm HDP.Notably, infants born to mothers with term HDP had an average population Z-Score of 0, compared to a below-average score of -0.96 for preterm infants born to mothers with HDP.
Interaction Between HDP and Birthweight
The study also demonstrated a strong multiplicative interaction between HDP and birthweight concerning CVD mortality in preterm versus term births, with relative excess risk due to interactions of 1.99 and -0.27, respectively. This reinforces the idea that the combination of preterm HDP and a normal-to-large infant size presents the highest CVD mortality risk for mothers.
This research underscores the critical need for a more personalized approach to postpartum cardiovascular care, particularly for women who experience preterm HDP and deliver larger infants. By fostering collaboration between specialists and prioritizing proactive screening, healthcare providers can substantially improve the long-term health outcomes for this vulnerable population.
