Delivery of a Small-For-Gestational-Age Infant and Risk of Maternal Cardiovascular Disease - A Population-Based Record Linkage Study

Background Delivery of small for gestational age (SGA) infants has been associated with increased risk of future maternal cardiovascular disease (CVD). However, whether the risk increases progressively with the greater severity of SGA and number of SGA infants has not been explored. Methods A population-based record linkage study was conducted among 812,732 women delivering live born, singleton infants at term between 1994 and 2011 in New South Wales, Australia. Birth records were linked to the mothers' subsequent hospitalisation or death records to identify CVD events (coronary heart disease, cerebrovascular events, and chronic heart failure) after a median of 7.4 years. Cox proportional hazard regression was used to estimate adjusted hazard ratios (AHR) [95% confidence interval (CI)] for the associations between the severity (moderate or extreme) of SGA and number of SGA infants and subsequent risk of maternal CVD, accounting for maternal age at last birth, socioeconomic status, parity, smoking, (pregestational and gestational) diabetes, and (chronic and pregnancy) hypertension. Results Compared to mothers of non-SGA infants, AHRs [95% CI] of CVD among mothers of moderately and extremely SGA infants were 1.36 [1.23-1.49], and 1.66 [1.47-1.87], respectively, while AHRs among mothers with 1, 2, and >= 3 SGA infants were 1.42 [1.30-1.54], 1.65 [1.34-2.03], and 2.42 [1.52-3.85], respectively, indicating a dose-response relationship. AHRs of specific CVD categories showed a similar pattern. Conclusions Delivery of an SGA infant was associated with a dose-dependent increase in the risk of maternal CVD according to both the severity of SGA and number of previous SGA infants.