Norethindrone & Ethinyl Estradiol (Estrostep): How it Works, Side Effects and Interactions

Used by almost 20 million women in the United States, Estrostep is one of the most popular birth control pills available.

Estrostep uses a combination of norethindrone and ethinyl estradiol, two hormones that can prevent pregnancy. Like other birth control pills, it’s taken daily, with a mix of active pills and inactive pills inside each pack.

If you’ve researched birth control options, norethindrone/ethinyl estradiol birth control pills like Estrostep are likely on your radar. Used effectively, norethindrone/ethinyl estradiol birth control can help you avoid becoming pregnant with few side effects for your overall health.

Estrostep is also one of three birth control pills approved by the FDA for use as a treatment for acne, meaning it can also improve your skin.

The specific process through which norethindrone/ethinyl estradiol birth control works is a little complicated, but easy to understand once you’re familiar with the basics. We’ve explained it, as well as the key benefits and side effects of norethindrone/ethinyl estradiol birth control, below.

How Do Norethindrone/Ethinyl Estradiol Birth Control Pills Work?

Estrostep and other norethindrone/ethinyl estradiol birth control pills work by using two female hormones, norethindrone and ethinyl estradiol, to stop you from becoming pregnant.

Norethindrone is a progestin—a type of hormone that can suppress your body’s production of certain sex hormones. It also contains a type of estrogen called ethinyl estradiol, which works alongside the norethindrone to prevent pregnancy.

Because Estrostep contains a combination of two different hormones, it’s known as a combined oral contraceptive (COCP) or “estrogen and progestin” pill.

Used together, norethindrone and ethinyl estradiol stop your ovaries from releasing eggs. This makes it impossible for sperm to come into contact with your eggs and result in pregnancy, as they potentially could through unprotected sex.

These two hormones also affect the amount of cervical mucus that’s present inside your uterus and cervix. This makes it more difficult for sperm to enter into your cervix, further reducing your risk of becoming pregnant.

A pack of Estrostep (or other norethindrone/ethinyl estradiol birth control medication) contains 28 pills. 21 of these pills are active, meaning they contain norethindrone and ethinyl estradiol, while another seven pills are reminder pills that contain iron.

Like other combined birth control pills, Estrostep and other norethindrone/ethinyl estradiol birth control pills are highly effective at preventing pregnancy when used properly. Estrostep has a success rate higher than 99% when used according to the medication's instructions.

This means that, if you use Estrostep (or other norethindrone/ethinyl estradiol birth control pills) exactly as prescribed, you have a higher than 99% chance of not becoming pregnant over the course of one year.  

“Real life” conditions aren’t always the same as those in a clinical trial. This means that if you occasionally miss a dose or take a pill late, Estrostep won’t be 99% effective at stopping you from becoming pregnant.

Norethindrone/Ethinyl Estradiol for Treating Acne

Estrostep is one of only three birth control pills approved by the FDA for treating and preventing acne. The other two are Yaz and Ortho Tri-Cyclen, which we’ve covered in separate guides.

As an acne treatment, the combination of norethindrone and ethinyl estradiol in Estrostep works by reducing your body’s androgen levels.

Acne is caused by several factors. One of the main causes of acne is excessive production of sebum, a type of natural oil that’s secreted by your pores to keep your skin hydrated, soft and healthy.

Androgens like testosterone stimulate the production of sebum. When your body’s production of testosterone is too high (such as during your period), it can result in outbreaks of hormonal acne that give you whiteheads, blackheads and even inflamed, infected pimples.

We’ve explained this entire process, as well as how factors like your period can affect acne, in our guide to hormonal acne.

The norethindrone and ethinyl estradiol in Estrostep reduce your body’s testosterone levels, in turn reducing the amount of sebum that’s secreted by your sebaceous glands. This makes you less likely to develop the blocked pores that can lead to acne outbreaks.

Most of the time, dermatologists prescribe birth control pills like Estrostep in combination with other medications to fight acne from multiple angles. Some of the most common acne drugs used with Estrostep are tretinoin (a topical treatment), isotretinoin and clindamycin.

Estrostep and other norethindrone/ethinyl estradiol birth control pills are typically only used for acne if you plan to take the pill for at least six months. It can take two to three months to notice results from norethindrone/ethinyl estradiol as an acne treatment.

What are the Benefits of Norethindrone/Ethinyl Estradiol Birth Control?

The biggest benefit of Estrostep and other norethindrone/ethinyl estradiol birth control is that it stops pregnancy. Used according to the instructions, Estrostep has a success rate of over 99% as a contraceptive.

