There was very little significant difference found with respect to major clinical outcomes in the choice of anesthesia employed during C-section. Some women, however had lower blood counts and shivering after C-section with general anesthesia and some experienced more nausea and vomiting with regional anesthesia.
This was the first such review to consider both neonatal and maternal outcomes related to regional or general anesthesia used during C-section. Previous reviews have considered only the baby's well-being -- not also the mom's.
"We found no evidence to suggest that one form of anesthesia was superior to the other for Caesarean section, when comparing general with regional anesthesia, in terms of major outcomes such as the well being of the baby," said lead author Dr. Bosede B. Afolabi, a senior lecturer and consultant at the Department of Obstetrics and Gynecology of the College of Medicine/Lagos University Teaching Hospital in Nigeria.
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
For the review, the authors analyzed sixteen randomized controlled trials involving 1586 women who had given birth by C-section. The women had received either regional or general anesthesia.
Multiple newborn outcome measures were considered in the review, including neonatal death, Apgar scores, umbilical pH, neonatal adaptive capacity scores and need for oxygen by mask or intubation.
Outcome measures involving the mom included maternal death, differences in hematocrit or hemoglobin levels (both measures of anemia) before and after C-section, incidence of postoperative wound infection, intraoperative pain, and satisfaction with the anesthetic technique used.
According to Afolabi, maternal or neonatal death was not reported in any trial in the review, underscoring the relative safety of the Caesarean procedure.
"There appeared to be reduced blood loss with the use of regional anesthesia, however, and this applied to both spinal and epidural forms," she said. "Despite the fact that the review did not find a difference in the need for blood transfusions, this reduced blood loss may be relevant, as wound healing is slower in people with anemia."
"This review confirms what we have known for the past 20 years -- for delivery, regional anesthesia is safer than general anesthesia," said Charles J. Lockwood, M.D., professor and chair of the Department of Obstetrics, Gynecology and Reproductive Sciences at Yale University School of Medicine.
"The studies in the review were generally small and there was no way to blind the physicians caring for mothers or their infants as to the method of anesthesia -- which may introduce biases," said Lockwood.
The review found that more women preferred to have general anesthesia compared to epidural and spinal anesthesia for subsequent procedures.
Both Afolabi and Lockwood agree that this review is not likely to change patterns of practice of physicians delivering babies by Caesarean section and that it is largely the preference of the woman -- to remain awake during the birth of her child or not -- as well as due consideration of her medical condition that should determine whether her physician provides regional or general anesthesia during her C-section.
With general anesthesia, the woman is unconscious during the C-section and unaware of the birth of her baby. During regional anesthesia, the woman is awake during the procedure but is numbed in the area where the C-section is performed.
During spinal and epidural anesthesia, an anesthetic agent is suffused into the area surrounding the spinal cord through an injection in the woman's lower back. This is usually performed by an anesthesiologist who is well-trained in the procedure.
With spinal anesthesia, the anesthetic medicine is injected directly inside the sac of fluid that surrounds the spinal cord, whereas with epidural anesthesia the anesthetic is given through a tiny "catheter" or tube that has been placed in the space overlying this sac of fluid.
"Virtually no OB facility in the United States routinely uses general anesthesia; in fact, its use is limited to very rare clinical settings," Lockwood said. "General anesthesia increases the risk of maternal aspiration pneumonia and of obstetrical hemorrhage," because the anesthetic gas inhibits the mother's contractions. "It also suppresses the newborn and causes the mother to miss the birth of her child because she is unconscious," he added.
"Regional anesthesia is preferable to general anesthesia except in rare circumstances -- for example, where obstetrical emergencies require immediate delivery and one cannot wait for the slower-acting regional anesthesia to take effect," Lockwood said.