Short- and Long-term Outcomes after Cesarean Section

Rosalie M Grivell; Jodie M Dodd

Disclosures

Expert Rev of Obstet Gynecol. 2011;6(2):205-215. 

In This Article

Outcomes in a Subsequent Pregnancy for Women with a Previous Cesarean Birth

Associations have been reported between prior CS birth and subsequent ectopic pregnancy,[57,61,62] placenta previa, placental abruption[57,61,62] and placenta accreta.[63] Hemminki and colleagues have conducted several retrospective cohort studies evaluating outcomes following cesarean birth involving over 16,000 women using hospital discharge data. Prior CS was identified as a risk factor for subsequent ectopic pregnancy, ranging from a 28% to 76% increase.[57,61,62]

Prior CS has been identified by several authors to be associated with an increased risk of poor placentation,[57,61,62] indicating an increased chance of placental abruption in a subsequent pregnancy (RR: 3.78–5.34). A similar magnitude of risk was identified for placenta previa (RR: 3.78–3.54).[61,62]

A strong association has also been identified between placenta accreta and prior cesarean birth. A large tertiary center in Australia recently reported a rise in placenta accreta over the past three decades.[63] In a retrospective review of 32 women with placenta accreta, 80% were found to have a previous CS and only half were diagnosed antenatally with ultrasound. Placenta accreta recurs in approximately a third of subsequent pregnancies[64] and is a risk factor for massive obstetric hemorrhage and hysterectomy in the index pregnancy.[65]

Several large population studies have identified prior CS as a risk for maternal ICU admission, hysterectomy, transfusion, cardiac and renal problems in a woman's next pregnancy.[33,66] The magnitude of risk ranged from 1.63-times (95% CI: 1.47–1.81) in the WHO study,[66] to over 3.5-times (RR: 3.7; 95% CI: 3.4–4.1) in the nationwide cohort study from The Netherlands.[33]

A prior cesarean birth is associated with a well-documented risk of uterine rupture following labor in a subsequent pregnancy.[34] A systematic review by Hofmeyr et al. reported a 1% worldwide prevalence of uterine rupture among women with a previous CS birth (86 studies). Of concern was the finding that in less-developed countries, uterine rupture contributed to up to 10% of maternal deaths.[34]

For women with a previous cesarean birth, the risk of complications in a subsequent pregnancy may vary with planned mode of birth. The systematic review by Guise et al. evaluated the incidence and consequences of uterine rupture in women with a previous cesarean birth.[67] A total of 21 studies were assessed as fair or good quality by objective criteria and included two large population-based retrospective studies, 15 prospective cohort studies, two case–control studies and two case series. The overall rate of symptomatic uterine rupture was 3.8 per 1000 women undergoing trial of labor. Comparative data from one retrospective and one prospective study indicated that trial of labor was associated with an increased risk of uterine rupture of 2.7 per 1000 cases (95% CI: 0.73–4.73). For women attempting vaginal birth, the additional risk of hysterectomy was 3.4 (0 to 12.6) per 10,000.[67] However, applicability of the results of the systematic review is reduced by the methodological quality and limitations of the primary studies.

Landon and colleagues conducted an observational study of women with a previous CS birth, comparing outcomes between women who underwent a trial of labor and women who birthed by elective repeat CS.[68] Uterine rupture was reported for 0.7% of women who underwent a trial of labor; however, uterine rupture was not recorded for any woman with an elective repeat cesarean delivery. For women undergoing a trial of labor, the risk of endometritis was significantly higher than in women undergoing repeated elective cesarean delivery (2.9% compared with 1.8%), as was the rate of blood transfusion (1.7% compared with 1.0%). The frequency of hysterectomy and maternal death did not differ significantly between the two modes of birth.[68]

There is a recognized risk of uterine rupture following IOL in the presence of a previous cesarean birth. Lydon-Rochelle et al. conducted a cohort study of 20,095 women with a first singleton birth by cesarean using a population-based date registry.[69] Trial of labor in the second birth was associated with a significant increase in the risk of uterine rupture, being threefold higher in women following spontaneous labor (RR: 3.3; 95% CI: 1.8–6.0), increasing to five- to 15-fold among women whose labor was induced, particularly following administration of prostaglandin preparations.[69]

These findings are consistent with those reported by Landon.[68] In this study, the overall risk of symptomatic uterine rupture was low at 0.7% of all women undergoing trial of labor, the rate being 0.4% (24 out of 6685) in women who entered labor spontaneously. Using women who labored spontaneously as a standard reference comparison, the risk of uterine rupture increased following oyxtocin augmentation (52 out of 6009 women; OR: 2.42; 95% CI: 1.49–3.93) or any IOL (48 out of 4708 women; OR: 2.86; 95% CI: 1.75–4.67), and particularly following the use of prostaglandin preparations (13 out of 926 women; OR: 33; 95% CI: 2.01–7.79).[68]

By contrast, Smith and colleagues, present data from over 36,000 women with a prior cesarean in Scotland, of whom 4600 underwent prostaglandin induction in a subsequent pregnancy.[70] The risk of uterine rupture and subsequent perinatal death following prostaglandin IOL was 11 out of 10,000 labors, compared with 4.5 out of 10,000 labors in the absence of prostaglandin induction.[70]

Despite the documented increased risk associated with IOL of uterine rupture, many obstetricians offer IOL with prostaglandin preparations and/or oxytocin.[71,72]

In all of the reported studies, while the RR of uterine rupture is increased following IOL, the absolute risk for any individual woman remains low.

For women with a prior cesarean birth who require IOL, mechanical cervical dilatation (for example with a Foley catheter) is being increasingly recommended to avoid the dangers associated with prostaglandin preparations. Bujold and colleagues report a similar risk of uterine rupture in women who underwent an IOL with a transcervical catheter compared with women who entered labor spontaneously.[73]

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