BACKGROUND AND PURPOSE:

• Knights et al. (PloS Medicine, 2023) compared the impact of routine third trimester ultrasound or point-of-care ultrasound (POCUS) with standard antenatal care on the incidence of overall and proportion of all term breech presentations

METHODS:

• Retrospective multicenter cohort study
  • St. George’s University Hospital NHS Foundation Trust (SGH) and Norfolk and Norwich University Hospital NHS Foundation Trust (NNUH)
• Population
  • Pregnancies at above 2 hospital systems in the UK  
• Exposures
  • Routine third trimester scan cohort performed by sonographers in ultrasound unit (SGH) | Implemented in 2020
    • Group 1: Offered and accepted scan
    • Group 2: Routine care
  • POCUS cohort performed at antenatal visit by midwives (NNUH)
    • Group 1: Historical cohort of women who received routine care
    • Group 2: POCUS at 36 to 37 week visit
• Study design
  • Undiagnosed breech presentation was defined as
    • Women presenting in labor or with ruptured membranes at term subsequently discovered to have a breech presentation
    • Women attending for induction of labor at term found to have a breech presentation before induction
  • The association of undiagnosed breech presentation at birth with adverse perinatal outcomes was analyzed with Bayesian regression model
• Primary outcome
  • Proportion of all term breech presentations that were undiagnosed
• Secondary outcomes
  • Mode of birth
  • Gestational age at birth
  • Birth weight
  • Emergency cesarean section
  • Neonatal adverse outcomes
    • Apgar score <7 at 5 minutes | Unexpected neonatal unit (NNU) admission | Hypoxic ischemic encephalopathy (HIE) | Perinatal mortality (including stillbirths and early neonatal deaths)

RESULTS:

• Deliveries before routine third trimester screening: 21,896 | After: 11,926
  • The rate of breech presentation was consistent across all groups
• Implementation of routine third trimester ultrasound reduced the incidence of undiagnosed breech presentations (P<0.0001)
  • Before routine screening: 14.2% | After routine screening: 2.8%
• The rate of undiagnosed breech was 71% lower after the implementation of universal ultrasound
  • Risk ratio (RR) 0.29 (95% CrI, 0.20 to 0.38)
  • Posterior probability was greater than 99.9%
• Among the pregnancies with breech presentation, there was also a very high probability (>99.9%) of reduced rate of low Apgar score (<7) at 5 minutes with routine screening
  • RR 0.23 (95% CrI, 0.14 to 0.38)
• There was moderate to high probability (89.5% and 85.1%) of a reduction in
  • HIE: RR 0.32 (95% CrI, 0.05 to 1.77)
  • Extended perinatal mortality rates: RR 0.21 (95% CrI, 0.01 to 3.00)
• Implementation of routine third trimester ultrasound with POCUS also reduced the incidence of undiagnosed breech presentations (P<0.0001)
  • Before: 16.2% | After: 3.5%
• Using informative priors, the proportion of all term breech presentations that were undiagnosed was 69% lower after the initiation of universal POCUS
  • RR 0.31 (95% CrI, 0.21 to 0.45)
  • Posterior probability was greater than 99.9%
• There was also a very high probability (99.5%) of a reduced rate of low Apgar score (<7) at 5 minutes with routine screening
  • RR 0.60 (95% CrI, 0.39 to 0.88)

CONCLUSION:

• Implementing routine third trimester ultrasound screening in-facility or using POCUS reduced the incidence of undiagnosed breech presentation at term
• Neonatal outcomes also improved
• The authors state

Our data suggest that a policy of either third trimester ultrasound or POCUS by healthcare providers could be effective in reducing the proportion of all term breech presentations that were undiagnosed at birth with an associated improvement in neonatal outcomes

Learn More – Primary Sources:

Impact of point-of-care ultrasound and routine third trimester ultrasound on undiagnosed breech presentation and perinatal outcomes: An observational multicentre cohort study

Related ObG Topics:

Can Universal Ultrasound Screening for Breech Presentation Reduce Fetal Mortality and be Cost-Effective?

Universal Ultrasound Screening for Fetal Macrosomia: Is It Cost-Effective?

Routine Third Trimester Ultrasound for Detection of Small for Gestational Age Fetuses