There is a unanimous agreement among Muslim scholars that washing the hair is obligatory for both men and women when performing ghusl. However, the woman who has braids is not obliged to unbraid them when performing ghuslafter intercourse. Rather, she can pour water over them till water reaches the roots of the hair and the scalp.
Sheikh Ahmad Kutty, a senior lecturer and Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:
“You need to wash your hair with water but you need not undo the plaited hair; it is sufficient for you to pour water over your head.
It is common knowledge that following sexual intercourse, both men and women are obligated to perform a complete ghusl (ritual bath) in order to be eligible to worship.
A complete ghusl involves washing the entire body including one’s hair; if however, due to medical or health reasons, one is advised by a physician not to wash the hair, then one should not wash the same. In such cases it is enough to wash the rest of the body and do tayammum (dry ablution) in lieu of the parts one has not washed.”