World Athletics bans transgender women from competing in female world ranking events• https://www.bbc.com, By Katie Falkingham
The governing body's president, Lord Coe, said no transgender athlete who had gone through male puberty would be permitted to compete in female world ranking competitions from 31 March.
A working group will be set up to conduct further research into the transgender eligibility guidelines.
"We're not saying no forever," he said.
Under previous rules, World Athletics required transgender women to reduce their amount of blood testosterone to a maximum of 5nmol/L, and stay under this threshold continuously for a period of 12 months before competing in the female category.
Lord Coe added the decision was "guided by the overarching principle which is to protect the female category".
He noted that there are currently no transgender athletes competing internationally in the sport.
The World Athletics Council also voted to reduce the amount of blood testosterone permitted for athletes with differences in sex development (DSD), such as South Africa's Caster Semenya.
DSD athletes will be required to reduce their blood testosterone level to below 2.5 nanomoles per litre, down from five, and must remain under this threshold for two years in order to compete internationally in the female category in any track and field event.
Under previous regulations, DSD athletes were only restricted in events ranging from 400m to a mile.
Interim provisions will be introduced for DSD athletes already competing in previously unrestricted events, requiring them to suppress their testosterone levels below 2.5nmol/L for a minimum of six months before they are allowed to compete again.