High-Risk Pregnancy Classification and Management

Definition and Core Principles

High-risk pregnancy is defined as any pregnancy in which the woman, fetus, or infant faces increased risk of death or residual injury requiring additional resources, procedures, or specialized care to optimize outcomes, according to the American College of Obstetricians and Gynecologists 1
The classification of high-risk pregnancy is not absolute and requires continuous reassessment throughout the reproductive lifespan, as recommended by the American Journal of Obstetrics and Gynecology 2

Preexisting medical conditions such as cardiovascular disease, including rheumatic heart valve disease, Marfan syndrome, and Ehlers-Danlos syndrome, significantly elevate pregnancy risk, as stated by the American Heart Association 1
Hypertensive disorders, including chronic hypertension and preeclampsia, are major risk factors, with the Centers for Disease Control and Prevention recommending close monitoring and management 3, 1
Diabetes mellitus, both pregestational and gestational, is a significant risk factor, according to the American Diabetes Association 1
Thrombophilia and history of venous thromboembolism, particularly with personal history of unprovoked or estrogen-related VTE, family history, or known thrombophilia, increase pregnancy risk, as reported by the Journal of Thrombosis and Haemostasis 4, 3
Autoimmune conditions, including systemic lupus erythematosus, and thyroid disorders are also risk factors, as stated by the American College of Rheumatology and the American Thyroid Association 4, 5

Risk assessment should begin before conception to optimize chronic medical conditions and identify modifiable risk factors, as recommended by the American Journal of Obstetrics and Gynecology 2, 8
The Society for Maternal-Fetal Medicine recommends evaluating five key areas at each assessment: healthcare system's ability to manage the condition, fetal and neonatal prognosis, patient's ability to manage the condition, woman's desire to continue pregnancy, and expertise of available healthcare practitioners, as stated by the American Journal of Obstetrics and Gynecology 2, 8
Risk increases with advancing gestational age as complications develop or medical interventions become necessary, according to the American Journal of Obstetrics and Gynecology 2

Various international guidelines use point-based systems for VTE risk, with scores ranging from 2 (moderate risk) to 4 (very high risk), as reported by the Journal of Thrombosis and Haemostasis 4
Hypertension severity classification includes adequately controlled hypertension, moderate risk (systolic 140-159 or diastolic 90-99 mm Hg), and high risk (systolic ≥160 or diastolic ≥100 mm Hg), as recommended by the Centers for Disease Control and Prevention 3

Avoid single-timepoint assessment, as risk is dynamic and evolves throughout pregnancy, according to the American Journal of Obstetrics and Gynecology 2
Don't overlook contextual factors, including socioeconomic status, geographic location, healthcare access, and implicit bias, which contribute to maternal outcomes, as reported by the American Journal of Obstetrics and Gynecology 7, 8