In a 2021 study, researchers asked over 500 participants a simple question.
How does the morning-after pill work?
Despite these pills' widespread use, 60% answered incorrectly.
Emergency contraceptives are often misunderstood.
In fact, even the phrase the morning-after pill is a misnomer.
So how do they work?
Each month, the brain and the ovaries prepare an egg to be released.
First, a group of immature eggs start to grow protective, fluid-filled sacs called follicles.
Around the eighth day, one of these follicles becomes mature or dominant, and the others are reabsorbed.
At this point, the brain signals the pituitary gland to produce luteinizing hormone, often just called LH.
A big surge in LH tells the dominant follicle to rupture, releasing the egg.
This is ovulation.
The egg travels to the fallopian tube, where it stays for about 24 hours.
And it's only in this very short window that it can be fertilized by sperm.
The rise of LH also stimulates the production of a hormone called progesterone.
When progesterone binds at specific receptors, this also helps to signal ovulation.
And high levels of progesterone are vital for preparing the uterine lining to support the possible implantation of a fertilized egg.
So where do emergency contraceptive pills come into play?
Emergency contraceptives are not abortion pills.
Instead, they work much earlier in the process, before pregnancy, by disrupting or delaying ovulation.
There are two main types of pills.
The first type, sometimes called Plan B, contains a molecule called levonorgestrel, which is structurally very similar to the body's hormone progesterone.
When taken, levonorgestrel interferes with the production of LH.
Because LH doesn't surge, there's no ovulation.
That said, Plan B needs to be taken before an LH surge.
It can't prevent ovulation once LH starts rising.
The second type of pill contains a molecule called ulipristal acetate.
It works by blocking progesterone from binding at receptors, thereby delaying ovulation.
Ulipristal acetate works even if LH has already begun to rise, which means it's effective in a wider window of time than Plan B.
Since both pills work by blocking or delaying ovulation, the name the morning-after pill can be misleading.
Emergency contraceptives are most effective when taken as soon as possible after sex to better the chance of disrupting ovulation before it occurs.
There is no need to wait until morning.
For this reason, many healthcare providers suggest having them on hand.
Yet emergency contraceptives may still prevent pregnancy, even if they're taken three to five days after sex, depending on the pill.
That's because sperm can live in the reproductive tract for about five days.
So, for example, if a person ovulates three days after having unprotected sex, there's still a chance of pregnancy.
Since it's difficult to know exactly where someone is in their cycle, it's best to take emergency contraceptives as soon as possible.
But perhaps the most widely held misconception about these pills is that they can harm a person's future fertility.
Decades of research have shown that this isn't the case, even if emergency contraceptives are taken multiple times.
In fact, the effects of both pills are short-lived, and they don't provide continued protection.
It's recommended that a person uses condoms for the remainder of their cycle and if they have unprotected sex again, then repeat use.
Of course, emergency contraceptive pills aren't fail-proof, as they neither prevent fertilization nor the implantation of a fertilized egg.
These pills are ineffective if someone has already ovulated or the LH surge has already peaked.
However, there is a third option that can protect against pregnancy even if a person has already ovulated.
Many people know copper intrauterine devices, or IUDs, as a form of long-term birth control, but they also work to prevent pregnancy if inserted soon after unprotected sex.
Unlike emergency contraceptive pills, a copper IUD can prevent pregnancy before and after fertilisation.
Copper is toxic to sperm and creates a uterine environment that makes implantation unlikely.
Of course, copper IUDs might be less accessible in an emergency situation.
They must be inserted by a trained healthcare provider.
But on the upside, they continue to prevent pregnancy for at least 10 years while in place.
Most healthcare providers agree that it's more effective, as well as less expensive, to use a regular form of birth control when trying to avoid pregnancy.
But if or when you need it, emergency contraceptives are a safe option to use.
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