I NVITED C OMMENTARY Maternal and Perinatal Outcomes Associated With a Tri of Labor After Prior Cesarean Delivery Emmanuel Bujold, MD,Robert J. Gauthier, MD,and Emily Hamilton, MD CURRENT COMMENTARY In December 2004, Landon et al. published the first results of an observational study that included 45,988 women with a singleton gestation and a history of cesarean delivery who gave birth between 1999 and 2002 at 19 academic medical centers in the United States. 1 The rates of selected adverse perinatal and maternal events were compared between women who underwent a trial of labor and those who underwent an elective repeat cesarean. According to the authors, among the 45,988 women, 17,898 (38.9%) underwent a trialof labor,and 15,801 (34.4%) had an elective repeated cesar- ean delivery. The remaining 12,289 women who had a repeatcesarean delivery were excluded of the analysis: 9013 of thesewomen had an indication for a repeat operation, and 3276 women (7.1%) presented in early labor withouta documented plan for a trialof laborbefore a cesarean delivery. Looking at the maternal outcomes, the authors reported a higher rate of endometritis (2.9% versus 1.8%) and blood transfusion (1.7% versus 1.0%) in women undergoing a trial of labor compared to the women undergoing elective repeat cesarean births. The frequency of hysterectomy and of maternal death did not differ significantly between the groups. Looking athe neonatal outcomes, a diagnosis of hy- poxic-ischemic encephalopathy was made in 12 infants (8 per 10,000) born at term whose mothers underwent a trial of labor,and in no infants whose mothers underwent an elective repeat cesarean birth (P ⬍ .001). Neonatal death occurred in infants born to 13 of the women who underwent trial of laborand 7 infantsborn afterelectiverepeat cesarean birth (OR 1.82; CI 0.73– 4.57), which was not statistically significant. Seven of the neonatal deaths in the trial of labor group were related to uterine rupture. The authorsconcluded that 1) a trialof laborwas associated with greater perinatal risks than elective repeat cesarean delivery without labor,and 2)this information was relevant for counseling women about theirchoices after a cesarean birth. However, we believe that the reader should understand that these rates reflect both procedure-related event sation) as well as how women were selected (associa for each group. Unequal distribution of women with oth medical conditions will increase complication rates i group.Differing degrees of selection rigor in the two groups affect complication rates and inflate the diffe between the two groups. Using the information from this study to counsel future mothers must include the fol four caveats. First,the authors of this study found that women who underwent a trial of laborweremorelikely to have antepartum stillbirth. Women with antepartum stillbirth may have chosen trial of labor,decreasing this rate in elective repeat cesarean birth, conversely increasing it in the women in the trial of labor group, thereby artificially exaggerating the difference between groups. Second, in the same way, women with systemic dis such assickle celldisease orpreeclampsia, may have chosen trial of laborto avoid surgical complications. In fact,two of three deaths in the trial of labor group were related to underlying illness (one had preeclampsia w hepatic failure, and one had sickle cell crisis with cardi arrest), whereas six of seven deaths in the elective rep cesarean group could be related to surgery (four were caused by a suspected amniotic fluid embolism, one from hemorrhage, and the other from anesthetic complica However, the authors did not consider that maternal d secondary to amniotic fluid embolism to be related t mode of delivery. From the results of this study, one interpret the rate of maternal death related to the m delivery asapproximately 1 of 17,898 (6 deathsper 100,000)for women undergoing a trial of laborand approximately 6 of 15,801 (38 deaths per 100,000) for women undergoing an elective repeat cesarean delivery. This increment of maternal deathswith elective repeat cesarean birth would be compatible with a recently four-fold increase. 2 Thus, the rates of complications in th women who underwent trialof labormay partly reflect choice or selection bias, which placed more women with medicalcomplications in the trialof laborgroup,and comparison is further distorted by the authors’ exclu the deathssecondary to amniotic fluid embolism asa procedure-related death in the electiverepeatcesarean group. Third, there were 3276 (7.1%) women who entered Address correspondence to Emmanuel Bujold, MD,FRCSC,Department of Obstetrics and Gynecology, Sainte-Justine Hospital, 3175 Côte Ste-Catherine Montréal, QC,Canada H3T 1C5. E-mail: emmanuel.bujold@umontreal.ca Journal of Midwifery & Women’s Health • www.jmwh.org 363 © 2005 by the American College of Nurse-Midwives 1526-9523/05/$30.00 • doi:10.1016/j.jmwh.2005.06.001 Issued by Elsevier Inc.