Background and Objectives: Post-term pregnancies are associated with increased risks of perinatal complications. This study aimed to evaluate potential cardiac electrophysiological changes in pregnant women by comparing the QRS duration, interval of corrected QT (QTc), and frontal QRS-T angle [f(QRS-T)] between term and post-term pregnancies. Materials and Methods: In this observational prospective study, 120 pregnant women were enrolled—60 term (37–41 weeks) and 60 post-term (≥42 weeks). All participants underwent standard 12-lead electrocardiography (ECG) and caesarean section with spinal anaesthesia. The QTc interval, QRS duration, and frontal QRS-T angle were measured. Demographic parameters such as age, gestational week, height, and weight were recorded. The SPSS software was used to analyse the data with p < 0.05 as the threshold for significance. Results: Post-operative QTc interval (417.3 ± 20.5 vs. 410.2 ± 14.5, p = 0.032) and f(QRS-T) (28 [16–55] vs. 22 [14–34], p = 0.042) were significantly higher in the post-term group than in the term group. When the change in the f(QRS-T) angle was analysed, there was a significant widening of this angle in the post-term group (from 21 [11–37] to 28 [16–55], p = 0.002). The increased f(QRS-T) angle reflects greater heterogeneity in ventricular depolarisation and repolarisation, which may indicate sub-clinical myocardial stress or altered autonomic regulation in the post-term period. Although no overt arrhythmias were observed, subtle changes in P-wave morphology and QT dispersion were more prevalent in the post-term group. Conclusions: Prolonged QRS duration and an increased f(QRS-T) angle in post-term pregnancies can reflect the underlying changes in cardiac electrophysiology related to prolonged gestation. These ECG parameters may serve as non-invasive indicators of sub-clinical cardiac stress, which could be relevant for anaesthetic risk assessment and perinatal management.

Background/Objectives: Pregnancy is associated with profound physiological alterations that, together with anemia and spinal anesthesia, may influence myocardial repolarization. The frontal QRS-T [f(QRS-T)] angle has emerged as a reliable electrocardiographic parameter for evaluating repolarization heterogeneity. Materials and Methods: This observational prospective study included 100 term pregnant women [18–45 years, American Society of Anaesthesiologists (ASA) II] undergoing elective cesarean delivery under spinal anesthesia at Sanliurfa Training and Research Hospital between May and August 2025. Participants were divided into two groups: anemic (Hb < 10.5 g/dL, n = 50) and non-anemic (Hb ≥ 10.5 g/dL, n = 50). Standard monitoring and 12-lead ECGs were performed preoperatively and postoperatively. The f(QRS-T) angle was calculated as the absolute difference between QRS and T axes; values > 180° were adjusted by subtracting from 360°. Results: Demographic variables were comparable between groups. No significant differences were observed in mean arterial pressure or heart rate. Preoperative QTc and f(QRS-T) angle values did not differ significantly. However, postoperative QTc was prolonged in the anemic group compared with non-anemic women (426.3 ± 19.2 ms vs. 417.2 ± 20.7 ms, p = 0.026). Likewise, the postoperative f(QRS-T) angle was significantly higher in anemic patients (29.5 [16.0–45.3] vs. 20.5 [9.8–34.5], p = 0.017). Within-group analysis revealed significant postoperative increases in both QTc (p < 0.001) and f(QRS-T) angle (p < 0.001) in the anemic group, but not in controls. Hemoglobin levels correlated negatively with postoperative QTc (r = −0.267, p = 0.008) and f(QRS-T) angle (r = −0.264, p = 0.008). Conclusions: In anemic patients undergoing cesarean delivery under spinal anesthesia, the postoperative QTc interval and f(QRS-T) angle increased significantly compared with both baseline values and non-anemic counterparts. Assessment of the f(QRS-T) angle, a simple and inexpensive ECG-derived parameter, may aid in perioperative risk stratification and enhance patient safety.