Variation of Electrocardiographic Indices in Normal Pregnancy: A Systematic Review and Meta-analysis

Introduction: Heart disease is a significant cause of maternal mortality. An Electrocardiogram (ECG) is the most common diagnostic modality available for its detection. ECG indices display a variety of changes during normal pregnancy. Aim: To analyse changes in electrocardiographic indices during pregnancy compared to controls and at different trimesters in normal pregnant patients. Materials and Methods: Data on relevant published articles in English were retrieved from PubMed using predefined search terms, including MeSH, manual searches, and references from 1932 to 2025. Normal pregnant patients without clinical heart or systemic disease were included in the study. Nineteen ECG indices were compared between pregnant and non pregnant groups. The p-value50% indicating substantial heterogeneity. The Newcastle–Ottawa Scale (NOS) and an adapted version (NOS-xs) were used to assess the risk of bias of the included studies Results: After initial screening, 25 studies were included in a pregnant group (4645 patients) and a control group of non pregnant women (1191 patients) The statistical analysis was performed for values of the control compared to the 1st, 2nd, and 3rd trimesters, as well as the control versus the average value of all three trimesters for each of the ECG indices. Only the ECG indices of heart rate and Mean Corrected QT (QTc) interval showed increased statistical significance at p-value=0.0332 and p-value=0.0050, respectively, in the comparison of the control group versus the average value of all three trimesters of pregnancy. The remaining ECG indices did not show any statistically significant differences in any comparison. The magnitude of variation was found to be small by the pooled estimate of effect size. Overall, the risk of bias of the included studies was found to be low to moderate in most of the included studies. Conclusion: A statistically significant small magnitude increase was noted only for heart rate and mean QTc in the pregnant group compared to the non pregnant control. The meta-analysis could not demonstrate statistically significant changes in any of the ECG indices between the trimesters of pregnancy