Agreement between maternal report and medical records on use of medications during early pregnancy in New York

Abstract

Background: Studies evaluating associations between medication use in pregnancy and birth outcomes rely on various sources of exposure information. We sought to assess agreement between self-reported use of medications during early pregnancy and medication information in prenatal medical records to understand the reliability of each of these information sources.

Methods: We compared self-reported prescription medication use in early pregnancy to medical records from 184 New York women with deliveries in 2018 who participated in the Birth Defects Study To Evaluate Pregnancy exposureS. We assessed medications used chronically and episodically, and medications within 12 therapeutic groups. We calculated agreement using kappa (κ) coefficients, sensitivity, and specificity. We assessed differences by case/control status, maternal age, education, time to interview, and interview language.

Results: Medications used chronically showed substantial agreement between self-report and medical records (κ = 0.75, 0.61-0.88), with agreement for therapeutic groups used chronically ranging from κ = 0.61 for antidiabetics to κ = 1.00 for antihypertensives. Prescription medications used episodically showed worse agreement (κ = 0.40, 0.25-0.54), with the lowest agreement for opioid analgesics (κ = 0.20) and anti-infectives (κ = 0.33). Agreement did not differ by the characteristics examined, although we observed potential differences by interview language.

Conclusions: Among our sample, we observed good agreement between self-report and medical records for medications used chronically and substantially less agreement for medications used episodically. Differences by source may be due to poor recall in self-reports, non-adherence with prescribed medications and lack of complete prescription information within medical records. Limitations should be considered when assessing prescription medication exposures during early pregnancy in epidemiologic studies.

Keywords: agreement; exposure misclassification; kappa; pregnancy; prescription medications; self-report; validity.