Combined Birth Control vs. Progestin-Only "Mini-Pills": What's the Difference?

Are you considering going on oral birth control? While most people associate oral birth control with the old, singular nickname “the pill,” the massive variety of different birth control pills that are available today can make choosing the right option for you — mainly between combined birth control and progestin-only birth control — surprisingly difficult. 

Luckily, choosing the right birth control pills for your health, needs and lifestyle isn’t as difficult as you might think. 

Below, we’ve covered the two different types of oral birth control that are available today, from conventional combined birth control pills to progestin-only birth control. We’ve looked at how each type of pill works, as well as the main advantages and disadvantages of each one. 

Combined Birth Control vs. Progestin-Only Birth Control

All birth control pills contain female hormones. These hormones allow them to prevent you from becoming pregnant by stopping your ovaries from releasing eggs. With no eggs released, you’ll have a much lower risk of becoming pregnant, no matter how sexually active you are.

When you use birth control, your cervical mucus also becomes thicker, making it more difficult for sperm to enter into your uterus. 

Birth control pills are highly effective if used right. If you follow the instructions and take your pill at the same time every day without ever missing a dose, your risk of becoming pregnant falls to less than one percent.

While all birth control pills contain female hormones, not all pills contain the same hormones, or the same combination of hormones. Most birth control pills fit into one of two categories:

• Combined birth control pills. Also known as combined oral contraceptives, or COCPs, these birth control pills contain an estrogen (usually ethinyl estradiol) and a progestin.
  
  
• Progestin-only birth control pills. These birth control pills only contain a progestin hormone and do not have any ethinyl estradiol content.

The specific progestin hormones used in birth control can vary between brands. Some widely used progestins for birth control are drospirenone (used in Yaz), levonorgestrel (Vienva), norgestimate (Ortho Tri-Cyclen) and norethindrone (Estrostep).

These pills all use a combined formula, meaning each pill contains a combination of the active progestin hormone and ethinyl estradiol. 

Progestin-only birth control pills often use the same progestins as combined birth control pills, but without any ethinyl estradiol. For example, norethindrone (the progestin in Estrostep) also works as a form of birth control on its own in medication like Micronor and Sharobel. 

Both types of birth control work for their intended purpose, meaning your risk of getting pregnant will decrease significantly regardless of whether you choose a combined birth control pill or a pill that only contains a progestin.

As well as containing different hormones, combined birth control pills and progestin-only pills will usually contain different amounts of each hormone. Normally, the amount of progestins used in progestin-only pills is lower than the amount of progestins used in combined birth control. 

For example, Estrostep contains a combination of 1mg of norethindrone acetate and 20mg, 30mg or 35mg of ethinyl estradiol, depending on the cycle week. 

Sharobel, a progestin-only birth control that also contains norethindrone, only contains a small 0.35mg dose of the progestin.

This is why progestin-only birth control pills are often called “mini-pills.” Not only do they only contain one hormone, but they also have a significantly lower total amount of hormones than equivalent combined birth control pills.

Strengths and Weaknesses of Combined Birth Control Pills

Combined birth control pills have several unique advantages, such as their effects on your skin and risk of developing acne. However, they also have several disadvantages that might make a progestin-only form of birth control more suitable for you. 

Some of the key advantages of combined birth control pills include:

• A lower risk of developing acne. Combined birth control pills like Yaz, Ortho Tri-Cyclen and Estrostep are all approved by the FDA as treatments for acne. Studies tend to show that these pills work well for stopping acne breakouts caused by hormonal fluctuations.
  
  
• Milder, more tolerable periods. Combined birth control pills can make your period less intense and painful, especially if you normally have a heavy, uncomfortable period. Many women also experience a shorter period after starting combined birth control.

• A significantly reduced pregnancy risk. Combined birth control pills block pregnancy from two different angles: By thickening your cervical mucus to stop sperm from getting into your uterus, and by stopping your ovaries from releasing eggs.
  
