P-293: r-hCG microdose combined with elective single embryo transfer as an efficient protocol

Abstract

Multiple pregnancies are considered the most serious complication in IVF treatment for both mother and child. Many countries are trying to decrease the number of embryos transferred in order to avoid the multiple pregnancy rate of 20-30% in IVF cycles compared to 1.6% in natural conception. Retrospective studies identified age, number and quality of embryos as the most important factor influencing the rate of multiple births. However, a strategy involving the transfer of only one embryo would be expected to result mainly in singleton pregnancies but might also lead to a considerable decrease in the overall birth rate. Previous studies conducted by our group (O-174, O-195, ESHRE 2005) showed that r-hCG microdose as source of LH associated with lower doses of r-FSH, in order to preventing ovarian hyperstimulation syndrome, is an alternative to good prognosis patients leading to same implantation and pregnancy rates when compared to standard protocols. We designed this study to evaluate the efficiency of r-hCG microdose protocol and elective embryo transfer in preventing multiple pregnancies without impairment the ART outcomes. Prospective study. The study included 48 patients (48 ICSI cycles), younger than 35 years old, BMI ≤ 29 Kg/m2, basal FSH < 10 mIU/mL, with regular menstrual cycles, and at least four oocytes retrieved. Controled ovarian hiperstimulation were achieved throught GnRH agonist and 225 IU of r-FSH (Gonal-F®, Serono) from day-3 of menstrual cycle. When the leading follicle reached 14mm, 7.7μg of r-hCG (0.1 mL of a solution containing 250 μg of r-hCG) equivalent to 200 IU of LH activity per day (r-hCG microdose) was initiated. Two groups were established according to number of embryos transferred, control (CT) group (n= 22) in which it were transferred two or more embryos, and elective single embryo transfer (eSET) group (n=26) that had one elective good embryo transferred. Statistical analyses used χ2 or Student t test as appropriate, and p < 0.05 was considered statistically significant. The CT and eSET groups were similar regarding the mean maternal age (29.5 ± 3.75 x 29.9 ± 4.3; P=0.729), and BMI (24.7 ± 4.1 x 22.7 ± 3.1; P=0.073). Since the eSET group had intentionally aimed to transfer fewer embryos, the step down stimulation protocol was done earlier, and consequently the total r-FSH dose administered was lower (1334 ± 258 IU) than CT (1865 ± 264 IU) (P < 0.001), as mean number of MII oocytes recovered (eSET: 9.5 ± 6.5 x CT: 15.0 ± 9.7; P = 0.029). The average number of embryos transferred on control group were 3.5 ± 0.7 in which at least one had one good morphology; on the eSET group, one elective good morphology embryo was transferred. The implantation (21.4% x 26.9; P=0.608) and pregnancy rates (45.5% x 26.9%; P = 0.181) on CT and eSET groups respectively, were statistically similar; however, the multiple pregnancy rate was 22.7% on CT and zero on eSET group. Our results support that elective SET combined with r-hCG microdose protocol allows reduces the costs of treatment, as well as decreases the risk of ovarian hyperstimulation syndrome and multiple pregnancy.