Of the 210 million pregnancies worldwide each year, 87% occurs in developing countries. Twenty-two million terminations of pregnancy per year of a total of 42 million are legal within a local judicial system [¹].

Medical abortion using prostaglandins became an alternative method for surgical abortion of first and second trimester pregnancies in the early 1970s [²]. This procedure appears to be an effective and safe method for abortion, although it might bear certain risks for women with a uterine anomaly.

The prevalence of congenital anomalies due to Müllerian duct malfusion has been estimated between 0.1% in an unselected population and 6% in women undergoing diagnostic imaging [³, ⁴].

In the Netherlands, these congenital anomalies are mostly detected before the termination of a pregnancy, as ultrasound investigation is routine in early pregnancy. However, detection is less likely in developing countries since diagnostic tools are scarce [⁵].

There is little knowledge about the risk of serious adverse outcome, i.e. uterine rupture in medical termination of pregnancy in the presence of a uterine anomaly [⁶, ⁷].

In this paper we present a case report and a review of the literature on the use of misoprostol for termination of pregnancy in women with uterine anomaly. Published risk percentages of uterine rupture in using misoprostol for medical abortion enabled us to calculate this risk in a population of pregnant women in developing countries requesting abortion.

A 32-year-old primigravida presented herself at our outpatient department requesting a termination of pregnancy. Ultrasound scan revealed a vital intrauterine pregnancy of 8 weeks and a uterine anomaly in the form of a class II or a class III malformation (unicornuate uterus with a rudimentary horn or a uterus didelphys). Generally in our clinic all women requesting a termination of pregnancy are counseled for a surgical as well as a medical procedure while taking all contraindications into consideration. Although our patient preferred a medical procedure, the attending physician doubted the safety of medical termination with misoprostol, deciding upon the surgical procedure instead.

Since the introduction of misoprostol, there has been concern about its safety. The manufacturer has sent several warning letters against the unlicensed use of misoprostol during pregnancy [²⁰].

Risks concerning the use of misoprostol are its teratogenic properties, hyperstimulation of the uterus, pregnancy loss and uterine rupture. Most of these safety issues have been addressed. Regimens used in obstetric and gynecological practice that are in accordance with professional guidelines are considered effective and safe [¹³, ²¹].

These guidelines, based on best available evidence, presume that the medical workup before a termination of pregnancy is carried out, is up to standard. Physical examination and access to ultrasound diagnostics are essential in this. Ultrasound scanning can give an accurate estimation of gestational age, reducing the incidence and severity of complications [²²], but can also reveal the presence of uterine anomalies. Unfortunately, sensitivity of ultrasound scanning is only 26% in cases of corneal pregnancy [⁷]. Generally the identification of uterine anomalies is difficult and will need well-trained personnel. Criteria for recognition have been listed by Mavrelos et al. [²³]. During an established pregnancy, ascertaining the exact type of mullerian anomaly is extremely challenging, with a definite diagnosis of the subclass being possible only outside pregnancy.

Most pregnant women in developing countries do not have access to ultrasound investigations or even physical examination by skilled professionals [¹, ²⁴]. Even so, a class II anomaly can be easily missed on routine examination in the absence of an associated cervical or vaginal abnormality [⁶]. Particularly for this group of women, it is important to know whether the administration of misoprostol is safe without any knowledge on the presence of a uterine anomaly.

The precise risks of uterine rupture with misoprostol for termination of pregnancy in the presence of uterine anomalies are not known. Only a few case reports are available. There is still a lack of evidence of safety for the use of misoprostol in settings where diagnostic and therapeutic tools are scarce. The relatively low frequency of these uterine anomalies indicates that on a large scale, the drug is safe, but the exact rate of complications in women affected by Mullerian anomalies remains unknown and is possibly higher than in the general population. Calculations on the prevalence of uterine malformations and the incidence of possibly related serious complications in cases of termination of pregnancy support our opinion that diagnostic ultrasound scanning prior to medical termination of pregnancy to rule out a potentially dangerous uterine anomaly is not mandatory, although large scale studies would be needed to provide a definitive answer toward the need of ultrasound scanning.

Caring for pregnant women with congenital uterine malformations can be particularly challenging, with increased risks of complications arising from surgical and medical ToPs alike. These women might benefit from individualized protocols (e.g. lower doses, use of mifepristone prior to misoprostol).

Conflict of interest statement None.

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