Ovarian hyperstimulation syndrome: pre-ovulatory serum concentrations of interleukin-6, interleukin-1 receptor antagonist and tumour necrosis factor-alpha cannot predict its occurrence.

The pathogenesis of the ovarian hyperstimulation syndrome (OHSS) is poorly understood. Since significant elevations in cytokines are found in OHSS, our objective was to conduct a prospective case-controlled study to assess if pre-ovulatory cytokine serum concentrations can predict its occurrence. The study group was selected from in-vitro fertilization patients who subsequently developed severe OHSS, along with a matched group who did not develop this complication (n = 20), and a healthy normal control group (n = 10). Interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1RA) and tumour necrosis factor-alpha (TNFalpha) measurements were performed with sensitive immunoassays and confirmed with bioassays. Serum IL-6 (mean concentrations +/- SEM: 4. 38 +/- 0.36 pg/ml), IL-1RA (829 +/- 292 pg/ml) and TNFalpha (15.5 +/- 1.32 pg/ml) concentrations did not show differences throughout the normal menstrual cycle group. Cytokine variability and pre-ovulatory values were similar in OHSS compared to controlled ovarian hyperstimulation (COH) patients. However, average follicular phase serum IL-6 concentrations were higher in OHSS (8.71 +/- 0.41 pg/ml) and COH (7.66 +/- 0.38 pg/ml) patients than in normally menstruating women (4.34 +/- 0.99 pg/ml) (P < 0.0001). Pre-ovulatory serum IL-6 concentrations were also higher in OHSS (9 +/- 0.94 pg/ml) and COH (7.3 +/- 0.97 pg/ml) patients than in controls (4.57 +/- 1.1 pg/ml) (P < 0.01 and P < 0.04 respectively). All IL-1RA and TNFalpha concentrations were comparable in all the groups. This study suggests that cytokine measurements cannot be used to predict the occurrence of OHSS prior to the administration of human chorionic gonadotrophin.