The number of IVF blunders reported by fertility clinics has more than doubled in the four years since an official report criticised safeguards in place.

These safeguards are meant to prevent errors such as the wrong embryo being implanted into a woman. A significant rise in the number of adverse "incidents" logged is explained by better reporting procedures rather than a slide in standards, according to the Human Fertilisation and Embryology Authority (HFEA).

In 2007-08 there were 182 adverse incidents reported to the HFEA, more than double the 79 incidents in the previous year – when the Government set up an inquiry under Professor Brian Toft into how to improve safety procedures.

This year's figures, to be published next month, are set to be even higher. In licensed IVF clinics the mechanism of reporting has improved, an HFEA spokeswoman said: "The law says that clinics must report serious incidents, but we also want to know about the less serious incidents." Of the 182 incidents in 2007-08, eight were in the most serious category, involving errors such as fertilising eggs with the wrong sperm or stimulating a woman's ovaries so much that it risked her long-term health. One of the mix-ups was in Wales and the other at Guy's Hospital in London. In these two cases the wrong embryo or wrong sperm was used, the spokeswoman said. Another 54 incidents fell into the grade B category and included mishaps such as losing embryos in the lab.

The HFEA says it wants to avoid a culture of blame, which might discourage reporting by clinics.