From the Guidelines
Vacuum-assisted delivery should not be performed before 34 weeks of gestation due to the increased risk of complications in premature infants. The American Journal of Obstetrics and Gynecology recommends delivery at 37 weeks of gestation in pregnancies with fetal growth restriction and an umbilical artery Doppler waveform with decreased diastolic flow but without absent/reversed end-diastolic velocity or with severe fetal growth restriction with estimated fetal weight less than the third percentile 1. However, for premature infants, the risks associated with vacuum extraction, such as intracranial hemorrhage, are significant concerns.
Key Considerations
- Premature infants have fragile skulls with incomplete ossification, making them more susceptible to injury from vacuum extraction.
- The risks of complications, such as intraventricular hemorrhage, are already elevated in premature infants, and vacuum extraction could potentially exacerbate these risks.
- Alternative delivery methods, such as cesarean section or forceps (in specific situations), are preferred for pregnancies less than 34 weeks.
Recommendations
- Vacuum extraction should only be considered at or beyond 34 completed weeks of gestation.
- For pregnancies less than 34 weeks, alternative delivery methods should be preferred to minimize harm to premature infants.
- Institutions may have slightly different protocols, but the 34-week threshold represents the general consensus for safe vacuum-assisted delivery. The study by the Society for Maternal-Fetal Medicine consult series #52: diagnosis and management of fetal growth restriction 1 provides guidance on the management of fetal growth restriction, but it does not specifically address the use of vacuum extraction in premature infants. However, the recommendations for delivery at 33-34 weeks of gestation for pregnancies with fetal growth restriction and absent end-diastolic velocity 1 suggest that caution should be exercised when considering delivery methods for premature infants.
From the Research
Gestational Age for Premature Vacuum-Assisted Delivery
- The gestational age considered premature for vacuum-assisted delivery is less than 34 weeks, as indicated in the study 2.
- Another study 3 suggests that failed vacuum-assisted delivery is associated with an increased risk of preterm delivery at less than 37 weeks of gestation in the subsequent birth.
- However, the study 4 does not provide a specific gestational age for premature vacuum-assisted delivery, but rather identifies predictors for failed vacuum-assisted vaginal delivery.
- The study 5 includes women with singleton pregnancies beyond 34 weeks' gestation, implying that 34 weeks is the threshold for prematurity in this context.
- The study 6 investigates the association between ultrasonographic estimated fetal weight and adverse maternal and neonatal outcomes after vacuum-assisted delivery, but does not specifically address the gestational age for premature vacuum-assisted delivery.
Key Findings
- The study 2 found that cesarean delivery during the second stage of labor of gestations less than 34 weeks was associated with a higher rate of lower Apgar scores and longer length of stay.
- The study 3 found that a history of failed vacuum-assisted delivery is associated with a higher risk of preterm delivery at less than 37 weeks of gestation in the subsequent birth.
- The study 5 found that neonatal birth trauma and adverse outcomes following vacuum extraction are no more common in neonates weighing less than 2500g than those with higher birth weights, even in failed vacuum cases.