Association between offspring size at birth and maternal cardiovascular disease mortality
Nine large data linkage studies assessed the association between offspring birthweight/SGA and maternal cardiovascular disease mortality1, 2, 4, 15-20 and one assessed the association between delivery of a SGA infant and the occurrence of maternal CVD3 (table 2). Of the studies reporting on maternal CVD mortality, two studies demonstrated aHRs of 2.0 and 2.2 for each 1kg decrease in offspring birthweight15, 18 and five studies demonstrated aHRs between 0.75 and 0.89 for each 1 SD increase in offspring birthweight1, 2, 4, 19, 20(table 2). Four studies assessed maternal CVD mortality in relation to giving birth to a SGA vs AGA infant and reported aHRs between 1.31 – 3.5 among women who gave birth to SGA compared to AGA infants2-4, 16 (table 2). A large data linkage study of 812,732 women demonstrated that, compared to women who gave birth to non-SGA infants, the aHR for first occurrence of CVD among women who gave birth to moderately SGA infants (birthweight between 3rd – 10th percentile) was 1.36 (95% CI, 1.23 to 1.49) and among women who gave birth to severe SGA infants (birthweight <3rd centile) was 1.66 (95% CI, 1.47 to 1.87)3 (table 2). That study also showed a linear increase in aHR for first occurrence of CVD of 1.42 (95% CI, 1.30 to 1.54), 1.65 (95% CI, 1.34 to 2.03) and 2.42 (95% CI, 1.52 to 3.85) for women who gave birth to one SGA infant, two SGA infants and three SGA infants respectively, compared to women who gave birth to non-SGA infants3 (table 2). Three studies were included in the meta-analysis on CVD mortality among women who gave birth to SGA compared to AGA infants, providing data on 2,584,533 individuals (figure 3) 2, 4, 16. The pooled data shows a significantly increased CVD mortality among women who gave birth to SGA infants compared to those who gave birth to AGA infants (RR 1.45, 95% CI 1.40 to 1.52); heterogeneity: Chi2 P 0.48; I2 = 0%)