Prediction of delivery mode by ultrasound-assessed fetal position in nulliparous women with prolonged first stage of labor T. M. Eggebø, W. A. Hassan, K. Å. Salvesen, E. A. Torkildsen, T. B. Østborg and C. C. Lees Volume 46, Issue 5, pages 606–610 View the free-access article: http://onlinelibrary.wiley.com/doi/10.1002/uog.14773/full Influence of ultrasound determination of fetal head position on mode of delivery: a pragmatic randomized trial T. Popowski, R. Porcher, J. Fort, S. Javoise and P. Rozenberg Volume 46, Issue 5, 520–525 View the free-access article: http://onlinelibrary.wiley.com/doi/10.1002/uog.14785/full

1. UOG Journal Club:
November 2015
Prediction of delivery mode by ultrasound-assessed fetal position in
nulliparous women with prolonged first stage of labor
T.M. Eggebø, W.A. Hassan, K. Å. Salvesen, E.A. Torkildsen, T.B.
Østborg, and C.C. Lees
Journal Club slides prepared by
Dr. Katherine Goetzinger
(UOG Editor for Trainees)
Influence of ultrasound determination of fetal head position on mode
of delivery: a pragmatic randomized trial
T. Popowski, R. Porcher, J. Fort, S. Javoise and P. Rozenberg

2. UOG Journal Club: November 2015
Prediction of delivery mode by ultrasound-assessed fetal position in
nulliparous women with prolonged first stage of labor
T.M. Eggebø, W.A. Hassan, K. Å. Salvesen, E.A. Torkildsen, T.B.
Østborg, and C.C. Lees

3. Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015
• The frequency of occiput posterior (OP) fetal head position at the time
of delivery is 5–7% and has been associated with an increased risk of
Cesarean section
• Ultrasound assessment has been shown to be superior to digital
examination as a method to determine fetal head position in labor
• In current practice, ultrasound assessment of fetal head position is
thought to be useful prior to attempting operative vaginal delivery;
however, its utility in the first stage of labor remains uncertain

4. To investigate whether transabdominal ultrasound
assessment of fetal head position is associated with rate
of Cesarean section in nulliparous women with a
prolonged active first stage of labor
Objective
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

5. Eligibility Criteria
• Women with a live singleton fetus in cephalic presentation at or after
37 weeks ’ gestation according to a second-trimester scan
• Prolonged active first stage of labor diagnosed by pre-defined standards
Data Collection
• Fetal head position was assessed by both digital vaginal examination by
birth attendant and ultrasound examination by research team
• Birth attendants and research team members were blinded to each
others’ assessments
Methodology
Prospective Observational Study
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

6. Primary Outcome
• Mode of delivery: Vaginal vs Cesarean section
Secondary Outcomes
• Operative vaginal delivery
• Remaining time in labor
Statistical Analysis
• Predictive values
• Multivariate logistic regression analysis
• Kaplan–Meier survival analysis
• Cohen’s kappa
Methodology
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

7. Results: OP position to predict Cesarean section
Test Characteristics
Sensitivity: 54%
False-positive rate: 29%
Positive predictive value: 38%
Negative predictive value: 83%
Positive likelihood ratio: 1.9
Negative likelihood ratio: 0.65
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015
• Fetal head position was assessed successfully in 142/150 women
• 19/50 (38%) pregnancies with a fetus in the OP position were delivered
by Cesarean section vs 16/92 (17%) in the non-OP position
• OR 2.9 (95% CI, 1.3–6.7); P = 0.01

8. Results: Kaplan–Meier Survival Analysis
Time from ultrasound exam
to delivery was not
significantly longer for
women with a fetus in OP
position
P = 0.37
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

9. Results: Mode of delivery in Relation to Ultrasound-
Assessed Fetal Head Position
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015
Mode of delivery
Fetal Head Position P
OA OT OP
Spontaneous Vaginal
51% 19% 31% 0.28
Operative Vaginal
46% 27% 27% 0.30
Cesarean section 26% 20% 54% 0.02

10. Conclusions
• OP fetal head position assessed by transabdominal ultrasound is
significantly associated with delivery by Cesarean section in nulliparous
women with a prolonged first stage of labor
• Ultrasound-assessed fetal head position is not associated with operative
vaginal delivery or with remaining time in labor
• The agreement between a digital vs ultrasound assessment of OP head
position remains poor
• Information gained by ultrasound assessment of fetal head position in
women with a prolonged first stage of labor could be clinically helpful in
planning delivery interventions
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

