SAN DIEGO – A shift from a conventional private practice model to a 24-hour obstetrician and midwifery model was associated with a dramatic decrease in the nulliparous term single vertex cesarean delivery rate, and an increase in the vaginal birth after cesarean delivery rate among privately insured women who were delivered at a community hospital in California.
But in a larger cross-sectional population-based study involving multiple community hospitals, no difference was seen in the primary cesarean rate, the successful vaginal birth after cesarean (VBAC) rate, or maternal morbidity for laboring women who gave birth in hospitals with an obstetrician available around the clock versus hospitals not using a laborist model.
Researchers who worked on the two studies said the differences might be explained by multiple factors, including the midwifery component in the single-center study, and a lack of information about exactly how laborists functioned at the various centers included in the larger, multicenter study.
In the single-center prospective cohort study, conducted at Marin General Hospital in Greenbrae, Calif., the nulliparous term single vertex cesarean delivery (NTSV CD) rate among privately insured women fell from 32.2% prior to the model change, to 25% after the switch. There was an immediate 5% decrease, followed by a nearly 2% decrease each year thereafter.
Prior to the switch to a laborist model, the NTSV CD rate had been increasing by 0.6% annually, similar to national trends, Dr. Melissa Rosenstein of the University of California, San Francisco, reported at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
Further, the VBAC rate, which had been decreasing slightly each year before the change, increased from 13% to 22% after the change, and increased by about 8% per year thereafter, she said.
Previously, privately insured women were managed by their individual obstetricians; only publicly insured women utilized the laborist model at the hospital.
The rates of NTSV CD and VBAC among publicly insured women did not change significantly during the study period – the NTSV CD rates were 15.7% and 15.8% before and after the change, and VBAC rates were 33.9% and 27.9% before and after the change, she said.
The study included all singleton term deliveries at the community hospital between January 2005 and April 2014. The model shift occurred in April 2011. Overall, 3,684 NTSV deliveries and 1,375 deliveries in women with a prior cesarean delivery were included in the analysis.
“The changes were seen to a statistically significant degree only in the group of women exposed to the practice change, suggesting causation rather than secular trends for other hospitalwide interventions,” Dr. Rosenstein said.
But a larger, multicenter study found no difference between 43 hospitals with laborists and 139 without laborists on a range of outcomes, including the primary cesarean delivery rate (13.9% vs. 14.1%), the rate of maternal composite morbidity (10.3% vs. 10.8%), the rate of severe maternal complications (1.25% vs. 1.07%), and the successful VBAC rate (55.8% vs. 59.8%).
The researchers relied on structured 1-hour interviews conducted with labor and delivery nurse managers from 182 community hospitals with 221,247 deliveries in California between November 2012 and January 2014. They also considered discharge data and information regarding hospital policies and practices.
So why were the findings so different? Dr. Rosenstein, who worked on the single-center study, stressed the importance of the midwives in the laborist model used at Marin General Hospital.
“The other study didn’t include the midwifery component, which I think is a very important part of the Marin General Hospital experience,” Dr. Rosenstein said. “Not only does our hospital have midwives, but they work closely and collaboratively with physicians and participate in twice-daily rounds to discuss patient management.”
The principal investigator in the multicenter study, Dr. Kimberly Gregory, director of the division of maternal-fetal medicine at Cedars-Sinai Medical Center in Los Angeles, agreed, noting that midwifery is already known to make a difference.
“What we don’t know is what model of laborists, if any, makes a difference,” she said.
Other models that employ both midwives and dedicated obstetricians in labor and delivery, while having separate physicians for gynecologic and emergency care, are showing promise, Dr. Gregory said.
Another major difference between the two studies was the lack of categorization of hospitals by “how laborists actually functioned on the unit” in her study, Dr. Gregory said.
Since the multicenter study didn’t look at the specific roles of laborists on the hospital unit, it’s unclear whether they took care of just a few patients, or whether they managed all of the obstetrics patients, Dr. Rosenstein said.