This will be a long one, but two articles on c-section were recently brought to my attention for discussion here.
The first is a recent study of what happens when women attempt VBAC and how their outcomes change after having had a VBAC successfully. The authors prospectively looked at 13,532 VBAC attempts from 1999-2002 at several U.S. academic medical centers among women who were considered candidates for it – those with singleton pregnancies, with at least one previous c-section by a low transverse, and ultimately delivered an infant of at least 20 weeks gestation or 500 grams. They looked at outcomes such as VBAC success, uterine rupture and dehiscense, thromboembolism, maternal death, other maternal complications, and a few neonatal outcomes such as NICU admission, Apgar scores, and death.
Among the findings:
- VBAC success was significantly more likely with more prior successful VBACs, at 63.3% for those with no prior VBACs, 87.6% for those with one, and 90.9% for those with two or more successful VBACs (outcomes and likelihood of success did not change significantly as you go from 2 to 3 to more, so were lumped together).
- Frequency of uterine rupture declined with increasing history of successful VBACs, at 0.87% for those with none prior, 0.45% for those with one, and 0.43% for those with two or more.
- Rates of transfusion and endometritis also declined significantly with each successful past VBAC.
- Although there were two maternal deaths in those with no previous VBAC, the rate was not statistically significant between groups, nor were outcomes such as infant death (there were 58/9,012 for no prior VBAC, 17/2,900 for one, and 7/1,620 for two or more), NICU admission, or hysterectomy.
The bottom line? Unfortunately, the study does not indicate that rates of maternal or infant death are reduced, or that neonatal outcomes improve (data on neonatal outcomes was not presented). It does indicate that each successful VBAC increases the chances that the next VBAC attempt will be successful, and reduces the chances of uterine rupture or dehiscence. This seems important to know, as it is may be difficult for some women to get that first VBAC under their belts given some hospitals’ policies against the procedure.
The second study is a 2006 paper on outcomes with repeat cesarean deliveries, and comes from many of the same authors as the 2008 piece. This prospective study looked at 30,132 women undergoing c-section, again at multiple U.S. academic medical centers from 1999-2002. The authors examined maternal outcomes for women undergoing first-time cesareans compared to those with increasing numbers of repeat sections (similar to how the first study looked at increasing VBACs). They focused solely on women who had a c-section without labor, not those who attempted labor and ultimately had a cesarean. The outcomes studied included placenta accreta and previa, bladder, bowel or ureteral injury, need for hysterectomy or blood products, ICU admission, infection, maternal death, and other adverse outcomes.
- Placenta accreta, hysterectomy, blood transfusion ≥4 units, cystostomy, ileus, bowel and ureteral injury, need for postoperative ventilation, ICU admission, and duration of operative time and hospital stay significantly increased with increasing number of c-sections.
- Wound dehiscence, deep vein thrombosis, pulmonary embolism, reoperation, and maternal death were not increased with increasing number of c-sections.
Neonatal outcome data was not provided in this study, nor was a clear explanation of which of these women would be considered candidates for vaginal birth in the first place. The bottom line? Maternal morbidity increases with each c-section if you look at problems such as need for ICU admission and certain injuries; mortality does not appear to be affected. The authors suggest that their findings should be considered by women planning large families as they investigate their birth options, which seems like a reasonable use of the data.
Ultimately, what these studies suggest is that VBACs get safer in some ways and more successful for women after they have had one prior successful VBAC, and that each successive c-section may result in more complications for the mother.