What is the risk of stillbirth after 30 weeks gestation?

Risk of Stillbirth After 30 Weeks Gestation

The risk of stillbirth after 30 weeks gestation is relatively low but increases with advancing gestational age, with rates ranging from approximately 0.4% at 34 weeks to 0.8% at 30 weeks.

Stillbirth Rates by Gestational Age

The risk of stillbirth varies significantly by gestational age:

• 30-32 weeks: In-hospital mortality rates are approximately 5-8% 1, 2, 3
• 33-34 weeks: Mortality decreases significantly to approximately 0.4-0.5% 2
• After 34 weeks: Risk continues to be relatively low but begins to rise again after 39 weeks 4

Risk Factors That Increase Stillbirth Risk

Several conditions significantly increase the risk of stillbirth after 30 weeks:

• Fetal Growth Restriction (FGR): Particularly when estimated fetal weight is below the 3rd percentile or when abnormal umbilical artery Doppler studies are present 1
• Preeclampsia: Associated with a 1.5-2.2 fold increased risk of stillbirth 1
• Placental Abruption: Associated with an 82% increased risk of adverse outcomes including stillbirth 1
• Abnormal Fetal Movement: Significant reduction in fetal activity (14-fold increased risk) or sudden excessive fetal activity (4.3-fold increased risk) in the preceding two weeks 5

Monitoring and Prevention

For pregnancies beyond 30 weeks, appropriate monitoring can help reduce stillbirth risk:

• Regular fetal movement monitoring: Women should be educated about monitoring fetal movements and reporting abnormalities 5
• Ultrasound surveillance: For high-risk pregnancies, particularly those with FGR, regular assessment of fetal growth, amniotic fluid volume, and umbilical artery Doppler is recommended 1
• Timing of delivery:
  • For FGR with normal umbilical artery Doppler: Consider delivery at 38-39 weeks 1
  • For FGR with abnormal umbilical artery Doppler (but without absent end-diastolic flow): Consider delivery at 37 weeks 1
  • For FGR with absent end-diastolic flow: Consider delivery at 33-34 weeks 1
  • For FGR with reversed end-diastolic flow: Consider delivery at 30-32 weeks 1

Outcomes for Babies Born at 30-34 Weeks

While avoiding stillbirth is critical, it's important to understand the outcomes for babies born at these gestational ages:

• 30 weeks:

  • Survival rate: ~92% 2
  • Cerebral palsy risk: ~6.3% 2
  • Cognitive impairment risk: ~35.3% 2

• 34 weeks:

  • Survival rate: ~99.6% 2
  • Cerebral palsy risk: ~0.7% 2
  • Cognitive impairment risk: ~23.9% 2

Key Pitfalls in Stillbirth Prevention

• Failure to recognize reduced fetal movements: Women whose pregnancies ended in stillbirth were less likely to monitor fetal movements and less likely to be instructed to do so by healthcare providers 5
• Misinterpreting abnormal fetal activity: Excessive fetal activity described as "frantic" or "wild" may be a warning sign rather than reassurance 5
• Delaying delivery in high-risk situations: Particularly with severe FGR or abnormal Doppler studies, timely delivery decisions are critical 1
• Inadequate monitoring of high-risk pregnancies: Regular ultrasound surveillance is essential for detecting problems before stillbirth occurs 1

In summary, while stillbirth after 30 weeks is relatively uncommon in developed healthcare settings, the risk varies by gestational age and presence of complications. Appropriate monitoring and timely intervention can significantly reduce this risk, particularly in high-risk pregnancies.