Obstetric management in vacuum-extraction deliveries

Fundal pressure to shorten the second stage of labor: Systematic review and meta-analysis

OBJECTIVES

Systematically review the evidence on fundal pressure to expedite vaginal delivery.

STUDY DESIGN

Literature search in electronic databases. Randomized controlled trials of fundal pressure to expedite delivery were included in this systematic review and meta-analysis. The primary outcome was the length of the second stage.

RESULTS

We identified 10 randomized controlled trials. Fundal pressure was associated with a shorter length of the second stage of labor (mean difference (MD) -20.33 min, 95% confidence intervals (CI) -28.55, -12.11). Sub-group analysis with only manual pressure or a belt confirmed the association. There was no significant difference in the rate of vaginal delivery (relative risk (RR) 1.00, 95%, CI 0.98, 1.02), one and five minute Apgar scores (MD 0.10, 95%, confidence intervals -0.05, 0.24; and MD 0.02, 95%, CI -0.12, 0.15), neonatal trauma (RR 0.33, 95%, CI 0.01, 7.90), vaginal/perineal laceration (RR 0.83, 95%, CI 0.57, 1.22), cervical laceration (RR 1.30, 95%, CI 0.21, 8.02), episiotomy (RR 1.08, 95%, CI 0.96, 1.21), cesarean section rate (RR 0.72; 95%, CI 0.34, 1.51), operative vaginal deliveries (RR 0.79; 95%, CI 0.55, 1.13) and neonatal intensive care admissions (RR 0.33, 95%, CI 0.01, 7.90). However, patients receiving fundal pressure had a lower umbilical cord arterial pH (MD -0.03, 95%, CI -0.04, -0.01), and a 3.5 non-significantly higher incidence of Apgar scores < 7 at 5 min (4.9% vs 0.7%, RR 3.48, 95%, CI 0.57, 21.32).

CONCLUSIONS

Fundal pressure in the second stage is associated with a 20-minute decrease in the length of labor and a small decrease in neonatal umbilical artery pH.

Prospective assessment of vacuum deliveries from midpelvic station in a tertiary care university hospital: Frequency, failure rates, labor characteristics and maternal and neonatal complications

BACKGROUND

Midpelvic vacuum extractions are controversial due to reports of increased risk of maternal and perinatal morbidity and high failure rates. Prospective studies of attempted midpelvic vacuum outcomes are scarce. Our main aims were to assess frequency, failure rates, labor characteristics, maternal and neonatal complications of attempted midpelvic vacuum deliveries, and to compare labor characteristics and complications between successful and failed midpelvic vacuum deliveries.

STUDY DESIGN

Clinical data were obtained prospectively from all attempted vacuum deliveries (n = 891) over a one-year period with a total of 6903 births (overall cesarean section rate 18.2% (n = 1258). Student's t-test, Mann-Whitney U-test or Chi-square test for group differences were used as appropriate. Odds ratios and 95% confidence intervals are given as indicated. The uni- and multivariable analysis were conducted both as a complete case analysis and with a multiple imputation approach. A p-value of <0.05 was considered statistically significant.

RESULTS

Attempted vacuum extractions from midpelvic station constituted 36.7% (n = 319) of all attempted vacuum extractions (12.9% (n = 891) of all births). Of these 319 midpelvic vacuum extractions, 11.3% (n = 36) failed and final delivery mode was cesarean section in 86.1% (n = 31) and forceps in the remaining 13.9% (n = 5). Successful completion of midpelvic vacuum by 3 pulls or fewer was achieved in 67.1%. There were 3.9% third-degree and no fourth-degree perineal tears. Cup detachments were associated with a significantly increased failure rate (adjusted OR 6.13, 95% CI 2.41-15.56, p< 0.001).

CONCLUSION

In our study, attempted midpelvic vacuum deliveries had relatively low failure rate, the majority was successfully completed within three pulls and they proved safe to perform as reflected by a low rate of third-degree perineal tears. We provide data for nuanced counseling of women on vacuum extraction as a second stage delivery option in comparable obstetric management settings with relatively high vacuum delivery rates and low cesarean section rates.

