high-risk pregnancy

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High-Risk Pregnancy



A high risk pregnancy is one in which some condition puts the mother, the developing fetus, or both at higher-than-normal risk for complications during or after the pregnancy and birth.


A pregnancy can be considered a high-risk pregnancy for a variety of reasons. Factors can be divided into maternal and fetal. Maternal factors include age (younger than age 15, older than age 35); weight (pre-pregnancy weight under 100 lb or obesity); height (under five feet); history of complications during previous pregnancies (including stillbirth, fetal loss, preterm labor and/or delivery, small-for-gestational age baby, large baby, pre-eclampsia or eclampsia); more than five previous pregnancies; bleeding during the third trimester; abnormalities of the reproductive tract; uterine fibroids; hypertension; Rh incompatability; gestational diabetes; infections of the vagina and/or cervix; kidney infection; fever; acute surgical emergency (appendicitis, gallbladder disease, bowel obstruction); post-term pregnancy; pre-existing chronic illness (such as asthma, autoimmune disease, cancer, sickle cell anemia, tuberculosis, herpes, AIDS, heart disease, kidney disease, Crohn's disease, ulcerative colitis, diabetes). Fetal factors include exposure to infection (especially herpes simplex, viral hepatitis, mumps, rubella, varicella, syphilis, toxoplasmosis, and infections caused by coxsackievirus); exposure to damaging medications (especially phenytoin, folic acid antagonists, lithium, streptomycin, tetracycline, thalidomide, and warfarin); exposure to addictive substances (cigarette smoking, alcohol intake, and illicit or abused drugs). A pregnancy is also considered high-risk when prenatal tests indicate that the baby has a serious health problem (for example, a heart defect). In such cases, the mother will need special tests, and possibly medication, to carry the baby safely through to delivery. Furthermore, certain maternal or fetal problems may prompt a physician to deliver a baby early, or to choose a surgical delivery (cesarean section) rather than a vaginal delivery.
Most women will see one healthcare provider during pregnancy, either an obstetrician, a midwife, or a nurse practitioner. Women who have a medical problem may need to see a medical specialist as well. Women diagnosed with a high-risk pregnancy may also need the expert advice and care of a perinatologist. A perinatologist is a medical doctor (obstetrician) who specializes in the care of women who are at high risk for having problems during pregnancy. Perinatologists care for women who have preexisting medical problems as well as women who develop complications during pregnancy.


A woman with a high-risk pregnancy will need closer monitoring than the average pregnant woman. Such monitoring may include more frequent visits with the primary caregiver, tests to monitor the medical problem, blood tests to check the levels of medication, amniocentesis, serial ultrasound examination, and fetal monitoring. These tests are designed to track the original condition, survey for complications, verify that the fetus is growing adequately, and make decisions regarding whether labor may need to be induced to allow for early delivery of the fetus.


Treatment varies widely with the type of disease, the effect that pregnancy has on the disease, and the effect that the disease has on pregnancy. Additional tests may help determine the need for changes in medication or additional treatment.


