BACKGROUND Torsion is the most common gynecologic emergency of the adnexal mass occurring during pregnancy. We report the clinical data of a case of twin pregnancy with adnexal torsion after in vitro fertilization (IVF) and embryo transfer, in which the patient underwent surgery for adnexal detorsion and experienced preterm delivery. One child died as a neonate, and the other child was diagnosed with hematological disease, which, to our knowledge, has not been reported previously. We also performed a systematic literature review to increase knowledge of the need for prompt surgical intervention. METHODS The patient was a 32-year-old pregnant woman, who presented to our center with acute onset of stabbing and non-radiating continuous lower left abdominal pain after urination, of 6 hours duration. METHODS Physical examination revealed that the lower abdominal tenderness was worse on the left side, and there were no signs of peritonitis. Transvaginal ultrasonographic examination indicated a multiloculated left ovary measuring 12.1 × 7.1 cm with sparse blood flow. The size of the largest cyst was 7.2 × 6.6 cm, the right ovary appeared normal, and two live fetuses were seen. METHODS laparoscopy was performed 1.5 hours later, which revealed a cystic and multilocular left ovary with a black purplish surface and thin wall. The left ovary and left fallopian tube had undergone 720° torsion (3 rotations), and detorsion was performed laparoscopy. RESULTS The left adnexa recovered to near normal appearance 20 minutes postoperatively. The patient was discharged from hospital 5 days postsurgery, without complications. Unfortunately, the patient delivered two preterm babies at 30 weeks of gestation. CONCLUSIONS We should be alert to the possible risk of adnexal torsion in pregnant women after IVF. Adnexal torsion necessitates prompt surgical intervention, detorsion and preserving ovarian function are the main treatment methods. Furthermore, the possibility of recurrence, and pregnancy outcomes for the patient, as well as newborn health, should be considered.