Cardiovascular disease (CVD) is the leading cause of pregnancy-related maternal death in the United States, driven by rising rates of hypertension, diabetes mellitus (DM), obesity, smoking, and advanced maternal age. Up to two-thirds of CVD-related maternal deaths are preventable with proper counseling and targeted interventions. This discussion focuses on strategies to reduce CVD risk during pregnancy.

Clinical Conditions

Cardiac output in pregnant patients can increase by 30-50% during pregnancy and labor. Although many pregnant patients can accommodate this physiological stress, those with pre-existing cardiovascular (CV) conditions may experience clinical deterioration.¹ Without the implementation of effective preventive strategies, both maternal and neonatal health can be adversely affected. Adverse pregnancy outcomes (APOs) include preterm birth, gestational diabetes mellitus (GDM), pre-eclampsia, gestational hypertension, small-for-gestational-age infants, placental abruption, and neonatal complications.²

APOs increase the risk of long-term maternal CVD, including arrhythmias, hypertension, heart failure, peripartum cardiomyopathy, valvular disorders, coronary artery disease, and DM.³ During pregnancy, patients typically experience reduced stress responsiveness of the hypothalamic-pituitary-adrenal axis, accompanied by a shift in the immune system toward an anti-inflammatory state.⁴ These changes can elevate the risk of long-term maternal CVD if preventive strategies are not undertaken.

Risk factors such as chronic hypertension, DM, dyslipidemia, obesity, smoking, and sleep-disordered breathing significantly contribute to adverse maternal and neonatal outcomes. Unfortunately, except for smoking, the prevalence of these risk factors has increased among expectant patients.⁵ Chronic hypertension among pregnant patients has more than doubled from 2008 to 2021, partly because of advanced maternal age and socioeconomic disparities, mainly in rural areas.⁶ Chronic hypertension in pregnancy is defined as systolic blood pressure (BP) ≥140 mm Hg and/or diastolic BP ≥90 mm Hg before 20 weeks of gestation or persisting for 12 weeks postpartum.

Additionally, data from a 2009 study showed that 18.9% of women with a history of GDM developed type 2 DM within 9 years of pregnancy.⁷ Pre-GDM is of particular concern due to its association with a threefold to fivefold increased risk of congenital heart defects. Dyslipidemia, compounded by the rising obesity epidemic, further complicates pregnancy and increases the risk of APOs, long-term CV events, and neonatal health issues.

Whereas the rate of smoking during pregnancy has decreased, the rising use of e-cigarettes poses new risks, including increased chances of preterm birth and low birth weight.⁸ Additionally, the development of maternal obstructive sleep apnea further heightens the risk of gestational hypertension and pre-eclampsia. To address these interconnected issues, early screening and management by specialized cardio-obstetrics teams are essential. Such proactive measures facilitate comprehensive preconception risk assessment and preventive care, ultimately improving both maternal and fetal health outcomes.

Advised Therapeutic Approach

Hypertension management during pregnancy requires careful consideration of the patient's age and the gestational age. As most antihypertensive medications are excreted in breast milk, their potential effects on neonates and infants must be considered. The American Heart Association (AHA) advises that treatment for hypertension should be delayed if pre-eclampsia is diagnosed. Specifically, for pregnant patients at term, intervention should only occur if BP readings are critically high. The treatment plan is then reassessed after delivery.⁹ The National High Blood Pressure Education Program (NHBPEP) recommends several treatments for managing pre-existing hypertension that are considered safe for use in pregnant individuals, thereby indicating their safety for infants. These treatments include methyldopa, labetalol, beta-blockers (excluding atenolol), slow-release nifedipine, and diuretics. For outpatient management, beta-blockers such as labetalol (100-200 mg twice daily, with a maximum of 2400 mg daily), dihydropyridine calcium channel blockers such as nifedipine (30-60 mg daily, with a maximum of 120 mg daily), and methyldopa (250 mg two or three times daily, with a maximum of 3000 mg daily) are commonly used. In cases of acute hypertensive crisis, intravenous labetalol, hydralazine, and immediate-release nifedipine have demonstrated high efficacy in rapidly lowering BP, often achieving significant results with an initial dose.¹⁰ The safety profile of these medications for both the patient and the fetus makes them suitable options in the management of hypertension during pregnancy.

