There is no formal or universally accepted definition of a high-risk pregnancy. Generally, however, a high-risk pregnancy involves at least one of the following:
The woman or baby is more likely to become ill or die than usual.
Complications before or after delivery are more likely to occur than usual.
Many women with complex high-risk condition benefit from treatment at a specialized center that provides care for by doctors who specialize in high-risk pregnancies.
Maternal mortality
Maternal mortality refers to the death of women when death is caused by complications of pregnancy and childbirth.
In the United States, 19 women died for every 100,000 deliveries in 2017. In the United States, almost half of pregnancy-related deaths occur in black women. The maternal mortality rate is higher in the United States than in other Western countries, such as the following:
Germany: 7 deaths per 100,000 deliveries
The Netherlands: 5 deaths
Poland: 3 deaths
Spain: 4 deaths
Sweden: 4 deaths
Switzerland: 5 deaths
The United Kingdom: 7 deaths
However, almost all maternal deaths occur in developing countries. Over two thirds occur in sub-Saharan Africa (including Nigeria), and almost one fifth occur in South Asia (including India).
Comparing Mortality Ratios for Mothers in Different Countries
In this graph, the maternal mortality ratios in different countries are compared. Maternal mortality refers to the number of women who die because of problems related to pregnancy and who die during pregnancy or soon after delivery. The maternal mortality ratio is the number of such deaths for every 100,000 live births (delivery of a living baby). In 2013, ratios ranged from 1 (Belarus) to 980 (Chad) deaths per 100,000 live births (these countries are not shown below). The maternal mortality ratio is substantially higher in the United States (28 per 100,000 live births) than in most other Western countries.  Data from WHO, UNICEF, UNFPA, The World Bank, and the United Nations Population Division. Geneva, World Health Organization, 2014. |
The maternal death rate varies greatly by race and ethnicity worldwide. In the United States, the maternal death rate is over 3 times higher in black women and 2.5 times higher in American Indian and Alaska native women than in white women. In Brazil, the maternal mortality is about 5 times higher in women of African descent than in white women. In the United Kingdom, it is many times higher in black women than in white women.
The most common causes of death in pregnant women are
Bleeding Excessive Uterine Bleeding at Delivery Excessive bleeding from the uterus refers to loss of more than 2 pints of blood or symptoms of significant blood loss that occur within 24 hours of delivery. After the baby is delivered, excessive... read more (hemorrhage), which accounts for over one fourth of deaths
High blood pressure, including preeclampsia Preeclampsia and Eclampsia Preeclampsia is new high blood pressure or worsening of existing high blood pressure that is accompanied by excess protein in the urine and that develops after the 20th week of pregnancy. Eclampsia... read more (a type of high blood pressure that develops during pregnancy)
Abortion Abortion Induced abortion is the intentional ending of a pregnancy by surgery or drugs. A pregnancy may be ended by surgically removing the contents of the uterus or by taking certain drugs. Complications... read more or miscarriage Miscarriage A miscarriage is the loss of a fetus due to natural causes before 20 weeks of pregnancy. Miscarriages may occur because of a problem in the fetus (such as a genetic disorder or birth defect)... read more
An abnormally located pregnancy (ectopic pregnancy Ectopic Pregnancy Ectopic pregnancy is attachment (implantation) of a fertilized egg in an abnormal location. In an ectopic pregnancy, the fetus cannot survive. When an ectopic pregnancy ruptures, women often... read more )—that is, one not in its usual location in the uterus
Disorders that women had before they became pregnant (such as obesity and infectious diseases, including HIV infection)
Problems that contribute to deaths in pregnant women include
When a pregnant woman has a problem, she and her family members delay seeking medical care.
The woman does not have transportation to a health care facility.
Care at a health care facility is delayed.
About 3 of 5 of maternal deaths could be prevented.
Perinatal mortality
Perinatal mortality refers to the death of fetuses and newborns that occur around the time of delivery. In the United States, the perinatal mortality rate is 6 to 7 deaths per 1,000 deliveries.
