BACKGROUND
During the second stage of labor, in case of a need for a fetal extraction at midcavity,
the choice of attempting the procedure between operative vaginal delivery and cesarean
delivery is difficult. Moreover, guidelines on this subject are not clear.
OBJECTIVE
This study aimed to identify antenatal and intrapartum parameters associated with
a failed midcavity vacuum-assisted delivery and its association with maternal and
neonatal adverse outcomes.
STUDY DESIGN
This was a single-center, retrospective, cohort study conducted at a tertiary maternity
hospital in France from January 2010 to December 2020. Women with singleton pregnancies
under epidural analgesia with nonanomalous cephalic presenting fetuses and gestational
ages at ≥37 weeks of gestation, who were submitted to midcavity vacuum-assisted delivery,
were included. Following the American College of Obstetricians and Gynecologists definition,
midcavity was defined as the presenting part of the fetus (ie, the fetal head) found
at stations 0 and +1. For research purposes, all patients were submitted to transperineal
ultrasound to evaluate the head-to-perineum distance, however, this measurement did
not affect the decision to perform a midcavity vacuum-assisted delivery. The primary
outcome of the study was failed midcavity vacuum-assisted delivery leading to cesarean
delivery or the use of a different instrument to achieve vaginal delivery.
RESULTS
Overall, 951 cases of midcavity vacuum-assisted delivery were included in this study.
Failed midcavity vacuum-assisted delivery occurred in 242 patients (25.4%). Factors
independently associated with failed midcavity vacuum-assisted delivery included maternal
height (adjusted odds ratio, 0.96; 95% confidence interval, 0.94–0.99; P=.002), duration of the active phase of the first stage of labor (adjusted odds ratio,
1.11; 95% confidence interval, 1.05–1.17; P<.001), nonocciput anterior fetal head position (adjusted odds ratio, 1.47; 95% confidence
interval, 1.06–2.04; P=.02), z score of the head-to-perineum distance (adjusted odds ratio, 1.23; 95% confidence
interval, 1.05–1.43; P=.01), and birthweight of >4000 g (adjusted odds ratio, 2.04; 95% confidence interval,
1.28–3.26; P=.003). Women submitted to a failed midcavity vacuum-assisted delivery were more likely
to have a major postpartum hemorrhage (7.1% vs 2.0%; P<.001), whereas neonates were more likely to have an umbilical artery pH of <7.1 (30.5%
vs 19.8%; P=.001), be admitted to the neonatal intensive care unit (9.6% vs 4.7%; P=.005), and have a severe caput succedaneum (14.9% vs 0.7%; P<.001). Subgroup analysis on all patients with a fetal head station of 0 found that
the head-to-perineum distance was the only independent variable associated with failed
midcavity vacuum-assisted delivery (adjusted odds ratio, 1.66; 95% confidence interval,
1.29–2.12; P<.001). The area under the receiving operating characteristic curve of the head-to-perineum
distance in this subgroup population was 0.67 (95% confidence interval, 0.60–0.73;
P<.001), and the optimal cutoff point of the head-to-perineum distance measurement
discriminating between failed and successful midcavity vacuum-assisted deliveries
was 55 mm. It was associated with a 0.90 (95% confidence interval, 0.83–0.95) sensitivity,
0.19 (95% confidence interval, 0.14–0.25) specificity, 0.36 (95% confidence interval,
0.30–0.42) positive predictive value, and 0.80 (95% confidence interval, 0.66–0.90)
negative predictive value.
CONCLUSION
Study data showed that a high fetal head station, measured using the head-to-perineum
distance, and a nonocciput anterior position of the fetal head are independently associated
with failed midcavity vacuum-assisted delivery. The result supported the systematic
assessment of the sonographic head station and position before performing a midcavity
vacuum-assisted delivery.
