Screening for breech presentation using universal late pregnancy ultrasonography: A prospective cohort study and cost-effectiveness analysis

David Wastlund, Alexandros Moraitis, Alison Dacey, Ulla Sovio, Edward Wilson, Gordon C.S Smith

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Despite the relative ease with which breech presentation can be identified through ultrasound screening, the assessment of fetal presentation at term is often based on clinical examination only. Due to limitations in this approach, many women present in labour with an undiagnosed breech presentation, with increased risk of fetal morbidity and mortality. This study sought to determine the cost-effectiveness of universal ultrasound scanning for breech presentation near term (36 weeks of gestational age [wkGA]) in nulliparous women.

Methods and findings
The Pregnancy Outcome Prediction (POP) study was a prospective cohort study between January 14, 2008 and July 31, 2012, including 3879 nulliparous women who attended for a research screening ultrasound examination at 36 wkGA. Fetal presentation was assessed and compared for the groups with and without a clinically indicated ultrasound. Where breech presentation was detected, an external cephalic version (ECV) was routinely offered. If the ECV was unsuccessful or not performed, the women were offered either planned caesarean section at 39 weeks or attempted vaginal breech delivery. To compare the likelihood of different mode of deliveries and associated long-term health outcomes for universal ultrasound to current practice, a probabilistic economic simulation model was constructed. Parameter values were obtained from the POP study, and costs were mainly obtained from the English NHS.

179 out of 3879 women (4.6%) were diagnosed with breech presentation at 36 weeks. For most women (96), there had been no prior suspicion of non-cephalic presentation. ECV was attempted for 84 (46.9%) women and was successful in 12 (success rate: 14.3%). Overall, 19 of the 179 women delivered vaginally (10.6%), 110 delivered by elective Caesarean section (61.5%) and 50 delivered by emergency caesarean section (27.9%). There were no women with undiagnosed breech presentation in labour in the entire cohort. On average, 40 scans were needed per detection of a previously undiagnosed breech presentation. The economic analysis indicated that, compared to current practice, universal late-pregnancy ultrasound would identify around 14,826 otherwise undiagnosed breech presentations across England annually. It would also reduce emergency caesarean section and vaginal breech deliveries by 0.7 and 1.0 percentage points, respectively; around 4,196 and 6,061 deliveries across England annually. Universal ultrasound would also prevent 7.89 neonatal mortalities annually. The strategy would be cost-effective if fetal presentation could be assessed for £19.80 or less per woman. Limitations to this study included that fetal presentation was revealed to all women, and that the health economic analysis may be altered by parity.

According to our estimates, universal late pregnancy ultrasound in nulliparous women: (1) would virtually eliminate undiagnosed breech presentation, (2) would be expected to reduce fetal mortality in breech presentation, and (3) would be cost-effective if fetal presentation could be assessed for less than £19.8 per woman.
Original languageEnglish
Article numbere1002778
JournalPLoS Medicine
Issue number4
Publication statusPublished - 16 Apr 2019

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