A 37-year-old woman, gravida 2 para 1, arrived in our emergency clinic at 16 2/7 weeks of a spontaneously conceived pregnancy for abdominal pain. She was on oral antibiotics for 2 days to treat a suspected urinary tract infection with no improvement. Blood tests, abdominal ultrasound and intrauterine fetus were all normal. She left our emergency unit with laxatives. Four days later, she returned to our clinic with severe abdominal pain. We repeated abdominal and foetal ultrasonography and identified a left para-uterine 7×5 cm mass. As adnexal torsion was suspected, we performed an emergency laparoscopy. At laparoscopy, we found a left haematosalpinx and realised a left salpingectomy. Histology confirmed the presence of a heterotopic pregnancy (HP). This case illustrates the importance of exploring the adnexa in a gravid woman presenting with abdominal pain in the first and early second trimesters. Although rare, excluding a HP may prevent a life-threatening haemorrhage.

Background

First described in 1761 as an autopsy finding,¹ heterotopic pregnancy (HP) is defined as concomitant pregnancies developing at two different implantation sites. Most often, an intrauterine pregnancy is seen with a tubal ectopic pregnancy. However, other implantations sites have been described.² Long considered to be a rare event accounting for 1/30 000 spontaneous pregnancies,³ the incidence of HP has increased with the use of assisted reproductive procedures, reaching rates of 1/100 in this population.⁴ We report a case of spontaneous HP diagnosed at 17 weeks of amenorrhoea, treated by laparoscopy and followed by the normal development of the intrauterine pregnancy.

Case presentation

A 37-years-old pregnant woman, gravida 2 para 1, consulted our emergency clinic at 16 2/7 weeks of amenorrhoea for abdominal pain, which started 2 days before. Her pregnancy was spontaneously conceived. She was initially treated with cefuroxime prescribed by her gynaecologist who suspected cystitis, but failed to improve. In our service, she had problem of acute left pelvic pain irradiating to the back and left thigh. The patient denied having had vaginal bleeding, urinary or digestive symptoms. She did not have any relevant medical history, except for a normal vaginal delivery 16 months earlier.

On clinical examination, her heart rate was 84 beats/min, blood pressure was 100/55 mm Hg with a temperature of 37.3°C. The abdominal wall was tender without guarding nor rebound. On pelvic examination, there was a small quantity of blood in the vagina, and no adnexal mass was palpable on bimanual examination. The uterus was measured at 17 cm, as expected for the gestational age.

Investigations

In order to exclude a urinary tract infection, we performed a blood analysis and a urine dipstick/culture. Both examinations were normal (red blood cell count of 114 g/L, white cell count of 6.6×10⁹/L, C reactive protein 12.7 mg/L, creatinine 47 µmol/L). Nephrolithiasis and appendicitis were ruled out by an abdominal ultrasonography. Obstetrical ultrasonography showed a viable fetus corresponding to the weeks of amenorrhoea. However, the adnexa were not described initially. The patient left our emergency unit with laxatives for suspected constipation.

Four days later, she returned to our emergency unit with severe abdominal pain. At clinical examination, she had signs of peritoneal irritation. We repeated laboratory exams. Blood test revealed a decrease in the haemoglobin value (101 g/L vs 114 g/L). White cell blood count was stable. Ultrasonography showed an ongoing intrauterine pregnancy, but also a poorly vascularised left para-uterine 7×5 cm mass (figure 1) sensitive to probe passage.