Electrocardiographic Changes during Normal Pregnancy
01 December 2017 (online)
Background Pregnancy is a physiologic condition which is unique in that it alters the physiology of each organ in the body. Cardiovascular changes during pregnancy are significant and start at 6 to 8 weeks of gestation. Physiologic cardiovascular changes during pregnancy suggest the chance of altered electrocardiographic (ECG) parameters during pregnancy. Study of variations in ECG in normal pregnant women serves as a basis to detect pathologic changes in pregnant women.
Material and Methods This is a cross-sectional data of case series of pregnant women across all stages of gestation who attended antenatal clinic of our teaching hospital, on Women's Day (March 8, 2017). A 12-lead ECG was recorded in all the participants in supine position. The parameters noted from the ECG include heart rate, PR interval, QRS duration, QRS axis, corrected QT (QTc) interval, and ST-T changes.
Results Total 151 pregnant women were studied. The average age was 23.38 ± 3.49 years. With respect to gestational age, 12 (7.94%), 48 (31.78%), and 91 (60.26%) women were in the first, second, and third trimesters of pregnancy, respectively. With respect to parity, 60 (39.7%) were primigravidae and 91 (60.26%) were multigravidae. The mean ECG heart rate was increased (100.15 ± 12.48 beats/min). The mean systolic blood pressure (109.67 ± 9.34 mm Hg) and the mean diastolic blood pressure (71.32 ± 6.89 mm Hg) were decreased. The mean of ECG intervals and durations (PR, QRS, QTc) were in normal range (0.14 ± 0.01, 0.08 ± 0.008, and 407.83 ± 11.98, respectively). There was no abnormal P-wave dispersion. Even though the QTc was in normal range in 63.56% of pregnant women, this parameter was in upper quadrant of the normal range. General linear regression demonstrated that systolic blood pressure and palpitations were the only variables to independently predict QTc in upper quadrant of normal range (p = 0.05, 0.03, respectively).
Conclusion The cardiovascular hemodynamic adaptation to pregnancy is a well-established fact that is also seen in our study. There is shortening of PR interval and QRS duration. Even though QTc is with in normal range, in more than half (63.56%) of pregnant women, it is in the upper quadrant of the normal range.
- 1 Misra J, Dutta B, Ganguly D. Electrocardiographic study in pregnant women in normal and toxemia of pregnancy. J Obstet Gynaecol India 1986; 36: 635-638
- 2 Healy TEJ, Knight PR. Wylie Churchill-Davidson's A Practice of Anesthesia. 7th ed. London, UK: Arnold; 2003: 351-361
- 3 Heymann PW. Alterations of the cardiac physical examination in normal pregnancy. Clin Obstet Gynaecol 1975; 18: 18-54
- 4 Ganong WF. Review of Medical Physiology. 22nd ed. New York, NY: McGraw-Hill; 2005: 547-576
- 5 Hill CC, Pickinpaugh J. Physiologic changes in pregnancy. Surg Clin North Am 2008; 88 (02) 391-401 , vii
- 6 Voss A, Malberg H, Schumann A. , et al. Baroreflex sensitivity, heart rate, and blood pressure variability in normal pregnancy. Am J Hypertens 2000; 13 (11) 1218-1225
- 7 Julian DG, Wenger NK. , eds. Heart disease and heart surgery during pregnancy. In: Women and Heart Disease. London: Martin Dunitz; 2000
- 8 Katz R, Karliner JS, Resnik R. Effects of a natural volume overload state (pregnancy) on left ventricular performance in normal human subjects. Circulation 1978; 58 (3 Pt 1): 434-441
- 9 Burwell CS. Circulatory adjustments to pregnancy. Bull Johns Hopkins Hosp 1954; 95 (03) 115-129
- 10 Stein PK, Hagley MT, Cole PL, Domitrovich PP, Kleiger RE, Rottman JN. Changes in 24-hour heart rate variability during normal pregnancy. Am J Obstet Gynecol 1999; 180 (04) 978-985
- 11 Madras V, Challa N. Electrocardiographic variations during three trimesters of normal pregnancy Int. J Res Med Sci 2015; 3 (09) 2218-2222
- 12 Carruth JE, Mivis SB, Brogan DR, Wenger NK. The electrocardiogram in normal pregnancy. Am Heart J 1981; 102 (6 Pt 1): 1075-1078
- 13 Kole S, Shenoy J, Shivakumar J, Suvarna P, Prasannakumar J. Variations in electrical activity of the heart as the pregnancy progresses. Natl J Physiol Pharm Pharmacol 2014; 4 (03) 187-190
- 14 Nandini BN, Shivakumar DG, Manjunath A, Girish BM. Shortening of PR- interval in different trimesters of pregnancy—a cross-sectional study. Int J Biol Adv Res 2011; 2 (11) 421-426
- 15 Lechmanová M, Kittnar O, Mlcek M. , et al. QT dispersion and T-loop morphology in late pregnancy and after delivery. Physiol Res 2002; 51 (02) 121-129
- 16 M S, S C, Brid SV. Electrocardiographic QRS axis, Q wave and T-wave changes in 2nd and 3rd trimester of normal pregnancy. J Clin Diagn Res 2014; 8 (09) BC17-BC21
- 17 Montanez A, Ruskin JN, Hebert PR, Lamas GA, Hennekens CH. Prolonged QTc interval and risks of total and cardiovascular mortality and sudden death in the general population: a review and qualitative overview of the prospective cohort studies. Arch Intern Med 2004; 164 (09) 943-948