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 conditions benefit from treatment at a specialized center that provides care by doctors who specialize in high-risk pregnancies.
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 weight Problems in a previous pregnancy, including the... 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. For some couples, genetic evaluation Genetic Screening Before Pregnancy 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 advisable. 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 weight Problems in a previous pregnancy, including the... 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 weight Problems in a previous pregnancy, including the... 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 women are often 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. Symptoms of diabetes may... 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 a chronic, recurring complex disorder characterized by excess body weight. Obesity is influenced by a combination of factors that includes genetics, hormones, behavior, and the environment... read more 
