The use of forceps or vacuum methods during vaginal deliveries has decreased in recent years in Canada, but the rates of trauma to mothers and babies during these procedures have increased, researchers report

"In Canada and most industrialized countries, cesarean-delivery rates have increased over the last several decades while rates of operative vaginal delivery – the use of forceps and vacuum methods – have declined. These opposing trends have led to recommendations to increase forceps and vacuum delivery rates as a strategy to decrease cesarean-delivery rates,"  told Dr. Giulia M. Muraca of the University of British Columbia.

"Our results suggest that encouraging higher rates of forceps and vacuum delivery as a strategy to decrease the cesarean delivery rate could lead to substantial increases in obstetric trauma and severe birth trauma," she said.

Using data from the Canadian Institute for Health Information, Dr. Muraca and her colleagues reviewed almost 2 million singleton hospital deliveries between 37 and 41 weeks’ gestation in the provinces of Alberta, Manitoba, Saskatchewan, and Ontario between 2004 and 2014.

Obstetric trauma included damage to the perineum, cervix, vagina, and uterus; to pelvic organs, joints, and ligaments; to the bladder and urethra; and to the broad ligament of the uterus. Severe birth trauma included intracranial damage and damage to the skull, long bones, central and peripheral nervous systems, liver and spleen.

During the study, obstetric trauma rates increased from 6.6% to 7.2% of deliveries in nulliparous women (P<0.001), and from 2.5% to 3.0% in those with prior cesarean delivery (P<0.001), the team reports in CMAJ, online June 18.

Increases in obstetric trauma were greatest with operative vaginal deliveries, where rates jumped from 16.6% to 19.4% in nulliparous women (P<0.0001) and from 13.8% to 18.7% in those with prior cesarean delivery (P=0.0001).

Obstetric trauma was particularly common with forceps deliveries in nulliparous women, in whom rates rose from 19.4% to 26.5% (P<0.0001), and in parous women with prior cesarean delivery, who saw a rise from 16.6% to 25.5% (P=0.02). In parous women without prior cesarean delivery, the trauma rate went from 10.3% to 14.3% of deliveries (P=0.0001).

Among those who had an operative vaginal delivery during this period, the rates of severe birth trauma grew significantly in nulliparous women (from 4.5 to 6.8 per 1,000 deliveries) and in parous women without prior cesarean delivery (from 6.5 to 10.6 per 1,000 deliveries).

Severe birth trauma

In nulliparous women, the increase in severe birth trauma was greatest in deliveries that used the sequential vacuum and forceps methods (from 7.4 to 14.3 per 1,000 deliveries; P=0.01).

"Women need to be informed about the substantially increased risk of severe obstetric injury following all forceps and vacuum deliveries and about the relevant long-term quality-of-life implications," Dr. Muraca urged.

Dr. Christopher Ng, a clinical instructor in the department of obstetrics and gynecology at the University of British Columbia, writes in an editorial about the study, "Debate continues about the safety of operative vaginal deliveries, given the possibility that general obstetric skills have declined."

"We have reached a critical juncture in obstetrics: we can either accept a rapidly diminishing role for operative vaginal delivery or rise to the challenge of optimizing the training and decision-making skills of our providers of obstetric care," Dr. Ng cautions.

Dr. Kate Dielentheis, an assistant professor in the department of obstetrics and gynecology at the Medical College of Wisconsin (MCW) in Milwaukee, told Reuters Health by email, "Because this was an observational study with collection of data from a database, one can never know what the outcomes would have been for these women and babies had a different route of delivery been performed."

"There is no study (and it would never be ethical to do one) that compares and randomizes cesarean section to vaginal delivery. We know that cesarean delivery and trial of labor involve certain risks," noted Dr. Dielentheis, who was not involved in the study. "It is a constant dance to decide with a patient the safest, most effective route of delivery that entails the least amount of risk to the mother and the baby."