VBAC/TOLAC spacing limit

[HeartsOpenWide, RN]

For those of you that work at hospitals that allow VBACs, what is the spacing limit between the C/S and the time allowed to have a VBAC? Our hospital requires 18 months. I know ACOG recommends a 24 month birth spacing in general but does not mention for VBACs/TOLAC.

[LibraSunCNM, BSN, MSN, CNM]

We do VBACs fairly frequently but have no spacing policy that I'm aware of. Is there actual evidence that less than 18 months in between is more likely to result in rupture?

[ominousdusk]

ACOG recommends 18 months for VBACs, but there is no evidence than an interval of less than 18 months increases rupture risk. There was 1 study that suggests a VBAC success rate is slightly lower (4% less) in a birth interval less than 18 months for a VBAC induction. But there is no difference in the success rate for a VBAC with an interval less than 18 months for spontaneous labor.

so basically that 18 month rule is not founded on any actual evidence. it should be they don't recommend augmentation before an 18 month interval, not VBACs in general.

[rbytsdy]

ACOG doesn't have a specific recommendation for interval delivery spacing with VBAC - at least not in their VBAC practice bulletin. There are only a few studies on spacing of deliveries related to VBACs. While most of them do show an increased risk of uterine rupture with shorter intervals, the studies are rather flawed because the sample sizes are very small. The various authors don't necessarily define the intervals the same way (one author may group women "under 13 months from cesarean to VBAC," "12-24 months from cesarean to VBAC" and "24 months + from cesarean to VBAC." Another author may group women as "up to 18 months from cesarean to VBAC" and "beyond 18 months from cesarean to VBAC." It's hard to draw consistent recommendations from the research. The studies were done years ago when older suturing (chromic) was more commonly used and that may have contributed to UR rates. Also, the studies were done at 1 institution which weakens the evidence. Ideally, you draw from several institutions.

As far as I know, VBAC guidelines are the providers decisions at my hospital. I don't believe we have a hospital policy.