Objective: To evaluate the effect of low-dose aspirin, which was administered at or before the 16th week of pregnancy due to maternal characteristics and history of a pre-existing medical condition, on prevention of pre-eclampsia, and on the birth of a small-for-gestational-age (SGA) neonate without pre-eclampsia in nulliparas in primary settings.
Methods: We performed a case-control study using population-based data on 47 271 nulliparas with a singleton pregnancy who delivered in Slovenia from 2013 to 2017. The treated group received low-dose aspirin. For the untreated group, propensity score matching was used to perform a 1:1 matching. In the matched sample, we calculated the odds ratios (OR) with a 95% confidence interval (95% CI) with a two-way test for pre-eclampsia, as well as SGA neonates.
Results: In the treated group (n=584), the odds for an SGA neonate were significantly increased by 42.7% (OR 1.427, 95% CI 1.001-2.034). However, we found no significant effect on the odds for pre-eclampsia (OR 1.308, 95% CI 0.847-2.022).
Conclusions: In anticipation of more substantial population-based data studies, in the Slovenian population, preventive treatment with low-dose aspirin due to maternal characteristics and history of a pre-existing medical condition is not beneficial for the prevention of pre-eclampsia and can harm fetal growth.
Keywords: Aspirin; Pre-eclampsia; Pregnancy; Prevention; Propensity score matching; Small for gestational age.
© 2020 International Federation of Gynecology and Obstetrics.