Stillbirth at 40 weeks can result from a few common underlying factors, often related to problems with the placenta, fetal conditions, maternal health, infections, or acute obstetric events. At term (around 40 weeks), the most frequently implicated issues are placental dysfunction and placental abruption, with other contributing factors increasing risk. Here’s a concise overview to help you understand the main causes and how they’re evaluated. What commonly causes stillbirth at term
- Placental problems
- Placental insufficiency or failure: the placenta fails to deliver adequate oxygen and nutrients to the fetus, which can lead to fetal growth restriction or intrauterine demise.
- Placental abruption: the placenta detaches from the uterine wall before or during labor, which can deprive the fetus of oxygen and cause bleeding or pain in the mother.
- Fetal or genetic conditions
- Chromosomal abnormalities or severe congenital anomalies that are incompatible with life.
- In some cases, undetected fetal infection or inflammation can contribute.
- Maternal health conditions
- Hypertension or preeclampsia: high blood pressure disorders are a well-known risk factor for stillbirth at term.
- Diabetes or poor metabolic control: both type 1 and type 2 diabetes increase stillbirth risk, especially with poor glucose management.
- Obesity and certain autoimmune or chronic conditions can also elevate risk.
- Infections
- Maternal infections, including certain bacterial or viral infections, can be associated with stillbirth, sometimes without obvious symptoms.
- Obstetric complications
- Problems with the umbilical cord (e.g., knots, prolapse, or compression) can lead to acute fetal distress.
- Other rare obstetric events that compromise fetal well-being.
How clinicians assess and manage risk at term
- Routine monitoring: at term, clinicians may use fetal heart rate monitoring, ultrasound assessments of fetal growth and amniotic fluid, and maternal tests to evaluate placental function and fetal well-being.
- Risk factor review: prior pregnancy outcomes, maternal blood pressure, diabetes status, BMI, smoking, and infection history inform risk.
- If concern arises: more intensive surveillance, consideration of delivery timing, and investigations after a stillbirth (placental pathology, maternal blood tests, fetal autopsy, and infection screening) help determine cause and guide future pregnancies.
Important notes
- A large proportion of stillbirths at term occur without a clearly identifiable cause, even after thorough evaluation.
- When a stillbirth occurs, a detailed review of the pregnancy and appropriate testing is typically performed to ascertain potential contributing factors and to inform care in future pregnancies.
If you’re seeking guidance for a specific situation (for example, your own pregnancy at 40 weeks, or concerns about risk factors like hypertension or diabetes), I can tailor information to that context and discuss what kinds of tests or monitoring are commonly recommended in current guidelines.
