From the Guidelines
The risk of uterine rupture is significantly increased in women with previous cesarean deliveries who undergo labor induction, particularly with prostaglandins, and thus, spontaneous labor is preferred, with oxytocin induction being a safer alternative when necessary. For women with a prior cesarean, spontaneous labor carries approximately a 0.5-0.7% risk of uterine rupture, while induction with oxytocin increases this risk to about 1-1.5% 1. Prostaglandin induction, especially with misoprostol, poses a significantly higher risk, with some studies suggesting a 5-10 fold increased rupture risk in women with uterine scars 2, 1. The increased rupture risk with induction agents relates to their mechanism of action, creating strong, sometimes hyperstimulated contractions that place additional stress on scarred uterine tissue.
Key Considerations
- For women without prior uterine surgery, the risk of uterine rupture is extremely low, about 0.01%, regardless of labor onset method 3.
- When induction is necessary in women with a prior cesarean, mechanical methods like Foley catheter dilation are preferred initially, followed by oxytocin if needed, while avoiding prostaglandins entirely due to the higher risk of uterine rupture 1.
- Close monitoring during labor with continuous fetal heart rate assessment and vigilance for warning signs (sudden pain, vaginal bleeding, fetal distress, or maternal hypotension) is essential for early detection of potential rupture, particularly in higher-risk scenarios 3.
Recommendations
- Avoid the use of misoprostol in women with previous cesarean delivery due to the increased risk of uterine rupture 2, 1.
- Consider individualized plans for labor and vaginal birth after cesarean delivery (VBAC), taking into account the patient's risk factors, such as the presence of a classic uterine scar or a short inter-delivery interval 3.
From the FDA Drug Label
Maternal deaths due to hypertensive episodes, subarachnoid hemorrhage, rupture of the uterus and fetal deaths due to various causes have been reported associated with the use of parenteral oxytocic drugs for induction of labor and for augmentation in the first and second stages of labor A major adverse effect of the obstetrical use of Cytotec is the hyperstimulation of the uterus which may progress to uterine tetany with marked impairment of uteroplacental blood flow, uterine rupture (requiring surgical repair, hysterectomy, and/or salpingo-oophorectomy), or amniotic fluid embolism The risk of uterine rupture increases with advancing gestational ages and with prior uterine surgery, including Cesarean delivery. Grand multiparity also appears to be a risk factor for uterine rupture.
The risk of uterine rupture is increased with the use of oxytocin or misoprostol for induction of labor. Key factors that increase this risk include:
From the Research
Risk of Uterine Rupture
- The risk of uterine rupture during trial of labor after a previous cesarean delivery is a significant concern, with studies indicating varying rates of rupture depending on the method of labor induction 6, 7, 8, 9, 10.
- A study published in 2012 found that the rate of uterine rupture was lowest with oxytocin induction at 1.1% (95% CI, 0.9%-1.5%), followed by dinoprostone at 2% (95% CI, 1.1%-3.5%), and highest with misoprostol at 6% (95% CI, 0.74%-51.4%) 6.
- Another study published in 1999 found that the overall rate of uterine rupture among women undergoing induction of labor was 2.3%, compared to 0.7% among women with spontaneous labor (P = .001) 7.
- A meta-analysis published in 2021 found that women who had spontaneous labor had a significantly higher rate of vaginal birth after cesarean (VBAC) and a lower rate of uterine rupture compared to induced labor, with pooled rates of uterine rupture in women using oxytocin and women not using oxytocin in trial of labor after cesarean (TOLAC) being 1.4% and 0.5%, respectively (p = 0.0002) 8.
- A study published in 2004 found that uterine rupture occurred in 4 of 41 patients with previous cesarean delivery who had labor induced with misoprostol, resulting in a rate of uterine rupture of 9.7% (P < 0.001) 9.
- A retrospective review published in 2005 found that the risk of uterine rupture or dehiscence in women who required induction of labor with previous cesarean sections was 2.4% (95% CI, 0.8-5.6%), with all cases occurring in the group of women with no previous vaginal deliveries 10.
Comparison of Induction Methods
- Oxytocin induction has been associated with a lower risk of uterine rupture compared to misoprostol induction 6, 9.
- Dinoprostone has been found to have a higher risk of uterine rupture compared to oxytocin induction 6.
- Prostaglandin E(2) gel has been associated with an increased risk of uterine rupture, although the difference was not statistically significant 7.