You’re born with hundreds of thousands of immature eggs in your ovaries. Each egg carries half a potential baby’s genetic information. (The other half, of course, comes from sperm!) Every month, your body chooses one promising egg to mature. Once the chosen egg is ready, it’s released into your fallopian tubes. It’ll stay there for a day or two, waiting for sperm. If it’s fertilized, it’ll travel into your uterus, implant on the wall, and become a baby!

The science of eggs

A telling sign of healthy eggs is a healthy menstrual cycle. Every month, your body develops and releases a single egg. A healthy cycle:

  • lasts for about four weeks or longer
  • has no blood spotting mid-cycle
  • results in ovulation (the release of an egg, so sperm can fertilize it) about two weeks before your period begins

In this department, timing is everything. It’s really helpful to have an idea of when you’ll ovulate. Try to have sex more often during your ‘fertility window’, the four or five days leading up to ovulation, and a day following it. There’s no risk in having too much sex — it doesn’t hurt the quality of sperm. Just make sure you don’t feel pressured, and that you’re both still having fun.

How am I supposed to know when I’m ovulating?

Figuring this out is easy for some women, and difficult for others. It depends on how regular your cycle is. Ovulation happens roughly 14 days before your period starts. So for those with a regular cycle, using a calendar to track it may be enough. All you need to do is count back about 14 days from when you expect to get your period. There are also tracker apps available for iPhone and Android. Some will even send you a notification when it’s time to get busy!

What if I don’t have a regular cycle?

If your cycle is irregular, you’ll have a harder time predicting your window. Try to be conscious of any ovulation symptoms you experience. These vary from woman to woman, but more common symptoms include:

  • tender breasts
  • mild bloating
  • cramping
  • mood swings
  • fatigue
  • increased libido
  • clear, slippery lubrication

Changes in your lubrication down there are often the easiest sign: when it’s clear and slippery, you’re likely ovulating; when it’s opaque and sticky, you’re probably not.

If you’re still struggling to figure out when you ovulate, there are more sophisticated techniques. Many people recommend basal body temperature charting. We don’t – it’s a lot of work, and the data it produces is difficult to interpret.

Instead, we encourage you to use a home urinary LH detection kit. It checks your urine for certain hormones, and is a much more simple and reliable approach. You can probably pick one up at your pharmacy.

You probably already know the basics of your cycle, but let’s explore it a bit more. A woman’s cycle normally runs about 4 weeks, but it’s normal and healthy for a cycle to be anywhere from 21 to 36 days long. The menstrual cycle is powered by estrogen and progesterone hormones, and is generally divided into three phases:

1. The follicular phase

Counting from the first day of your period, the first seven days or so are the follicular phase.

Remember that menstrual bleeding is your body’s way of removing the unused “nursery” (thickened, extra lining) in your uterus, since there wasn’t a fertilized egg to use it.

But now that your body is gearing up for a new egg, it needs to build a new nursery for it. So estrogen levels creep up slowly, stopping the menstrual bleeding, stimulating the thickening of the uterine walls, and singling out one “chosen egg” to start maturing.

2. Ovulation

Mid-cycle, or just before, the luteinizing hormone spikes. It causes the ovarian follicle to release the mature, chosen egg. This takes about a day.

3. The luteal phase

Now that the mature egg has left the ovarian follicle, it travels to the fallopian tube where it waits for a couple days to be fertilized by sperm.

Meanwhile, the now-empty ovarian follicle begins producing progesterone, which maintains the thickened uterine lining (the nursery).

If a fertilized egg doesn’t implant in your uterus within about two weeks, progesterone production sharply drops, and that extra cushy uterine lining will begin to contract and shed, beginning menstrual bleeding (your period) and completing the menstrual cycle.

Fertility challenges

Healthy eggs are the foundation of a successful pregnancy. Many fertility issues begin with eggs that are having a little trouble.

For example, sometimes they’re unable to multiply properly into a fetus after they’re fertilized, leading to chromosome-related problems with the baby (like Down’s syndrome). “Low quality” eggs can also have a harder time implanting and holding onto the uterine walls, which can make contraception harder or cause a very early miscarriage.

Figuring out your egg quality can be hard. It’s usually estimated based on your age, egg quantity (or “ovarian reserve”), your cycle, as well as previous pregnancy and IVF history.

Low egg quality usually affects older women, as their ovarian reserve will naturally diminish, and the healthiest eggs may have already been used. But if you have a good ovarian reserve, it’s usually assumed that you have some good eggs in there. It’s rare for women under 35 to have problems in this department, but it’s possible. Sometimes younger women suffer from low egg quality because of conditions relating to smoking, chemotherapy, radiation, or endometriosis.

Short and irregular cycles may be signs of low ovarian reserve, but they could also be harmless and innocent – simply caused by environmental factors like stress, travel, and illness.

Similarly, mid-cycle spotting can be a sign of a problem. Remember that empty follicles are responsible for producing the hormone progesterone, and progesterone is responsible for maintaining the thickened uterine lining (the “nursery” in your uterus) after ovulation. If the follicles are having problems producing progesterone, there won’t be enough progesterone to maintain that nursery. This can cause mid-cycle spotting, as the extra uterine lining is prematurely and incompletely shed. This also means the fertilized egg may not have a stable nursery to develop in, causing fertility issues.

On the other end of the spectrum, a woman with very high ovarian reserve who has long and irregular periods may be suffering from polycystic ovary syndrome (PCOS). In a nutshell, immature eggs release hormones of their own. When a woman has too many immature eggs, the increased level of hormones confuses your body as it tries to mature and release its eggs. The good news is that hormone therapy for PCOS is an option, and the outcome is usually excellent!


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