Intervention Review

Choice of instruments for assisted vaginal delivery

  1. Fidelma O'Mahony1,*,
  2. G Justus Hofmeyr2,
  3. Vijay Menon3

Editorial Group: Cochrane Pregnancy and Childbirth Group

Published Online: 10 NOV 2010

Assessed as up-to-date: 4 OCT 2010

DOI: 10.1002/14651858.CD005455.pub2

How to Cite

O'Mahony F, Hofmeyr GJ, Menon V. Choice of instruments for assisted vaginal delivery. Cochrane Database of Systematic Reviews 2010, Issue 11. Art. No.: CD005455. DOI: 10.1002/14651858.CD005455.pub2.

Author Information

  1. 1

    University Hospital of North Staffordshire, Academic Unit of Obstetrics and Gynaecology, Stoke-on-Trent, UK

  2. 2

    University of the Witwatersrand, University of Fort Hare, Eastern Cape Department of Health, Department of Obstetrics and Gynaecology, East London Hospital Complex, East London, Eastern Cape, South Africa

  3. 3

    North Staffordshire Trust, Old Teaching Department, Maternity Unit, City General Site, Stoke-on-Trent, UK

*Fidelma O'Mahony, Academic Unit of Obstetrics and Gynaecology, University Hospital of North Staffordshire, Newcastle Road, Stoke-on-Trent, ST4 6QG, UK. fidelma.o'

Publication History

  1. Publication Status: New
  2. Published Online: 10 NOV 2010




  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Resumen
  5. 摘要


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.


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

Search methods

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.


Plain language summary

  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Resumen
  5. 摘要

Instruments for assisted vaginal delivery

This review of 32 studies (6597 women) looks at assisted or instrumental vaginal deliveries in women in the second stage of labour. The importance of this review is due to the fact that Instrumental delivery is a frequent intervention in childbirth and in some cases may result in harmful outcomes for either mother or baby or both.

The main comparisons are between the forceps or the ventouse. There are also comparisons between different types of ventouse. The outcomes which are analysed are the success of the particular instrument in achieving the delivery and the rate of complications for both mother and baby. Not all studies considered all outcomes, and in particular, there were differences in the types of complications encountered by mothers and babies. In addition, we identified no studies for some comparisons.

The results showed that the forceps was the better instrument in terms of achieving a successful delivery. However, it was also associated with higher rates of complications for the mother. These were perineal trauma, tears, requirements for pain relief and incontinence. There were risks of injury to the baby with both types of instrument.

Comparisons between different types of ventouse revealed that the metal cup was better at achieving successful delivery than the soft cup,.but with more risk of injury to the baby. There were no significant differences between the handheld and the standard vacuum.

Decisions as to which instrument is best will, therefore, depend upon individual situations where the urgency with which the baby needs to be delivered will be balanced against potential risks to the mother and baby.



  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Resumen
  5. 摘要


Elección de instrumentos para el parto vaginal asistido

El parto vaginal instrumental o asistido se usa comúnmente para acelerar el parto para el beneficio de la madre o del recién nacido o de ambos. A veces se asocia con complicaciones significativas tanto para la madre como para el recién nacido. Las circunstancias clínicas, la elección del profesional y la disponibilidad de instrumentos específicos pueden influir en la elección del instrumento.


Evaluar diferentes instrumentos en cuanto al logro de un parto vaginal y la prevención de una morbilidad significativa para la madre y el recién nacido.

Estrategia de búsqueda

Se hicieron búsquedas en el Registro Especializado de Ensayos Controlados del Grupo Cochrane de Embarazo y Parto (Cochrane Pregnancy and Childbirth Group) (31 mayo 2010).

Criterios de selección

Ensayos controlados con asignación aleatoria sobre el parto vaginal asistido con diferentes instrumentos.

Obtención y análisis de los datos

Dos revisores evaluaron la calidad de los ensayos, extrajeron los datos y los examinaron en cuanto a su exactitud de forma independiente.

Resultados principales

En esta revisión, se incluyeron 32 estudios (6 597 mujeres). En comparación con la ventosa, fue menos probable que el fórceps fracasara en el logro de un parto vaginal con el instrumento asignado (cociente de riesgos [CR] 0,65; intervalo de confianza [IC] del 95%: 0,45 a 0,94). Sin embargo, con el fórceps hubo una tendencia a más cesáreas y significativamente más desgarros de grado tres o cuatro (con o sin episiotomía), traumatismo vaginal, uso de anestesia general e incontinencia de flatos o alteración de la continencia. La lesión facial fue más probable con el fórceps (CR 5,10; IC del 95%: 1,12 a 23,25). Mediante un modelo de efectos aleatorios debido a la heterogeneidad entre los estudios, hubo una tendencia hacia menos casos de cefalohematoma con el fórceps (CR promedio 0,64; IC del 95%: 0,37 a 1,11).

