Can troponin I (cardiac biomarker) levels increase during pregnancy?

Troponin I in Pregnancy

Troponin I remains within normal range during uncomplicated pregnancy and should not be elevated by pregnancy itself or the process of vaginal or cesarean delivery. 1

Normal Pregnancy

• Troponin I levels are not elevated during normal pregnancy and remain within the normal reference range in the absence of cardiovascular morbidities. 1
• The physiological changes of pregnancy (increased cardiac output, blood volume, heart rate) do not cause troponin elevation. 1
• Troponin I remains undetectable during labor and delivery, with the highest reported level being 0.134 ng/mL, which is below the diagnostic cutoff of 0.15 ng/mL for myocardial infarction. 2
• Neither vaginal nor cesarean delivery causes troponin I elevation, with median levels remaining <0.3 ng/mL before and after both types of delivery (well below the 2.0 ng/mL threshold for myocardial ischemia). 3

Pre-eclampsia and Gestational Hypertension

There is controversy regarding troponin elevation in pre-eclampsia, with conflicting evidence in the literature. 1

• Multiple studies show troponin I may be elevated in pre-eclampsia compared to uncomplicated pregnancy, though this finding is not consistent across all research. 4, 5
• When troponin I is elevated in pre-eclampsia, it likely reflects actual myocardial stress or necrosis rather than a false-positive result. 4, 5
• One study found no difference in troponin I levels between pre-eclamptic patients (mean 0.008 ng/mL) and controls (mean 0.01 ng/mL), with the highest level being 0.04 ng/mL in both groups. 6

Clinical Interpretation Algorithm

When troponin I is elevated in a pregnant patient, you must investigate for underlying cardiac pathology rather than attributing it to pregnancy alone. 1

Step 1: Recognize that elevation indicates pathology

• An increase in troponin I should lead to consideration of underlying ischemic heart disease, even if pre-eclampsia is present. 1
• Troponin elevation reflects cardiomyocyte necrosis and warrants cardiac investigation. 1

Step 2: Consider pregnancy-specific cardiac conditions

• Spontaneous coronary artery dissection (more prevalent peripartum, especially around delivery and early postpartum). 1
• Peripartum cardiomyopathy. 1
• Coronary vasospasm from ergometrine given for postpartum bleeding. 1
• Severe postpartum hemorrhage with hemorrhagic shock leading to ischemic ECG changes and wall motion abnormalities. 1

Step 3: Evaluate for non-coronary cardiac causes

• Myocarditis and pericarditis. 1
• Acute heart failure. 1
• Tachyarrhythmias. 1
• Pulmonary embolism (highest risk immediately postpartum with incidence 0.1-0.67 per 1000 pregnancies). 1
• Cardiac trauma. 1

Step 4: Rule out life-threatening differential diagnoses

• Aortic dissection. 1
• Acute pulmonary embolism. 1
• Pre-eclampsia with cardiac involvement. 1

Step 5: Obtain serial measurements

• A single troponin measurement is insufficient; obtain serial levels to demonstrate a rising and/or falling pattern characteristic of acute myocardial injury. 1
• Serial measurements at 3-6 hour intervals are essential, as 10-15% of patients may not show initial elevation. 1, 7

Step 6: Perform echocardiography

• Echocardiography can be safely used to evaluate wall motion abnormalities in pregnant patients. 1
• Immediate echocardiography is indicated in pregnant women presenting with dyspnea or embolic events. 1

Critical Pitfalls to Avoid

• Do not dismiss troponin elevation as "normal for pregnancy"—it is not. 1
• Do not attribute chest pain or dyspnea solely to pregnancy without cardiac evaluation when troponin is elevated. 1
• Timely diagnosis is often delayed because presenting symptoms are incorrectly attributed to normal pregnancy. 1
• Point-of-care troponin tests have substantially lower sensitivity than central laboratory methods and should not be relied upon exclusively. 1, 7
• Troponin may remain elevated for up to 2 weeks after myocardial injury, complicating interpretation. 1, 7

Prognostic Significance

• When troponin elevation occurs in pregnancy, it carries the same adverse prognostic significance as in non-pregnant patients, indicating increased risk of mortality and adverse cardiovascular outcomes. 1
• Cardiovascular disease is the largest single cause of maternal mortality, with no significant improvement in recent decades. 1