Purpose: Early timed follicular aspiration (ETFA) of one ovary 10-12 hr after administration of chorionic gonadotropin (hCG) is an attempt to prevent severe ovarian hyperstimulation syndrome (OHSS). After the introduction of early timed follicular aspiration ETFA of one ovary in IVF/ET cycles at high risk for severe OHSS, no cases of severe OHSS were registered in the Ljubljana IVF/ET program. In the period before preventive ETFA (1984-1992) there were 16 cases of severe OHSS of 4798 IVF/ET cycles followed by 577 clinical pregnancies. After the introduction of ETFA (1992-1993) there were no cases of severe OHSS of 2289 IVF/ET cycles followed by 364 clinical pregnancies.
Methods: We attempted to evaluate the significance of this observation by comparing two groups of female infertility IVF/ET cycles at high risk for severe OHSS. The occurrence of severe OHSS and clinical parameters in the two groups of IVF/ET cycles at high risk for severe OHSS were compared.
Results: In the group of 106 IVF/ET female infertility cycles at high risk of severe OHSS with preventive ETFA, there were no cases of severe OHSS. In the control group of 92 IVF/ET female infertility cycles at high risk for severe OHSS with normally timed follicular aspiration (NTFA) of both ovaries, severe OHSS occurred in 16 cases. The difference in the occurrence of severe OHSS between the two groups is highly significant (P < 0.005), both in hMG/hCG- and in GnRHa/hMG/hCG-induced IVF/ET cycles. No difference in live birth rate (16 vs. 16%) between the two groups was noted.
Conclusions: Considering these results we conclude that ETFA is another successful option to decrease the incidence of severe OHSS in assisted reproduction. The preventive effect of follicular aspiration seems to depend on its timing.