Name That Trauma:: Lena on a Clock That Strikes 13

Hello! I hope
You can help me.
I have never actually seen this movie it's one of those movies that one of my childhood friends told me about.
Never forgot her telling me, but have never been able to find it.
I don't have much to go on.
I'm going to guess it's a 70's movie. Whether it was made for TV or not I'm unsure.
It has a nurse living or working in someone's home. Her last name might be Green??
I believe there is a child in the house.
A clock strikes 13 times instead of 12 at midnight.
I know it's not much to go on?
Thanks, Lena