Vaginal birth after caesarean section versus elective repeat caesarean section: assess neonatal downstream outcomes too. BJOG. 2006;113(7):852-853. (original) (raw)

We were interested in Pare et al’s paper showing an excess increase in hysterectomy in subsequent pregnancies for women having elective repeat caesarean sections (CS) (1). Further valuable information is added to the risk assessment women, obstetricians and midwives must make; both when considering a primary CS or waiting for labour in a subsequent pregnancy. The National Institute of Clinical Excellence has examined the health risks of CS and concluded that, even for a first CS, maternal request alone is not an indication for elective major surgery and requires the use of counseling to explore women’s motives, and a second opinion (2), because of the imbalance of health risks to mothers and babies which only widens with increasing parity and increasing numbers of caesareans. It is generally better to labour (even if that ends in emergency CS) and especially in settings that achieve high vaginal delivery rates. This is not only because of the future maternal morbidity that repeat caesareans cause (which can only increase as the caesarean rate rises), but also because of increasing risks to babies. Poor fetal outcomes are sometimes used to justify avoiding vaginal birth after CS (VBAC) entirely, or to avoid VBAC at home or in midwifery-led childbirth centres in particular. For example, VBACs in childbirth centres were eliminated in the US based on an increase of 1/1000 perinatal deaths among women having a VBAC after one CS in childbirth centres (3) despite higher successful vaginal birth rates. But logic would suggest that for those women planning or experiencing further pregnancies, VBAC after one CS may be safer overall in a childbirth centre than in the hospital. This is because childbirth centers had a mean 87% successful VBAC rate compared to 10% in US hospitals (3). The UK has an overall 33% VBAC rate (4). Intrapartum perinatal mortality due to uterine rupture during labour has to be balanced against reports suggesting an increase in third trimester unexplained stillbirths in future pregnancies following CS. Although no one has yet examined the rate of unexplained third trimester stillbirths after two or more cesareans , the rate of unexplained stillbirths after one CS has been shown to be 1/500 vs. 1/1000 after one vaginal birth (5) in observational studies. If this association of CS with subsequent stillbirth is confirmed, it is a fetal argument against elective repeat CS. One theory suggests that the unexplained fetal demise is a complication resulting from the uterine scar, although a plausible mechanism is as yet unknown. Thus, it is possible that the rate of unexplained stillbirths may increase even further with increasing numbers of scars, and in any case, would not be expected to decrease. When an increased risk of stillbirth is added to the excess increase in hysterectomy (1) and long-established respiratory risks of elective CS, it is at least arguable that childbirth centres may statistically be a safer place for women after one CS who wish to have more children, unless and until hospitals match their typical 87% successful VBAC rate. Of course, using a childbirth centre in the first labour and avoiding the first CS might be the best overall preventative approach for the health of mothers and babies. References: 1. Pare E, Quinones J, Macones G. Vaginal birth after cesarean section versus elective repeat cesarean section: assessment of maternal downstream health outcomes. BJOG 2006; 113:75-85. 2. National Collaborating Centre for Women’s and Children’s Health, National Institute for Clinical Excellence. Caesarean Section. London: RCOG Press, 2004. 3. Lieberman E. Ernst E. Rooks J. Stapleton S. Flamm B. 2004. Results of the national study of vaginal birth after cesarean in birth centers. Obstet Gynecol. Nov. 104(5 Pt 1): 933-42. 4. Thomas J, Paranjothy S. Royal College of Obstetricians and Gynaecologists Clinical Effectiveness Support Unit. The National Sentinel Caesarean Section Audit Report. London: RCOG Press, 2001. 5. Smith GC, Pell JP Dobbie R. Caesarean section and risk of unexplained stillbirth in subsequent pregnancy. Lancet. 2003 Nov 29;362:1779-84.