Congenital malformations of the female genital tract are defined as deviations from the normal anatomy that result from embryological maldevelopment of the Müllerian or paramesonephric ducts [1,2]. Septate uterus is the most common congenital uterine anomaly resulting from the failure of resorption of the midline septum after the fusion of two Müllerian ducts. Septate uterus is defined as a uterus with a normal outline and an internal indentation at the fundal midline exceeding 50% of the uterine wall thickness. Septate uteri are subdivided into two sub-classes according to the degree of uterine corpus deformity: incomplete/partial septate and complete septate uterus. A partial septate uterus is a single fundus and cervix with a uterine septum that partially divides the uterine cavity above the internal cervical os, and a complete septate uterus is characterized by the existence of a septum that fully divides the uterine cavity up to the internal cervical os with or without a cervical and/or vaginal septum [1]. Adverse reproductive outcomes that have been attributed to septate uteri include infertility, pregnancy loss, and poor obstetric outcomes, such as malpresentation and preterm delivery. However, many women with uterine septa do not experience any reproductive difficulties [2,3].

First trimester surgical abortion is an effective and safe procedure when its completion can be confirmed with careful inspection of the aspirate [4]. However, if attempts at surgical abortion fail, steps must be taken to carefully assess the clinical technique and patient's anatomy. Uterine anomaly has been recognized as an occasional contributing factor to failed surgical abortion [5].

Here, we present a case that was successfully managed with operative hysteroscopy-assisted dilatation and evacuation (D&E) under ultrasound guidance in a woman with complete septate uterus in whom previous ultrasound-guided D&E for the management of missed abortion had failed.

A 33-year-old woman (gravida 2 para 1) with a history of amenorrhea for 8 weeks and 4 days presented with two consecutive failed surgical abortions. She had a previous history of preterm delivery by cesarean section at gestational age of 33 weeks under the diagnosis of breech presentation in 2011. A uterine anomaly was found incidentally during surgery. On May 3, 2014, pregnancy was confirmed by detecting gestational sac in the endometrial cavity using ultrasonography at 5 weeks and 2 days of gestation. One week later, the crown-lump length (CRL) was consistent with an age of 6+0 weeks without a fetal heartbeat. At 8 weeks of gestation, a fetal heartbeat was still not observed and CRL had not increased. Under the diagnosis of missed abortion, she planned to undergo D&E. Ultrasound-guided D&E was attempted, but the suction cannula could not reach the uterine cavity with the gestational sac at a local clinic and a secondary referral hospital.

After the failed surgical abortion, she was referred to our hospital. A pelvic examination revealed a single uterine cervical opening without vaginal septum. Ultrasonography revealed two separate uterine cavities with a 2.8-cm gestational sac in the left-sided cavity but no definite fetal pole. A septum dividing the uterine cavity was observed, but fundal indentation was not definite (Fig. 1A). For pregnancy termination, ultrasound- and/or operative hysteroscopy-guided surgical abortion was planned. The day before the operation, misoprostol 400 µg was inserted intravaginally to soften the uterine cervix. After adequate dilatation of the uterine cervix, a curette was inserted into the uterine cavity under ultrasound guidance; however, it did not reach the left-sided uterine cavity containing the gestational sac. When a hysteroscope was inserted into the uterine cavity, it passed easily into the empty right-sided uterine cavity but could not be passed into the left-sided cavity. During the operation, slight communication to left-sided cavity was noted just above the cervical internal os. After the communication was widened using hysteroscopic resection of the uterine septum, the hysteroscope could enter the left-sided cavity with the conceptual tissue (Fig. 1B-D). After further resection of the uterine septum, conceptual tissue was successfully removed by curettage and vacuum aspiration under ultrasound guidance. Because the placental tissue was within the uterine septum, we did not perform a septectomy. The patient was discharged without complications on the same day. Two weeks later, magnetic resonance imaging (MRI) was performed to enable a more accurate diagnosis of the Müllerian anomaly. MRI revealed that the septum extended nearly to the external cervical os without fundal indentation, suggesting complete septate uterus with cervical septum. There were no specific findings in the endometrial cavity or either ovary. There was no urologic anomaly (Fig. 2A). According to the European Society for Human Reproduction and Embryology/European Society of Gynecological Endoscopy (ESHRE/ESGE) classification system, the female genital anomaly was classified as U2bC1V0.

