A stillbirth is the death of a baby after 28 weeks of pregnancy, occurring either before or during birth. In the United States, about 21,000 babies are stillborn each year, affecting roughly 1 in 175 births. While the term is sometimes used more broadly, the World Health Organization defines stillbirth specifically as fetal death in the third trimester, distinguishing it from earlier pregnancy losses classified as miscarriage.
What Causes Stillbirth
Stillbirth rarely has a single, simple explanation. Research from the National Institute of Child Health and Human Development divides the causes into several overlapping categories: obstetrical complications (29%), placental abnormalities (24%), fetal malformations (14%), infections (13%), umbilical cord abnormalities (10%), hypertensive disorders like preeclampsia (9%), and other medical complications (8%). In about 24% of cases, no definitive cause is found even after thorough evaluation.
Placental problems are among the most common identifiable causes. The placenta is the organ that delivers oxygen and nutrients from the mother to the baby, and when it doesn’t function properly, the consequences can be fatal. Blood vessel problems in the placenta, blood clots behind it, inflammation, and infection of the placental membranes are all significantly linked to stillbirth. In many cases, these placental issues develop silently, without obvious symptoms beforehand.
Preeclampsia, a dangerous rise in blood pressure during pregnancy, roughly quadruples the odds of stillbirth. Bleeding before delivery and premature rupture of the membranes also carry elevated risk. Chromosomal abnormalities in the baby, such as Down syndrome or other genetic conditions, account for a portion of cases as well, though they aren’t always tested for.
Risk Factors That Increase the Chances
Certain characteristics of the pregnant person or the pregnancy itself are associated with higher stillbirth risk. These don’t cause stillbirth directly, but they increase the probability:
- Maternal age 35 or older
- Pre-existing diabetes or high blood pressure
- Having overweight or obesity
- Tobacco, marijuana, or alcohol use during pregnancy
- Exposure to secondhand smoke
- Black or African American race/ethnicity
- Previous stillbirth, miscarriage, or pregnancy loss
- Pregnancy with twins, triplets, or more
- Never having given birth before
- Use of assisted reproductive technology
- Major stressful life events in the year before pregnancy
- Environmental exposures, including air pollution and extreme heat
For the baby, being smaller than expected for the stage of pregnancy is a known risk factor. This often results from growth restriction, where something about the pregnancy prevents the baby from developing at a normal pace. Low socioeconomic status is also consistently associated with higher rates of stillbirth, likely reflecting disparities in access to prenatal care, nutrition, and environmental exposures.
Warning Signs to Be Aware Of
The most widely recognized warning sign is a noticeable decrease in fetal movement. If you’ve been feeling your baby move regularly and that movement slows down or stops, that change is worth taking seriously. Many providers encourage “kick counts,” where you track how often you feel the baby move during a set period each day, typically starting in the third trimester.
It’s worth noting that a decrease in movement doesn’t always indicate a problem, and ultrasound assessment after reduced movement doesn’t reliably identify which babies are at risk. One study found that ultrasound abnormalities were no more common in women reporting decreased fetal movement than in controls. Still, reduced movement remains the primary signal available to pregnant people, and reporting it promptly gives providers the opportunity to evaluate fetal heart rate and other indicators of well-being.
How Stillbirth Is Managed
Once fetal death is confirmed, typically through ultrasound, the next step is delivery. Most people deliver vaginally through induced labor rather than surgery. Induction usually involves medications that help the cervix soften and contractions begin. The WHO recommends a specific combination of medications for this purpose, and research supports starting the process relatively soon after diagnosis rather than waiting, since a longer gap between learning of the loss and beginning labor tends to increase anxiety.
In some cases, expectant management (waiting for labor to begin on its own) is an option. For people who have had a previous cesarean delivery, providers may use different induction methods to reduce the risk of complications with the surgical scar. The physical recovery after delivery is similar to recovery from any vaginal birth, though the emotional experience is, of course, profoundly different.
Tests to Determine the Cause
After a stillbirth, a series of evaluations can help identify what went wrong. The American College of Obstetricians and Gynecologists recommends a standard workup that includes a fetal autopsy, examination of the placenta under a microscope, and chromosomal testing of the baby. Maternal blood tests typically screen for infections like syphilis and parvovirus, check thyroid function, look for blood clotting disorders, and test for conditions where the mother’s immune system may have affected the pregnancy.
A test for fetal-maternal hemorrhage checks whether the baby’s blood crossed into the mother’s bloodstream, which can sometimes be a cause of death. Toxicology screening may also be performed. Together, these evaluations identify a probable cause in roughly three out of four cases, though sometimes the answer remains uncertain even after thorough testing.
Agreeing to an autopsy can be a difficult decision during an already devastating time, but it provides the most detailed information and can be important for understanding whether the same problem could affect a future pregnancy.
The Emotional Toll on Parents
The psychological impact of stillbirth is severe and lasting. Parents who experience stillbirth have a substantially higher risk of depression, anxiety, and post-traumatic stress disorder compared to parents with live births. In one study, mothers were nearly seven times more likely to have high depression scores two months after stillbirth. While the risk decreased over time, it remained elevated at eight months. Fathers are affected too: one study found they were about six times more likely to score high for depression at both two and eight months after the loss.
PTSD is particularly common. One study found that 60% of mothers who experienced stillbirth met diagnostic criteria for PTSD. Another found that mothers had more than four times the risk of receiving a PTSD diagnosis in the year following stillbirth compared to mothers with live births. Perhaps most striking is how long the effects can persist: a study assessing women 5 to 18 years after stillbirth found that one-third still reported PTSD symptoms above clinical thresholds.
These numbers highlight that grief after stillbirth isn’t something that simply resolves in weeks or months. It is a major psychological event that affects both parents, and the intensity of the response is normal given the magnitude of the loss. Support from mental health professionals experienced in pregnancy loss, peer support groups, and bereavement programs offered by many hospitals can all play a role in recovery.
Monitoring in High-Risk Pregnancies
For pregnancies complicated by conditions like diabetes, high blood pressure, or fetal growth restriction, providers use several surveillance tools to monitor the baby’s well-being in the third trimester. These include fetal heart rate monitoring (non-stress tests), ultrasound evaluation of amniotic fluid levels and fetal movement, and Doppler measurements of blood flow through the umbilical cord. These techniques have been in clinical use for nearly four decades and help guide decisions about whether early delivery is safer than continuing the pregnancy.
In some high-risk situations, providers recommend delivering before the due date to reduce the chance of stillbirth in the final weeks. The specific timing depends on the condition involved and its severity. This is one of the clearest ways that prenatal care directly reduces stillbirth risk, by identifying pregnancies where intervention can make a difference and acting before a crisis occurs.