Birth weight of term born offspring in relation to long-term maternal cardiovascular morbidity and mortality

Previous studies have identified associations between offspring birth weight (BW) and future maternal cardiovascular health, but many studies lack sufficient adjustment for confounders such as pregnancy complications, gestational age, maternal body mass index (BMI), and smoking. This study aimed to assess whether the association between term offspring BW and maternal cardiovascular risk is independent of these factors. We used data from the Copenhagen Perinatal Cohort (1959–1961). After excluding women with diabetes, preeclampsia, preterm births, and twin pregnancies, 5,766 women remained. Cardiovascular outcomes were obtained from Danish national registries with up to 45 years of follow-up. Hazard ratios (HR) with 95% confidence intervals (CI) were estimated using Cox regression, adjusting for smoking during pregnancy, maternal BMI, hypertension, and gestational age at birth. Additional analyses were conducted in populations stratified by smoking status and adjusted for cigarette consumption per day. Offspring BW below 3000 grams (g) was associated with higher maternal cardiovascular mortality (< 2500 g: 2.16 1.54–3.03, 2500–2999 g: 1.41 1.09–1.81) compared to the reference category (offspring BW 3500–3999 g). The risks of maternal major cardiovascular events and stroke were higher when offspring BW was below 2500 g (1.35 1.01–1.79, 1.51 1.09–2.08) and lower if offspring BW was above 3999 (0.78 95% CI 0.61–0.99, 0.78 0.59–1.03) compared to the reference. No associations were found with ischemic heart disease. Associations persisted after stratification by smoking. Lower BW of term offspring from uncomplicated, singleton pregnancies is inversely associated with long-term maternal cardiovascular risk, independent of smoking during pregnancy.