The absence of impediments.

The Shaykh : The sixth is the absence of impediments. This is specific to the woman, in that she must not be menstruating or experiencing post-natal bleeding, because menstruation and post-natal bleeding are impediments to the validity of fasting. The Prophet (peace and blessings be upon him) said regarding the menstruating woman: The Muslims have agreed that fasting is not valid for the menstruating woman, and it is not obligatory for her; rather, it is forbidden for her. The same applies to the woman experiencing post-natal bleeding. So the conditions are now six: Islam, sanity, reaching puberty, ability, residence, and the absence of impediments.