---
title: "Vitamin C and the Efficacy of Birth Control Pills | Sutter Health"
description: "I've been on birth control for five years. I did not skip a dose, but I'm having mid-cycle bleeding after having unprotected sex. I took vitamin C for a cold and read that excessive amounts can cause birth control to stop working. Is this true?"
url: "/ask-an-expert/answers/vitamin-c-the-efficacy-of-birth-control-pills-1051061398"
---

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# Vitamin C and the Efficacy of Birth Control Pills

* * *

Medically reviewed by

-   Susan Maayah, M.D.

## Question

I've been on birth control for five years. I did not skip a dose, but I'm having mid-cycle bleeding after having unprotected sex. I took vitamin C for a cold and read that excessive amounts can cause birth control to stop working. Is this true?

## Answer

Taking vitamin C will not interfere with the efficacy of your birth control pill.

You should not be concerned about pregnancy unless you missed your pills or started your pack late.

If your mid-cycle bleeding is just an isolated episode, it is not concerning but if it becomes a monthly recurring symptom, you should see your doctor.

## Explore related topics

PregnancyWomen's health

## Meet our care team

Susan Maayah, M.D.

Obstetrics and Gynecology

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