The Premier 15s league will be suspended for at least two weeks to help reduce the spread of coronavirus.
Rounds 11 and 12 have been postponed with a possible restart date of Saturday 30 January.
The league has been given "elite sport" status by the government and has continued playing throughout lockdown despite no testing for the players.
The Women's Six Nations has also been pushed back, with organisers aiming to start in spring or summer.
Nicky Ponsford, he Rugby Football Union's (RFU) head of women's performance, said organisers were hoping Premier 15s games could be played over the February and March dates originally set aside for the delayed Women's Six Nations "providing it is safe to do so".
Player welfare is behind the decision to postpone the Premier 15s, with last weekend's fixtures also called off.
Organisers took into account the fact that most players in the league are amateur, with jobs outside of sport. Some Premier 15s players work for the NHS and the decision will allow them to focus more on work.
The league had already been playing under adapted laws to reduce contact.
The RFU said it would "continue to review and monitor" and provide an update "in due course".
Ponsford added: "While we aim to return at the end of the month, we are conscious this is a fluid situation and we will continue to review and evaluate during this playing break."
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