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High-Risk Pregnancy

  • When a woman and her fetus face a higher-than-normal chance of experiencing complications
  • Risk factors include pre-existing diabetes, organ transplant, chronic high blood pressure
  • Diagnosis includes using technology such as obstetrical ultrasound, fetal echocardiography
  • Involves high-risk pregnancy program

High-Risk Pregnancy


Whether planning for or anticipating the birth of your baby, every woman hopes for an uneventful pregnancy and easy delivery. For most, this is exactly what happens. However, women can face unexpected difficulties and complications.

Our experts in Maternal-Fetal Medicine can help. 

"At Yale Medicine, you'll have access to a multitude of medical and surgical specialists, whether it's working with a thoracic surgeon for a pregnant patient who had an aortic dissection to taking care of patients who have transplanted kidneys and livers," says Katherine Campbell, MD, MPH, a high-risk pregnancy specialist. "For the baby, we collaborate with geneticists, genetic counselors, pediatric cardiologists, neonatologists and pediatric urologists." 

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.

What factors can make a pregnancy high-risk?

Many factors, including those that affect the mother, the fetus and issues the arise during pregnancy, can make a pregnancy high-risk. 

Maternal risk factors include:

  • Pre-existing diabetesPregnancy 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.) We provide individualized glucose management plans, home glucose meter loans and one-on-one counseling and support through our diabetic nurse educators who are specifically trained and experienced in the management of diabetes. Patients can also work with our nutritionists and perinatologists.
  • Organ transplant: "We 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. The Yale Center for Hemostasis and Thrombosis works to advance our understanding of how thrombosis affects pregnancy and to develop better treatments for it. Our specialists consult regularly with patients to design a plan of care that is optimal and safe 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. Our Recurrent Pregnancy Loss Program works with couples who have lost multiple pregnancies. We evaluate each case to develop a plan. Because this issue can be emotional as well as physical, Yale Medicine offers and encourages counseling for couples who have suffered one or more miscarriages.
  • 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."

What makes Yale Medicine's approach to high-risk pregnancies unique?

Yale Medicine has a large, multidisciplinary team of specialists who are leaders in their fields. We come together when needed to help create care plans for high-risk patients in order to help them successfully navigate pregnancy. 

Yale New Haven Hospital also has an inpatient 18-bed Maternal Special Care Unit dedicated to women with high-risk pregnancies. Yale Medicine physicians developed many of the methods and procedures used today to safely navigate pregnancy. These include obstetrical ultrasound, fetal echocardiography, fetal heart rate monitoring, noninvasive fetal anemia assessment, percutaneous umbilical blood sampling (PUBS), in-utero fetal blood transfusion and invasive therapies such as fetoscopy and fetal surgery.

"We also staff our labor floor 24-7 with maternal-fetal specialists, which no one else does in the state," Dr. Campbell says. "So for any type of complicated pregnancy, there is no waiting until morning to be seen. Plus, we have expertise in complex Cesarian deliveries and other situations." 

In many cases, Yale Medicine physicians coordinate with the patient's primary ob-gyn. The goal is to have a familiar face on the patient's team and to receive some care close to home.

Yale Medicine's team also includes social workers, psychological and psychiatric services, nursing support, as well as community-wide programs to support the loss of pregnancy.

"We make a personal connection with mothers and families. Being a large academic center, Yale is often a family's ultimate stop. They've been to other places and now they are with us, and we help them," Dr. Campbell says. "A big part of our practice is women coming back for a second pregnancy and we talk about what she can do to optimize it, sometimes even pre-conception."