Because the patient experienced adverse obstetrical events, including preterm delivery and miscarriage, an operative hysteroscopic septectomy was planned for the next pregnancy. Upon entry to the endometrial cavity, diffuse endometrial polyps and a uterine septum were noted (Fig. 2B). However, a cervical septum was not found. Operative hysteroscopic uterine septectomy and endometrial polypectomy were performed on September 5, 2014. She was discharged uneventfully later the same day. After the operation, an intrauterine Foley catheter was inserted for 1 week, and high-dose continuous cyclic estrogen-progestin therapy with conjugated equine estrogen 1.25 mg was taken PO bid for 28 days, followed by medroxyprogesterone acetate 10 mg qd for 14 days for 2 months. The pathology finding of the uterine septum was “endomyometrial tissue showing proliferative phase.”

Surgical abortion is a very safe procedure when performed legally. The overall major complication rate for first trimester surgical abortions is about 0.5%. Complications include failed abortion, incomplete abortion, hemorrhage, infection, and uterine perforation [6]. Although failed abortion is very rare, with an incidence of 0.08–4.2%, it may have serious consequences such as bleeding, infection, need for additional surgery, and persistent pregnancy. Causes of failed abortion include poor technique, cervical stenosis, marked uterine anteversion or retroversion, endometrial distortion, uterine fibroids, very early gestational age, and uterine anomaly [7]. There are several reports on failed surgical termination in patients with uterine anomalies, including bicornuate uteri [8], non-communicating rudimentary horn [9,10], and septate uteri [7,11]. Failed surgical abortion was also reported in women with Robert’s uterus, a rare variant of septate uterus consisting of a non-communicating hemicavity or a contralateral unicornuate uterine cavity in a single uterine body with a normal fundus [12]. In Korea, however, there are few reports on failed surgical abortion in patients with uterine anomalies. In fact, we found only one case report on hysteroscopy-assisted therapeutic abortion after two consecutive failures of induced abortion in a woman with uterus didelphys, obstructed hemivagina, and cervicovaginal fistula [13]. Here, we reported a rare case that was successfully managed with operative hysteroscopy-assisted D&E under ultrasound guidance in a woman with a complete septate uterus in whom ultrasound-guided D&E had failed to manage a missed abortion.

Although ultrasound guidance is not routinely used during surgical abortion, it may increase the success rate and decrease the incidence of retained products of conception and uterine perforation. Ultrasound-guided surgical abortion is more valuable in cases of surgical abortion in women with uterine anomaly as well as after failed abortion [7,11]. However, ultrasound guidance may not be useful in cases of uterine anomaly with no or small communication. In the present case, a suction cannula could not reach the left-sided pregnant hemicavity despite ultrasound guidance.

Hysteroscopy can be useful in identifying pregnancy in women with a uterine anomaly. This is most helpful in the case of septate uterus [7,11]. In the present study, MRI revealed that the patient had complete septate uterus with cervical septum, but the left cervical canal and cervical septum could not be identified upon entering the cervix using a hysteroscope after uterine cervical dilatation. We identified the tiny communication just above isthmus level and a left-sided hemicavity with conceptual tissue. After widening the communication, we easily performed D&E under ultrasound guidance.

In the present case, a female genital anomaly was classified into U2bC1V0 according to the ESHRE/ESGE classification system. Unlike on MRI, however, the cervical septum could not be identified during hysteroscopy. Because the right-sided cervical canal was predominant and the left-sided cervical canal was too narrow to pass through, the right-sided canal was passed easily after cervical dilatation. The genital anomaly might have been Robert’s uterus with an inactive blind hemicavity without hematometra. Communication of the isthmic portion might have been created during the previous Cesarean section. It was previously suggested that fusion and resorption begin at the isthmus and proceed simultaneously in the cranial and caudal directions [14]. Although fusion and resorption defects frequently affect the superior uterine segment only or both segments with the transversal limit of the junction between them at an isthmic level (corresponding to the second portion or fusion area of both Müllerian ducts), segmental defects are possible [15]. Although it has not been reported until now, Robert's uterus with isthmic communication may be possible.

In conclusion, women with female genital anomaly are at risk of failed surgical abortion. In such patients, operative hysteroscopy and ultrasound are useful for locating the site of pregnancy and successfully performing the surgical abortion.