Barcey T. Levy, PhD, MD George R. Bergus, MD Arthur Hartz, PhD, MD Marty Lofgren, MD Kelly Goldsborough, MD Iowa City, Iowa Submitted, revised, August 2, 1999. From the Department of Family Medicine (B.T.L., G.R.B., A.H., M.L., K.G.) and the Public Policy Center (A.H.), University of Iowa, Iowa City. This paper was presented at the 32nd Society of Teachers of Family Medicine Annual Spring Conference, April 29, 1999, Seattle, Washington. Reprint requests should be addressed to Barcey T. Levy, PhD, MD, 01292 E Pomerantz Family Pavilion, Department of Family Medicine, University of Iowa, Iowa City, IA 52242. E-mail: barcey-levy@uiowa.edu.
References
Limitations
Although a double-blind clinical trial with women randomized to a PCB or an alternative form of analgesia would be the best way to study the safety of PCBs, such a study would be very difficult and would require millions of dollars. We decided, therefore, to take advantage of the types of analgesia used at our hospital to study the safety of PCBs with an observational prospective design. The main limitation of this design is that an adverse effect of a PCB could be obscured if patients who received a PCB had characteristics that would put them at a lower risk than other patients in our study. However, detailed clinical comparisons of the 2 groups of patients did not reveal significant differences. In addition, the effect of the use of a PCB was very similar in the multivariate and the univariate analyses, providing evidence that differences between these groups were unlikely. Our results may not apply to high-risk pregnancies, since the women in our study were very healthy (high-risk patients were referred to the nearby tertiary-care hospital). However, this type of referral pattern is not uncommon.
We found that neither PCB nor nalbuphine use were associated with significantly lower umbilical artery pH values in univariate or multivariate analyses. Both PCB and intravenous nalbuphine provide effective obstetric analgesia, since substantial proportions of women reported excellent or good relief following PCB use (70%) or following nalbuphine use (64%) in this and other studies. Because of strong evidence for its safety, submucosal injection of a PCB using 1% lidocaine should be considered a viable form of obstetric analgesia. PCBs may be especially useful for women giving birth in hospitals where obstetric anesthesia services are not readily available.
Acknowledgments
Our study was partially supported by a grant from the American Academy of Family Physicians/American Academy of Family Physicians Foundation (G9415), the University of Iowa Department of Family Medicine, the Iowa Academy of Family Physicians Foundation, and Mercy Hospital, Iowa City, Iowa. This study would not have been possible without the support of the nurses and obstetricians at Mercy Hospital.
