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Date of last update: 10/14/2017.

Forum Name: Obstetrics

Question: Antibiotics, the pill and pregnancy

 abandond1 - Sun Dec 21, 2008 1:39 pm

Can someone tell me if the following situation is possible?

My wife had consistently taken the pill, without a break for over 6 years. Over that time, if she has ever missed a day (which was rare) she would double up on her pill intake. In that time she had never gotten pregnant.

For the last year or two, of those 6 years, she had been prescribed Ortho Tricyclin. Near the end of this period she required antibiotics (a penicillin derivative of some kind) for a lung infection. We had not been having sexual intercourse for about 3 months and she was still taking her pill regularly. However, we did have sex once, in the middle of the time she was on antibiotics. Six to eight week later she was pregnant, swearing that she had not adjusted her use of the pill.

My question is, how plausible is this?
This all happened years ago and I have two beautiful young children now, that I would never be without. However, my wife had used deception a number of times in the past, prior to this, to keep me near her family's town and quash jobs I have been offered that would require me to travel. I found out recently that she had confided in a friend, before we married, that she would do whatever it took to build a life with me.

The lies she has told to get things her way have generated a lot of tension in our relationship and prior to our having any children we were on the verge of divorce. However, she knows that I would never see a child of mine grow up without a father and this all seemed amazingly well timed to coincide with a move I had planned at that time, prior to being told she was pregnant with our first child. I feel I have a right to know if her claims are plausible (In other words, this truly was an amazing series of coincidences) or was this another cooked up scenario, tailor made to leverage my belief in being a good father. This won't effect my commitment to my kids, but I do want to know whom I am dealing with when it comes to my wife's tactics in the long run.

Many thanks,
Needs Some Honesty
 Debbie Miller, RN - Tue Dec 23, 2008 12:50 pm

User avatar Hello,
The chances of pregnancy while taking the pill are about 1%. In other words, of 100 women taking the pill as prescribed, one will become pregnant in the year. So, while it is a reliable method, it is not perfect so pregnancy can and does occur while taking the pill. Antibiotics have been shown to decrease the effectiveness a bit, but it has also appeared to be mostly with a rarely used antibiotic, Rifampin. This did lead us to wonder if others might also decrease the contraceptive ability of the pill. We don't know definitively, partly because some become pregnant anyway - even without antibiotics. So, it would be difficult to determine without some more extensive study, if it was related to the antibiotic use or just the random 1% pregnancy.

If you have relationship issues and trust is a concern, I would recommend couples thereapy with a certified family counselor.

Best wishes.

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