(1087) Electrocardiogram Changes Associated with Pregnancy and Pregnancy Trimesters

Pregnancy is a physiologic high-volume state. Physiologic electrocardiogram (ECG) changes in pregnancy have been reported but not well characterized. We hypothesize that certain ECG features are more likely to be present in pregnant compared to non-pregnant individuals, reflecting physiologic cardiac volume and compliance changes. The objective of this study is to evaluate ECG changes in normal pregnancies by trimester compared to women who are not pregnant.

Study Design: This is an analysis of a database that includes 22,034 ECGs on 7,298 individual patients from 18-50 years of age who were pregnant at least once between 2011 to 2024 in a single tertiary medical center. Univariate and multiple generalized linear mixed effect models were performed to evaluate associations between four ECG features (QRS interval, QTc interval, PR interval, and heart rate) in pregnancy and by trimester compared to those in women who were not pregnant or within 6 months postpartum.

Results: After excluding patients with pre-existing cardiac morbidity, or affected hypertensive disorders of pregnancy, 5,574 ECGs from 2,988 patients were included: 3,423 of ECGs (61%) were obtained outside of pregnancy or the 6 months postpartum period, 2,151 (39%) of ECGs during pregnancy or postpartum. Shorter QRS duration, QTc interval, PR interval, and higher heart rate were associated the pregnancy or 2 weeks postpartum state (Table 1). The shorter QRS duration, PR interval, and higher heart rate were associated with the second, third trimester, and two weeks postpartum, and these changes resolved within 6 months postpartum (Table 2).

Conclusion: Four ECG features were found to be associate with pregnancy. The association is present particularly in the 2nd and 3rd trimester when cardiovascular changes are most pronounced. Future research includes extracting subtle patterns beyond well characterized ECG features to further investigate associations with normal pregnancy and to evaluate how they can be used to predict pathologic cardiovascular changes associated with pregnancy and postpartum.