I would think there would be scores of such apps a search away on the Play Store. Anyway bsafe seems to be popular (https://play.google.com/store/apps/details?id=com.bipper.app.bsafe)
I don't have personal experience with these, so try and let us know your findings
Yes there are many apps that can actually help women and children in unwanted conditions. Some will alert family and friends about the situation, some can alert you of danger zones, and some can be used to create a safety-zone leaving it creates an alert. I like Citizen COP as it can arrange police help within couple of minutes. Check it out that police at you area is connected with this or not at http://citizencop.org/
Get the complete list of such products at "personal safety apps at wikipedia"