What is the average gestational age at delivery for quadruplets and what are the associated mortality risks?

Average Gestational Age at Delivery and Mortality Risks for Quadruplet Pregnancies

The average gestational age at delivery for quadruplet pregnancies is approximately 31-32 weeks, with mortality risks including a neonatal mortality rate of approximately 18% and stillbirth rate of 13%, primarily due to complications of extreme prematurity.

Gestational Age at Delivery for Quadruplets

Quadruplet pregnancies typically deliver significantly earlier than singleton or twin pregnancies due to multiple factors:

• The mean gestational age at delivery for quadruplets ranges from 31.4 to 32.5 weeks according to available research 1, 2
• A more recent study examining quadruplet pregnancies over an 11-year period reported a mean gestational age at delivery of 32.2 weeks 3
• This early delivery is primarily due to:
  • High rates of preterm labor (97% of quadruplet pregnancies) 3
  • Pregnancy-induced hypertension (occurring in up to 32% of cases) 2, 3
  • Fetal growth restriction after 34 weeks 2

Mortality Risks in Quadruplet Pregnancies

Mortality risks in quadruplet pregnancies are significantly higher than in singleton pregnancies:

• Stillbirth rate: Approximately 13% (57 stillbirths among 438 fetuses in higher-order multiples) 3
• Neonatal mortality rate: Approximately 18% (77 neonatal deaths among 438 fetuses) 3
  • Early neonatal deaths (first week): 7%
  • Late neonatal deaths: 10%
• Corrected perinatal mortality rate: 67 per 1000 births 2

Factors Affecting Mortality Risk

Several factors influence the mortality risk in quadruplet pregnancies:

• Gestational age at delivery: The most critical factor, with significantly higher mortality rates at earlier gestational ages
• Birth weight: Extreme low birth weight is the primary cause of neonatal death 3
• Respiratory distress syndrome: More common in quadruplets than triplets 3
• Mode of delivery: Cesarean section is performed in approximately 89% of quadruplet deliveries 2

Management Considerations

Management of quadruplet pregnancies requires intensive monitoring and interventions:

• Early diagnosis (typically by 9-10 weeks' gestation) 2
• Institution of bed rest by approximately 16-17 weeks 2
• Tocolytic therapy is commonly used (83% of cases) beginning around 24-25 weeks 2
• Antenatal corticosteroids for fetal lung maturity
• Close monitoring for maternal complications:
  • Preeclampsia (25-32%)
  • Anemia (25-33%)
  • Gestational diabetes (27%)
  • Postpartum hemorrhage (10%) 3

Delivery Timing Considerations

Due to the high-risk nature of quadruplet pregnancies:

• Delivery should be considered at 34 weeks in most cases due to evidence of growth restriction after this point 2
• Earlier delivery may be indicated for maternal complications (particularly preeclampsia) or evidence of fetal compromise
• Cesarean delivery is the most common mode of delivery for quadruplets due to the difficulty of ensuring adequate fetal surveillance during labor 4

Recent Trends

There has been improvement in outcomes for higher-order multiple pregnancies over time:

• Neonatal mortality has decreased from 17.3% to 5.9% in more recent years, likely due to improved neonatal care 5
• Specialized perinatal care has demonstrated the potential for improved outcomes, with some centers reporting no perinatal deaths and minimal long-term morbidity 1

In summary, quadruplet pregnancies represent high-risk gestations with significant risks of preterm delivery and associated mortality. Specialized multidisciplinary care and close monitoring are essential to optimize outcomes.