[Clinical study on in vitro maturation of immature oocytes transferred from conventional in vitro fertilization.].

OBJECTIVE:To investigate clinical effect of in vitro maturation (IVM) of immature oocytes transferred from conventional in vitro fertilization embryo transfer (IVF-ET) cycles. METHODS:From January 2008 to June 2009, medical documents of 155 infertile patients underwent IVF-ET in the Reproductive Medical Center of First Affiliated Hospital of Wenzhou Medical College were analyzed retrospectively. If more than 20 oocytes were monitored after 5 - 7 days of ovulation induction or follicular developmental retardation were confirmed after 8 - 13 days of ovulation induction, according to patients' wish, IVM were transferred in 60 cycles (group A). In the mean time, IVF was continued in 95 cycles (group B). The mean dosage of gonadotropin, the cancellation rate of cycles, the mean numbers of oocytes retrieved and maturation, the rate of fertilization and excellent quality embryos, pregnancy outcome and the incidence rate of ovarian hyperstimulation syndrome (OHSS) were compared and analyzed. RESULTS:The rates of embryo transfer were 92% (55/60) in group A and 63% (60/95) in group B, which showed significant differences (P < 0.05). In group A, the mean dosage of the gonadotropin, the mean number of oocytes retrieved, the cleavage rate and OHSS rate were (1030 +/- 468) U, 10 +/- 6, 82.2% (231/281) and 0, and were (1544 +/- 338) U, 14 +/- 4, 94.0% (502/534) and 35% (21/60) in group B, respectively, all data above exhibited statistical difference between two groups (P < 0.05). However, the rates of fertilization and excellent quality embryos had no significant differences between two groups (P > 0.05). In group A, the rate of clinical pregnancy per transfer was 53% (29/55) and multiple pregnancy was 14% (4/29), and were 47% (28/60) and 32% (9/28) in group B, they all had no significant differences (P > 0.05). CONCLUSION:IVM of immature oocytes used in conventional IVF cycles not only obtained a high clinical pregnancy rate, but also reduced gonadotropin using dosage and avoided OHSS completely.