Aspirin nonadherence elevates risk for preeclampsia, preterm delivery in high-risk pregnancy
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High-risk pregnant women who were nonadherent to prescribed aspirin experienced greater risk for poor clinical outcomes compared with women who were adherent, according to research published in Hypertension.
Compared with those who were adherent to aspirin, high-risk pregnant women with actual inadequate adherence, or less than 90% adherence, prescribed aspirin had higher incidence of:
- early-onset preeclampsia (17% vs. 2%; OR = 1.9; 95% CI, 1.1-8.7);
- late-onset preeclampsia (41% vs. 5%; OR = 4.2; 95% CI, 1.4-19.8);
- intrauterine growth restriction (29% vs. 5%; OR = 5.8; 95% CI, 1.2-8.3);
- preterm delivery (27% vs. 10%; OR = 5.2; 95% CI, 1.5-8.7); and
- likelihood of increase in antihypertensives antenatally (60% vs. 10%; OR = 4.6; 95% CI, 1.2-10.5).
In addition, a Kaplan-Meier analysis identified a lower incidence of premature delivery in pregnant women who were at least 90% adherent to prescribed aspirin compared with women who were nonadherent (HR = 0.3; 95% CI, 0.2-0.5).
“Despite the high prevalence of nonadherence with medications in pregnancy, it remains largely unrecognized and underreported,” Renuka Shanmugalingam, MBBS, FRACP, consultant nephrologist at the South Western Sydney Local Health District and the Western Sydney University School of Medicine, and colleagues wrote. “The lack or difficulty in establishing a gold standard assessment of medication adherence is a key factor.”
Researchers assessed 220 high-risk pregnant women from three centers in the South Western Sydney Local Health District. Clinic data, blood sample and self-reported adherence assessments were collected every 4 weeks from 12 to 36 weeks of gestation. According to the study, nonadherence was defined as normal platelet function analyzer 100 (PFA-100) and nondetectable plasma salicylic acid in less than 90% of time points.
Putting findings into practice
“It essentially comes down to effective communication. As a result of these findings, the clinicians in the institute where this study was conducted, South Western Sydney Local Health District, Australia, have improved the way women are counseled on the use of aspirin in pregnancy,” Shanmugalingam told Healio. “The risk-reduction benefit, the importance of adherence and strategies to minimize accidental omission are discussed with these women at the time of discussing their need for aspirin. We also discussed possible side effects (increased risk of bleeding and bruises) and discuss actions plans for if this occurs. At the end of the consultation, the women are now provided with an information sheet to help them consolidate the discussion.
“This is certainly an area of growing interest,” Shanmugalingam said in an interview. “There is a need for a randomized controlled trial comparing 100 mg to 150 mg of aspirin as a recent meta-analysis appears to suggest better outcomes with the use of 150 mg of aspirin in pregnant women. Our study was underpowered for this analysis. More data of the efficacy and safety of 150 mg of aspirin in pregnancy is required.”
Research into perinatal outcome needed
“The Shanmugalingam trial provides evidence of the importance of adherence,” Brett C. Young, MD, obstetrician-gynecologist at Beth Israel Deaconess Medical Center, and colleagues wrote in a related editorial. “Before universal adoption of aspirin for all high-risk pregnant women, it is important to note that the potential long-term consequences of aspirin exposure to developing fetuses are unknown.
“More studies to critically evaluate long-term safety are needed,” Young and colleagues wrote. “A clinical trial in the United States with incorporation of both aspirin adherence measurements, and risk stratification with biomarkers to evaluate aspirin’s effect on prevention of preeclampsia and more importantly improvement of perinatal outcomes is sorely needed.” – by Scott Buzby
Disclosures: The study authors and Young report no relevant financial disclosures. Please see the editorial for all other authors’ relevant financial disclosures.
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