Elena asked
I have a question about switching to a new birth control. I finished my last placebo pill of Blisovi Fe 1mg/.02mg on Sunday Dec. 31st. I went Monday and Tuesday without any active pills and started a new birth control on Wednesday Jan 3rd called levonorgestrel and ethinyl estradiol tablet ups .1mg/.02mg How long will it take to be fully protected with this new pill? Also, what is the difference between these different pill? One is 1mg and one is .01. Is one a lower dose? Less effective?
Answer
How quickly birth control pills are effective in preventing ovulation and pregnancy primarily depends on when you begin taking them. The two most common ways to start birth control pills are:
- First Day Starter
- Sunday Starter
Below, we discuss both methods and whether or not you need to utilize back-up contraception (e.g. condoms) when beginning therapy.
First Day Starter
A first day starter is also referred to as a 'Day One' starter. With this method, you begin taking your birth control pills on the first day of menses (i.e. your period). For the vast majority of birth control products, back-up contraception is NOT needed as your pills will be effective in preventing ovulation and pregnancy.
Back-Up Birth Control: Not required
Sunday Starter
With this method, you being taking your birth control pills on the first Sunday after menses (i.e. your period) begins. During the first cycle with a Sunday start, you should NOT rely on the pills to prevent contraception. The general recommendation for Sunday starters is to use back-up contraception until you take 7 consecutive days of active birth control pills.
Back-Up Birth Control: Yes, until you have taken 7 days of 'active' birth control pills
Other Backup Birth Control Considerations
In regard to switching between products, per your question, you are switching from one combined oral contraceptive pill to another combined oral contraception pill. Combined oral contraceptive refers to a product that contains both an estrogen and a progestin.
In general, if you have been taking your prior combined birth control product for at least 3 months and switch to another combined product your next cycle without missed doses, back-up birth control isn't necessary and you will be protected from pregnancy with the pill alone.
However, in your situation, you have missed two doses of active pills. Your last placebo pill was on Sunday, and you were supposed to take your new active pills Monday, but did not until Wednesday.
Most birth control products recommend to use back-up contraceptive methods if you miss two active doses in the first 2 weeks of your birth control pills. Be sure to use back-up contraception until you have taken 7 consecutive days of active pills.
Lastly, in regard to your product question, the main difference between combined hormone birth control pills is the progestin used. The estrogen (ethinyl estradiol) is the same in the vast majority of products and ranges from 10 to 50 mcg (.01 to .05 mg).
There are over 10 different progestins available in a wide range of products. Different progestins have different potencies, but the difference in potency does not correlate to contraceptive efficacy. When used correctly, all combined birth control pills are over 97% effective.
The progestin in Blisovi is norethindrone while the progestin in your new product is levonorgestrel. Each progestin has unique properties. For example, norethindrone is well tolerated but is sometimes associated with breakthrough bleeding or spotting. Levonorgestrel has androgenic activity, which may improve libido but could cause acne.
