No abstract

Blastocyst transfer was associated with an increased MZT incidence. We have to be aware of the potential risk of MZT caused by blastocyst transfer. However, further studies are required to assess the correlation among specific AH types, embryo culture conditions, and MZT incidence.

The results suggest that the SET policy improved perinatal outcomes in Japan. The impact of SET policy was different in fresh and frozen cycles for several perinatal outcomes.

Obesity, which disturbs lipid and glucose metabolism, is a recent medical concern. It threatens human health and also has adverse effects on reproductive functions by causing insulin resistance/hyperinsulinemia, especially in women with polycystic ovary syndrome (PCOS). For PCOS patients to prevent these adverse effects, it is important to take into account improving their lifestyles by exercise and proper diets. The relationship between insulin resistance/hyperinsulinemia and reproductive disorders should be understood as fully as possible in order to provide effective treatment. It is well known that insulin resistance and compensatory hyperinsulinemia can be triggered by obesity with visceral fat accumulation. Hyperinsulinemia affects granulosa cells in small follicles and theca cells. This condition induces early response to luteinizing hormones on granulosa cells of small follicles and causes premature differentiation of these cells, which eventually results in anovulation. For improvement of anovulation because of hyperinsulinemia, insulin-sensitizing agents (biguanide and thiazolidinedione derivatives) are useful. Hyperinsulinemia may adversely affect the endometrial functions and environment, and evoke implantation disturbance. Treatment with an insulin-sensitizing agent (metformin) improves the levels of glycodelin, insulin-like growth factor binding protein 1, and blood flow in spiral arteries during the peri-implantation period. It supports endometrial function, improves the endometrial environment, and facilitates embryo implantation. The rate of early pregnancy loss during the first trimester is 30-50% in women with PCOS, which is threefold higher than for normal women. Metformin treatment improves the levels of insulin, the homeostasis model assessment for insulin resistance, and plasminogen activator inhibitor activity, and decreases early pregnancy loss. It goes without saying that lifestyle change is fundamental for improving reproductive performance in addition to treatment with insulin-sensitizing agents.

Purpose This study aimed to evaluate the efficacy, safety, and trends in assisted reproductive technology (ART) in Japan. Methods Data pertaining to treatment cycles, pregnancy rate, live birth rate, age distribution, single embryo transfer rate, and multiple pregnancy rate were analyzed for patients registered in the national ART registry system of Japan from 2007 to 2010. Results The total number of treatment cycles was 161,164, 190,613, 213,800, and 242,161 in 2007, 2008, 2009, and 2010, respectively. The number of ART treatments administered to patients aged ≥40 years was 31.2 %, 32.1 %, 33.4 %, and 35.7 %, respectively, showing an increasing trend from 2007 to 2010. In each of these years, the total pregnancy rate per embryo transfer was 24.4 %, 21.9 %, 22.3 %, and 21.9 % for fresh cycles, respectively, and 32.0 %, 32.1 %, 32.5 %, and 33.7 % for frozen cycles, respectively. The single embryo transfer rate was 49.9 %, 63.6 %, 70.6 %, and 73.0 %, respectively, showing an increasing trend, while the multiple pregnancy rate was 11.5 %, 6.8 %, 5.3 %, and 4.8 %, respectively, showing a decreasing trend. Conclusions From 2007 to 2010 in Japan, the number of ART treatment cycles, number of elderly patients treated, and the single embryo transfer rate increased, while the multiple pregnancy rate decreased. However, the overall pregnancy rate remained stable during the study period.