Effect of late coasting used in the prevention of ovarian hyperstimulation syndrome on oocyte quality

Objective: To detect the effect of late coasting on oocyte quality. Design: Retrospective study. Setting: Samir Abbas Medical Center Materials and methods: Patients where estradiol level was over 4000 pg/ml and late coasting was used as a method to prevent OHSS, and patients where estradiol level was over 4000 pg / ml but no coasting was done Main outcome measure(s) : Oocyte quality. Results: number of mature oocytes was identical in both groups,however the significant difference was in the oocyte recovery rate which was higher in the control group (120) than in the coasting group(92) Conclusion(s): Oocyte quality is not affected after using coasting as a method for prevention of OHSS. Effect of late coasting used in the prevention of ovarian hyperstimulation syndrome on oocyte quality Ovarian hyperstimulation syndrome (OHSS) is a potentially fatal iatrogenic complication of gonadotrophin administration used in IVF procedures (1) its incidence ranges from 0.5 to 10 % in all ovarian stimulation treatment cycles and up to 20% in high-risk cases (2). The factors leading to this syndrome have not been explained, it seems that there is release of vasoactive substances secreted by the ovaries under HCG stimulation, playing a key role in triggering this syndrome. The hall mark of this condition is a massive fluid shift resulting in profound intravascular depletion and haemoconcentration. (3). Risk factors for developing OHSS include PCOS, young (less than 35 years), lean patients, with high serum estradiol levels. Correspondence: Dr. Samir Abbas medical center (IVF unit), Jeddah, P.O. Box 12190, KSA. Tel. 009662-6530000 Ext. 228, 230, Fax 009662-6513813, E-mail: [email protected] Several methods for preventing ovarian hyperstimulation syndrome or reduce its side effects has been suggested, one of which is coasting. Coasting means withholding gonadotrophins whilst continuing GNRH administration for pituitary down regulation until serum E2 concentrations drop below a given threshold (4). The reported efficacy has not been uniformly consistent probably due to different criteria to apply coasting with estradiol rise more than 3000 pg/ml 6000 pg/ml, or leading follicle size ranging from 16 mm to 20 mm with a coasting duration ranging from 1-11 days (5). The coasting strategy reduces or entirely avoids the need to abandon the cycle or cryopreserve all the embryos, reduces the cost, and patient distress (6). The fall in estrogen during coasting may be due to partial atresia of granulosa cells (7) as granulosa cells are more susceptible to gonadotrophin withdrawal and atresia than are developing oocytes (8). Middle East Fertility Society Journal Vol. 10, No. 1, 2005 Copyright © Middle East Fertility Society 68 Shaltout et al. Late coasting and oocyte quality in OHSS MEFSJ Additionally FSH has been demonstrated to be a potential inhibitor of granulosa cell apoptosis, therefore, by withdrawing FSH, apoptosis may be enhanced (9). Coasting popularity is probably related to its simplicity rather than to definite evidence to its efficacy. It has been suggested that atresia occurring during prolonged coasting maybe associated with impaired outcome of IVF treatment (10). The aim of this study is not only to detect the efficacy of coasting in the prevention of OHSS but mainly also to detect the effect of coasting on oocyte quality. MATERIALS AND METHODS Our study is a retrospective study in which data was collected for IVF patients attending Dr Samir Abbas Medical Center, (Jeddah) during the period between 1-10 -2002 till 30 92003.The patients were divided into 2 groups, including Group 1 coasting group consisting of 86 patients, while Group 2 control group consisting of 100 patients In both groups, pituitary desensitization by GNRH agonist (Decapeptyl, Ferring, Germany) starting from mid luteal phase of preceding menstrual cycle then gonadotrophins 2-4 ampoules/day (Menogon 75 I.U., Ferring, Germany) was initiated when serum estradiol level was less than 50 pg/ml, dose was adjusted according response. When at least 2 follicles reached 18 mm in diameter, HCG (Pregnyl Organon, Netherlands,) 10,000 I.U. was administered intramuscular. In the coasting group, coasting was applied when estradiol level was more than 4000 pg/ml with 30% of follicles more than 18 mm in diameter. Daily measurement of estradiol was done till it became less than 4000 pg/ml the HCG was given and oocytes retrieved after 32-38 hours. The coasting duration was up to 3 days, as all patients had decrease in estradiol level to less than 4000 pg/ ml by that time. Intracytoplasmic sperm injection was performed in both groups. The oocyte recovery rate was defined as the total number of oocytes obtained divided by the number of follicles having the diameter of at least 16 mm on the day of HCG administration. Oocyte maturity was diagnosed by the extrusion of the first polar body, with a fluffy expanded cumulus; corona radiata still associated to the zona and with a clear or sometimes homogenously granulated cytoplasm. Ovarian hyperstimulation syndrome was diagnosed according to the classification of Golan et al 1989, including it as early and late onset moderate and severe OHSS (11). Differences between coasted group and control group were assessed using student t test, logarithmic transformation of variables was performed in order to normalize distribution, other wise, nonparametric tests was used, including Microsoft excel, results are expressed as a mean with standard deviation or as a median with percentile range of 25%-75%).