Birth control has been a leading method for preventing pregnancy since its approval by the U.S. Food & Drug Administration (FDA) in 1960.
Low estrogen, or low dose, birth control is a type of hormonal birth control that has a lower dosage of hormones than most other oral contraceptives.
According to the CDC, from 2017-2019, 65.3% of women aged 15-49 years in the United States used contraception, with oral contraceptives being one of the most common methods.
There are many birth control methods available, and each comes with its own set of risks and benefits.
Low estrogen birth control options are often chosen for people who can’t take higher doses of hormones due to personal or medical reasons.
Symptoms associated with your menstrual cycle, family history, and certain medical conditions are considered when determining if a low estrogen birth control is the right fit.
There are other low dose birth control pills, but they include hormones other than estrogen.
Some low-dose pills mirror traditional birth control pills and contain both estrogen and progestin (a synthetic form of progesterone), while others may contain only progestin and no estrogen.
In this article, I’ll explain how this type of birth control works and then dive deeper into the effectiveness, benefits, risks, and side effects you can typically expect with low estrogen oral contraceptives.
How Birth Control Pills Work
Essentially, birth control pills have two primary effects: 1) They prevent your body from ovulating, and 2) They prevent sperm from coming in contact with available eggs.
The two hormones found in most birth control pills, estrogen and progesterone, signal your body to stop releasing eggs and preparing for pregnancy.
That means there is no egg available to fertilize—thus, pregnancy cannot occur.
Additionally, the hormones in birth control pills help prevent sperm from coming in contact with the egg (if one is released) by thickening the cervical mucus.
In this case, even if you do by chance ovulate, your chances of becoming pregnant are still lower than if you were not on birth control.
Low-Dose Birth Control Pills
There are two types of low-dose birth control pills: those that contain both estrogen and progestin (sometimes called combination birth control pills), and those that contain only progestin.
Low-dose combination birth control pills
Combination birth control pills contain both estrogen and progestin.
These pills are a reliable form of contraception that is over 99% effective if taken correctly and is easily reversed.
Fertility can return to normal shortly after stopping the pills.
Combination birth control pills come in different mixtures of active and inactive pills, including:
- Conventional packs: This is the most common type and contains 21 active pills and seven inactive pills. Packs containing 24 active pills and four inactive pills are also available; these are known as shortened pill-free intervals and result in shorter periods. With both conventional packs, one pill is consumed every day and a new pack is started only when you complete the old one (every 28 days). Bleeding occurs every month during the time frame when you take the last 4-7 inactive pills.
- Continuous dosing or extended cycle: These typically contain 84 active pills and seven inactive pills. Bleeding generally occurs only four times a year during the seven days you take the inactive pills. A 365-day pill also is available, which should be taken every day at the same time. For some, periods stop altogether. For others, periods become significantly lighter.
Low-dose progestin-only birth control pills
Also known as the “minipill” or POP, progestin-only pills are oral contraceptives that don’t have estrogen, making them ideal for people sensitive to the effects of the hormone or for those who should not take estrogen due to their medical history.
The minipill also contains a lower dose of progestin than what you’d find in a combination birth control pill.
Unlike combination pills, it is essential that you take the minipill at the same time every day for it to work as well as other pills.
Taking the minipill just a few hours late can reduce its effectiveness.
As with combination pills, the minipill is an easily reversible method of contraception.
Your fertility is likely to return to normal shortly after you stop taking it.
The minipill is also considered safe to use while breastfeeding.
Amount of hormones in low dose pills
The most commonly used combination birth control pills (which deliver both estrogen and progestin) contain between 30-35 micrograms of estrogen.
These pills were actually once considered an extremely low dose because original formulations of birth control contained up to 150 micrograms of estrogen.
However, modern low dose and ultra-low-dose formulations of combination birth control pills contain 20 or less micrograms of estrogen.
