Emergency contraception: Clinical sciences

Emergency contraception is used to prevent unintended pregnancy after unprotected or inadequately protected sexual intercourse. Many patients don’t fully understand what emergency contraception is or how it differs from medical abortion, which is why some of them don’t use it when needed. While medical abortion is used to end a confirmed pregnancy, emergency contraception works by preventing pregnancy after sexual intercourse and is ineffective after implantation. Different types of emergency contraception are available, including levonorgestrel, ulipristal acetate, combined oral contraceptives, and intrauterine devices. Okay, let’s talk about what to do when a patient presents after unprotected or inadequately protected sexual intercourse and does not desire pregnancy.

The good news is that there are no exams or testing necessary! In fact, emergency contraception should be utilized as soon as possible after unprotected or inadequately protected intercourse. So, there’s no need to wait for any test results, not even a pregnancy test! First, ask how long it’s been in days or hours since intercourse and go from there.

Here’s a clinical pearl! Always counsel patients on emergency contraception. Unfortunately, you may not know if your patient is experiencing intimate partner violence or if they’ve been or ever become a victim of sexual assault; so routinely discussing and prescribing emergency contraception can make a big difference. The oral levonorgestrel product is available over the counter without age restriction.

Okay, if it’s been up to 5 days, or 120 hours, since intercourse the patient can receive emergency contraception.

The first and most commonly used option is oral levonorgestrel, commonly known as Plan B. This method is most effective the sooner it’s taken from the act of unprotected sexual intercourse, ideally when taken within 72 hours, but continues to reduce the risk of pregnancy up to 120 hours. Unlike every other form of emergency contraception out there, a prescription is not required and levonorgestrel can be purchased over the counter! Now, levonorgestrel is a progestin-only hormonal pill and it works primarily by preventing or delaying ovulation. This medication becomes less effective after the LH surge has begun and is not effective after ovulation has already occurred. Most patients tolerate it well, however some common side effects include nausea and vomiting.

Be sure to give some information to your patient about this method. First, since ovulation is prevented or delayed, your patient can become pregnant after taking levonorgestrel if they have another unprotected intercourse in the same menstrual cycle. Therefore, it’s important to counsel them to abstain from intercourse or use barrier protection going forward.

Next, if your patient wants to begin using long-term birth control, like oral contraceptive pills, an IUD, or other hormonal methods, you can initiate it right away; however, you must remember to let them know that abstinence or barrier protection is necessary during the first 7 days as the hormones take effect.

As a final piece of advice, tell your patient to try and avoid repeated use of hormonal emergency contraception and instead consider long-term options. While it is okay to use multiple doses, even in the same menstrual cycle, there’s no long-term information on the safety if used frequently. Additionally, the high level of levonorgestrel in each dose may cause menstrual irregularities, making it harder for patients to reliably track their cycles.

Let’s move on to another option for emergency contraception, called ulipristal acetate. This is the most effective form of oral emergency contraception and maintains its effectiveness for up to 5 days, or 120 hours, after intercourse. Now, ulipristal acetate is a selective progesterone receptor modulator or anti-progestin pill. It works similarly to levonorgestrel in that it delays or prevents ovulation, it’s not effective after the LH peak or after ovulation has already occurred, and like levonorgestrel options, it does not affect implantation of a fertilized egg. The most common side effects are nausea and vomiting as well. If choosing this route, take this opportunity to counsel your patient on its use as an episodic intervention rather than an effective long-term method of birth control, and discuss long-term options if they’re not on them.

Alright, there’s a catch. If your patient wants to begin using long-term hormonal birth control, be sure to let them know that they should wait 5 days after taking ulipristal acetate. This is because ulipristal acetate and hormonal contraception both compete for the same progesterone receptors and can basically cancel each other out. This actually increases the risk of an undesired pregnancy! Additionally, advise your patients to use barrier protection for 14 days or until their next menses, whichever comes first.

Here’s a clinical pearl! Body weight influences the effectiveness of oral emergency contraception. Levonorgestrel and ulipristal acetate might be less effective in patients who are overweight or obese, with data that levonorgestrel could be less effective than ulipristal in these patients. Both remain viable options nonetheless, and this should not be a reason to withhold them, but consider suggesting an IUD as an alternative in this population.

Okay, another method for emergency contraception is using a high dose of oral contraceptive pills, called the Yuzpe method, to prevent pregnancy. The Yuzpe method is the least effective form of emergency contraception, but can be a good option if your patient cannot readily access other methods. Be warned, this one requires some math! So, the Yuzpe method involves taking two calculated doses of combined oral contraceptive pills, 12 hours apart. The aim is to take a number of pills that provide at least 100 micrograms of ethinyl estradiol and 0.5 milligrams of active progestin, preferably levonorgestrel. In other words, your goal is to load up on the progestin portion of oral contraceptive pills to reach the effective dose needed to prevent or delay ovulation. Since there are many different doses of combination pills, the number of tablets needed for each dose will vary.