In a recent retrospective study published in Scientific Reports, researchers from China investigated the effectiveness of low-dose aspirin (LDA) in reducing adverse pregnancy outcomes in the special case of twins conceived via assisted reproductive technology (ART).

They found that while LDA could effectively preclude preeclampsia (PE) without a significant bleeding risk, it could not prevent specific complications in twin pregnancies, with a more pronounced preventive effect in mothers under 30 years of age.

Study: Potential impact on using aspirin as the primary prevention of adverse pregnancy outcomes in twins conceived using ART. Image Credit: fizkes/Shutterstock.com

Background

Despite advancements in ART since 1978, perinatal outcomes in ART pregnancies fail to surpass those in non-assisted pregnancies. The increased use of ART has led to a rise in twin pregnancies, contributing to several complications in management.

Twins exhibit over 50% prevalence of preterm labor (PTL), with significantly elevated risks of PE and cesarean delivery compared to singletons. Additionally, the psychological burden on mothers of multiples and those undergoing ART is significant owing to heightened expectations of better outcomes.

Evidence suggests that the use of LDA before 16 weeks of gestation may help in reducing the risk of PE and that of delivering a small-for-gestational-age (SGA) neonate.

Despite a randomized trial showing a lower incidence of preterm labor with aspirin use, concerns about potential postpartum bleeding risk exist.

Limited studies have explored the effectiveness of LDA in twin pregnancies, particularly those from ART. Therefore, researchers in the present study aimed to evaluate whether LDA improves pregnancy outcomes in ART-related twin pregnancies.

About the studyTop of Form

The present retrospective cohort study included 665 women aged 18–55 years with twin pregnancies from ART in the period between 2016 and 2021. The inclusion criteria involved twins diagnosed by ultrasound before 16 weeks.

Prenatal, delivery-related, and neonatal health data were obtained from standardized electronic records. The women with missing maternal prenatal health records and those with a history of the use of selective serotonin reuptake inhibitors or low-molecular-weight heparin were excluded. The final follow-up involved 510 participants– 257 in the control group and 253 in the LDA group.

Obstetricians implemented varying aspirin use policies in twin pregnancies from ART, randomly assigning 100 mg/day aspirin at the initial prenatal visit (10–16 gestational weeks) in the LDA group, considering the limited evidence on the safety of aspirin in this context.

The primary outcomes of the study focused on pregnancy complications, including common issues like gestational age at delivery, PE, hypertensive disorders, gestational diabetes, premature rupture of membranes, previa placental abruption, placenta accreta placenta, intrahepatic cholestasis of pregnancy (ICP), abnormal thyroid function, abnormal amniotic fluid, and mode of delivery.

Secondary outcomes were specific complications in twins, such as SGA, selective intrauterine growth restriction, twin reverse arterial perfusion sequence, twin-to-twin transfusion syndrome, stillbirth, and abortion.

The safety of aspirin was assessed based on postpartum hemorrhage, uterine artery embolization, transfusion, and transfer to ICU (short for intensive care unit). At the same time, birth-related characteristics encompass sex ratio, birth weight, and NICU (short for neonatal ICU) transfer.

The complications and adverse outcomes in pregnancy were defined based on specific criteria, aligning with international practice recommendations. Statistical analysis included the determination of mean and standard deviation and using the chi-square test, Student’s t-test, and Fisher exact test.

Results and discussion

The population comprised 476 dichorionic and 34 monochorionic twins, with 500 conceived through IVF-ET (short for in vitro fertilization and embryo transfer) and 10 through IUI (short for Intrauterine insemination).

During this 6-year-long study, an increasing trend in twin pregnancies from ART was observed, in addition to a rising prevalence of the use of aspirin in this group. Comparisons between aspirin users and non-users revealed varying impacts on pregnancy complications.

While overall hypertensive disorders were higher in aspirin users (p < 0.05), PE incidence was found to be lower in this population (p < 0.05).

Aspirin use did not significantly affect gestational age at delivery, nor was it found to increase bleeding risk. Further, cesarean section rates were significantly lower in the aspirin group.

Neonatal outcomes showed no significant differences except for gender. Aspirin use also did not appear to reduce their admission to NICU.

Detailed analysis and age stratification of mothers revealed a potentially more pronounced protective effect of aspirin on adverse outcomes in mothers under 30 years of age.

Conclusion

Overall, this novel study provides insights into the complex relationship between aspirin use and maternal and neonatal outcomes in twin pregnancies from ART.

Initiation of LDA at an early gestational age significantly reduces the risk of PE without increasing serious bleeding-related complications.

These findings encourage healthcare professionals to weigh the advantages and disadvantages of LDA use in specific cases to improve pregnancy outcomes while ensuring safety.