Is 37 Weeks Gestational Age Considered Full Term?
No, 37 weeks is not considered full term—it is classified as "early term" and carries significantly higher neonatal morbidity compared to deliveries at 39-40 weeks. 1
Current Gestational Age Classification
The American College of Obstetricians and Gynecologists (ACOG) replaced the outdated single designation of "term" with more precise categories to reflect varying neonatal outcomes 1:
- Early term: 37 0/7 to 38 6/7 weeks 1
- Full term: 39 0/7 to 40 6/7 weeks 1
- Late term: 41 0/7 to 41 6/7 weeks 1
- Post-term: ≥42 0/7 weeks 1
This reclassification was necessary because research demonstrated that neonatal outcomes, particularly respiratory morbidity, vary substantially within the previously broad 37-42 week "term" range 1, 2.
Why 37 Weeks Is Not Full Term: The Evidence
Neonatal morbidity is significantly elevated at 37 weeks compared to 39 weeks across all delivery precursors. 3 Key findings include:
- NICU admission rates: Early term neonates (37-38 weeks) have 1.64 times higher odds of NICU admission compared to full term infants (39-41 weeks) 4
- Respiratory complications: Early term births show 1.93 times higher odds of requiring respiratory support 4
- Hypoglycemia: 4.9% in early term versus 2.5% in full term infants (adjusted OR 1.92) 4
- Need for mechanical ventilation: 4.57 times higher odds at 37-38 weeks versus 39-41 weeks 4
The greatest difference in morbidity occurs between 37 and 39 weeks, regardless of whether delivery is by cesarean section or vaginal route 3.
Clinical Implications for Delivery Timing
For uncomplicated pregnancies, delivery should occur at 39-40 weeks, and elective delivery before 39 weeks is not recommended. 5 Delivering at 38 weeks versus 39-40 weeks in healthy pregnancies increases risks of respiratory distress syndrome, NICU admission, and other neonatal complications without maternal benefit 5.
Exceptions: Medical Indications for Delivery at 37 Weeks
Delivery at 37 weeks is appropriate only for specific high-risk conditions 6:
- Preeclampsia at ≥37 weeks: Women with preeclampsia should be delivered once they reach 37 weeks' gestation 6
- Severe fetal growth restriction: Estimated fetal weight <3rd percentile warrants delivery at 37 weeks regardless of Doppler findings 5
- Fetal growth restriction with abnormal Doppler: Decreased diastolic flow on umbilical artery Doppler indicates delivery at 37 weeks 5, 7
Common Pitfalls to Avoid
- Do not use the outdated term "term pregnancy" for 37 weeks: This terminology obscures the increased neonatal risks and may lead to inappropriate early elective deliveries 1, 2
- Avoid elective procedures at 37-38 weeks: The designation "early term" should prompt careful consideration before any non-medically indicated intervention 1
- Ensure accurate dating: First-trimester ultrasound before 21 weeks is critical to avoid iatrogenic early-term delivery based on inaccurate gestational age assessment 8, 5
The bottom line: 37 weeks represents early term pregnancy with measurably worse neonatal outcomes than full term (39-40 weeks), and this distinction has important implications for timing elective deliveries and counseling patients about delivery expectations.