Overview of High-Risk Pregnancy – Gynecology and Obstetrics

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In a high-risk (at-risk) pregnancy, the mother, fetus, or neonate is at increased risk of morbidity or mortality before or after delivery.

In 2015, overall maternal mortality rate in the US was 14/100,000 deliveries, as estimated by the WHO; incidence is 3 to 4 times higher in nonwhite women. Almost 50% of pregnancy-associated deaths in the US occur in non-Hispanic black women. The maternal mortality rate is higher in the US than in other Western countries (eg, Germany, Netherlands, Poland, Spain, Sweden, Switzerland, United Kingdom).

Maternal mortality ratios in selected countries

Maternal mortality ratio refers to the number of women who die from pregnancy-related causes during pregnancy or within 42 days of the end of the pregnancy per 100,000 live births. In 2015, ratios ranged from 3 (Finland) to 1360 (Sierra Leone) per 100,000 live births (countries not shown). The maternal mortality ratio is higher in the US than in other Western countries.

Data from WHO, UNICEF, UNFPA, The World Bank, and the United Nations Population Division. Trends in Maternal Mortality: 1990 to 2015. Geneva, World Health Organization, 2015.

The most common causes of maternal death worldwide are

Nearly half of maternal deaths are preventable.

Perinatal mortality rate in offspring in the US is about 6 to 7/1000 deliveries; deaths are divided about equally between those during the late fetal period (gestational age > 28 weeks) and those during the early neonatal period (< 7 days after birth).

The most common causes of perinatal death are

Other maternal characteristics that increase the risk of perinatal mortality include maternal age (much younger or older than average), unmarried status, smoking, and multiple gestations.

  • 1. Say L, Chou D, Gemmill A, et al: Global causes of maternal death: A WHO systematic analysis. Lancet Glob Health 2 (6) :e323–33, 2014. doi: 10.1016/S2214-109X(14)70227-X.

Risk assessment is part of routine prenatal care. Risk is also assessed during or shortly after labor and at any time that events may modify risk status. Risk factors are assessed systematically because each risk factor present increases overall risk.

Several pregnancy monitoring and risk assessment systems are available. The most widely used system is the Pregnancy Assessment Monitoring System (PRAMS), which is a project of the CDC and state health departments. PRAMS provides information for state health departments to use to improve the health of mothers and infants. PRAMS also enables the CDC and states to monitor changes in health indicators (eg, unintended pregnancy, prenatal care, breastfeeding, smoking, drinking, infant health).

High-risk pregnancies require close monitoring and sometimes referral to a perinatal center. When referral is needed, transfer before rather than after delivery results in lower neonatal morbidity and mortality rates.

The most common reasons for referral before delivery are

Pregnancy Risk Assessment

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