Heterotopic Pregnancy: A Case Report and Literature Review

Heterotopic pregnancy, the simultaneous presence of an intrauterine and an extrauterine gestation, is rare after spontaneous conception.We describe a 30-year-old woman, gravida 2, with a previous left tubal ectopic pregnancy treated with methotrexate, who presented at 5+3 weeks of gestation with vaginal spotting and mild lower abdominal pain.Transvaginal ultrasound showed a left adnexal mass measuring 22 x 16 x 18 mm and a fundal intrauterine sac-like structure (mean sac diameter of 10 mm) without a yolk sac or fetal pole, which was reported as a possible pseudosac.Serum human chorionic gonadotropin (hCG) was 10,292 IU/L.Laparoscopic left salpingectomy confirmed an unruptured tubal ectopic pregnancy, which was verified histologically.A positive urine pregnancy test at the routine three-week postoperative check led to an ultrasound scan showing a viable intrauterine pregnancy with a crown-rump length of 23 mm (9+0 weeks).This matched the gestational age of the intrauterine sac seen before surgery, confirming that the two pregnancies had coexisted.The pregnancy was later complicated by late-onset fetal growth restriction, preceded by abnormal uterine artery Doppler at 20 weeks, and a healthy female infant weighing 2,250 g (1.2nd centile) was delivered by planned caesarean section at 37+2 weeks.An intrauterine sac-like structure should be regarded as a possible early intrauterine pregnancy even when an ectopic pregnancy is clearly visualised, and the post-salpingectomy pregnancy test provides an important safety net.