How can one of the most widely-used medications be so confusing? Why are there so many kinds and how do they differ from each other? What will make my birth control less effective?

These are all questions that many people have asked and pondered about birth control, and sometimes it can be hard to find reliable information. We’re here to break it down and answer these most asked questions about birth control and contraception.

Some quick definitions:

COC-Combined Oral Contraception: combination of estrogen and progestin hormones, will normally contain ethinyl estradiol AND a progestin component such as drospirenone, norethindrone, levonorgestrel, norgestimate. The COC prevents pregnancy by preventing ovulation, making the uterine lining unsuitable for egg implantation, by thickening cervical mucus to prevent sperm entry, and slowing of egg motility.

POP’s aka “minipill”: progesterone hormone only pill, will normally contain norethindrone OR drospirenone. POP’s prevent pregnancy by thinning the endometrium and thickening the cervical mucus making it harder for sperm to migrate to the egg. POP’s also slow the egg movement through the fallopian tubes and lower midcycle hormone levels that suppress ovulation at certain points during your menstrual cycle (not continuously during a menstrual cycle like COC’s).


How long does it take for my birth control to work? What can I do to prevent pregnancy until it does? 

COC: can take up to 7 days to become effective and protect against pregnancy.

POP’s: Can take 2 days to become effective and protect you against pregnancy.

For all birth controls methods, it can be important to use back-up methods for the first 7 days after starting the medication. Back-up methods include the use of condoms or other contraceptive devices or abstinence.


My birth control looks different than last time, but the pharmacist says it’s the same medication. What does this mean?

Medications like birth control can be developed by several different companies and manufacturers. When the pharmacy receives a prescription, we select products based on the written strength and formulation of the active ingredients. Sometimes this means there may be multiple options to select from for birth control that have the same active ingredients with the same strength and formulation. What may differ between the medications made by different manufacturers is the filler ingredients and the packaging which will not impact the efficacy of the birth control. Your pharmacists are trying their best to keep the medication from same manufacturers, but sometimes the product might be out of stock or not preferred by your insurance plan.

So, if your medication looks different from last time, you can always check with the pharmacist just in case to make sure it’s the same drug but a different manufacturer.


I forgot my pill yesterday! When should I take my next pill?

As soon as you remember!

COC: If close to you next dose, it is okay to double up and take the missed dose and scheduled dose, then resuming your normal schedule

POP’s: do not double up if you remember close to the time you take your next dose


….Am I still protected if I forgot to take it last night?

Check with your pharmacist to ensure that, for the product that you use, you are following the manufacturers recommendations. General information is below for reference.

COC: YES. If a single pill is missed take the missed pill as soon as you notice and then continue taking one pill each day as prescribed. Depending on when you remember your missed pill, you may end up taking two pills on the same day. No additional contraception is required because one missed pill does not reverse ovarian suppression. If you have missed more than one day of COC make sure to use a back-up contraceptive method for 7 days and consider taking emergency contraception if unprotected intercourse occurs during this period of time.

POP’s: NO. In order for POP’s to be effective they need to be taken at the same time every day. If you miss your pill by >3 hours, plan to use back-up methods for at least 48 hours and consider taking emergency contraception if unprotected intercourse occurs during this period of time.


Help! I was sick after taking my pill, will it still work if I had an episode of vomiting?

COC If you experience vomiting or severe diarrhea within 3 hours of taking your pill it will be as if you missed your dose. You can retake your pill and plan to continue taking your birth control as scheduled as long as it is only one missed pill.

POP’s: If you experience vomiting or severe diarrhea within 3 hours of taking your pill it will be as if you missed your dose, continue taking the pill at your normal time plan to use back-up methods for at least 48 hours.


What are some back-up options or emergency contraceptives available?

Plan B (Levonorgestrel)- an over-the-counter (OTC) option for emergency contraception. Plan B can be used within 72 hours of a unprotected sexual intercourse or failed contraceptive method. Plan B is most effective in women that are under a BMI 25 (~160 lbs in an average height woman). The most common side effects are nausea, vomiting, and light-headedness.

Ella (Ulipristal Acetate)- a prescription medication for emergency contraception. Ella can be used within 120 hours (5 days) after an unprotected sexual intercourse or failed contraceptive method. Ella needs to be prescribed by a doctor and it is most effective in women under a BMI of 30 or less. The most common side effects are nausea, vomiting, and light-headedness.

 For more information about emergency contraception please see one of our previous blogs

Can I drink alcohol after taking this medication?

Alcohol will not impact the effectiveness of birth control.


Will my new antibiotic make my oral birth control less effective?

Almost all antibiotics should not affect your birth control. Only rifampin, rifampicin and rifabutin, which are rarely prescribed, have been shown to impact the effectiveness of your contraception. If you have concerns it is recommended to discuss this with your pharmacist. Often individuals on oral birth control are counseled to use a back up method during the antibiotic treatment and for 7 days after to avoid this risk.


What medications can interact with my birth control?

There are limited medications that interact with oral birth control effectiveness; however, antiepileptic medications (medications to reduce seizures) such as phenytoin, carbamazepine, topiramate, and barbiturates can impact effectiveness. If you need medications for a seizure condition, talk to your doctor about other medications you can use to control your seizure that are compatible with POP’s.

Herbal product St. John’s Wort can also interact with birth control so make sure to consult with your doctor before trying this herbal product.

In general it is a good idea to let your pharmacist know all medicines you are taking so they can run a drug interaction check on all medicines, not just oral birth control.

Can I just skip the placebo/ “sugar” pills so I don’t have a period?

Always talk to your doctor first before changing the way you take your medication. Taking the medication differently than prescribed can lead to unforeseen changes in your menstrual cycle or additional side effects.


I heard that birth control can be dangerous?

The use of contraception with estrogen has been associated with an increased risk of blood clots, increased blood pressure, heart attack, stroke, and cervical cancer. The risk of blood clots varies with estrogen dose and patient factors such as age, obesity, and smoking status. While the relative risk is increased, the absolute increase in risk is still low for most women and does not outweigh the numerous benefits of this contraceptive method, including protection against ovarian and endometrial cancer. If you are person with additional risk factors for blood clots and cardiovascular disease, your doctor may recommend taking POPs, or using another form of birth control altogether, instead of combined oral contraception. This is because POP’s do not contain estrogen and may have less of a risk of these dangerous side effects in patients with more risk factors.

Prepared by Katelin Lambert PharmD Candidate 2022