Milk of Magnesia and Birth Control: Potential Interactions & Side Effects

Question
Hi,
I took some Philips Milk of Magnesia for some constipation I've been having. I am on birth control Necon 1/35 and have been taking it continuously for about two months. I'm about to start my eighth week of active pills, I skipped my last two inactive pill weeks because my periods would have come at inconvenient times. I have a couple of questions for you. First, does milk of magnesia reduce the effectiveness of my BC pills? Also, is gas, bloating, and constipation a common side effect of skipping the inactive pills for two months? When I first looked up my symptoms, I saw a lot of posts on pregnancy boards about my symptoms, so it got me spooked even though I have not missed at pill at any time over the last two months (one night around 11 pm I got sick and threw up, but I have been taking my pills at 8 am since January, and I had taken my pill that morning and took the next one when I woke up at 8 am the next day). Thanks for any reassurance you can give.

Answer
Hi andromeda1084,

Milk of magnesia does not reduce effectiveness of the pill. If you have diarrhea right after you take the pill it can reduce absorption of the pill, which would be like missing the pill for that day. Milk of magnesia should not be giving you diarrhea, however, if you plan on taking it on a regular basis I recommend giving your doctor a call. Vomiting can also reduce absorption but for that to happen it would need to be soon after taking the pill. Vomiting in the evening will not affect the pill you took in the morning. As long as you have taken the pill correctly with no missed pills, you are most likely not pregnant.

Constipation and bloating are side effects of birth control pills. Many of the side effects of birth control pills and pregnancy are similar because they are hormonal side effects. In a way, the pill "tricks" your body into thinking it is pregnant so it does make sense. Skipping the inactive pill week can sometimes cause side effects to appear. If these symptoms continue I recommend calling your doctor to discuss. There could be other reasons for the constipation, such as diet changes. Also, as we grow older our body's reaction to certain foods can change, so it could be from something you are eating.

I hope this helps. If you have further questions let me know.

-Mia