Repeat Cesareans Increasingly Risky

Essentially, the first study says repeat VBAC's get safer, while repeat cesareans get riskier.

Study from Case Western that just came out in Obstetrics & Gynecology(2008;111:285- 291).
The study's OBJECTIVE: To estimate the success rates and risks of anattempted vaginal birth after cesarean delivery (VBAC) according to thenumber of prior successful VBACs.
METHODS: From a prospective multicenter registry collected at 19 clinicalcenters from 1999 to 2002, we selected women with one or more prior lowtransverse cesarean deliveries who attempted a VBAC in the currentpregnancy. Outcomes were compared according to the number of prior VBACattempts subsequent to the last cesarean delivery.
RESULTS: Among 13,532 women meeting eligibility criteria, VBAC successincreased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%,and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively(P<.001). The rate of uterine rupture decreased after the first successfulVBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%,0.52%(P=.03) . The risk of uterine dehiscence and other peripartumcomplicationsalso declined statistically after the first successful VBAC. No increase inneonatal morbidities was seen with increasing VBAC number thereafter.
CONCLUSION: Women with prior successful VBAC attempts are at low risk formaternal and neonatal complications during subsequent VBAC attempts. Anincreasing number of prior VBACs is associated with a greater probability ofVBAC success, as well as a lower risk of uterine rupture and perinatalcomplications in the current pregnancy.
Contrast that study with another from Obstetrics & Gynecology(2006;107:1226- 1232) which found that there is maternal morbidity associatedwith multiple repeat cesareans.
OBJECTIVE: To estimate the magnitude of increased maternal morbidityassociated with increasing number of cesarean deliveries.
METHODS: Prospective observational cohort of 30,132 women who had cesareandelivery without labor in 19 academic centers over 4 years (1999–2002).
RESULTS: There were 6,201 first (primary), 15,808 second, 6,324 third, 1,452fourth, 258 fifth, and 89 sixth or more cesarean deliveries. The risks ofplacenta accreta, cystotomy, bowel injury, ureteral injury, and ileus, theneed for postoperative ventilation, intensive care unit admission,hysterectomy, and blood transfusion requiring 4 or more units, and theduration of operative time and hospital stay *significantly increased *withincreasing number of cesarean deliveries. Placenta accreta was present in 15(0.24%), 49 (0.31%), 36 (0.57%), 31 (2.13%), 6 (2.33%), and 6 (6.74%) womenundergoing their first, second, third, fourth, fifth, and sixth or morecesarean deliveries, respectively. Hysterectomy was required in 40 (0.65%)first, 67 (0.42%) second, 57 (0.90%) third, 35 (2.41%) fourth, 9 (3.49%)fifth, and 8 (8.99%) sixth or more cesarean deliveries. In the 723 womenwith previa, the risk for placenta accreta was 3%, 11%, 40%, 61%, and 67%for first, second, third, fourth, and fifth or more repeat cesareandeliveries, respectively.
CONCLUSION: Because serious maternal morbidity increases progressively withincreasing number of cesarean deliveries, the number of intended pregnanciesshould be considered during counseling regarding elective repeat cesareanoperation versus a trial of labor and when debating the merits of electiveprimary cesarean delivery.