The United Nations should get involved but the first thing they ought to do is to verify those claims to know if indeed the Turkey government is silencing the women after the failed coup. The opposition may be using some women to try and give a bad image to the government of the day.
Some women’s groups say they are being specifically targeted. On Twitter, many women talking about the coup attempt are reporting an increase in harassment on the streets. Others are railing against misogynist language used by all sides, reducing women to pawns, or spoils of war. The United Nations need to get involved.
The UN should get involved and at least discover what is going on. They can find out if woman's rights are being violated and then decide if they need to get involved based on that inforamtion. If women are not being silenced, they do not need to speak out, and nothing needs to be done.
The United Nations was founded to increase co-operation between nations. If they get involved in the domestic problems of Turkey without a proper mandate it will weaken its power to deal with Turkey on bigger issues in the future. People who disagree with the current government are being silenced due to the attempted coup, but there does need to be a cooling off period. If the situation doesn't improve, which it should in time, United Nations involvement may be required to be revisited in the future, but no action is required at this time.