The prognosis depends in large part on the specific medical condition. Some medical conditions make it difficult to get pregnant and lead to a higher risk of problems in the baby. An example of this type of condition is thyroid disease. In thyroid disease, the thyroid gland (located in the neck) may produce too much or too little thyroid hormone. Abnormal levels of thyroid hormone can cause problems in pregnancy and affect the health of the baby. Fortunately, thyroid disease can be treated with medication. As long as the level of thyroid hormone is controlled throughout pregnancy, there should be no problems for mother or baby.
There are many medical conditions that usually do not interfere with pregnancy, but are themselves affected by pregnancy. This group includes asthma, epilepsy, and ulcerative colitis. For example, some women with ulcerative colitis experience a worsening of their symptoms during pregnancy, while others will have no change or may get better during pregnancy. The same is true of asthma; some women notice that their asthma symptoms are better during pregnancy, some find their asthma worse, and some women notice no change in symptoms during pregnancy. No one understands why this is so, but due to this unpredictability, all women with chronic illnesses should be monitored carefully throughout pregnancy.
There is also a group of medical conditions that can have a major impact on pregnancy. Women with lupus (disease caused by alterations in the immune system that result in inflammation of connective tissue and organs) or kidney disease face real risks during pregnancy. Pregnancy can cause their symptoms to worsen significantly and can lead to serious illness. Because these diseases can affect the mother's ability to supply oxygen and nutrients to the baby through the placenta, they can cause problems for the baby as well. These babies may not be able to grow and gain weight properly (intrauterine growth retardation). There is also an increased risk of stillbirth.
Diabetes is a medical condition that is both affected by pregnancy and affects pregnancy. Diabetes can lead to miscarriages, birth defects, and stillbirths. When a woman monitors her blood sugar carefully and treats high levels with insulin, the risk of these negative outcomes drops a great deal. Unfortunately, pregnancy makes diabetes much harder to control. In general, blood sugar and the need for insulin to control it rise throughout pregnancy.
Most medical conditions do not lead to complications in pregnancy. With frequent visits to healthcare providers, and careful attention to medication, women with medical problems usually enjoy healthy, successful pregnancies. There are a few medical conditions that can cause health risks to both mother and baby during pregnancy. Women with these medical problems should consider these risks before deciding to become pregnant. Many of these women will benefit from the care of a perinatologist during pregnancy. Only rarely (in the case of severe heart disease, for example) are the risks to the mother so high that she should not consider pregnancy at all.


A pre-pregnancy visit with a healthcare provider is especially important for a woman who has a medical problem. The doctor will discuss how women with this condition usually fare during pregnancy. For some diseases (such as lupus), pregnancy can mean increased risk of health problems for mother and baby.
Sometimes, the medication a woman needs to control a medical condition can cause problems for the baby. There may be another medication available that is safer for use in pregnancy. In some cases there is no other medication, and a woman must weigh the risks to the baby when deciding whether or not to become pregnant.
A woman who has not had a pre-pregnancy visit should contact a healthcare provider as soon as she learns she is pregnant. Often, the provider will schedule the first prenatal visit within a day or two, instead of waiting until eight to 10 weeks of pregnancy. This is because certain medical conditions can increase the risk of miscarriage. The provider will want to be sure that any medication is adjusted properly to increase the chance of having a successful pregnancy.



Beers, Mark H., et al., editors. "High-Risk Pregnancies." In The Merck Manual of Diagnosis and Therapy. Rahway, NJ: Merck Research Laboratories, 2004.

Key terms

Gestational diabetes — Diabetes of pregnancy leading to increased levels of blood sugar. Unlike diabetes mellitus, gestational diabetes is caused by pregnancy and goes away when pregnancy ends. Like diabetes mellitus, gestational diabetes is treated with a special diet and insulin, if necessary.
Preeclampsia — A disease that only affects pregnant women. The most common signs and symptoms are increased blood pressure, swelling in the hands and feet, and abnormal results on special blood and urine tests.
Premature labor — Labor beginning before 36 weeks of pregnancy.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.

high-risk pregnancy

Obstetrics A pregnancy which is at risk for ↑ M&M due to fetal, maternal or placental defect. See High risk infant.
High-risk pregnancy  
Fetal high-risk factors APGAR score of <4 at 1 min, birth weights of < 2500 g or
> 4500 g, gestational age < 37 or > 42 weeks, fetal malformation, fetal-maternal blood group incompatibility and twinning
Maternal high-risk factors Previous in utero or neonatal death, infection, true DM–gestational diabetes is less risky to the infant, premature rupture of membranes, maternal age < 16 and > 40, alcohol, drug or tobacco use, gestation beginning within 6 months of previous delivery, poor prenatal care, severe emotional stress, accidents or general anesthesia, use of teratogenic medication
Placental and intrauterine high-risk factors Placenta previa, short umbilical cord, single umbilical artery, abruptio placentae, oligohydramnios  
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

high-risk pregnancy

A pregnancy in which maternal factors such as diabetes mellitus, hypertension, kidney disease, viral infections, vaginal bleeding, multiple pregnancies, substance abuse, age under 17 or over 35, or toxic exposures are present. Pregnancy in association with these conditions is more likely to compromise the health of the mother or developing fetus than are normal pregnancies.
See also: pregnancy
Medical Dictionary, © 2009 Farlex and Partners