Soft cup vacuum extractor versus forceps delivery

Instruments for assisted vaginal birth

BACKGROUND

Assisted vaginal births are carried out to expedite birth for the benefit of mothers and babies but are sometimes associated with significant morbidity for both. Various instruments are available, broadly divided into forceps and vacuum cups, and choice may be influenced by clinical circumstances, operator preference, experience and availability.  OBJECTIVES: To evaluate the different instruments in terms of success in achieving a vaginal birth, and the risk of morbidity for mother and baby.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (14 May 2021), and reference lists of retrieved studies.

SELECTION CRITERIA

We selected randomised controlled trials of assisted vaginal birth using different instruments. The review did not include quasi-randomised trials, cluster-randomised trials or cross-over designs. The review included trials for which abstracts alone were available as long as there was sufficient information to assess eligibility.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. We used the GRADE approach to assess the certainty of evidence.  The main outcomes assessed included failed delivery with allocated instrument, any maternal trauma, third- and fourth-degree tears, postpartum haemorrhage, any neonatal trauma, low Apgar and low umbilical artery pH.  MAIN RESULTS: We included 31 studies involving a total of 5754 women.  Risk of bias criteria were largely assessed as 'unclear', due to a lack of detail in trial reports. Blinding would have been challenging for all trials due to their inability to conceal the type of instrument used from either the woman or the operator, which is reflected in the risk of bias assessment. Any type of forceps versus any type of vacuum cup (12 studies, 3129 women) Forceps may be less likely to fail in achieving vaginal birth: risk ratio (RR) 0.58, 95% confidence interval (CI) 0.39 to 0.88; 11 studies, 3080 women; low certainty. 'Any maternal trauma' may be slightly more likely with forceps: odds ratio (OR) 1.53, 95% CI 0.98 to 2.40; 5 studies, 1356 women; low certainty; and third- or fourth-degree tears may also be more likely with forceps: RR 1.83, 95% CI 1.32 to 2.55; 9 studies, 2493 women; low certainty. There is no evidence of a difference in the incidence of postpartum haemorrhage (PPH) between the two groups: RR 1.71, 95% CI 0.59 to 4.95; 2 studies, 523 women; low certainty, because the evidence is very imprecise due to a very wide CI.  More women in the forceps group reported requiring pain relief. There is probably no evidence of difference in rates of low Apgar: RR 0.83, 95% CI 0.46 to 1.51; 7 studies, 1644 women; moderate certainty; or low umbilical artery pH in the forceps group compared to any vacuum: RR 1.33, 95% CI 0.91 to 1.93; 2 studies, 789 women; low certainty; both of these outcomes are imprecise and have wide CIs that include both benefit and harm. There were also lower rates of fetal trauma with 'any forceps' (cephalhematoma, retinal haemorrhage and jaundice). The composite outcome of 'any neonatal trauma' was not reported. Low-cavity forceps versus any vacuum cup (2 studies, 218 women) We included two small studies with 218 participants in this comparison, but we judged most of the evidence as very low certainty, hence it was not feasible to make judgements on the difference in the rates of failed delivery, any maternal trauma or third- and fourth- degree tears. PPH and low umbilical artery pH were not reported. Soft vacuum cup versus any rigid cup (9 studies, 1148 women) Failed delivery may be more likely in the soft vacuum cup group: RR 1.62, 95% CI 1.21 to 2.17; 9 studies, 1148 women; low certainty. There may be no difference in the rates of 'any maternal trauma': OR 0.63, 95% CI 0.24 to 1.67; 2 studies, 348 women; low certainty, but the confidence interval is wide, indicating possible benefit or harm. There may be no difference in the rates of third- or fourth-degree tears: RR 0.93, 95% CI 0.35 to 2.44; 4 studies, 619 women; low certainty. There is probably no difference in the rates of PPH: RR 0.89, 95% CI 0.49 to 1.61; 5 studies, 737 women; moderate certainty between the soft and rigid cup groups.   There may be little or no difference in the incidence of low Apgar scores: RR 0.82, 95% CI 0.49 to 1.37; 9 studies, 1148; low certainty; or low umbilical artery pH: RR 0.80, 95% CI 0.47 to 1.36; 1 study, 100 women; low certainty. Handheld vacuum versus any vacuum cup (4 studies, 968 women) There may be no difference in the rates of failures with allocated instrument: RR 1.35, 95% CI 0.81 to 2.25; 4 studies, 962 women; low certainty, any maternal trauma: OR 1.16, 95% CI 0.71 to 1.88; 2 studies; 394 women; low certainty, PPH: RR 0.31, 95% CI 0.03 to 2.92; 1 study, 164 women; low certainty, low umbilical artery pH: RR 1.06, 95% CI 0.71 to 1.59; 1 study, 164 women; low certainty, or low Apgar scores: RR 1.25, 95% CI 0.34 to 4.61; 3 studies, 784 women; low certainty) between the two groups. There is probably no difference in the rates of third- or fourth-degree tears between the 'handheld vacuum' and 'any vacuum cup' groups: RR 1.15, 95% CI 0.62 to 2.12; 4 studies, 962 women; moderate certainty.