The prevalence of uterine fundal pressure during the second stage of labour for women giving birth in health facilities: a systematic review and meta-analysis

BACKGROUND

Uterine fundal pressure involves a birth attendant pushing on the woman's uterine fundus to assist vaginal birth. It is used in some clinical settings, though guidelines recommend against it. This systematic review aimed to determine the prevalence of uterine fundal pressure during the second stage of labour for women giving birth vaginally at health facilities.

METHODS

The population of interest were women who experienced labour in a health facility and in whom vaginal birth was anticipated. The primary outcome was the use of fundal pressure during second stage of labour. MEDLINE, EMBASE, CINAHL and Global Index Medicus databases were searched for eligible studies published from 1 January 2000 onwards. Meta-analysis was conducted to determine a pooled prevalence, with subgroup analyses to explore heterogeneity.

RESULTS

Eighty data sets from 76 studies (n = 898,544 women) were included, reporting data from 22 countries. The prevalence of fundal pressure ranged from 0.6% to 69.2% between studies, with a pooled prevalence of 23.2% (95% CI 19.4-27.0, I2 = 99.97%). There were significant differences in prevalence between country income level (p < 0.001, prevalence highest in lower-middle income countries) and method of measuring use of fundal pressure (p = 0.001, prevalence highest in studies that measured fundal pressure based on women's self-report).

CONCLUSIONS

The use of uterine fundal pressure on women during vaginal birth in health facilities is widespread. Efforts to prevent this potentially unnecessary and harmful practice are needed.

Impact of clinical practice guidelines for vacuum-assisted delivery on maternal and neonatal outcomes in Japan: A single-center observational study

AIM

Practice guidelines for vacuum-assisted delivery in Japan were revised in 2014 to improve clinical safety. We aimed to determine the success rates of vacuum delivery before and after the release of the revised guidelines.

METHODS

This retrospective observational study included singleton deliveries at term gestation. Success rate of vacuum delivery, duration of extraction, number of tractions and maternal and neonatal injuries were compared between 2011-2014 and 2015-2019.

RESULTS

Vacuum extraction was attempted in 249 (15%) of 1657 deliveries. Duration of extraction was shorter in 2015-2019 (median, 3.0 min; interquartile range [IQR], 1.0-5.8 min) than in 2011-2014 (median, 4.0 min; IQR, 2.0-6.5 min; P = 0.0045). No significant differences were seen in success of vacuum extraction (98%), prolonged (>20 min) duration of extraction (1.5%) and repeated (>5 pulls) tractions (3.1%) in vacuum deliveries during 2011-2014, compared to success of vacuum extraction (94%), prolonged duration of extraction (1.6%) and repeated tractions (1.1%) in those during 2015-2019. Likewise, no significant differences were identified in maternal or neonatal injuries.

CONCLUSION

Successful vacuum-assisted deliveries and shortened duration of extraction were still confirmed after guideline revision. However, because of consistent safe practice with vacuum delivery from before the revision, improvements in maternal and neonatal injuries were not observed.

Fundal pressure during the second stage of labour

BACKGROUND

Fundal pressure during the second stage of labour (also known as the 'Kristeller manoeuvre') involves application of manual pressure to the uppermost part of the uterus directed towards the birth canal, in an attempt to assist spontaneous vaginal birth and avoid prolonged second stage or the need for operative birth. Fundal pressure has also been applied using an inflatable belt. Fundal pressure is widely used, however methods of its use vary widely. Despite strongly held opinions in favour of and against the use of fundal pressure, there is limited evidence regarding its maternal and neonatal benefits and harms. There is a need for objective evaluation of the effectiveness and safety of fundal pressure in the second stage of labour.

OBJECTIVES

To determine if fundal pressure is effective in achieving spontaneous vaginal birth, and preventing prolonged second stage or the need for operative birth, and to explore maternal and neonatal adverse effects related to fundal pressure.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (30 November 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of fundal pressure (manual or by inflatable belt) versus no fundal pressure in women in the second stage of labour with singleton cephalic presentation.

DATA COLLECTION AND ANALYSIS

Two or more review authors independently assessed potential studies for inclusion and quality. We extracted data using a pre-designed form. We entered data into Review Manager 5 software and checked for accuracy.

