Incidence of Ovarian Hyperstimulation Syndrome (OHSS) in cases subjected to Controlled Ovarian Hyperstimulation

Objective: Ovarian hyperstimulation syndrome is an iatrogenic complication of ovulation induction applied with gonadotrophins. In this study, we aimed to determine the OHSS incidence for cases taken into IVF- ICSI / ET cycle and subjected to controlled ovarian hyperstimulation in our clinic. In addition, for allowing an evaluation on the risk factors of OHSS, it was targeted to make a comparison between the patient groups developing and not developing OHSS.Materials and Methods: In our study, IVF- ICSI / ET cycles subjected to controlled ovarian hyperstimulation between 1st of January, 2006 and 30th of December, 2009 in the Clinic of Obstetrics and Gynecology of Çukurova University, School of Medicine were evaluated. Patients developing OHSS and patients not developing OHSS were set as two different groups. File of each patient was searched for information on age, weight, height, body mass index, presence of PCOS, OHSS history, basal USG findings, E2, FSH, LH levels measured on the 3rd day on menstruation, treatment protocols applied, gonadotrophine doses and periods applied, hCG doses and types applied, hCG day mature follicle number, aspired small follicle number, collected oocytes number and presence of pregnancy.Results: Number of cycles for the groups developing OHSS and not developing OHSS were 69 and 1373 respectively. Incidences of moderate OHSS and intense OHSS were determined to be 4% and 0.2% respectively. On the other hand, incidence for all OHSS cases was 4.7%. OHSS development was seen to be higher for patients having high basal LH values, LH/FSH ratios and hCG day E2 values. HCG day mature follicle numbers, aspired preovulatory follicle numbers, aspired small follicle numbers and collected oocyte numbers for the OHSS developing group were found to be higher than the other group (p = 0.0001). Risk of OHSS development was determined to be 7.6 times higher (95% confidence interval 4.3 ? 13.5) for patients having PCOS when compared top the patients not having PCOS. OHSS risk was found to be higher for the patients having pregnancy (p = 0.0001). Risk of OHSS development was 15.2 times higher (95% confidence interval 4.71 ? 49.35) for patients having a history of OHSS when compared with the ones not having such a history. Possibility of OHSS development was 7.7 times higher (95% confidence interval 4.6 ? 12.8) for patients whose hCG day E2 values were higher than 3000 pg/ml. The comparison made between the antagonist protocol and the long luteal agonist protocol showed that there is no statistically significant difference between the two groups in terms of OHSS development (p = 0.069). Our study also revealed that there is no statistically significant difference between urinary 10000 IU and recombinant 250 mcg hCG in terms of OHSS development (p = 0.992). Although age, body mass index and LH/FSH were determined to be risk factors for OHSS in the single variable analysis, they are not included in the list of risk factors according to the the multiple logistic regression analysis. When the OHSS developing patients group (n=69) was analyzed, 51 of the patients were seen to have early type OHSS and remaining 18 of them were seen to have late type OHSS. On the other hand, 8 of the cases were determined to be mild OHSS, 58 were determined to be moderate OHSS and 3 were determined to be severe OHSS.Conclusion: In our study it was found that E2 values higher than 3000 pg/ml, LH/FSH ratio higher than 2 and presence of PCOS history are risk factors for OHSS. It is thought that the minimum dose required for proper follicle development must be applied for patients having high risk and treatment protocols must be individualized. Follicle development must be closely monitored during the treatment process by use of ultrasonography and estradiol follow-up. For vulnerable cases, patients must be hospitalized and closely monitored.Keywords: IVF-ICSI/ET cycles, hCG, estradiol, gonadotrophin, OHSS