ABSTRACT
OBJECTIVE: To test the hypothesis that ovarian vascularity is increased in women developing ovarian hyperstimulation syndrome (OHSS) and to assess its value as a predictor of OHSS during in-vitro fertilization (IVF). METHODS: 118 subjects undergoing their first cycle of IVF had a three-dimensional (3D) transvaginal ultrasound scan in the early follicular phase of the menstrual cycle preceding IVF treatment. 18 of them developed moderate or severe OHSS and 100 subjects had normal ovarian response. Antral follicle count, ovarian volume, and ovarian vascularity (vascularization index (VI), flow index (FI) and vascularization flow index (VFI)) were compared between OHSS and control groups. Multiple regression analysis was used to assess the predictive value of these variables against age, body mass index and basal follicle-stimulating hormone level for the development of OHSS. RESULTS: The ovarian blood flow indices VI (11.1 +/- 11.6 vs. 8.6 +/- 7.3%; P = 0.23), FI (38.0 +/- 4.8 vs. 38.0 +/- 5.5; P = 0.95) and VFI (4.2 +/- 3.3 vs. 3.5 +/- 3.1; P = 0.40) were similar in the OHSS group and the normal responders. While antral follicle count was significantly higher in women developing OHSS (33.0 +/- 15.1) than in the control group (19.2 +/- 9.9, P < 0.001), ovarian volume did not differ between the two groups (10.6 +/- 3.8 vs. 8.9 +/- 4.8 cm(3), respectively, P = 0.11). On multiple regression analysis, antral follicle count was the only significant predictor of OHSS (P < 0.01). CONCLUSIONS: Women developing OHSS during IVF do not demonstrate an increased ovarian blood flow as measured by 3D ultrasound but do have a significantly higher antral follicle count, which is the only significant predictor of OHSS.
