the Contraceptive Effects of Oral Birth Control Pills

Oral contraceptives

I started taking Estelle (21 pills) for menstrual regulation and contraception in mid-December.
The doctor advised me to start taking it now (I began on January 2), but my period hasn't arrived yet.
How long does it take for the contraceptive effect to kick in? I've seen many different opinions online, and I was too embarrassed to ask the doctor.

Qiao Hu, 20~29 year old female. Ask Date: 2017/01/03

Dr. Cao Guotao reply Obstetrics and Gynecology

Hello, you can start taking the contraceptive pill on the fifth day of your menstrual period.
It doesn't have to be taken at the exact same time; taking it around the same time is sufficient.
As long as you take it regularly, it will be effective for contraception.
Wishing you good health!

Reply Date: 2017/01/03

More Info

Understanding the contraceptive effects of oral birth control pills, particularly the combination pills like the one you mentioned (often referred to as "the pill"), is crucial for anyone considering their use for contraception or menstrual regulation.
Oral contraceptives work primarily by preventing ovulation. They contain hormones (estrogen and progestin) that inhibit the natural cyclical hormones in your body, which are responsible for ovulation. When taken correctly, these pills can be over 99% effective in preventing pregnancy. However, the effectiveness can vary based on when you start taking them in relation to your menstrual cycle.

If you start taking the pill during the first five days of your menstrual cycle, it is effective immediately. However, if you start taking it at any other time, it is generally recommended to use an additional form of contraception (like condoms) for the first seven days of taking the pill. This is because your body needs time to adjust to the hormones and to suppress ovulation effectively.

In your case, since you started taking the pill on January 2nd and your period has not yet arrived, it's important to consider a few factors:
1. Timing of Start: If you started taking the pill outside of the first five days of your menstrual cycle, you may need to wait a week for it to become fully effective. If you started within that window, it should be effective immediately.

2. Missed Period: It's not uncommon for your menstrual cycle to be irregular when you first start taking the pill. Some women experience lighter periods or even missed periods during the first few months of taking the pill as their bodies adjust to the new hormone levels. If you have been taking the pill consistently and correctly, this could be a normal side effect.

3. Pregnancy Test: If your period does not arrive within a week of when you expect it, it might be wise to take a pregnancy test to rule out pregnancy, especially if you had unprotected intercourse before starting the pill or if you missed any doses.

4. Consulting Your Doctor: Since you have concerns about your missed period and the effectiveness of the pill, it would be beneficial to consult your healthcare provider. They can provide personalized advice based on your health history and any other medications you may be taking.

5. Other Factors: Stress, changes in weight, and other health conditions can also affect your menstrual cycle. If you are experiencing significant stress or changes in your lifestyle, this could also contribute to a missed period.

In summary, while the pill is a highly effective form of contraception, it may take some time for your body to adjust, and it’s important to follow the guidelines for starting the pill to ensure its effectiveness. If you have any doubts or concerns, especially regarding a missed period, consulting with your healthcare provider is always the best course of action. They can help clarify any uncertainties and ensure that you are using the pill effectively for your contraceptive needs.

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