AUTHORS' CONCLUSIONS

This review provides low-certainty evidence that forceps may be more likely to achieve vaginal birth and have lower rates of fetal trauma, but at a greater risk of perineal trauma and higher pain relief requirements compared with vacuum cups. There was low-certainty evidence that rigid vacuum cups may be more likely to achieve a vaginal birth than soft cups but with more fetal trauma, whilst handheld vacuum cups had similar success rates compared to other cups. There was no evidence of a difference in the rates of third- or fourth-degree tears or postpartum haemorrhages between types of cups, but wide confidence intervals around the estimates indicate further research is needed in this area.

KIELLAND'S FORCEPS: PAST, PRESENT AND FUTURE

Kielland's forceps have been in obstetric practice for over 80 years but their use causes a wide spectrum of reactions in obstetricians. Those that have been well tutored in their use argue that they are a very effective instrument to achieve vaginal delivery in the malpositioned fetus, avoiding the problems of full cervical dilation caesarean section, with low complications in their hands. These exponents of the instrument argue that the “art” of obstetrics is demonstrated in the use of Kielland's forceps. However, others claim that Kielland's forceps are dangerous with high complication rates and that they should be confined to the obstetric museum. This paper reviews the history of the instrument and its inventor, to consider evidence for its effectiveness and its safety, to briefly consider other methods for delivery of the malpositioned fetus at full cervical dilation and finally to complete the journey by considering the future with particular emphasis on training the new generation of obstetricians.

WITHDRAWN: Vacuum extraction versus forceps for assisted vaginal delivery

BACKGROUND

Proponents of vacuum delivery argue that it should be chosen first for assisted vaginal delivery, because it is less likely to injure the mother.

OBJECTIVES

The objective of this review was to assess the effects of vacuum extraction compared to forceps, on failure to achieve delivery and maternal and neonatal morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register. Date of last search: February 1999.

SELECTION CRITERIA

Acceptably controlled comparisons of vacuum extraction and forceps delivery.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Ten trials were included. The trials were of reasonable quality. Use of the vacuum extractor for assisted vaginal delivery when compared to forceps delivery was associated with significantly less maternal trauma (odds ratio 0.41, 95% confidence interval 0.33 to 0.50) and with less general and regional anaesthesia. There were more deliveries with vacuum extraction (odds ratio 1.69, 95% confidence interval 1.31 to 2.19). Fewer caesarean sections were carried out in the vacuum extractor group. However the vacuum extractor was associated with an increase in neonatal cephalhaematomata and retinal haemorrhages. Serious neonatal injury was uncommon with either instrument.

AUTHORS' CONCLUSIONS

Use of the vacuum extractor rather than forceps for assisted delivery appears to reduce maternal morbidity. The reduction in cephalhaematoma and retinal haemorrhages seen with forceps may be a compensatory benefit.

Choice of instruments for assisted vaginal delivery

BACKGROUND

Instrumental or assisted vaginal birth is commonly used to expedite birth for the benefit of either mother or baby or both. It is sometimes associated with significant complications for both mother and baby. The choice of instrument may be influenced by clinical circumstances, operator choice and availability of specific instruments.

OBJECTIVES

To evaluate different instruments in terms of achieving a vaginal birth and avoiding significant morbidity for mother and baby.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2010).

SELECTION CRITERIA

Randomised controlled trials of assisted vaginal delivery using different instruments.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality, extracted the data, and checked them for accuracy.