The most common causes of death in fetuses and newborns are
Disorders in the mother, such as high blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more
, diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , obesity Obesity Obesity is excess body weight. Obesity is influenced by a combination of factors, which usually results in consuming more calories than the body needs. These factors may include physical inactivity... read more 
, or an autoimmune disorder Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers autoimmune disorders is not known. Symptoms vary depending... read more Infections
Abnormalities in the placenta—one that detaches too soon (placental abruption Placental Abruption Placental abruption is the premature detachment of a normally positioned placenta from the wall of the uterus, usually after 20 weeks of pregnancy. Women may have vaginal bleeding and/or severe... read more ) or is mislocated (placenta previa Placenta Previa Placenta previa is attachment (implantation) of the placenta over the opening of the cervix, in the lower rather than the upper part of the uterus. Women may have painless, sometimes profuse... read more
)Genetic abnormalities in the fetus
Risk Assessment During Pregnancy
Certain conditions or characteristics, called risk factors Risk Factors for High-Risk Pregnancy Some risk factors are present before women become pregnant. These risk factors include Certain physical characteristics, such as age, and social characteristics of women Problems in a previous... read more 
, make a pregnancy high risk. As part of routine care during pregnancy Medical Care During Pregnancy Ideally, a couple who is thinking of having a baby should see a doctor or other health care practitioner to discuss whether pregnancy is advisable. Usually, pregnancy is very safe. However,... read more , doctors check for these factors to determine the degree of risk for a particular woman and baby and thus to provide better medical care. Genetic evaluation Genetic Screening Genetic screening is used to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder. Hereditary genetic disorders are disorders of chromosomes or... read more is particularly important. It involves assessing the couple’s family history and, if needed, analyzing blood or tissue samples (such as cells from the inside of the cheek). This evaluation is done to determine whether a couple is at increased risk of having a baby with a hereditary genetic disorder.
Factors that can affect risk in women include
Problems that develop during labor and delivery Introduction to Complications of Labor and Delivery Usually, labor and delivery occur without any problems. Serious problems are relatively rare, and most can be anticipated and treated effectively. However, problems sometimes develop suddenly... read more
Disorders that were present before pregnancy Disorders Present Before Pregnancy Some risk factors are present before women become pregnant. These risk factors include Certain physical characteristics, such as age, and social characteristics of women Problems in a previous... read more
, such as chronic high blood pressure High Blood Pressure During Pregnancy High blood pressure (hypertension) during pregnancy is classified as one of the following: Chronic hypertension: Blood pressure was high before the pregnancy. Gestational hypertension: Blood... read more (hypertension), diabetes Diabetes During Pregnancy For women who have diabetes before they become pregnant, the risks of complications during pregnancy depend on how long diabetes has been present and whether complications of diabetes, such... read more , sexually transmitted infections Infections During Pregnancy , or kidney infections Urinary Tract Infections During Pregnancy Urinary tract infections are common during pregnancy, probably because the enlarging uterus and hormones produced during pregnancy slow the flow of urine in the tubes that connect the kidneys... read more Disorders that develop during pregnancy Disorders During Pregnancy Some risk factors are present before women become pregnant. These risk factors include Certain physical characteristics, such as age, and social characteristics of women Problems in a previous... read more
, such as gestational diabetes Gestational diabetes For women who have diabetes before they become pregnant, the risks of complications during pregnancy depend on how long diabetes has been present and whether complications of diabetes, such... read more or preeclampsia Preeclampsia and Eclampsia Preeclampsia is new high blood pressure or worsening of existing high blood pressure that is accompanied by excess protein in the urine and that develops after the 20th week of pregnancy. Eclampsia... read more
High-risk pregnancies must be closely monitored, and sometimes women are referred to a center that specializes in managing these pregnancies.
The most common reasons for referral before delivery are
Preterm labor Preterm Labor Labor that occurs before 37 weeks of pregnancy is considered preterm. Babies born prematurely can have serious health problems. The diagnosis of preterm labor is usually obvious. Measures such... read more (often due to premature rupture of the membranes Prelabor Rupture of the Membranes (PROM) Prelabor rupture of the membranes is the leaking of amniotic fluid from around the fetus at any time before labor starts. After the membranes rupture, labor often soon follows. If labor does... read more )
Disorders that were present before or that develop during the pregnancy, such as diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , high blood pressure High Blood Pressure High blood pressure (hypertension) is persistently high pressure in the arteries. Often no cause for high blood pressure can be identified, but sometimes it occurs as a result of an underlying... read more
, and severe (morbid) obesity Obesity Obesity is excess body weight. Obesity is influenced by a combination of factors, which usually results in consuming more calories than the body needs. These factors may include physical inactivity... read more
