A prospective cohort study of all emergent cesarean deliveries performed at 13 medical centers compared maternal and neonatal outcomes between 2,498 women who had a vertical incision and 1,027 who had a transverse incision. The use of a vertical incision shortened the median incision-to-delivery interval by 1 minute (3 vs 4 minutes; P < .001) for primary cesarean and by 2 minutes (3 vs 5 minutes; P < .001) for repeat cesarean. However, a vertical incision was associated with higher rates of endometritis (15% vs 11%; P = .006) and postpartum transfusion (7% vs 5%; P = .01) for primary cesarean, as well as a higher rate of postpartum transfusion (15% vs 8%; P = .02) for repeat cesarean. No differences in the rates of wound hematoma and infection were noted.
A retrospective cohort study in 424 morbidly obese women compared maternal morbidity between 41 women who had a vertical skin incision and 383 women who had a transverse incision for cesarean delivery. A vertical incision was associated with a dramatic increase in the risk of a classical uterine incision (65.9% vs 7.3%; P < .001), but there were no differences in the rates of blood transfusion or wound breakdown or infection between the two groups. However, these findings should be interpreted with caution because women who received a vertical incision were older (31.0 ± 6.2 years vs 27.1 ± 6.7 years; P <.001), and there was no mention of the type of vertical skin incision in relation to the umbilicus or the use of drains. A randomized trial is needed to determine the optimal skin incision in morbidly obese women.
4. Use blunt, not sharp, expansion of the uterine incision
Blunt expansion is associated with less blood loss
Sekhavat L, Firouzabadi RD, Mojiri P. Effect of expansion technique of uterine incision on maternal blood loss in cesarean section. Arch Gynecol Obstet. 2010;282(5):475–479.
A prospective, randomized trial explored the rate of lateral extension of the uterine incision and estimated blood loss in 200 full-term primiparas undergoing cesarean delivery. Women were assigned to blunt expansion (n = 100) or sharp expansion (n = 100). Blunt expansion was associated with lower estimated blood loss (375 ± 95 mL vs 443 ± 86 mL; P <.05) but no differences in the rate of lateral extension (5% vs 6%). These findings reveal that blunt expansion of the uterine incision in primiparas is safer and easier than sharp expansion.
Nonclosure after cesarean delivery is associated with a higher rate of adhesion formation
Cheong YC, Premkumar G, Metwally M, Peacock JL, Li TC. To close or not to close? A systematic review and a meta-analysis of peritoneal non-closure and adhesion formation after caesarean section. Eur J Obstet Gynecol Reprod Biol. 2009;147(1):3–8.
Shi Z, Ma L, Yang Y, Wang H, et al. Adhesion formation after previous caesarean section—a meta-analysis and systematic review. BJOG. 2011;118(4):410–422. doi: 10.1111/j.1471-0528.2010.02808.x.
A systematic review and meta-analysis that included two randomized trials and one prospective study compared the rate of adhesions after cesarean delivery between women who had peritoneal closure (n = 110) and those who did not (n = 139). Nonclosure was associated with a substantial increase in the rate of subsequent adhesion formation (adjusted odds ratio, 4.23; 95% confidence interval [CI], 2.06–8.69). However, this review did not consider risk factors such as creation of a bladder flap or type of uterine incision.
A subsequent systematic review (n = 4,423) compared the rate of adhesions associated with closure and nonclosure of the peritoneum according to cesarean technique (Stark’s, modified Stark’s, or classic lower-segment). The classic lower-segment technique involves dissecting the bladder off the uterus and closure of both peritoneal layers (visceral and peritoneal). Neither Stark’s technique nor the modified Stark’s technique dissects the bladder from the uterus; both techniques use single-layer closure of the uterine incision. Stark’s technique leaves the peritoneal layer open, whereas the modified Stark’s technique closes the peritoneal layer. This review revealed that closing the peritoneum in modified Stark’s cesarean delivery was associated with a lower rate of subsequent adhesions—both in terms of total adhesions and individual grades of adhesions.
6. Use double-layer uterine closure
Despite its lack of effect on maternal morbidity, double-layer closure reduces risk of rupture during VBAC
The CAESAR study collaborative group. Caesarean section surgical techniques: a randomised factorial trial (CAESAR). BJOG. 2010;117(11):1366–1376. doi: 10.1111/j.1471-0528.2010.02686.x.
This large multicenter, randomized trial evaluated maternal infectious morbidity in women undergoing single- (n = 1,483) and double-layer (n = 1,496) closure of the uterine incision. The total rates of maternal infectious morbidity (16.1% vs 16.9%), wound infection (12.8% vs 12.7%), severe morbidity (0.5% vs 0.7%), and readmission within 6 weeks (2.6% vs 2.7%) were similar between groups for single- and double-layer closure, respectively. However, retrospective and case-control studies reveal that double-layer closure is associated with lower rates of uterine dehiscence and rupture during vaginal birth after cesarean (VBAC).