What Causes Delay In Periods Post Intercourse Despite Being On Ortho Novum?

Posted on Wed, 19 Nov 2014

Question: I take ortho novum 1/35 28 day birth control. I take it the same time each day and havent missed any pills. I however was on zithromax antibiotic snd had sex during that time. I also had sex with my husband after the antibiotic time and panicked and took plan B. Im now worried about the antibiotic making my birth control not work because my period usually starts by now. I read that this can be a plan b side effect but im terrified and wondering how at risk i am. Ex: i started my placebo pills friday and no period yet. I start new pills upcoming friday

Answered by Dr. Richa Agarwal (29 minutes later)

Brief Answer:
Period can be delay due to plan-b.

Detailed Answer:
Hi,

Thanks for writing to us about it.

I can understand your concern, though.

It is true that earlier you were on birth control pill and taking antibiotics you should advise to use another method of contraception like condom for 7 days but in recent studies there is no need of additional contraception requires.

But if vomiting and diarrhea occur due to antibiotic, then precaution advice on your birth control leaflet should be adopted.

In your case your period may be delayed due to I-pill (plan- b) because it contains hormone in high dosages and they cause hormonal imbalance and change in the menstrual cycle.

Merely to be safer side if you will not resume your period within 7 days of your expected period date, then you should go for a pregnancy test to rule out pregnancy.( Do not worried about it the chances of pregnancy are very less in your case).

Hope I have answered your query if you have further questions I will be happy to assist you.

Good luck.
Regards
Dr.Richa

Above answer was peer-reviewed by : Dr. Prasad