A Day-by-Day Guide to Your Reproductive Cycle

So you’ve heard that your menstrual cycle should be approximately 28 days long. But what exactly does that mean? When are you most likely to get pregnant? When will PMS symptoms be at their worst? And what exactly is happening on each day? Here’s a day-by-day breakdown of what’s actually going on inside your vital reproductive organs—plus a few tips on how to make the most of each day—whether you’re trying to conceive or not. And remember: A “normal” cycle can range anywhere from 21 to 36 days, so this is approximate and only counts if you’re not on the pill. (Otherwise, it’s the pill talking, not your ovaries.) Make a mental note; this information is crucial knowledge for all women. The more you know, the better you’ll be able to prepare for each phase of your cycle.

Day 1

The first day of your period is also the first day of your cycle. Unless you’re pregnant, hormone levels plummet, and the blood and tissues lining the uterus break down and shed. The next 28 days are all about your ever-optimistic uterus prepping for the possibility of a nine-month houseguest.

Day 2

The period continues. The second day of your cycle is generally a heavy one. And while your PMS symptoms have cleared, you might have some cramps that accompany the bleeding. This may be a day for super tampons that you’ll have to change regularly. If you find a small clot in your pad, don’t panic. That’s perfectly normal for this point in your cycle. But if you’re going through a box of tampons in a day and passing plum-sized clots, get checked out by a doctor.

Day 3

This is often the final “heavy” day of bleeding. You’ll probably continue to see red blood. You may also experience some changes in your vaginal pH around now, which could lead to yeast infections and bad odors. If so, try an over-the-counter vaginal probiotic like Pro-B to balance things out.

Day 4

Your period usually starts to lighten up and may change in color from bright red to brown.

Day 5

If you generally have a five-day period, a panty liner will usually be enough for today.

Day 6

For many, this is the first day you’ll be free from a period. Others have periods that last up to 7 days, though, which is perfectly normal.

Day 7

By now, your period should be completely or almost gone. This means that your body is gearing up for next month. Small follicles (little cysts on the ovaries that will release an egg or two) are starting to form. Estrogen levels are starting to rise; testosterone is still low; and progesterone is still absent.

Day 8

Those follicles are growing and preparing to release an egg. As the eggs start to develop, they produce estrogen, so estrogen levels will start to rise. Testosterone and progesterone levels will stay the same.

Day 9

Over the next few days, one follicle will continue to develop toward reaching maturity. That extra estrogen causes the lining of the uterus, rich with blood and nutrients, to thicken, so it’s ready if a fertilized egg implants.

Day 10

Estrogen production should now be off the charts. And your endometrium, or the lining of the womb, continues its plans to house a potential pregnancy.

Day 11

If you’re trying to conceive, now’s the time to kick your efforts into high gear since you’re either ovulating or getting close to ovulation. If you’re not always in the mood, now would be a great time to introduce a lubricant into your routine to make planned sex more enjoyable. Be sure to choose a fertility friendly one for best sperm motility. Other lubes can harm sperm.

Day 12

Even though you may not be ovulating yet, your fertility levels are high due to increased estrogen production—and because sperm can survive a few days in the woman’s body. Your cervical mucous is flowing and stretchy, and the main follicle should be fully ready to release an egg while the others shrivel up. You may notice increased libido around this time as testosterone (The main libido hormone!) levels are surging. This is nature’s way of encouraging sex at peak baby-making time.

Day 13

Estrogen levels are peaking, and your body is about ready for the egg to emerge from the ovarian follicle (aka ovulation.)

Day 14

You’re ovulating! The egg is released from the follicle. You may feel a twinge of pain or have a little spotting, which is perfectly normal. This is your best baby-making day, so if you’re trying, whip out the lube and get to it. If you’re not, don’t skip that condom.

Day 15

Your egg is starting its journey down the tube in hopes of a sperm rendezvous. If you don’t want that to happen, but had a condom mishap, it’s not too late to take emergency contraception. If you’re trying to get pregnant, intercourse on the day after ovulation (just in case) is good practice. If things start to get funky down there (a common occurrence with frequent intercourse), reach for RepHresh gel to keep your vaginal pH in check. Now your estrogen and testosterone levels are starting to drop, while progesterone levels are rising rapidly.

Day 16

The egg, ever hopeful, is still hanging out in the tube waiting for Prince Sperm.

Day 17

The lining of the uterus is getting thick. If the egg has successfully united with sperm, it will soon make its home there. If conception hasn’t taken place within 24 hours of ovulation, the egg will die. Estrogen levels are on the way down, while progesterone levels are sky high.

Day 18

Now estrogen will start to make its comeback. Progesterone levels are still up there.

Day 19

If you’re trying to get pregnant or concerned that you might accidentally be pregnant, don’t head to the drugstore yet. It’s still too soon to take a pregnancy test.

Day 20

The end of your cycle is nearing, and it’s around this time that PMS symptoms will start to rear their ugly heads. You may feel slightly bloated and moody.

Day 21

If you’re trying to get pregnant and want to confirm that you’ve ovulated, this is the perfect time for your doctor to check to see if your progesterone is elevated.

Day 22

Time to check your tampon stash so you won’t have to make a midnight trip in a few days.

Day 23

PMS is in full swing. Treat yourself to a bubble bath or your favorite candy bar.

Day 24

About a week after ovulation, your progesterone levels will be at a high. Estrogen will start to drift down.

Day 25

This will probably be your worst PMS day. Expect major bloat. And don’t be surprised if running out of ketchup brings on unexpected weeping.

Day 26

Don’t, I repeat, don’t get on the scale. It’s not you; it’s that pre-menstrual fluid retention.

Day 27

Get excited: PMS symptoms are winding down.

Day 28

This is about the time that your cycle comes to an end. If you’re not pregnant, your period is on its way. The uterine lining is at its thickest to get ready to shed. If you start taking ibuprofen today, (the day before you bleed,) it actually works better to reduce pain—and decrease your flow. Tomorrow, the cycle starts again.