A previous post (and comment), led me to investigate this topic further. I’d heard of previous C-section scars giving way; and I’d heard of uterine rupture in the case of labor induction or augmentation; but I’d never heard of an unscarred uterus rupturing.
This study talks about it. Unfortunately, it is just an abstract, so I’ve got a few questions which I’m sure could be answered if I had access to the full study. Oh, well. It identified 13 ruptures in an unscarred uterus, and says 3 were caused by car wrecks, and were excluded from the study; oxytocin was used in 4 cases; prostaglandin in 3; vacuum or forceps in 3; 2 were in women who were grand multiparas; and 2 had fetal malpresentation. It gave a rate of 1 uterine rupture in an unscarred uterus per 16,849 births. Questions I have include whether all of these ruptures were complete, or if some were dehiscence; and whether any of the women with an “unscarred uterus” had any prior uterine surgery (including a D&C, which carries with it a slight possibility of a punctured uterus). I’m assuming that all of the ruptures were complete, considering that in the study discussed in the previous post, all three uterine ruptures in unscarred uteri were complete. Of those three, two occurred in women with prior D&C, but one said she had had no prior uterine surgery.
The numbers above add up to more than 10, though, so I can’t tell from the abstract whether or not obstetric intervention was used in all of them, or if some women had both oxytocin induction or augmentation and forceps removal of the baby. It’s seems reasonable that the babies that were in a poor position were also more likely to have induction of labor or vacuum/forceps use, since such women tend to have longer and slower labors (probably the contractions help to guide the baby into a better position if given enough time; but many hospital and/or doctor protocols don’t allow that much time).
Moving along, there is this tantalizing abstract which talks about a woman whose uterus ruptured after misoprostol was used to induce labor at 29 weeks (for an intra-uterine fetal demise). It says it includes “a review of all cases of uterine rupture with misoprostol induction,” which I’d like to be able to see. There were numerous other case studies and reports of women who suffered a ruptured uterus with second-trimester abortions, typically associated with misoprostol use, sometimes with a previous C-section.
Here’s one due to fundal pressure (when the mom was pushing, somebody pressed on the top of her uterus, to “help” her push her baby out). The World Health Organization relegates this to “Practices for which Insufficient Evidence Exists to Support a Clear Recommendation and which Should be Used with Caution while Further Research Clarifies the Issue.”
This case was extremely interesting, in that the researchers said, “To the best of our knowledge, this is the first documented rupture of a gravid [pregnant] uterus occurring before onset of labour without previous risk factors.” The woman denied having a D&C or any previous abortions, didn’t have any uterine malformations or anything which were known risk factors. She went to the hospital at 32 weeks gestation because of sharp abdominal pain. Quite interesting, especially since it gives a short summary of various risk factors that other reports and studies have not mentioned. Mother and baby were fine.
This study from Ireland noted a rupture rate in unscarred uteri at 0.02% (8 cases out of more than 48,000 women who had had a previous pregnancy, not counting 0 cases out of nearly 28,000 first-time moms). But there is this case study in which a first-time mom had an unexplained uterine rupture.
This woman from California had her uterus rupture during second-stage labor (pushing), which was blamed on the rate of oxytocin (Pitocin, “Pit”) for labor induction. The researchers noted that despite having contractions every 2-3 minutes, the rate kept being increased during first- and second-stage labor. Although an emergency C-section was performed, the baby had signs of asphyxia.
So, rupture of an unscarred uterus can happen but is blessedly rare, especially when drugs used to induce or augment labor are avoided.
Filed under: studies & stuff Tagged: | abortion, baby, birth, cytotec, induction, labor induction, miso, misoprostol, oxytocin, pge2, pregnancy, pregnant, pro-life, prostaglandin, prostin, uterine rupture