  Generally, combined birth control pills have the highest success rates of any form of oral contraceptive.

Like all contraceptives, combined birth control pills also have weaknesses. Some of the biggest weaknesses of combined birth control pills include:

• Breastfeeding issues. Some women experience problems breastfeeding if they use a combined oral contraceptive. This is typically due to the effects that extra estrogen can have on your body’s ability to make breastmilk.
  
  
• Headaches and period discomfort. Some women experience headaches and period discomfort after starting combined birth control. This is often caused by fluctuations in your body’s estrogen levels, which may trigger headaches and migraines.

• Weight gain. Many women experience mild weight gain after they start using combined birth control pills. This is almost always fluid retention caused by estrogen, and is rarely the result of fat or muscle gain.

• Blood clots. While blood clots are extremely rare in healthy women on birth control, it’s still possible for them to occur. Your risk of experiencing a blood clot from birth control is highest if you’re over age 35, a smoker and use a combined birth control pill.
  
  If you’re at a high risk of suffering a blood clot or stroke, your doctor might recommend using a progestin-only birth control form of birth control instead of a combined pill. 

Strengths and Weaknesses of Progestin-Only Birth Control Pills

Progestin-only birth control pills have several benefits, the biggest of which is that they’re more suitable if you’re sensitive to hormones like estrogen. They’re also a better option if you plan to breastfeed, as they’re less likely to affect milk volume. 

Other benefits of progestin-only birth control pills include:

• No estrogen-specific side effects. Because progestin-only birth control pills don’t use ethinyl estradiol, they generally don’t cause estrogen-specific side effects such as fluid retention and migraines.
  
  
• Fewer effects on breastfeeding. Progestin-only birth control pills are generally a safer option if you plan to breastfeed, as they generally don’t affect your body’s production of breast milk.

• A lower risk of blood clots and stroke. While progestin-only birth control pills can still increase your risk of blood clots and stroke, they’re generally regarded as a safer option for women with a high risk of experiencing cardiovascular side effects from birth control.

• Fewer drug interactions. If you use other prescription medication that can interact with estrogen, a progestin-only birth control pill might reduce your risk of experiencing a drug interaction.

• A faster return to fertility. If you want to get pregnant, you’ll generally get your fertility back faster after you stop using progestin-only birth control than you would after stopping a combined birth control pill. 

Progestin-only birth control pills also have several weaknesses, several of which aren’t present in combined birth control pills. These weaknesses include:

• No protection against acne. Because progestin-only mini-pills don’t contain estrogen, they’re far less effective as treatments for acne. Currently, the FDA hasn’t approved any progestin-only birth control pills as acne treatments.
  
  
• Slightly less protection against pregnancy. While progestin-only birth control pills are effective at preventing pregnancy, missing a pill can make you more at risk of becoming pregnant than you would be if you missed a combined birth control pill.

• Higher risk of ectopic pregnancy. If you become pregnant while using progestin-only birth control, you have a higher-than-normal risk of ectopic pregnancy (a pregnancy in which the embryo attaches outside the uterus). 

Which Type of Birth Control Pill is Best For You?

There’s no “best” birth control pill for everyone. In fact, there’s no “best birth control pill” period.  The best birth control pill is subjective, and all depends on you. Combined birth control pills and progestin-only pills both offer a range of unique advantages and disadvantages, meaning that one type of pill could be a better match for your needs, lifestyle and health than the other.

As with anything contraceptive-related, the best tactic is to talk to your doctor about your needs and expectations. They’ll be able to choose a form that offers the protection you need while helping you avoid any health risks and adverse birth control side effects. 

Learn More About Birth Control

Interested in learning about specific birth control pills? Our guides to Yaz, Estrostep and Ortho Tri-Cyclen go into detail on three of the most widely used birth control pills, all of which can be used as treatments for hormonal acne.

Worried about the effects birth control could have on your skin, waistline or heart? Our guide to birth control side effects puts birth control side effects into context, with real scientific data on how uncommon most birth control side effects really are.