Entre los diferentes tipos de ventosa, fue más probable que la copa de metal diera lugar a un parto vaginal exitoso en comparación con la copa blanda, con más casos de lesión del cuero cabelludo y de cefalohematoma. La ventosa manual se asoció con más fracasos que la ventosa de metal, y con una tendencia a menos fracasos que la ventosa blanda.

En general, parece que el fórceps o la copa de metal son los más efectivos para lograr un parto vaginal, pero con un riesgo mayor de traumatismo materno con el fórceps y de traumatismo neonatal con la copa de metal.

Conclusiones de los autores

Existe una función reconocida del fórceps y todos los tipos de ventosa en la práctica clínica. Debe recalcarse la función del entrenamiento del profesional con cualquier elección del instrumento. Al elegir un instrumento debe considerarse el aumento de los riesgos de un fracaso del parto con el instrumento elegido desde el fórceps hasta la ventosa con copa de metal, manual o con copa blanda, y las ventajas y desventajas entre los riesgos de traumatismo materno y neonatal identificados en esta revisión.


Traducción realizada por el Centro Cochrane Iberoamericano



  1. Top of page
  2. Abstract
  3. Plain language summary
  4. Resumen
  5. 摘要







我們搜尋了Cochrane Pregnancy and Childbirth Group's Trials Register (2010年5月31日) 。






本篇回顧中,我們納入了32個研究 (6597位婦女) 。使用產鉗輔助陰道生產,失敗機率較使用真空吸引器低 (risk ratio (RR) 0.65, 95% confidence interval (CI) 0.45 to 0.94) 。然而,使用產鉗輔助陰道生產的婦女會有較高剖腹產傾向,更多機會產生3度或4度會陰裂傷 (不論是否有外陰切開術) 、陰道損傷、全身麻醉劑的使用及排氣失禁或排便控制能力改變。使用產鉗較有可能造成嬰兒臉部受傷 (RR 5.10, 95% CI 1.12 to 23.25) 。由於各研究間的異質性,我們使用隨機效應模式,結果顯示使用產鉗造成頭顱血腫的機率似乎較小 (average RR 0.64, 95% CI 0.37 to 1.11) 。不同的真空吸引器具中,使用金屬吸引器比使用軟式吸引器更容易完成陰道生產,但較有可能造成頭皮受傷或頭顱血腫。使用手持式吸引器的失敗率比金屬吸引器高,比軟式吸引器低。整體而言,使用產鉗和金屬真空吸引器的輔助陰道生產效果較好,但使用產鉗會增加母親受傷的風險,而使用金屬真空吸引器會增加嬰兒受傷的風險。





此翻譯計畫由臺灣國家衛生研究院 (National Health Research Institutes, Taiwan) 統籌。


輔助陰道生產:本篇回顧包括32篇研究 (6597位婦女) ,主要討論婦女第二產程時輔助性陰道生產。本篇回顧的重要性在於,生產時常會需要器具的輔助,這樣做有時會對母親或嬰兒,甚至兩者產生有害的結果。研究主要是針對產鉗與真空吸引器使用結果的比較,也有對不同種類真空吸引器之間的使用結果比較。結論探討輔助器具對陰道生產成功率以及對母親或新生兒併發症發生率的影響,並非所有的研究都有討論到這些結果,而母親和新生兒可能遇到的併發症也並不相同。此外,我們沒有找到有關某些器具之間比較的研究。結果顯示選擇使用產鉗有較高輔助生產成功率,然而也有較高的母親併發症發生率,包括會陰創傷、撕裂傷、需要使用止痛劑以及失禁。對新生兒而言,兩種器具都有可能造成併發症。不同種類真空吸引器之間的比較結果顯示,金屬真空吸引器輔助生產成功的機率較軟式吸引器高,但有較高風險對嬰兒造成傷害,比較手持式和標準式吸引器結果沒有顯著差異。判定選用何種器具較好,應視狀況而定,要在加快生產的急迫性與母親和嬰兒面臨的潛在風險間取得平衡。