Advances in Women's Health

In 2020, the U.S. Department of Health and Human Services identified severe maternal morbidity as a public health priority. The reported incidence of severe maternal morbidity more than doubled between 1999 and 2017 and affected about 1 in 60 women in 2017. Of particular concern is the three-fold increased risk of severe maternal morbidity for racial and ethnic minority women compared to non-Hispanic White women.

It has been suggested that the use of labor neuraxial analgesia for vaginal delivery reduces the risk of postpartum hemorrhage, the leading cause of preventable severe maternal morbidity. With that in mind, Alexander M. Friedman, MD, MPH, a maternal-fetal medicine specialist, and Jean Guglielminotti, MD, PhD, an anesthesiologist at New York-Presbyterian/Columbia University Irving Medical Center, joined with anesthesiology and epidemiology colleagues to evaluate the association between labor neuraxial analgesia for vaginal delivery and severe maternal morbidity. Drawing on data from the New York State Inpatient Database, they conducted a retrospective, cross-sectional study of more than half a million women hospitalized for vaginal delivery.

The Columbia study builds on earlier research in France that analyzed vaginal births between 2004 and 2006. That research reported a 47 percent decreased risk of severe postpartum hemorrhage, defined as a decrease in postpartum hemoglobin concentration greater than 4 g/dL for women who received labor neuraxial analgesia compared with those who did not. The proposed mechanism is that the presence of the epidural catheter enables prompt and effective management of postpartum hemorrhage because interventions to halt bleeding require anesthesia.

Dr. Friedman and Dr. Guglielminotti thought it important to replicate the association identified in the French study given the advances that have taken place in obstetric and anesthesia care in the last 15 years, as well as the significant differences in healthcare systems and maternal health outcomes between the U.S. and France. As the researchers noted, the maternal mortality ratio in the U.S. is twice the maternal mortality ratio in France and other high-income countries.

In their study, the Columbia team analyzed the medical records of 575,524 women who were hospitalized for a vaginal delivery between January 1, 2010, and December 31, 2017. The mean age was 28 years; 44.9 percent were non-Hispanic White. The team noted whether patients received no analgesia or neuraxial analgesia, as well as the occurrence of severe maternal morbidity and postpartum hemorrhage. They also stratified according to race and ethnicity and to the comorbidity index (CMI-OB) for obstetric patients. A total of 400,346 women (69.6 percent) were in the low-risk group and 175,178 (30.4 percent) were in the high-risk group; 272,921 women (47.4 percent) received neuraxial analgesia.

In this cross-sectional study of 575,524 women with vaginal delivery in New York hospitals from 2010 to 2017, use of neuraxial analgesia was associated with a 14 percent decrease in risk of severe maternal morbidity.

The Columbia researchers established the association between labor neuraxial analgesia and decreased risk of postpartum hemorrhage, extending it to decreasing the risk of severe maternal morbidity. Specific findings, which were published in the February 22, 2022, issue of JAMA Network Open, included:

• Severe maternal morbidity occurred in 7,712 women, of whom 2,748 had postpartum hemorrhage
• Incidence of severe maternal morbidity (before weighting) was 1.3 percent with neuraxial analgesia compared with 1.4 percent without neuraxial analgesia
• Adjusted odds ratio of severe maternal morbidity (after weighting) remained lower for women with neuraxial analgesia
• Decreased risk of severe maternal morbidity associated with neuraxial analgesia was similar between non-Hispanic White women and racial and ethnic minority women and between low-risk and high-risk women
• About one-fifth of the observed association of neuraxial analgesia with the risk of severe maternal morbidity was mediated through the decreased risk of postpartum hemorrhage

The researchers note that decreased risk of postpartum hemorrhage accounted for one-fifth of the protective association of labor neuraxial analgesia. This suggests that there are other mechanisms linking labor neuraxial analgesia to the decreased risk of severe maternal morbidity, which may include:

• Sustained intrapartum hemodynamic monitoring of parturient women with neuraxial analgesia, which enhances maternal monitoring and early detection of blood loss immediately after delivery
• Adequate intravenous access and fluid resuscitation
• Continuous anesthesia availability and oversight of the process of labor and delivery and preparedness for acute events

Dr. Friedman and Dr. Guglielminotti suggest that increasing access to and utilization of epidural during childbirth, especially for racial and ethnic minority women, could be a feasible strategy to improve maternal health and reduce disparities in maternal health.