between infant birth weight centiles and maternal cardiovascular outcomes at 6
Lu1; A Henry1,2; L Roberts2,3; G Davis1,2,3
1University of New South Wales, Randwick, NSW, Australia
2Department of Women's and Children's Health, St George Hospital,
Kogarah, NSW, Australia
3University of technology Sydney, Ultimo, NSW, Australia
Aims: To examine the correlation between infant birth weight
centiles and maternal cardiovascular outcomes at six months postpartum.
Additionally, to compare these outcomes, stratified by infant birth weight
centile, in mothers who had a hypertensive disorder of pregnancy versus an
Methods: Retrospective cohort study of 238 women and their
singleton infants involved in the P4 study at St George Hospital, NSW. Birth
weight centiles were calculated using three different methods; the Intergrowth
21-st and Australian national birth weight percentile charts and an
Australia-specific customised birth weight calculator obtained from
www.gestation.net. Maternal cardiovascular outcomes included mean systolic and
diastolic 24-hour ambulatory blood pressures, cholesterol, low-density
lipoprotein, high-density lipoprotein and triglyceride levels.
Results: Using simple linear regression, all three methods of
centile measurement when compared with cardiovascular outcomes individually,
demonstrated a coefficient of determination (R-squared) value of less than 1%.
Using linear regression, when maternal cardiovascular outcomes of mothers with
a hypertensive disorder of pregnancy were compared to those with an
uncomplicated pregnancy, an R-squared value of 13.5% was obtained. When
performing the same comparison, stratified by infant birth weight, an R-squared
value of 13.6% was obtained. This change was not significant (P > 0.05).
Conclusions: Low R-squared values
suggest a limited relationship between centiles and cardiovascular outcomes.
Furthermore, as the difference in R-squared value when stratified by infant
birth weight centile differed by a minimal amount (0.1%), the impact of
centiles as a predictor of cardiovascular outcomes in women at six months
postpartum is negligible, whether they had a hypertensive disorder of pregnancy
or an uncomplicated pregnancy. Thus, although women with preeclampsia are more
likely to have growth-restricted babies, these findings suggest that the baby’s
birth weight is unlikely to contribute to predictive modeling of the mother’s
cardiovascular risk at six months postpartum.