Researchers at Kyushu University have shown that reduced oxygen and mechanical compression are two environmental factors playing a role in creating and maintaining a supply of dormant egg cells in mice to ensure a long period of fertility. These insights into this critical but poorly understood process will further the understanding and development of reproductive biology and medicine.
Africa is projected to be home to nearly 3 billion people by 2100, but rapid population growth will cause widespread environmental degradation unless effective family planning becomes widespread policy, according to new research that tracked increased population pressures on the continent's ecosystems.
While female fertility comes to an irrevocable end with the menopause (at a consistently average age of 51 years), men are not constrained by similar biological senescence. Studies have shown that sperm counts may decline and DNA damage in sperm cells may increase over time, but the celebrity fatherhood of ageing actors and rock stars perpetuates the myth that male fertility might last forever.
Intracytoplasmic sperm injection (ICSI), the world's favored means of fertilization in assisted reproduction, offers no benefit over conventional in vitro fertilization in fertility treatments without a male factor indication, according to results of a large multicenter study.
Ovarian reserve, a term widely adopted to reflect the number of resting follicles in the ovary and thus a marker of potential female fertility, has been found in a large-scale study to be adversely affected by high levels of air pollution.
The adverse effect of maternal smoking during pregnancy is well established and associated with several negative neonatal outcomes (such as low birth weight and preterm birth). It is also evident in some studies that the semen quality of men exposed to prenatal maternal smoking is generally more impaired than that of unexposed men. However, there is little known about the effect of paternal smoking in the time leading up to and during pregnancy.
The latest annual data collected by ESHRE from European national registries (for 2016) show another rise in the cumulative use of IVF in the treatment of infertility, although success rates after IVF or ICSI appear to have reached a peak, with pregnancy rates per started treatment calculated at 27.1% after IVF and 24.3% after ICSI.
The transfer of embryos cultured for five or six days (instead of two or three) after fertilization in IVF and ICSI has become routine in many fertility clinics. Many (but not all) studies show that transferring these longer and better developed embryos -- known as blastocysts -- will increase the chance of pregnancy and live birth.
The increasingly popular trend for fertility clinics to freeze all IVF embryos for later transfer has been shown in a large multicenter randomized trial to offer no improvement in delivery rates over traditional 'fresh' embryo transfers. 'Our findings give no support to a general freeze-all strategy in normally menstruating women,' said investigator Dr. Sacha Stormlund from Copenhagen University Hospital in Denmark.
Despite a time limit imposed in many countries on the freeze-storage of sperm, a new study from China has found that the long-term cryopreservation of semen in a sperm bank does not affect future clinical outcomes. Results of the study are presented today in Vienna at the 35th Annual Meeting of ESHRE by Dr. Chuan Huang of the Changsa-Hunan Sperm Bank in China.