In my experience, women who are commitedly child free by choice almost never end up with a baby, regardless of how sexually active they are. Draw your own conclusions!
I've name changed for this thread. I did not want children. My husband never said he did, I don't remember ever having the conversation, it was maybe something for the future.
I was busy doing housework, he wanted sex (I know now I was in an abusive relationship, I didn't realise the extent of it at the time), we started having sex. I said "We [because to say you would have been a big mistake] need to stop, I don't want to get pregnant". He said "I'm not fucking about here" and carried on.
I knew within minutes that I was pregnant, I just knew. I'm Type 1 diabetic, I had not prepared for pregnancy by having as good control as possible (I have always done my best but it wasn't good enough for pregnancy). I went to the doctor and said I was worried there would be something wrong as it wasn't planned. I may as well not have spoken. I said the same to my diabetes doctor. Again, no notice was taken. It wasn't until quite late on in the pregnancy that I saw a doctor who did listen by which time it was too late to do anything. I was never told of any potential problems during scans. I even had a nurse saying she thought the doctor was being over the top with the checks I was having.
My son was born with a cleft lip and palate. A few hours later I was woken to be told there was a problem with his heart. He was rushed to the children's hospital where he was operated on. In his 24 weeks of life he had three major heart operations and was fed through a naso gastric tube. He spent much of his life in hospital.
I hadn't wanted a child but I would have given my life to save my son. On the other hand, I'm glad he hasn't had to live through a lifetime of operations and whatever other medical treatment he would have needed to live his life.
So yes, in my case, I wanted to be child free and I am but I'd rather have had the choice.