Aspirin, Birthweight, and Large-For-Gestational-Age Neonates: A Secondary Analysis of the ASPRE Trial.

OBJECTIVE

To investigate the effects of aspirin on the distribution of birthweight and its impact on the rates of large-for-gestational-age (LGA) neonates.

DESIGN

Secondary analysis of the Combined Multimarker Screening and Randomised Patient Treatment with Aspirin for Evidence-based Preeclampsia Prevention (ASPRE) trial.

SETTING

Thirteen hospitals in England, Spain, Belgium, Greece, Italy and Israel.

POPULATION

Participants of the ASPRE trial at increased risk of preterm pre-eclampsia (PE) who had a live birth.

METHODS

We compared the birthweight distributions and the rates of LGA neonates between the trial groups. Analyses were stratified according to the presence of pre-existing diabetes mellitus and the development of PE, and logistic regression was used to investigate independent predictors of LGA neonates with birthweight above the 90th percentile.

MAIN OUTCOME MEASURES

Birthweight distribution and rates of LGA neonates.

RESULTS

Among 1571 singleton, live neonates (777 from the aspirin group and 794 from the placebo group), aspirin was associated with a shift in birthweight from < 2500 to 2500-4000 g, and birthweight percentile from < 25th to 25th-75th percentiles, with no significant increase in LGA neonates (5.5% vs. 6.2%, p = 0.667). Logistic regression demonstrated a significant interaction between treatment and pre-existing diabetes (p-value 0.034), and a positive association between maternal weight and LGA neonates (adjusted odds ratio 1.040, 95% confidence interval 1.030-1.051, p < 0.001).

CONCLUSIONS

Aspirin use is associated with increased birthweight without increasing the rate of LGA neonates. Among women with pre-existing diabetes, aspirin may be associated with a higher rate of LGA neonates, warranting further investigation.