Asynchronous development of bilateral tubal pregnancy after IVF-ET: A rare case report and review of the literature.

Ectopic pregnancy (EP) is defined as the implantation and development of blastocysts outside the uterine cavity. Unilateral tubal pregnancy accounts for approximately 90% of all EP cases, whereas bilateral tubal pregnancy (BTP) is a rare variant. The incidence of BTP ranges from 1 in 750 to 1 in 1,580 of all ectopic pregnancies and is more common in women who have undergone assisted reproductive technology (ART) than in those with natural conception. However, asynchronous development in the BTP is even rarer. A 32-year-old woman underwent embryo transfer at our institution due to primary infertility (In vitro fertilization and embryo transfer with two Day 3, grade I, 8-celled fresh embryos). Nineteen days after the transfer, the patient experienced lower abdominal pain and vaginal bleeding. The β-HCG blood test revealed an elevated level of 7232 IU/L, and ultrasound imaging suggested right tubal pregnancy. Consequently, laparoscopic surgery was performed. Intraoperatively, the isthmus of the right fallopian tube appeared swollen, whereas the left fallopian tube appeared normal. Right salpingectomy was performed, and pathological examination confirmed the diagnosis of right tubal pregnancy. Twelve days postoperatively, the patient exhibited an asymptomatic elevation in β-HCG levels, and ultrasound imaging suggested left tubal pregnancy. The second laparoscopic examination revealed a thickened isthmus in the left fallopian tube. Bilateral tubal pregnancy with asynchronous development. Laparoscopic right salpingectomy and left salpingotomy was performed. Two weeks post-surgery, during follow-up, the patient reported no discomfort, and serum HCG levels normalized. Although asynchronous development of bilateral tubal pregnancy is an extremely rare form of ectopic pregnancy, women who have undergone ≥2 embryos transfer or ovulation induction treatment should be vigilant for the possibility of the above situation.