Keywords
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References
- Comparison of maternal and infant outcomes from primary cesarean delivery during the second compared with first stage of labor.Obstet Gynecol. 2007; 109: 917-921
- Comparison of maternal outcomes from primary cesarean section during the second compared with first stage of labor by indication for the operation.Eur J Obstet Gynecol Reprod Biol. 2014; 182: 43-47
- Operative vaginal birth: ACOG Practice Bulletin, Number 219.Obstet Gynecol. 2020; 135: e149-e159
- Royal College of Obstetricians and Gynaecologists. Assisted vaginal birth: Green-top Guideline No. 26.BJOG. 2020; 127: e70-e112
- Instrumental delivery: clinical practice guidelines from the French College of Gynaecologists and Obstetricians.Eur J Obstet Gynecol Reprod Biol. 2011; 159: 43-48
- Perinatal and maternal morbidity and mortality after attempted operative vaginal delivery at midpelvic station.CMAJ. 2017; 189: E764-E772
- Maternal and neonatal morbidity after attempted operative vaginal delivery according to fetal head station.Obstet Gynecol. 2015; 126: 521-529
- Perinatal and maternal morbidity and mortality among term singletons following midcavity operative vaginal delivery versus caesarean delivery.BJOG. 2018; 125: 693-702
- Early maternal and neonatal morbidity associated with operative delivery in second stage of labour: a cohort study.Lancet. 2001; 358: 1203-1207
- The effect of sequential use of vacuum and forceps for assisted vaginal delivery on neonatal and maternal outcomes.Am J Obstet Gynecol. 2001; 185: 896-902
- A cohort study of maternal and neonatal morbidity in relation to use of sequential instruments at operative vaginal delivery.Eur J Obstet Gynecol Reprod Biol. 2011; 156: 41-45
- Operative vaginal delivery.Williams obstetrics. 25th ed. McGraw-Hill Education, New York, NY2018
- Predictors for failure of vacuum-assisted vaginal delivery: a case-control study.Eur J Obstet Gynecol Reprod Biol. 2016; 200: 29-34
- Predictors of failed operative vaginal delivery in a contemporary obstetric cohort.Obstet Gynecol. 2016; 127: 501-506
- Risk factors and morbidity associated with suboptimal instrument placement at instrumental delivery: observational study nested within the instrumental delivery & ultrasound randomised controlled trial ISRCTN 72230496.BJOG. 2015; 122: 558-563
- Predictors of failed operative vaginal delivery: a single-center experience.Am J Obstet Gynecol. 2007; 197 (308.e1–5)
- Forceps and vacuum delivery: a survey of North American residency programs.Obstet Gynecol. 1996; 88: 622-625
- Operative vaginal delivery: a survey of fellows of ACOG.Obstet Gynecol. 1996; 88: 1007-1010
- Birth simulator: reliability of transvaginal assessment of fetal head station as defined by the American College of Obstetricians and Gynecologists classification.Am J Obstet Gynecol. 2005; 192: 868-874
- Sonographic prediction of outcome of vacuum deliveries: a multicenter, prospective cohort study.Am J Obstet Gynecol. 2017; 217 (69.e1–10)
- Angle of fetal head progression measured using transperineal ultrasound as a predictive factor of vacuum extraction failure.Ultrasound Obstet Gynecol. 2016; 48: 86-91
- Predicting the difficulty of operative vaginal delivery by ultrasound measurement of fetal head station.Am J Obstet Gynecol. 2017; 216 (507.e1–9)
- [Ultrasound in the diagnosis of fetal head engagement. A preliminary French prospective study].J Gynecol Obstet Biol Reprod (Paris). 2009; 38: 474-480
- Strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies.BMJ. 2007; 335: 806-808
- Interobserver agreement in intrapartum estimation of fetal head station.Int J Gynaecol Obstet. 2008; 101: 285-289
- Transabdominal and transperineal ultrasound vs routine care before instrumental vaginal delivery - a randomized controlled trial.Acta Obstet Gynecol Scand. 2021; 100: 1075-1081
- Intrapartum ultrasound before instrumental vaginal delivery: clinical benefits are difficult to demonstrate.Acta Obstet Gynecol Scand. 2021; 100: 988-989
- [The diagnosis of fetal head engagement: transperineal ultrasound, a new useful tool?].Gynecol Obstet Fertil. 2012; 40: 148-152
- Prediction of labor and delivery by transperineal ultrasound in pregnancies with prelabor rupture of membranes at term.Ultrasound Obstet Gynecol. 2006; 27: 387-391
- Comparison between ultrasound parameters and clinical examination to assess fetal head station in labor.Ultrasound Obstet Gynecol. 2013; 41: 425-429
- Instruments for assisted vaginal birth.Cochrane Database Syst Rev. 2021; 9CD005455
- ISUOG practice guidelines: intrapartum ultrasound.Ultrasound Obstet Gynecol. 2018; 52: 128-139
- [Instrumental delivery with perineum-fetal head distance >55 MM on ultrasound].Gynecol Obstet Fertil. 2016; 44: 82-87
- [Correlation between the perineal-to-skull measurement by tranperineal ultrasound, failure of vaginal operative delivery and maternal-fetal morbidity].J Gynecol Obstet Biol Reprod (Paris). 2013; 42: 541-549
Article info
Publication history
Published online: November 30, 2022
Accepted:
November 28,
2022
Received:
November 17,
2022
Footnotes
The authors report no conflict of interest.
No specific funding was received for this study.
The results of this study were presented as oral communications at the following 2 conferences: the International Society of Ultrasound in Obstetrics and Gynecology World Congress 2022 on Ultrasound in Obstetrics and Gynecology, September 16–18, 2022, London, United Kingdom, and the 27th European Board and College of Obstetrics and Gynaecology, European Congress of Obstetrics and Gyneacology, September 2–4, 2021, Athens, Greece.
Cite this article as: Head-to-perineum distance measured transperineally as a predictor of failed midcavity vacuum-assisted delivery. Am J Obstet Gynecol MFM 2022;XX:x.ex–x.ex.
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