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Stillbirth Causes

Factors Linked to Late Pregnancy Loss


Updated June 06, 2014

Giving birth to a stillborn baby is every pregnant woman's worst nightmare. When it does happen, it's natural to want to understand why. Unfortunately, answers are rarely to be found -- more than 70% of stillbirths are never explained. Doctors theorize that the majority of stillbirths probably have something to do with the placenta not functioning correctly, and they have some other specific theories on what causes this devastating type of pregnancy loss.

Chromosomal or Congenital Conditions

Just as chromosomal abnormalities cause the majority of miscarriages, certain chromosomal and congenital conditions can increase the risk that a baby will be stillborn. According to the March of Dimes, birth defects are a factor in about 15 to 20% of stillbirths.

Chromosomal abnormalities are usually determined at conception, but congenital problems can be caused by environmental influences. For example, low levels of folic acid -- an important nutrient found in fortified grains and leafy green vegetables -- can increase risk of having a baby affected by neural tube defects such as anencephaly.

Intrauterine Growth Restriction (IUGR)

Intrauterine growth restriction is a condition in which the baby is significantly smaller than expected for the number of weeks of pregnancy. In severe cases, this condition can cause stillbirth or increased risk of newborn loss, perhaps due to the baby not getting enough oxygen or other important nutrients.

In standard prenatal care, doctors closely monitor a baby's growth in order to have the best chance to intervene if a baby seems at risk. Health conditions and lifestyle factors in the mother can also increase the risk of intrauterine growth restriction, and doctors screen for these problems in prenatal care, too. Some specific risk factors are preeclampsia, pregnancy-induced high blood pressure, or smoking in pregnancy.

Placental Abruption

Placental abruption is a condition in which the placenta suddenly separates from the wall of the uterus during pregnancy, while the baby is still in the womb. It can happen because of maternal health conditions, trauma to the abdomen in later pregnancy, or because of congenital uterine malformations. Certain lifestyle factors, such as smoking or substance abuse, can also increase risk. Symptoms include abdominal pain, contractions, and vaginal bleeding. Any woman worried about the condition should see a doctor immediately.


Getting certain bacterial and viral infections later in a pregnancy can increase the risk of stillbirth; infections are a factor in 10 to 25% of stillbirths.

Cord Accidents

The March of Dimes states that random cord accidents play a role in about 15% of stillbirths. Cord accidents during pregnancy, such as a tight knot in the cord or the cord becoming too tightly wrapped around the baby's neck, are rare.

Rare Stillbirth Causes

Abdominal trauma, such as from a car accident or falling down stairs in later pregnancy, can also potentially cause a stillbirth. Studies also show that pregnancies past 42 weeks gestation are at increased risk for stillbirth, perhaps due to the placenta losing its ability to support the baby. Doctors usually recommend inducing labor in these pregnancies for this reason.


American Pregnancy Association, "Placental Abruption : Abruptio Placentae." Nov 2006. Accessed 8 Jan 2008.

American Pregnancy Association, "Stillbirth: Trying to Understand." Apr 2006. Accessed 8 Jan 2008.

March of Dimes, "Stillbirth." Quick Reference and Fact Sheets. Nov 2005. Accessed 8 Jan 2008.

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