Mid-pelvic forceps, vacuum deliveries associated with higher rates of trauma for mothers and babies

Written by Faculty of Medicine

Rates of maternal and infant trauma are higher in deliveries by mid-pelvic forceps or mid-pelvic vacuums compared with cesarean deliveries, according to new research by the Faculty of Medicine.

These mid-pelvic operative vaginal deliveries, carried out when the baby’s head is midway through the mother’s pelvis, account for about 3 per cent of singleton deliveries in Canada, approximately 10, 000 deliveries per year. In 2014, the American College of Obstetricians and Gynecologists encouraged increased use of forceps and vacuum delivery to reduce rates of cesarean deliveries.

The UBC researchers looked at data on 187,234 singleton births in Canada, excluding Quebec, over 10 years (2003–2013) that involved use of mid-pelvic forceps, mid-pelvic vacuum or cesarean delivery. Of these, about 41 per cent of women needed intervention because of poor uterine contractions and 59 per cent because of fetal distress.

Lead author and SPPH doctoral candidate Giulia Muraca.

The study, published in the CMAJ, was restricted to deliveries in which the baby’s head was midway through the maternal pelvis and did not include forceps and vacuum deliveries carried out when the baby’s head had descended further down the birth canal.

In deliveries that did not involve fetal distress, severe complications for the baby following mid-pelvic forceps and mid-pelvic vacuum were 80 per cent higher than cesarean delivery. The rate of severe birth trauma was five- to ten-fold higher in deliveries by mid-pelvic forceps and mid-pelvic vacuum compared with cesarean delivery. Severe obstetric tearing occurred in 19 per cent of women delivered by mid-pelvic forceps, 12 per cent of women delivered by mid-pelvic vacuum, and 20 per cent of women that delivered using a combination of mid-pelvic vacuum and forceps.

“It is important to understand that similar to cesarean deliveries, mid-pelvic forceps and vacuum deliveries are invasive procedures with their own risks — risks that we have now quantified and that should be communicated to women who may encounter them, especially when the risk is as high as one in five,” says lead author, Giulia Muraca, a doctoral candidate in the School of Population and Public Health.

“Women who are delivered by mid-pelvic forceps or mid-pelvic vacuum should be afforded the same standard of informed consent as women who consent to cesarean delivery. Ideally, this should take place prior to labour when women are considering their birth plans.”

The authors stress that there are circumstances during labour, such as fetal distress, when forceps and vacuum have potential to save lives through saving time compared with a cesarean delivery. The study was limited by the authors’ inability to assess the skill level of the physician or health care provider delivering the babies.

Still, Muraca says the results suggest that encouraging higher rates of forceps and vacuum delivery to reduce the cesarean delivery rate could increase rates of neonatal and maternal complications, unless we improve our criteria for choosing when to use it, or improve training in how to do it.

Muraca was interviewed for CMAJ’s podcast about the research, available here.

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