All about the morning-after pill and ovulation

When it comes to the morning-after pill, it’s all about timing. There’s one golden rule: The sooner you take it, the better it works. Studies have shown that the morning-after pill is 89% effective when taken within three days of unprotected sex — and potentially even more effective if taken sooner. In addition to timing, how well the pill works also depends on where you are in your menstrual cycle.

So how exactly can the morning-after pill’s effectiveness shift depending on where you are in your cycle? We’ve got you covered with some doctor-approved answers.

Let’s start with ovulation.

Believe it or not, the period is not the center of the menstrual cycle – it’s ovulation. Ovulation is the reason we have periods, with most hormonal fluctuations focused on this single event. Here’s how.

A new menstrual cycle (day 1) begins on the first day of your period, during which time your hormones are already telling your ovaries to get an egg ready for its big moment (ovulation). Preparation begins when a single immature egg is selected from one ovary to grow and “mature” over the following weeks (which typically takes about 14 days). When the egg is ready, ovulation officially kicks off with something called the LH (luteinizing hormone) surge. Levels of LH take about 24 hours to build up, finally reaching a high point and sending a signal to the ovary to release the mature egg.

Two things might occur after the egg is released:

1. Fertilization. When the egg is released, it may be fertilized by a sperm if sperm is present in the fallopian tube. If the egg is fertilized and implants on your uterine lining, then a pregnancy will begin.
2. Nothing. After release, the egg will survive for 12-24 hours. If the egg isn't fertilized by a sperm, it will pass from the uterus through the cervix or dissolve. When there is no fertilization, the uterus prepares to restart the menstrual cycle. It takes about 14 days after ovulation for the uterine lining to shed. This is your period and signals the start of a new cycle.

Ovulation takes place about halfway between your periods. For instance, if you have a 28-day cycle, ovulation would occur around or on day 14. But every woman's cycle is different, and the exact day of ovulation can differ from month to month and person to person.

Remind me – how does the morning-after pill work?

The Julie Morning After Pill™, Plan B One-Step®, Aftera®, Take Action® and other OTC morning-after pills are highly effective at preventing pregnancy by delaying ovulation. As we just covered, the whole ovulation process begins with the LH surge. From start to finish, this part of the ovulation process takes about a day. Then the egg is released. When taken before the LH surge begins, the morning-after pill blocks the surge and temporarily pauses ovulation.

When there’s no egg, there’s nothing to be fertilized. And voila! No pregnancy. Timing is everything.

Will the morning-after pill work if the ovulation process has already started?

So what’s the deal if the LH surge has already begun? Unfortunately, the morning-after pill will not work. But unless you’re keeping close tabs on your menstrual cycle, you probably don’t know exactly where you are in the ovulation process. Ultimately, if you're unsure whether or not ovulation has already started, there’s no harm in taking the Julie Morning After Pill™. It might work for you, but, if it doesn’t, it can’t harm you or a fertilized egg. Remember, it’s not an abortion pill.

Does the morning-after pill work after ovulation?

The straight answer is no, it will not work if you take it after ovulation. So if you have unprotected sex before you ovulate but wait to take the morning-after pill until after ovulation has passed, there is a chance of pregnancy (this is why it’s best to take it as soon as possible). But if you have unprotected sex after you ovulate and take the morning-after pill, it will have no impact on your chance of pregnancy – because there is zero chance of pregnancy until your next ovulation cycle.

There are two other types of emergency contraception that may be effective once the ovulation process has started, but they both require involving a medical provider. The first, Ella, is a prescription medication that can stop an LH surge if it has already started (though it will have no impact if the egg has been released). The second form is the intrauterine device (IUD), which must be inserted by a healthcare professional within five days after unprotected sex. The IUD is thought to be effective by making the uterine lining less supportive of implantation, though the way it works is not totally clear. Once inserted, it can remain in place and provide ongoing protection against pregnancy.

