Effect of early use of low-dose aspirin therapy on late-onset preeclampsia

Low-dose aspirin (LDA) therapy has been found to be effective in preventing the development of early-onset preeclampsia. However, its effect on late-onset preeclampsia has not been described. Our study was aimed at determining if LDA therapy prescribed from early in pregnancy modified the severity of late-onset preeclampsia.

A retrospective analysis of all women who were screened for early-onset preeclampsia at 11-13⁺⁶ weeks' gestation between April 2012 and October 2014 at our institution, and who subsequently developed late-onset preeclampsia. The treatment group consisted of women who were prescribed LDA therapy from early in pregnancy as a result of the screening. The control group consisted of women who did not receive LDA therapy.

The aspirin group was associated with earlier delivery at 38.0 (37.5-38.5) weeks' gestation versus 39.0 (38.7-39.4) weeks' gestation for the nonaspirin group (p < .01). The aspirin group was also associated with lower absolute birth weight 2851 (2646-3055) versus 3215 (3068-3362) grams in the nonaspirin group (p < .01). However, when normalised for gestational age at delivery, the proportion of foetuses that were small for gestation age (< 10th centile) were not significantly different between the two groups [28% in aspirin group versus 23% in nonaspirin group; p = .62]. No other significant difference was noted.

There was no difference in the clinical severity of late-onset preeclampsia between women screened as high risk for early-onset preeclampsia and subsequently prescribed LDA during their pregnancy, compared to women found to be at low risk and not prescribed LDA.