11. • Prospective multicenter study
design
• Birth attendants blinded to
ultrasound assessment of fetal
head position
• Focus on subgroup of
nulliparous patients with
prolonged first stage of labor
• Both association and predictive
characteristics evaluated
Strengths
• Relatively small sample size
• Two different definitions of
prolonged first stage of labor
• Fetal head position just prior to
delivery unknown
• No information available on
cervical dilation and fetal
station at time of evaluation
• Multiple indications for
Cesarean delivery
Limitations
Prediction of Delivery Mode by Ultrasound-Assessed Fetal Position in
Nulliparous Women with Prolonged First Stage of Labor
Eggebø et al., UOG 2015

12. UOG Journal Club: November 2015
Influence of ultrasound determination of fetal head position
on mode of delivery: a pragmatic randomized trial
T. Popwski, R. Porcher, J. Fort, S. Javoise and P. Rozenberg

13. Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015
• Occiput posterior (OP) and occiput transverse (OT) fetal head positions in
labor are associated with an increased risk of maternal and neonatal
complications
• When OP and OT positions are identified correctly, manual rotation of the
fetal head can be performed in an attempt to prevent complications owing
to these unfavorable fetal head positions
• Digital vaginal examination to assess fetal head position in labor is
inaccurate in up to 50% of cases
• No study has examined the potential benefits of routine ultrasound exam
for improving the management of labor and delivery

14. To evaluate the influence of ultrasound determination of
fetal head position on mode of delivery
Objective
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015

15. Design:
• Randomized controlled trial
• 1:1 allocation
• Digital vaginal exam group (VE)
• Digital vaginal exam + ultrasound verification exam group (VE+US)
Inclusion Criteria
• Singleton gestation in vertex presentation at ≥ 37 weeks’ gestation
• Cervical dilation ≥ 8 cm
• Epidural anesthesia
Exclusion Criteria
• Previous Cesarean delivery, pre-eclampsia, placenta previa or other
obstetric disorder, participation in another trial, refusal to sign consent
Methodology
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015

16. Outcomes
• Primary Outcome
• Operative delivery including Cesarean delivery and instrumental
vaginal delivery
• Secondary Outcomes
• Delivery criteria, maternal morbidity and neonatal morbidity
Statsitical Analysis
• Fisher’s exact tests to compare binary outcomes between the two groups
• Kappa statistic to evaluate observed agreement on fetal head position
between the two groups
Methodology
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015

17. Results
Outcome
VE
(n=959)
VE+US
(n=944)
RR
(95% CI)
P
Operative Delivery
27.1% 33.7% 1.24
(1.08–1.43)
0.002
Cesarean Delivery
4.9% 7.8% 1.60
(1.12–2.28)
0.01
Instrumental
Vaginal Delivery
22.2% 25.8%
1.16
(0.99–1.37)
0.07
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015
There was a statistically significant increased risk for
overall operative delivery and Cesarean delivery in the
VE+US group

18. Results
• The risk of episiotomy was significantly higher in the VE+US
group (35.4% vs 30.9%; P = 0.04)
• There was no difference in any other maternal or neonatal
outcomes between the two groups
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015
Overall agreement between VE and US exam was poor
Agreement: 65.4%
Kappa: 0.38 (95% CI, 0.33–0.44)

19. Conclusions
• Correction of digital vaginal determination of fetal occiput position
by ultrasound examination increased the rate of operative delivery
without decreasing maternal and neonatal morbidity
• Digital vaginal examination for determination of fetal head position
was inaccurate in 35% of cases
• Knowledge of occiput posterior position by ultrasound examination
did not increase attempts at manual rotation
• The routine use of ultrasound to assess fetal head position does
not alter labor management, but does increase the rate of operative
delivery
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015

20. • Randomized controlled trial
• Large sample size
• Quality assurance process to
establish proficiency in
ultrasound assessment
• Evaluation of clinically relevant
outcomes
• Systematic inclusion of all labor
patients, not limited to dystocia
cases
Strengths
• Clinicians not blinded to
ultrasound results
• Cannot confirm percentage of
patients with true OP fetal head
position in VE group
• Underpowered for neonatal
outcomes
• Low overall Cesarean section
rate
• Epidural anesthesia as
inclusion criteria
Limitations
Influence of ultrasound determination of fetal head position on mode of delivery:
a pragmatic randomized trial
Popowski et al., UOG 2015

21. Discussion Points
• What role should ultrasound play in the assessment of fetal head position in
labor?
• Is there a subgroup of patients that could benefit from ultrasound assessment
of fetal head position?
• What factors could affect the generalizabiltiy of the findings of both studies?
• Why do you think more accurate assessment of fetal head position with
ultrasound increased the rate of interventions in the study by Popowski et al.?
• How could the unblinding of fetal head position as determined by ultrasound
have biased the study results of Popowski et al.?
• What other clinical factors could be included to increase the predictive value of
ultrasound assessment of fetal head position in the study by Eggebø et al.?
• Will the findings from these studies alter your clinical practice in management
of labor?