The best way to prevent pregnancy throughout your cycle is to use a regular form of birth control, including:

• Daily birth control pill
• IUD
• Condom
• Diaphragm
• Patch
• Vaginal ring
• Shot
• Implant

Understanding your menstrual cycle — and when you're most likely to ovulate — can help you know if taking the Julie Morning After Pill™ will be effective after unprotected sex.

How do you know when you're ovulating?

Even though ovulation occurs monthly, it's not easy to know exactly when it’s happening. And even if your menstrual cycle is usually predictable, ovulation can be delayed by external factors like stress, diet changes, or even changing time zones. Of course it has to be confusing.

Here are two general ways to know if you're ovulating. The first is by tracking your cycle. There are a few different ways to do this, but they all take into account that ovulation normally occurs 14 days before day one of your next period. The second is by monitoring some (very subtle) body changes that may happen around the time of ovulation. These include changes in your vaginal discharge, temperature increase and cramps.

How do you track your cycle?

Before we dive into this, please remember that everyone is different and external factors can influence your menstrual cycle, making it potentially tricky to be super precise. That being said, here are are few trusted ways to keep tabs.

• Calendar method. There are various calendars and trackers you can use to track your menstrual cycle. Once a pattern is established, these trackers can usually estimate when you’re likely ovulating.
• Standard days. Tracking the last day and first day of your periods can be an effective way to count down to ovulation. If your period happens every 28 to 30 days, ovulation will generally occur in the middle of that (specifically, 14 days before your next period). But keep in mind that some people have menstrual cycles as short as 21 days and as long as 35 — how you track comes down to your unique cycle.
• Basal body temperature (BBT) method. Take your oral temperature and track your BBT daily by recording it in a journal or an app. Take note of fluctuations before and during ovulation.
• Cervical mucus method. Vaginal discharge is also another way to track your ovulation cycle. Secretions will change before ovulation to help prepare for potential sperm.

Ovulation symptoms

The hormonal changes that signal your ovaries to release an egg can cause certain signs or symptoms, but these symptoms can also be helpful indicators of ovulation. Ovulation is not the same for everyone, but chances are that you experience at least one of the most symptoms of ovulation, including:

• Pain. You may feel a twinge of pain or cramping. Known as mittelschmerz, or "middle pain" in German, this pain usually occurs each month from the left or right side of your lower abdomen, depending on which ovary is releasing the egg that month.
• Changes in saliva. Estrogen and progesterone can change the consistency of dried saliva before or during ovulation, causing distinct patterns to form. But drinking, smoking, eating, and brushing your teeth can mask this change.
• Body temperature. Basal body temperature (BBT), or your temperature when you first wake up in the morning, goes up by about ½ to 1°F during the 24-hour window after ovulation happens. If you don't become pregnant, your body will stay at that temperature until your period starts.
• Changes in cervical mucus. So about the aforementioned discharge…leading up to ovulation, you may end up seeing a change in your vaginal discharge because of the increase of this fluid in your cervix. This fluid thickens and sometimes takes on the consistency of egg whites to help transport sperm to an egg. Aw.

When should you take a pregnancy test?

The short answer is that it depends on when your period usually starts. However, periods aren't always consistent, so that kind of throws a wrench in the whole thing. Here are a few situations when a pregnancy test may be advised:

• If you regularly track your cycle and your period is a week late
• If you had unprotected sex and your period hasn’t arrived within 3 weeks
• If you took the Julie Morning After Pill™ (or another morning-after pill) and your period hasn’t arrived within 3 weeks

When used as directed, the Julie Morning After Pill™ is safe and effective. The most common side effect of the morning-after pill is changes in your period, so a late period isn’t necessarily a reason to panic. Other common side effects include nausea, lower stomach pain, tiredness, headache, dizziness, and breast tenderness. The Julie Morning After Pill™ will not protect you from HIV and other sexually transmitted diseases, and it will not end an established pregnancy (it’s not an abortion pill).

While we love to share useful and helpful information, the above shouldn’t replace the advice of your healthcare professional. For questions about birth control and other women’s health issues, please talk to your doctor.