Ovarian torsion 

Risk factors:
Ovarian mass
Women of reproductive age
Infertility treatment with ovulation induction
Signs / symptoms:
Sudden-onset unilateral pelvic pain
Nausea & vomiting
± Palpable adnexal mass
Diagnosis: ultrasound → Adnexal mass with absent Doppler flow to ovary
Treatment / management:
Laparoscopy with detorsion
Ovarian cystectomy
Oophorectomy if necrosis or malignancy