OBJECTIVETo investigate the factors related to clinical pregnancy outcomes of in vitro fertilization-embryo transfer (IVF-ET) in women with secondary infertility.

METHODSThe clinical, laboratory and follow-up data of 1129 cycles in 1099 patients with secondary infertility undergoing IVF-ET in Women's Hospital, Zhejiang University School of Medicine between July 2012 to July 2014 were retrospectively reviewed. The factors related to pregnancy outcomes were analyzed by univariate and logistic regression methods. The clinical pregnancy rates in women with different age and different number of embryos transferred were compared. The clinical outcomes of stimulation with gonadotropin releasing hormone (GnRH) agonist long protocol, GnRH agonist short protocol and GnH antagonist protocol were evaluated in secondary infertile patients aged ≥ 40 years.

RESULTSAmong 1129 cycles, 376 cases (33.30%) had clinical pregnancy and 753 cases (66.70%) had no clinical pregnancy. There were significant differences in age, body mass index, basal follicle-stimulating hormone level, antral follicle number,paternal age and number of embryos transferred between pregnancy and no pregnancy groups (P<0.05); while only maternal age (OR=0.900, 95% CI: 0.873~0.928, P<0.001) and the number of embryos transferred (OR=2.248, 95% CI: 1.906~2.652, P<0.001) were the independent factors affecting the clinical pregnancy outcome of IVF-ET. There was no significant difference in clinical pregnancy rate between women aged 30~40 years with two embryos transferred and those aged<30 years with two or three embryos transferred(P>0.05). There were no significances in clinical pregnancy rate among women aged ≥ 40 years using GnRH agonist long protocol,GnRH agonist short protocol and GnRH antagonist protocol for stimulation (P>0.05).

CONCLUSIONMaternal age and number of embryos transferred have independent effect on IVF-ET clinical pregnancy outcome of secondary infertile women. We suggest that no more than two embryos should be transferred for women in their thirties to minimize the risk of multiple pregnancy while still having an acceptable pregnancy rate. The pregnancy rate of patients over 40 years decreases significantly, and there is no difference in pregnancy rate by using GnRH agonist long protocol, GnRH agonist short protocol or GnRH antagonist protocol.