There are several other benefits of Estrostep, as well as other norethindrone/ethinyl estradiol birth control drugs. Like other combined oral contraceptives, Estrostep could potentially lower your risk of developing ovarian cysts, cancer of the ovaries or pelvic inflammatory disease.

Estrostep can also result in shorter, lighter periods, making it a good birth control option if you have long, heavy or uncomfortable periods.

As we’ve covered in the section above, norethindrone and ethinyl estradiol is also widely used as an acne treatment, as per its approval by the FDA.

How to Use Norethindrone/Ethinyl Estradiol Birth Control

Using Estrostep and other norethindrone/ethinyl estradiol birth control is very easy. Each pack of 28 tablets is sorted into four rows, each of which corresponds to a week. Your doctor will advise you to start on a Sunday after menstrual flow, or on the first day of menstrual flow.

For a Sunday-start regimen, start by taking the first white tablet from the top of the packet. The row with the tablet will be labeled “Sunday.” Take a white tablet each day for 21 days, then take the brown tablets for the next seven days.

Once you reach the end of the pack, start the second course of 28 tablets. Each pack starts with a Sunday tablet, meaning you do not need to miss any days after finishing each pack.

If your doctor recommends a day-1 regimen, start by attaching the adhesive strip provided by your doctor over the printed days on the packaging. Take one white tablet daily until you reach the brown tablets, then take one brown tablet daily for seven days to finish the pack.

The day after you finish the brown tablets, start the next cycle by attaching the day strip given to you by your doctor over the printed days on the packaging, then take the first white tablet. Take one white tablet daily for 21 days, then the seven brown tablets to complete the cycle.

Norethindrone/ethinyl estradiol birth control is most effective when you take it at the same time every day. Try to take each white tablet within one to two hours of the same time daily to make sure your hormone levels stay steady throughout the week.

If you forget to take a white (active) tablet, take the tablet as soon as you remember. Take the next tablet at the normal time.

If you forget to take two consecutive tablets during the first two weeks of your cycle, take two tablets as soon as you remember. The next day, take two tablets at the normal time. After this, you can return to your normal one-tablet-per-day dosage schedule.

If you forget to take two tablets in a row in week three of your cycle on a Sunday-start regimen, take one tablet until the next Sunday, then throw away the remaining tablets and begin the next pack of medication.

If you’re on a day-1 regimen and miss two consecutive tablets in week three of your cycle, throw away the rest of the pack and start a new pack of tablets. Do not skip any days—start using the new pack of tablets starting immediately.

If you miss three or more tablets in a row on a Sunday-start regimen, continue taking one tablet per day until Sunday, then throw away the remaining tablets and start a new pack.

If you’re on a day-1 regimen and miss three or more tablets in a row, throw away the remaining tablets and start using a new pack of tablets. Do not skip any days—start using the new pack of tablets immediately.

If you forget to take one or more brown (iron) tablets, throw away the brown tablets you missed and continue taking one brown tablet until you reach the end of the pack.

Norethindrone/ethinyl estradiol birth control becomes significantly less effective once you miss more than one tablet in a row. Make sure you use a second form of contraceptive, such as condoms, for at least one week after your missed pill.

Missing one or several doses of norethindrone/ethinyl estradiol birth control could significantly increase your risk of becoming pregnant. If you miss your period after forgetting to take a pill, contact your doctor.

If you’re using norethindrone/ethinyl estradiol birth control for acne, follow the same instructions as you would if you were using it as a contraceptive.

Norethindrone/Ethinyl Estradiol Birth Control Side Effects

Norethindrone/ethinyl estradiol birth control pills have similar side effects to other combined oral contraceptives. The most common side effects are typically mild hormonal issues caused by the combination of estrogens and progestins inside the medication. These side effects include:

• Weight gain. Bloating and weight gain are common on Estrostep and other birth control pills that use norethindrone and ethinyl estradiol. This weight gain is typically caused by water retention and is most common during the first one to two months of use.
  
  Weight gain caused by water retention is temporary and usually disappears if/when you stop using hormonal birth control. Water retention caused by Estrostep can often result in minor swelling of your ankles and feet.

• Vaginal bleeding/spotting. Norethindrone/ethinyl estradiol birth control can cause mild spotting and vaginal bleeding during the first few months of use. This usually stops after two to three months of using the medication.

• Breast tenderness. The combination of norethindrone/ethinyl estradiol in Estrostep can cause your breasts to become tender and even slightly painful.

• Increased breast size. The norethindrone and ethinyl estradiol in Estrostep can affect your breast tissue, resulting in a temporary increase in breast size that reverses after you stop using the medication.

