Ovarian Hyperstimulation Syndrome


Risk Factors

  • Age <30 y/o
  • Asthenic Build
  • Early Pregnancy (see Pregnancy, [[Pregnancy]])
  • Large Number of Small Follicles (8-12 mm) Observed on Ultrasound
  • Polycystic Ovaries or High Basal Antral Follicle Count on Ultrasound
  • Prior History of Ovarian Hyperstimulation Syndrome
  • Rapidly Increasing Serum Estradiol
  • Treatment with Follicle-Stimulating Hormone: lesser risk with clomiphene (see xxxx, [[xxxx]])
  • Use of Human Chorionic Gonadotropin (hCG): as opposed to progesterone for luteal phase support after *in vitro” fertilization


  • Iatrogenic Complication of Supraphysiologic Ovarian Stimulation in the Luteal Phase or Early Pregnancy During Infertility Treatment
    • Usually Follows Stimulation by Human Chorionic Gonadotropin (hCG)


  • Capillary Leak Syndrome


Abdominal/Pelvic Ultrasound (see Abdominal-Pelvic Ultrasound, [[Abdominal-Pelvic Ultrasound]])

  • Findings: large ovaries with a large number of follicles, referred to as “necklace sign”

Clinical Manifestations

Mild Ovarian Hyperstimulation Syndrome

Gastrointestinal Manifestations

  • Abdominal Bloating
  • Mild Abdominal Pain (see Abdominal Pain, [[Abdominal Pain]])

Reproductive Manifestations

  • Ovarian Size Usually <8 cm

Moderate Ovarian Hyperstimulation Syndrome

Gastrointestinal Manifestations

Reproductive Manifestations

  • Ovarian Size 8-12 cm

Severe Ovarian Hyperstimulation Syndrome

Gastrointestinal Manifestations

  • Ascites (see Ascites, [[Ascites]]): by clinical exam
  • Hypoproteinemia

Hematologic Manifestations

  • Hemoconcentration with Hct >45%

Pulmonary Manifestations

  • Pleural Effusion (see xxxx, [[xxxx]]): occasional

Reproductive Manifestations

  • Ovarian Size Usually >12 cm

Critical Ovarian Hyperstimulation Syndrome

Cardiovascular Manifestations

Gastrointestinal Manifestations

  • Ascites (see Ascites, [[Ascites]]): tense

Hematologic Manifestations

  • Hemoconcentration with Hct >55%
  • Hypercoagulable State (see Hypercoagulable State, [[Hypercoagulable State]])
  • Leukocytosis (see Leukocytosis, [[Leukocytosis]]): WBC >25k

Neurologic Manifestations

Pulmonary Manifestations

Renal Manifestations

  • Acute Kidney Injury (AKI) with Oliguria/Anuria (see Acute Kidney Injury, [[Acute Kidney Injury]])


  • Hospital Admission: recommended for severe-critical ovarian hyperstimulation syndrome
  • Culdocentesis (Outpatient): should be considered for the prevention of disease progression in moderate or severe ovarian hyperstimulation syndrome
  • Intravenous Fluid Resuscitation
    • Normal Saline (see Normal Saline, [[Normal Saline]])
    • Albumin (see Albumin, [[Albumin]]): can be considered if crystalloid is ineffective
  • Paracentesis: as required to relieve tense ascites
    • Indwelling Peritoneal Pigtail Catheter: may be considered in cases where repeat paracenteses are required
  • Analgesia: as required
    • Acetaminophen (Tylenol) (see Acetaminophen, [[Acetaminophen]])
    • Opiates (see Opiates, [[Opiates]])
    • Avoid NSAID with Anti-Platelet Properties
  • Anti-Emetics: as required
    • xxx
  • DVT Prophylaxis: routine


  • Epidemiology and prevention of ovarian hyperstimulation syndrome (OHSS): a review. Hum Reprod Update 2002; 8(6):559-577 [MEDLINE]
  • Joint Society of Obstetricians and Gynaecologists of Canada-Canadian Fertility Andrology Society Clinical Practice Guidelines Committee; Reproductive Endocrinology and Infertility Committee of the SOGC; Executive and Council of the Society of Obstetricians; Gynaecologists of Canada; Board of the Canadian Fertility and Andrology Society; Shmorgun D, Claman P.  The diagnosis and management of ovarian hyperstimulation syndrome.  J Obstet Gynaecol Can 2011; 33(11):1156-1162 [MEDLINE]