What is High-risk Pregnancy?

A high-risk pregnancy is one in which a woman and her fetus face a higher-than-normal chance of experiencing problems.

These risks may be due to factors in the pregnancy itself, or they may stem from preexisting maternal medical conditions, such as cancer, diabetes, or lupus. Events that occur during a pregnancy may also lead to high-risk status.

Maternal risk factors include:

• Pre-existing diabetes: Pregnancy can be difficult for women who have pre-existing diabetes. (This is different from gestational diabetes, which develops during pregnancy and typically ends with childbirth.)

• Organ transplant: "We (Yale Medicine) take care of a lot of patients who have received organ transplants, mostly kidney, but some liver transplants," Dr. Campbell says. "They can have worsening renal function in pregnancy and are a higher risk for preeclampsia (a complication caused by high blood pressure), hypertension and fetal growth restriction (when the fetus grows more slowly than normal)."

• Chronic high blood pressure: If a woman has severe, chronic high blood pressure, there is a higher risk of heart failure, bleeding in the brain, and kidney failure. Preeclampsia is another risk because it may also slow fetal growth, and cause premature birth or pregnancy loss.

• Blood clots: Thrombophilia, or a tendency to develop blood clots, may increase risks in pregnancy.

• Rheumatalogic diseases: Conditions such as lupus can increase a mother's risk of preeclampsia. Additionally, if the lupus is not controlled going into pregnancy, pregnancy can exacerbate a lupus flare up. 

• Heart disease (congenital or acquired)

• Infectious diseases (HIV, viral hepatitis, pyelonephritis (a potentially serious kidney infection)

• Cancer in pregnancy

• Psychiatric disease

Fetal risk factors include: 

• Birth defects, such as congenital heart defects 

• Chromosome problems, such as Down syndrome

• Genetic syndromes, such as Fragile X syndrome

• Inherited diseases, such as cystic fibrosis

• Fetal growth restriction: The fetus grows more slowly than normal. This may be due to high blood pressure, kidney disease, advanced diabetes, heart or respiratory disease, anemia, infection, substance abuse or smoking. Often, a cause for the fetal growth restriction is not found. Fetal growth restriction is sometimes referred to as intrauterine growth restriction.

• Fetal anemia, or an inadequate number or quality of red blood cells to carry oxygen to the cells and organs within the body. "Treating fetal anemia is highly specialized and is something we offer at Yale," Dr. Campbell says. "We also do in-utero blood transfusions."

Pregnancy-related risk factors include: 

• A history of multiple miscarriages or pregnancy losses: After two miscarriages, a woman's risk of losing a fetus rises to 20 percent. After three miscarriages, it rises to 30 percent, and after four, it rises to 40 percent. But even if a woman had four miscarriages, you still have a 60 percent chance of carrying a baby to term. 

• Stillbirth

• Preeclampsia and HELLP syndrome: HELLP is related to preeclampsia, a pregnancy complication caused by high blood pressure. It may cause low platelet levels, the breakdown of red blood cells and liver damage.

• Placental abruption: This is when the placental lining separates from the uterus of the mother prior to delivery. It is the most common pathological cause of late pregnancy bleeding.

• Abnormal placentation: Also known as placenta accreta, this occurs when blood vessels and other parts of the placenta grow too deeply into the uterine wall. 

• Preterm premature rupture of membranes: This occurs when the amniotic sac ruptures prior to 37 weeks of gestation and prior to the onset of labor.

• Too much or too little amniotic fluid. When levels of amniotic fluid are abnormal it can be associated with complications for the mother and problems for the baby.

• Infections: These include cytomegalovirus, or CMV, a common herpes virus; Zika; chorioamnionitis (in infection of the membranes that contain the amniotic fluid); Listeria; toxoplasmosis (a disease caused by a parasitic infection)

• Multi-fetal gestation (twins, triplets)

• Twin-to-twin transfusion syndrome: This occurs when identical twins share a placenta, which makes the blood flow uneven between babies. 
  

This is only a partial list of conditions and circumstances that may result in a pregnancy being labeled “high-risk.” If a mother is over the age of 35, the pregnancy may also be considered high-risk.

"As women get older, it increases the risk of having a baby with Down syndrome and older women are more prone to hypertension, diabetes and heart disease," Dr. Campbell says. "We use the age 35 as a marker, but the real issue is women over 40 or 45."

However, Dr. Campbell cautions that women should not panic if they qualify as "high risk." "I think we do a disservice to women by labeling them," she says. "We want to educate them. Pregnancy is already anxiety-provoking enough. My role is to make sure she understands what the risks are and what the treatments are and what we can do to achieve a healthy baby and a healthy mother."

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content is for informational and educational purposes and does not constitute medical advice

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https://www.yalemedicine.org/conditions/high-risk-pregnancy#:~:text=What%20is%20high%2Drisk%20pregnancy,cancer%2C%20diabetes%2C%20or%20lupus.