Fletcher, Horace M.; McCaw-Binns, Affette M.
Author Affiliation, Ana.
Department of Obstetrics, Gynaecology and Child Health
Rupture of the uterus after misoprostol induction of labour
Journal of Obstetrics and Gynaecology
Date of Publication
It is now standard practice to use dinoprostone prostaglandin pessaries or gel to ripen the cervix. Dinoprostone is however very expensive and is not always available in some countries. As a result, less expensive alternatives have been sought and this has led to the introduction of the drug misoprostol for cervical ripening (Alcaide and Sumpacio, 1989). Studies have now shown that misoprostol is significantly more effective than dinoprostone in inducing labour when repeat doses are used within 24 hours (Sanchez-Ramos et al, 1993;Wing et al 1995) even with doses as small as 25mg 4-hourly (Wing et al, 1995) With higher doses 50-100mg 4-hourly, the side effect of hyperstimulation was significantly greater than with dinoprostone (Sanchez-Ramos et al,1993). On the other hand, a single dose regime , as used in these two cases, of 100mg in 24 hours was not shown to be more potent than dinoprostone (Fletcher et al, 1994). In severe cases of uterine overstimulation, rupture of the uterus is also possible with prostaglandins (McKenzie, 1990). This is a known complication of all oxytocic agents and has been reported even with the smallest doses of dinoprostone (0.5mg dinoprostone gel) (Maymon et al, 1991). Rupture of the uterus with misoprostol has been reported twice previously, during induction of labour with 200mg at 38 weeks gestation (Aguero, 1996), and during induction of labour at 39 weeks with two doses of 25mg 4 hours apart (Bennett, 1997). In the two cases presented here, the rupture may have been caused by inappropriate use. In case 1 the dose used, 200mg was certainly too high. In case 2 oxytocin was started 5 hours after the second misoprostol tablet while the usual recommendation is to wait at least 12 hours. In both cases the anatomical position of the uterine rupture was identical, along the lateral aspect of the uterus within the broad ligament. This type of rupture was also described in the case with 0.5mg dinoprostone (Maymon et al, 1991) and also in the case with misoprostol described by Aguero (1996) and is typical of rupture of the unscarred uterus (Cunningham et.al, 1993). The two patients were also similar in other respects. They were both multiparous but of low parity, they both had pregnancy-induced hypertension and both were sickle positive (A/S in both cases sickle cell trait). The significance of these factors is however unknown. One patient also had a previous dilation and curettage for prevous spontaneous abortion which is a predisposing factor for uterine rupture in labour. The sudden upsurge in use of misoprostol for induction of labour worldwide, is certain to be followed by further reports of uterine rupture due to its use, especially in rural hospitals where care may be suboptimal. This can however be reduced by cautious use and careful monitering of all patients in whom it is being used. It is now becoming clear that the drug is effective even at dosages with 25mg 4- hourly. Once daily dosage with 50-100mg is now the standard in Jamaica but needs further study to establish safety conclusively. Larger doses, such as 200mg and use with oxytocin less than 12 hours after the last tablet, appear to be absolutely contraindicated. ....