All are normal physiological changes in pregnancy except:

Correct Answer: C. Pansystolic murmur

A pansystolic (holosystolic) murmur is NOT a normal physiological change in pregnancy and should always be investigated. While pregnancy induces significant cardiovascular adaptations—increased cardiac output (by 30–50%), stroke volume, heart rate, and plasma volume—these changes produce specific benign findings. Pansystolic murmurs indicate mitral or tricuspid regurgitation (organic valve disease or dysfunction), which is pathological. The normal murmurs of pregnancy are typically systolic ejection murmurs (due to increased flow across the aortic or pulmonary valve) or continuous murmurs (mammary souffle from breast vascularity), not regurgitant (pansystolic) murmurs. A pansystolic murmur in pregnancy warrants echocardiography to exclude rheumatic mitral stenosis with secondary regurgitation, prosthetic valve dysfunction, or cardiomyopathy—all serious conditions requiring maternal risk stratification per Indian guidelines (ICOG, FOGSI). The presence of a pansystolic murmur should never be dismissed as physiological and demands cardiology evaluation before labor management decisions are made.

Why the other options are wrong

A. Left axis deviation — Left axis deviation occurs in pregnancy due to the gravid uterus elevating and rotating the heart leftward, combined with increased left ventricular mass from volume overload. This is a well-documented normal ECG finding in pregnancy and is seen in 15–20% of pregnant women. It reflects mechanical displacement, not pathology, and resolves postpartum. B. Mild ST changes in inferior leads — Mild ST-segment depression and T-wave flattening in inferior leads (II, III, aVF) are common physiological changes in pregnancy, attributed to the horizontal heart position and increased left ventricular mass. These changes are benign, non-ischemic, and resolve after delivery. They should not be misinterpreted as acute coronary syndrome in a pregnant patient. D. Atrial and ventricular premature contractions — Atrial and ventricular ectopy increases in pregnancy due to enhanced sympathetic tone, increased catecholamine sensitivity, electrolyte shifts, and mechanical irritation from cardiac displacement. These arrhythmias are benign in structurally normal hearts and typically resolve postpartum. They are considered normal physiological adaptations unless frequent or symptomatic.

High-Yield Facts

Mnemonics

NORMAL MURMURS in Pregnancy Systolic Ejection murmur (aortic/pulmonary flow) + Mammary Souffle (continuous). Pansystolic = Pathological. ECG Changes in Pregnancy (CHEAT) Cardiac displacement (LAD), Heart rate ↑, Ectopy (APCs/VPCs), Arrhythmias benign, T-wave/ST changes inferior.

NBE Trap

NBE exploits the fact that students often conflate "murmur in pregnancy" with "physiological murmur," leading them to incorrectly assume all murmurs are benign. The trap is the word "pansystolic"—a regurgitant murmur that is never physiological and always requires investigation.

Clinical Pearl

In Indian obstetric practice, many pregnant women with rheumatic heart disease (RHD) present with pre-existing mitral stenosis. A new or worsening pansystolic murmur in such patients signals secondary mitral regurgitation or hemodynamic decompensation—a red flag for maternal mortality risk. Always echo before labor in any pregnant woman with a regurgitant murmur.

_Reference: DC Dutta's Textbook of Obstetrics (Cardiovascular Changes in Pregnancy); Harrison's Principles of Internal Medicine Ch. 295 (Pregnancy and Cardiovascular Disease)_