Epidural injections are administered into the space between the wall of the spinal canal and the sheath covering the spinal cord and anesthetize the abdominal, genital and pelvic areas. Spinal injections are administered into the fluid surrounding the spinal cord.
Previous research has suggested that epidural analgesia initiated early in labor when the cervix is dilated less than 4 centimeters is associated with an increased risk for cesarean delivery.
Based on that research, the American College of Obstetricians and Gynecologists recommended that epidural analgesia be delayed in women who have not previously given birth until their cervix dilates to 4 to 5 centimeters and that other forms of analgesia, for example, systemic opioid analgesia, be used until that time.
However, it is unclear whether increased risk for cesarean delivery is due to neuraxial [spinal or epidural] analgesia or can be explained by other factors, said Cynthia A. Wong, M.D., associate professor of anesthesiology at Northwestern University Feinberg School of Medicine, who led the study. Wong also is an anesthesiologist at Northwestern Memorial Hospital.
"Systemic opioid analgesia is often incomplete and has potential maternal and fetal side effects, including neonatal and maternal respiratory depression, especially when spinal or epidural opioids are administered concomitantly," Wong said.
The Northwestern study examined 750 full-term, nulliparous (no previous births) women in spontaneous labor, with cervical dilation less than 4 centimeters.