UOG Journal Club: December 2018 Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) T. Ghi, A. Dall’Asta, B. Masturzo, B. Tassis, M. Martinelli, N. Volpe, F. Prefumo, G. Rizzo, G. Pilu, L. Cariello, L. Sabbioni, A. M. Morselli-Labate, T. Todros and T. Frusca Volume 52, Issue 6 Journal Club slides prepared by Dr Fiona Brownfoot (UOG Editor for Trainees)

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Introduction Instrumental vaginal delivery by vacuum extraction is a widely performed obstetric procedure. Although successful in most cases, a 4–6% failure rate has been reported following attempted vacuum delivery. Fetal head malposition, mainly represented by occiput transverse and occiput posterior positions, is among the main determinants of failed fetal extraction using vacuum, as a high level of expertise is required in order to apply the suction cup on the flexion point. Evaluation of the fetal head position using transabdominal ultrasound (TAS), either during labor or before instrumental delivery, has proven to be far more accurate than vaginal examination. 2

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Aim of the study To assess whether sonographic diagnosis of fetal head position before vacuum extraction can reduce the incidence of failed procedure and improve maternal and perinatal outcomes in women undergoing instrumental delivery by vacuum extraction. 3

Methods Study design Setting Participants Randomised controlled trial. Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Methods Study design Randomised controlled trial. Setting University of Parma, involving several Italian maternity units with over 2000 deliveries/year and a vacuum delivery rate ≥ 4%, from April 2014 to June 2017. Participants Included: nulliparous women >18 years with term (37+0 to 41+6 weeks of gestation) singleton pregnancy that required instrumental delivery. Excluded: maternal age < 18 or > 50 years, any contraindication to instrumental vaginal delivery by vacuum extraction, fetal head station > +3 cm, emergency delivery necessary due to intrapartum fetal distress or when sonographic evaluation of fetal head position had been performed before randomization.

Methods Randomization Groups Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Methods Randomization All potentially eligible women were counseled regarding the study purpose and were provided with information material on admission. Informed consent for randomization was obtained in the early second stage of labor before active pushing. Randomization was carried out after the decision to perform instrumental delivery was made by the attending physician. Groups Control group: fetal head position and station were determined by vaginal examination (VE) before vacuum cup positioning. Intervention group: fetal occiput position was assessed by VE followed by transabdominal ultrasound (TAS) before vacuum cup positioning. Fetal head position was classified into occiput anterior (OA), when the position was between 10 h and 2 h on a clock face, or non-OA position which included occiput posterior and transverse position.

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Methods Outcome Primary outcome was incidence of failed vacuum extraction and need to perform emergency cesarean delivery. Note: forceps are not performed in most units in Italy, therefore, if the vacuum failed, patients had Cesarean section. Secondary outcomes: number of cup detachments, time between cup application and delivery, need for episiotomy, perineal tears involving the anal sphincter (third- or fourth-degree tears), postpartum hemorrhage (fall in hemoglobin level ≥ 4.0 g/dL within 24h from birth), neonatal trauma (intracranial hemorrhage, cephalohematoma, retinal hemorrhage, facial nerve palsy, brachial plexus injury and fractures), 5-min Apgar score < 7, neonatal acidosis (umbilical artery pH < 7.00 or base excess < −12 mEq/L), admission to neonatal intensive care unit and shoulder dystocia (failure to deliver the fetal shoulder with gentle downward traction on the fetal head) requiring additional obstetric maneuvers to effect delivery.

Results Study selection and characteristics Groups Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Results Study selection and characteristics 222 women were enrolled over the study period. 1 patient was excluded after allocation as a decision for Cesarean section was made. Groups Control 132 (59.7%) to VE only Intervention 89 (40.3%) to VE and ultrasound *** The baseline characteristics table is now in the supp file which I don’t have access to.

Results Baseline characteristics Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Results Baseline characteristics

Results Primary Outcome: Incidence of failed vacuum extraction Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Results Primary Outcome: Incidence of failed vacuum extraction 2 emergency Cesarean sections in the control group (VE only) and 0 in the intervention group (VE + ultrasound); P = 0.24. Secondary Outcomes: Higher incidence of episiotomy in intervention group; 86.5% vs 71.2%; P = 0.009.

Discussion Findings Study limitations Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Discussion Findings The rate of emergency Cesarean section due to failed vacuum delivery was not significantly different between women who underwent only VE of the fetal head position compared with those that had both VE and TAS assessment before delivery. Incorrect diagnosis of fetal head position was increased in the control group. Rate of episiotomy was higher in the VE plus TAS group. Study limitations The sample size was not reached. Perhaps this resulted from a change in practice in Italy where ultrasound is frequently used to determine fetal position in labour. There was a low incidence of failed vacuum deliveries. Perhaps this reflects recruitment bias where practitioners only included patients with extractions considered to be easy. 10

Discussion Conclusion Implications for practice Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Discussion Implications for practice VE plus ultrasound assessment of fetal head position before instrumental delivery does not reduce Cesarean section rate. Combination of VE and TAS assessment is more accurate at diagnosing fetal position than VE alone. Conclusion VE plus ultrasound assessment compared to VE only prior to instrumental delivery does not reduce the instrumental failure rate and cesarean section.

Randomised Italian Sonography for occiput POSition Trial Ante vacuum (R.I.S.POS.T.A.) Ghi et al., UOG 2018 Discussion points Given the low rate of failed instrumental deliveries, perhaps there was recruitment bias and only those with easier deliveries were included. Perhaps ultrasound might be useful for participants with more difficult instrumental deliveries and this should be the focus of future studies. Ultrasound might be useful in cases in which the fetal head position is difficult to determine at vaginal examination rather than in every instrumental delivery. 12