These pills seem to be just as effective as regular birth control pills but cause fewer side effects from estrogen, such as bloating, tender breasts, and nausea.
Many formulations are available for progestin-only oral contraceptives. One formulation contains 75 mcg of norgestrel. Another has 350 mcg of norethindrone.
In 2019, a dosage of 4 mg of drospirenone was approved as a progestin-only oral contraceptive.
Effectiveness and brand names
According to the CDC, oral contraceptives are between 93-96% effective when taken correctly.
This includes low dose birth control pills, which are now widely available.
Some common brands of low-dose combination birth control pills include:
- Apri (desogestrel and ethinyl estradiol)
- Aviane (levonorgestrel and ethinyl estradiol)
- Levlen 21 (levonorgestrel and ethinyl estradiol)
- Levora (levonorgestrel and ethinyl estradiol)
- Lo Loestrin Fe (norethindrone acetate and ethinyl estradiol)
- Lo/Ovral (norgestrel and ethinyl estradiol)
- Ortho-Novum (norethindrone and ethinyl estradiol)
- Yasmin (drospirenone and ethinyl estradiol)
- Yaz (drospirenone and ethinyl estradiol)
Common brands of the minipill, or progestin-only pill, are:
With both types of low dose pills, you can experience fewer, lighter, or more predictable periods because you will only bleed when you’re not taking active pills.
You may also experience fewer PMS symptoms or menstrual-related symptoms such as cramping.
Lastly, low dose pills can reduce the risk of endometrial cancer and ovarian cancer.
Even though they contain fewer amounts of hormones than other pills, low dose birth control pills still come with risks.
First, there is still a risk of pregnancy, particularly if you are prescribed the minipill and do not take it at the same time every day.
With all birth control pills, it is important that you stay on schedule and do not miss any doses.
A single missed dose increases your risk for pregnancy.
If you are on the combination pill, the hormone estrogen slightly increases the risk of heart health issues or stroke and may raise blood pressure.
It is important that you discuss all medical issues and family history with your provider to ensure you are prescribed the right birth control pill for you.
The risk of estrogen-related cardiovascular health problems is higher in people who smoke, are over the age of 35, have a family history of blood clots, have been diagnosed with heart disease, or have other risk factors for heart disease such as obesity or high blood pressure.
Generally, people who take low-dose birth control pills can expect fewer side effects than they’d have with standard birth control pills.
However, side effects can still happen.
Possible side effects of low-dose combination birth control pills include:
- Tender breasts
- Weight change
- Decreased libido
Compared to the combination pills, minipills can cause more initial bleeding or spotting between periods.
However, this often resolves after a few months of taking the minipill.
Other side effects of progestin-only pills include:
- Weight gain
- Sore breasts
- Mood swings
Some other serious, but rare, side effects for either type of low dose birth control are:
- Severe abdominal pain
- Chest pain, shortness of breath, or both
- Severe headaches
- Eye problems, such as blurred vision or a loss of vision
- Swelling or aching in the legs and thighs
- Severe dizziness
If you are taking any form of oral contraceptive and experience any of the above side effects, contact your healthcare provider immediately.
How to Choose the Right Birth Control
Every individual is different and will have unique needs when it comes to figuring out the right birth control approach.
Speaking with your healthcare provider will help you determine what option is right for you.
You should not take any birth control pill if you are pregnant or think you may be pregnant.
Low-dose birth control might not be the right option for those who :
- Experience migraines with aura
- Presently have, or have had, breast cancer in the past
- Have a family history of stroke, heart disease, or blood clots
- Have a history of elevated blood pressure or hypertension (even if it is under control with the use of medication)
However, there are sometimes exceptions to these categories.
If you are in one of these groups and are interested in low dose oral contraceptives, schedule an appointment with your healthcare provider to see if low-dose birth control is a safe option for you.
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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
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Oestrogen-free oral contraception with a 4 mg drospirenone-only pill: new data and a review of the literature. (2020.)
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