MAIN RESULTS

We included 32 studies (6597 women) in this review. Forceps were less likely than the ventouse to fail to achieve a vaginal birth with the allocated instrument (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.45 to 0.94). However, with forceps there was a trend to more caesarean sections, and significantly more third- or fourth-degree tears (with or without episiotomy), vaginal trauma, use of general anaesthesia, and flatus incontinence or altered continence. Facial injury was more likely with forceps (RR 5.10, 95% CI 1.12 to 23.25). Using a random-effects model because of heterogeneity between studies, there was a trend towards fewer cases of cephalhaematoma with forceps (average RR 0.64, 95% CI 0.37 to 1.11).Among different types of ventouse, the metal cup was more likely to result in a successful vaginal birth than the soft cup, with more cases of scalp injury and cephalhaematoma. The hand-held ventouse was associated with more failures than the metal ventouse, and a trend to fewer than the soft ventouse.Overall forceps or the metal cup appear to be most effective at achieving a vaginal birth, but with increased risk of maternal trauma with forceps and neonatal trauma with the metal cup.

AUTHORS' CONCLUSIONS

There is a recognised place for forceps and all types of ventouse in clinical practice. The role of operator training with any choice of instrument must be emphasised. The increasing risks of failed delivery with the chosen instrument from forceps to metal cup to hand-held to soft cup vacuum, and trade-offs between risks of maternal and neonatal trauma identified in this review need to be considered when choosing an instrument.

Obstetric vacuum extraction: state of the art in the new millennium

This article summarizes the current state of knowledge of obstetric vacuum extraction. The discussed topics include the history of vacuum extraction, indications and contraindications, technique of the procedure, currently marketed instruments, special uses of the vacuum extractor, comparison of vacuum extraction with forceps delivery, and maternal and fetal outcomes. Areas of controversy are identified and discussed. Vacuum extraction is replacing forceps as the preferred method of instrumental delivery.

Characteristics and outcome of deliveries by forceps after failed ventouse

With the increasing use of the ventouse, it is becoming common for deliveries to be completed by the application of forceps. We present 48 cases delivered by forceps after a failed ventouse and compare these with 63 cases delivered by forceps only. There was significantly higher incidence of caesarean sections and cephalhaematoma in the group where forceps delivery was attempted after a failed ventouse compared to those delivered with forceps only.

Trends in operative vaginal delivery rates and associated maternal complication rates in an inner-city hospital

OBJECTIVE

The aims of this study were to determine trends in operative vaginal delivery rates in a large inner-city hospital and to assess associated risks.

STUDY DESIGN

We performed a retrospective cohort study (1980-1996) of women with singleton term pregnancies who underwent operative vaginal delivery at Grady Memorial Hospital, Atlanta. Maternal complication rates were compared between forceps-assisted and vacuum-assisted methods.

RESULTS

There was a decline in forceps-assisted deliveries during the 1980s and an increase during the 1990s. The vacuum-assisted delivery rate was exceedingly low during the 1980s and increased during the 1990s. Women who underwent forceps-assisted delivery were more likely to be <24 years old, to be nulliparous, and to have had regional anesthesia, midline episiotomies, and infant presentations other than occipitoanterior (P <.001). Women who underwent forceps-assisted deliveries had increased risks of postpartum infection, cervical laceration, prolonged hospital stay, perineal laceration, and postpartum complications.

CONCLUSION

There were upward trends in the rates of operative vaginal delivery at this inner-city hospital. Women who underwent forceps-assisted delivery had greater rates of maternal complications than did those who underwent vacuum-assisted delivery.

Vacuum extraction versus forceps for assisted vaginal delivery

BACKGROUND

Proponents of vacuum delivery argue that it should be chosen first for assisted vaginal delivery, because it is less likely to injure the mother.

OBJECTIVES

The objective of this review was to assess the effects of vacuum extraction compared to forceps, on failure to achieve delivery and maternal and neonatal morbidity.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register. Date of last search: February 1999.

SELECTION CRITERIA

Acceptably controlled comparisons of vacuum extraction and forceps delivery.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Ten trials were included. The trials were of reasonable quality. Use of the vacuum extractor for assisted vaginal delivery when compared to forceps delivery was associated with significantly less maternal trauma (odds ratio 0.41, 95% confidence interval 0.33 to 0.50) and with less general and regional anaesthesia. There were more deliveries with vacuum extraction (odds ratio 1.69, 95% confidence interval 1.31 to 2.19). Fewer caesarean sections were carried out in the vacuum extractor group. However the vacuum extractor was associated with an increase in neonatal cephalhaematomata and retinal haemorrhages. Serious neonatal injury was uncommon with either instrument.

REVIEWER'S CONCLUSIONS

Use of the vacuum extractor rather than forceps for assisted delivery appears to reduce maternal morbidity. The reduction in cephalhaematoma and retinal haemorrhages seen with forceps may be a compensatory benefit.