To protect fetoplacental perfusion, hypertension management during pregnancy requires a cautious approach with less stringent treatment thresholds than those used for the general population. Women with chronic hypertension taking angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers should switch to alternative medications before conception to avoid risks of congenital abnormalities.¹¹ Because of limited and sometimes conflicting data, hypertension treatment guidelines for pregnant patients differ from those for the general population and vary among medical societies. For instance, the European Society of Cardiology (ESC) recommends treating chronic hypertension at higher thresholds (≥150/95 mm Hg), whereas stricter control is advised for gestational hypertension or pre-eclampsia (≥140/90 mm Hg). Recent study data, such as from the CHIPS (Control of Hypertension in Pregnancy Study) and CHAP (Chronic Hypertension and Pregnancy) studies, suggest that tighter BP control during pregnancy can reduce the risk of severe maternal hypertension, pre-eclampsia, preterm birth, and neonatal complications, underscoring the importance of tailored hypertension management to improve pregnancy outcomes (Figure 1).

Figure 1: Major Findings and Clinical Implications of the CHAP and CHIPS Studies

DM management is equally critical. The American Diabetes Association (ADA) recommends achieving preconception hemoglobin A1c concentration <6.5% and maintaining strict glucose control during pregnancy, with fasting glucose levels <95 mg/dL and postprandial levels <140 mg/dL at 1 hour and <120 mg/dL at 2 hours.¹² Insulin is the preferred treatment, with metformin as an alternative, supplemented by lifestyle modifications such as a carbohydrate-controlled diet and regular exercise.

Managing dyslipidemia and obesity before and during pregnancy is essential to reduce the risk of complications such as GDM and pre-eclampsia. Although lipid-lowering medications, including statins, are generally contraindicated during pregnancy because of potential fetal harm, newer therapies such as proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors and bempedoic acid have emerged. However, the safety of these medications in pregnancy is not well established, and patients should discontinue them before conception, opting for safer alternatives instead.¹⁰ Familial hypercholesterolemia (FH) presents risks for pregnant patients, especially because they cannot use statins during pregnancy. It is vital for all patients of childbearing age with FH who are taking lipid-lowering therapy to also receive prepregnancy counseling and contraception advice. Recommended contraceptive options include low-dose estrogen oral contraceptives, intrauterine devices, and barrier methods, with the latter two being preferable for women >35 years of age.¹³ Early diagnosis and treatment of FH are essential to reduce long-term CVD risk. For nonpregnant women with FH, aggressive management with statins, cholesterol absorption inhibitors, and possibly PCSK9 inhibitors is advised to normalize low-density lipoprotein cholesterol levels. The American College of Obstetricians and Gynecologists (ACOG) emphasizes that pregnant patients should aim for 150 min of moderate-intensity exercise each week and monitor. This dual focus on both diet and exercise is vital for mitigating CVD-related complications during pregnancy. A balanced diet and consistent physical activity significantly enhance expectant patients' health outcomes and supports their developing fetus' well-being. Glucagon-like peptide 1 (GLP-1) agonists are emerging treatments for DM and obesity, but insufficient safety data during pregnancy and lactation pose challenges for health care providers. Results of a 2023 study by the University of Amsterdam showed that women are advised to discontinue GLP-1 inhibitors prior to pregnancy.¹⁴

Figure 2: Therapeutic Approaches to Mitigating Risk Factors for Adverse Pregnancy Outcomes Associated with CVD

Smoking cessation should begin ≥15 weeks before conception, although quitting at any stage benefits maternal and fetal health. Nicotine replacement therapy should be used cautiously after a risk assessment, with varenicline and bupropion as alternatives. For sleep apnea, screening with a four-variable model is preferred, and continuous positive airway pressure (CPAP) remains the primary treatment. Postpartum care is critical, with ACOG recommending a comprehensive visit within 3 months.¹⁵ Telemedicine has improved care for hypertension and postpartum depression. Key practices include regular BP monitoring, DM screening, dyslipidemia management, smoking cessation support, and CPAP therapy. Expanding health care coverage and telehealth infrastructure is essential to improve access and reduce disparities in postpartum care.

Conclusion

CVD poses a significant risk to pregnant patients and is a leading cause of maternal mortality in the United States. Rising rates of chronic hypertension, DM, obesity, and advanced maternal age contribute to its prevalence. Preventive measures, including preconception counseling, early intervention by cardio-obstetrics teams, and effective management of chronic conditions, are vital for reducing APOs and long-term CVD risk. Comprehensive postpartum care, supported by telemedicine and expanded coverage, is essential for managing chronic conditions and preventing future CV complications.

References

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