MAIN RESULTS

Nine trials are included in this updated review. Five trials (3057 women) compared manual fundal pressure versus no fundal pressure. Four trials (891 women) compared fundal pressure by means of an inflatable belt versus no fundal pressure. It was not possible to blind women and staff to this intervention. We assessed two trials as being at high risk of attrition bias and another at high risk of reporting bias. All other trials were low or unclear for other risk of bias domains. Most of the trials had design limitations. Heterogeneity was high for the majority of outcomes. Manual fundal pressure versus no fundal pressureManual fundal pressure was not associated with changes in: spontaneous vaginal birth within a specified time (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.71 to 1.28; 120 women; 1 trial; very low-quality evidence), instrumental births (RR 3.28, 95% CI 0.14 to 79.65; 197 women; 1 trial), caesarean births (RR 1.10, 95% CI 0.07 to 17.27; 197 women; 1 trial), operative birth (average RR 0.66, 95% CI 0.12 to 3.55; 317 women; 2 studies; I² = 43%; Tau² = 0.71; very low-quality evidence), duration of second stage (mean difference (MD) -0.80 minutes, 95% CI -3.66 to 2.06 minutes; 194 women; 1 study; very low-quality evidence), low arterial cord pH in newborn babies (RR 1.07, 95% CI 0.72 to 1.58; 297 women; 2 trials; very low-quality evidence), or Apgar scores less than seven at five minutes (average RR 4.48, 95% CI 0.28 to 71.45; 2759 infants; 4 trials; I² = 89%; Tau² = 3.55; very low-quality evidence). More women who received manual fundal pressure had cervical tears than in the control group (RR 4.90, 95% CI 1.09 to 21.98; 295 women; 1 trial). No neonatal deaths occurred in either of the two studies reporting this outcome (very low-quality evidence). No trial reported the outcome severe maternal morbidity or death. Fundal pressure by inflatable belt versus no fundal pressureFundal pressure by inflatable belt did not reduce the number of women havinginstrumental births (average RR 0.73, 95% CI 0.52 to 1.02; 891 women; 4 trials; I² = 52%; Tau² = 0.05) or operative births (average RR 0.62, 95% CI 0.38 to 1.01; 891 women; 4 trials; I² = 78%; Tau² = 0.14; very low-quality evidence). Heterogeneity was high for both outcomes. Duration of second stage was reported in two trials, which both showed that inflatable belts shortened duration of labour in nulliparous women (average MD -50.80 minutes, 95% CI -94.85 to -6.74 minutes; 253 women; 2 trials; I² = 97%; Tau² = 975.94; very low-quality evidence). No data on this outcome were available for multiparous women. The inflatable belt did not make any difference to rates of caesarean births (average RR 0.56, 95% CI 0.14 to 2.26; 891 women; 4 trials; I² = 70%; Tau² = 0.98), low arterial cord pH in newborn babies (RR 0.47, 95% CI 0.09 to 2.55; 461 infants; 1 trial; low-quality evidence), or Apgar scores less than seven at five minutes (RR 4.62, 95% CI 0.22 to 95.68; 500 infants; 1 trial; very low-quality evidence). Third degree perineal tears were increased in the inflatable belt group (RR 15.69, 95% CI 2.10 to 117.02; 500 women; 1 trial). Spontaneous vaginal birth within a specified time, neonatal death, andsevere maternal morbidity or death were not reported in any trial.

AUTHORS' CONCLUSIONS

There is insufficient evidence to draw conclusions on the beneficial or harmful effects of fundal pressure, either manually or by inflatable belt. Fundal pressure by an inflatable belt during the second stage of labour may shorten duration of second stage for nulliparous women, and lower rates of operative birth. However, existing studies are small and their generalizability is uncertain. There is insufficient evidence regarding safety for the baby. There is no evidence on the use of fundal pressure in specific clinical settings such as inability of the mother to bear down due to exhaustion or unconsciousness. There is currently insufficient evidence for the routine use of fundal pressure by any method on women in the second stage of labour. Because of current widespread use of the procedure and the potential for use in settings where other methods of assisted birth are not available, further good quality trials are needed. Further evaluation in other groups of women (such as multiparous women) will also be required. Future research should describe in detail how fundal pressure was applied and consider safety of the unborn baby, perineal outcomes, longer-term maternal and infant outcomes and maternal satisfaction.