• Nausea and vomiting. Estrostep and other norethindrone/ethinyl estradiol birth control can cause nausea. This is most common during the first few months and usually stops after your body becomes accustomed to the effects of the medication.

• Mood changes, irritability and headache. The hormone combination in Estrostep can affect your mood, especially during your menstrual cycle. Many Estrostep users report irritability, sudden mood changes and headaches after starting the medication.

While these side effects can sound alarming, they’re usually fairly mild and tend to only have a minor effect on your life. The side effects listed above are most commonly reported during the first few months of using Estrostep and other norethindrone/ethinyl estradiol birth control pills.

Less Common, Serious Side Effects

Estrostep and other norethindrone/ethinyl estradiol birth control can also have more significant side effects. If you experience any of the side effects listed below, stop taking your birth control medication and contact your doctor as soon as possible:

• High blood pressure. Norethindrone/ethinyl estradiol birth control can potentially raise your blood pressure, especially if you’re susceptible to hypertension.
  
  Common signs of high blood pressure include shortness of breath, blurred vision, chest pains, severe headache and difficulty breathing. If you experience any symptoms of high blood pressure while using Estrostep, contact your doctor as soon as possible.

• Liver problems. Although norethindrone/ethinyl estradiol birth control isn’t particularly liver toxic, some people experience liver issues as a result of using birth control over a long period of time.
  
  Common signs of liver problems from birth control include dark urine, tiredness, yellow skin and/or eyes and clay-colored stools. If you notice any of these symptoms after you start using Estrostep or similar birth control, contact your doctor.

• Sleep problems, fatigue and tiredness. The hormones in Estrostep and other birth control can affect your sleep and contribute to fatigue. If you feel severely fatigued or have trouble sleeping after starting birth control, contact your doctor.

• Blood clots. Hormones such as norethindrone and ethinyl estradiol can increase your risk of experiencing a blood clot. This is a serious medical situation that requires urgent attention from a doctor.
  
  Common signs of a blood clot include sharp, stabbing pain in the chest, sudden loss of vision, shortness of breath and coughing up blood.

• Stroke. Estrostep and other birth control pills containing estrogens and progestins can increase your risk of stroke. Like a blood clot, a stroke is a serious medical emergency that requires urgent attention from a doctor.
  
  Common signs of a stroke include a sudden, severe headache, weakness or numbness in one side of the body, slurred speech, problems balancing and loss of vision.

On the whole, serious side effects from Estrostep and other norethindrone/ethinyl estradiol birth control pills are rare. However, it’s important to be aware of these side effects and seek medical attention as soon as possible if you notice any troubling symptoms.

Norethindrone/Ethinyl Estradiol Birth Control and Smoking

If you smoke cigarettes, you must disclose this fact to your doctor before considering any birth control pill, including norethindrone/ethinyl estradiol birth control pills such as Estrostep.

Smoking cigarettes significantly increases your risk of experiencing cardiovascular problems from birth control. This means you are at a significantly higher risk of having a stroke, a blood clot or developing high blood pressure if you smoke while using birth control.

Cardiovascular health risks are particularly high in women aged 35 or older. If you smoke, it’s essential that you talk to your doctor before considering any birth control pill.

Norethindrone/Ethinyl Estradiol Birth Control Interactions

Estrostep (norethindrone/ethinyl estradiol) and other birth control medications with the same active ingredients have 49 major drug interactions, as well as a wide range of moderate and minor drug interactions.

These interactions include commonly prescribed antibiotics, which can make birth control less effective at preventing pregnancy while increasing your risk of side effects. Estrostep can also interact with commonly used anticonvulsants and herbal products such as St. John’s Wort.

RXList and Drugs.com both have full lists of drugs that can interact with norethindrone/ethinyl estradiol birth control, with complete information medications to avoid while using Estrostep or similar birth control medications.

To avoid interactions, tell your doctor about any prescription and non-prescription medications you take before discussing birth control. Your doctor will be able to recommend a suitable birth control option for you that reduces your risk of drug interactions.

Learn More About Birth Control Medication

Used effectively, norethindrone/ethinyl estradiol birth control medication like Estrostep is a safe, effective way to prevent pregnancy. It’s also one of three birth control pills that the FDA allows to be prescribed for acne.

Would you like to learn more about the most effective birth control options? Our guides to Yaz (drospirenone/ethinyl estradiol) and Ortho Tri-Cyclen (ethinyl estradiol and norgestimate) cover two other FDA-approved birth control pills.

Our guide to birth control and acne also explains how you can use birth control medications like Estrostep to treat and prevent acne outbreaks.

Looking for more advice from the hers pros? Check out the blog.