Research Update: Vacuum Extractors and Forceps Are Both Associated with a Higher Risk of Shoulder Dystocia

Vacuum extractors and forceps are both tools that can be used to assist with a vaginal birth. In developed countries, vacuum extractors have become much more commonly used than forceps, and in certain situations are the safer choice. However, this tool also involves serious risks. For example, some studies have found an association between the use of vacuum extractors and a labor and delivery complication called shoulder dystocia.

What is shoulder dystocia?

Shoulder dystocia occurs in a vaginal, head-first birth in which additional maneuvers (other than gentle traction) are needed to deliver the body of the fetus after the head has already been delivered (1). In many cases, this occurs because the baby’s shoulder gets stuck behind a bone in the mother’s pelvis (called the symphysis pubis bone). Shoulder dystocia is an emergency situation that endangers both mother and baby; it increases the risk of the following complications:

Shoulder dystocia is especially common among infants who are macrosomic, or unusually large for gestational age (2).

Shoulder Dystocia in Babies

How risky is vacuum extraction?

Andrea Dall’Asta and colleagues from the University of Parma in Italy recently published the results of a meta-analysis (2) comparing the risks of shoulder dystocia in vacuum delivery, forceps delivery, and spontaneous vaginal delivery (SVD, also known as unassisted birth). Dall’Asta et al. conducted a literature search using MEDLINE, EMBASE, ScienceDirect, the Cochrane Library, and, including papers published up to May 2015.

Their analyses showed that both vacuum extractors and forceps had a higher risk of shoulder dystocia than spontaneous vaginal delivery (a nearly three times higher likelihood). However, there was no significant difference in risk between the use of vacuum extractors and forceps.

Dall’Asta et al. note that it is still not entirely clear whether the use of these birth-assisting tools actually increases the risk of shoulder dystocia, or if “a primary shoulder malposition inhibits fetal head descent, resulting in increased frequency of [vacuum extractor and forceps use].”

Additionally, they emphasize that the lack of significant difference between vacuum extractor and forceps use (with regard to shoulder dystocia) could be because forceps are rarely used for rotational maneuvers. In other words, if they were used under all the same circumstances, forceps might carry a higher risk of shoulder dystocia.  

Finally, Dall’Asta et al. suggest that the risk of shoulder dystocia may vary between different types of vacuum cups and forceps. However, there is no published data on this topic. Further research is needed.

Legal help for vacuum extractor and forceps injuries ABCLawGroup 3878a 002

If your baby had a vacuum extractor or forceps-assisted birth and now has a birth injury, the skilled attorneys at Reiter & Walsh ABC Law Centers can help. Birth injury cases require specific, extensive knowledge of both law and medicine. In order to achieve the best results, our team believes it’s critical to specifically and exclusively handle birth injury cases. With over 100 years of joint legal experience, our team has the education, qualifications, results, and accomplishments necessary to succeed. We’ve handled cases involving dozens of different complications, injuries, and instances of medical malpractice related to obstetrics and neonatal care.

Contact us in any of the following ways, and we’ll set up your free case review.

Free Case Review| Available 24/7| No Fee Until We Win

Call our toll-free phone line at 866-598-5405
Press the Live Chat button on your browser
Complete Our Online Contact Form


  1. Royal College of Obstetricians and Gynecologists. Shoulder dystocia. Guideline No. 42. London, UK: RCOG; 2005.
  2. Dall’Asta, A., Ghi, T., Pedrazzi, G., & Frusca, T. (2016). Does vacuum delivery carry a higher risk of shoulder dystocia? Review and meta-analysis of the literature. European Journal of Obstetrics & Gynecology and Reproductive Biology, 204, 62-68.

Share This Post

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply