Your Cycle: Week by Week

A rundown of what happens during a typical menstrual cycle and signs there's a problem.

Kristina Nickerson

Week One: Menstrual Phase

Day one of your cycle is the day you start bleeding.

The quick and dirty:

No egg implanted into your uterus so it doesn’t need the cushion it built up in the previous month. That blood and tissue is shed out of your vagina. This should last 3-7 days or whatever is normal for you.

The science:

The corpus luteum (dying ovarian follicle) from the egg that was released in the previous cycle has stopped producing progesterone without an hCG signal from a developing embryo. This causes blood to stop flowing to the top layer of the endometrium (the lining of your uterus) which then dies and is shed through the vagina.

Menstrual blood is blood and tissue that was used to build up this layer for a developing embryo and is not blood coming from your current circulating blood reserve.

Troubleshooting (talk to your doctor if):

  • You bleed for less than 2 days - This means your endometrium has not built up sufficiently. It can indicate an estrogen deficiency, anemia, malnutrition, thyroid problems, or something else.
  • Your bleeding fills a pad in an hour for several hours - This can indicate thyroid problems, PCOS, fibroids, anovulation, or something else.
  • Your bleeding lasts more than ten days - This can indicate thyroid problems, PCOS, fibroids, anovulation, an ectopic pregnancy, or something else.
  • You have pain while on the toilet, whether urinating or having a bowel movement. - This can indicate endometriosis or something else.
  • You have pelvic pain or pain during sex - This can indicate PCOS, endometriosis, or something else.
  • You have any other side effect that causes disruptions in your daily activities.

Fertility awareness:

Reliable

-Basal body temperature (BBT):
For the first three months, or if your cycle does not have an obvious pattern, you should take your BBT during this week. During week one, your BBT will likely be lower than your normal temperature during the day. Remember to see the forest, not the trees, one higher or lower temperature is meaningless without context.

-Cervical mucous/discharge:
For the first three months, or if your cycle does not have an obvious pattern, you should record your flow this week: volume, color, clots, etc. This won’t help with fertility, but it will help to plan out your feminine hygiene needs and allow you to notice if and when problems develop.

Not as accurate

-Cervix:
For the first three months, or if your cycle does not have an obvious pattern, you should check the feel and placement of your cervix during this week. During week one, you can expect your cervix to be low, firm, and slightly open. However, cervical cycles are different for everyone and you should establish a pattern before using any cervical information for fertility.

Without much evidence

-Ferning:
For the first three months, or if your cycle does not have an obvious pattern, you should check your ferning patterns this week. During week one, you can expect no ferning. However, ferning patterns are different for everyone and you should establish a pattern before using any ferning information for fertility.

Week Two: Follicular Phase

Ovulation occurs at the end of this week.

The quick and dirty:

This is the time when your egg is developing. It should last around 14 days from the start of menstruation, or however long is normal for you. This week is when you want to put in the most effort into getting sperm up there if you’re trying to get pregnant.

The science:

Estrogen increases this week, triggering the endometrium to begin building up. The estrogen spike just before ovulation triggers the production of Luteinizing Hormone (LH) which releases the most mature egg (or eggs) from its follicle on day 14 or whenever is normal for you. Once the egg is released, it will survive for only 12-24 hours. For the best chances of fertilizing the released egg, sperm should be waiting. Sperm need time to shed their protective coating, so you should make sure you have sperm heading in the right direction in the three days before ovulation. Doing so at least two of those three days is the best strategy. Some evidence suggests 24-48 hours before ovulation to be the best window for a successful sperm journey.

Ovulation triggers a progesterone spike which increases basal body temperature. The morning after ovulation, you will have a temperature spike of around 0.5F.

Troubleshooting (talk to your doctor if):

  • You are still bleeding at the end of this week - This can indicate ectopic pregnancy, thyroid problems, endometriosis, anemia, or something else.
  • You do not have egg white cervical mucus at all before ovulation - This can indicate PCOS, thyroid problems, dehydration, or something else.
  • You have pelvic pain or pain during sex - This can indicate PCOS, endometriosis, or something else.
  • You have any other side effect that causes disruptions in your daily activities.

Fertility awareness:

Reliable

-Basal body temperature (BBT): This week is especially important to properly check your BBT. During week two, your BBT will spike the morning after ovulation and stay high for at least three days. One day of high temps is not enough to show ovulation, a cycle with less than three days of high bbt is likely anovulatory. One data point is not enough, forest for the trees remember!

-Cervical mucous/discharge: This week is especially important to check your cervical mucus. The beginning of the week your mucus should be sticky and thick, getting thicker as the week progresses. A day or two before ovulation, your mucus should become the consistency of egg whites. This is the best predictor of when you are most fertile. The day you have EWCM is when your vagina and cervix are best able to host sperm. Sex is most likely to end in a baby at this time.

-Ovulation Predictor Kit (OPK): This week you should check for a spike in LH on an OPK stick every morning. The test line should become darker as you get closer to ovulation with it becoming darker than the control line 24-48 hours before ovulation.

Not as accurate

-Cervix: Your cervix should begin moving towards its fertile position this week. A fertile cervix is typically high, soft, and open. This is another indicator that you are in your fertile window. However, cervical position and feel can be unpredictable and you shouldn’t use this as your only indicator. Nor should you worry if it doesn’t go to the exact fertile position.

Without much evidence

-Ferning: Ferning should become more pronounced as you get closer to ovulation. When ferning becomes full and long, this is an indicator that you are in your fertile window. Ferning is not a reliable indicator of fertility and should not be used alone to predict fertility.

Week Three: Luteal Phase

Your egg travels down the fallopian tube this week.

The quick and dirty:

Your egg has been released from your ovary and travels down the fallopian tube. You may feel warm this week. The luteal phase should last between 12 and 16 days, and should be consistent in length. The follicular phase is affected by many factors, but the luteal phase should not be.

The science:

The follicle that the mature egg was released from, now called the corpus luteum, will produce progesterone, keeping your BBT raised this week. Estrogen levels will be lower than before ovulation, but high enough to keep your uterus prepping for a fertilized egg. The higher levels of progesterone will cause your endometrium to grow blood vessels to eventually feed blood to an implanted egg.

If your egg was fertilized it will be growing and splitting as it travels down the fallopian tube towards its new home in your endometrium. Do not test this week, hCG will not show up until sometime during week four, after the egg actually implants into the uterine lining. All you can do this week is make sure you’re getting your folic acid and wait.

Troubleshooting (talk to your doctor if):

  • You do not get a sustained temperature hike of at least three days. - This can indicate an anovulatory cycle and should be brought to the attention of your medical provider if you’re trying to get pregnant or it happens more than three times in a year.
  • You start bleeding less than ten days after ovulation - This can indicate a luteal phase defect, anovulation, PCOS, or something else.
  • You have pain while on the toilet, whether urinating or having a bowel movement. - This can indicate endometriosis or something else.
  • You have pelvic pain or pain during sex - This can indicate PCOS, endometriosis, or something else.
  • You have any other side effect that causes disruptions in your daily activities.

Fertility awareness:

Reliable

-Basal body temperature (BBT): Continue taking your BBT until you get at least three days of a sustained high temperature. For the first three months, or if your cycle does not have an obvious pattern, you should take your BBT during the entire week. Your temperature should stay high for at least three days after ovulation and will likely stay high this entire week. This doesn’t indicate pregnancy, only that you did ovulate.

-Cervical mucous/discharge: Keep checking your mucus until you get egg white consistency. For the first three months, or if your cycle does not have an obvious pattern, you should record your mucus for the entire week: volume, color, consistency, etc. This will help you see your hormonal pattern and see changes that could indicate pregnancy or health problems. Week three should bring cloudy sticky mucus or whatever is normal for you.

Not as accurate

-Cervix: For the first three months, or if your cycle does not have an obvious pattern, you should check the feel and placement of your cervix during this week. During week three the cervix should remain soft and the opening should close up.

Without much evidence

-Ferning: For the first three months, or if your cycle does not have an obvious pattern, you should check your ferning patterns this week. During week three there may continue to be ferning in a transitional pattern or not at all or whatever is normal for you.

Week Four: Luteal Phase

The corpus luteum dies this week unless an egg implants.

The quick and dirty:

If your egg was not fertilized, your body will not get the signal to keep up the uterine lining and your period will begin at the end of this week.

The science:

If your egg did not get fertilized the corpus luteum will die and progesterone and estrogen levels will drop. This will trigger a temperature drop the day before or day of the start of menstruation. It is perfectly normal for your temperature to fluctuate as long as there is an overall pattern, though. The dropping hormone levels can cause mood disruptions, bloating, and cramps this week. The luteal phase ends 14 days after ovulation or whatever is normal for you.

If your egg was fertilized it will begin producing hCG this week. The hCG produced by the fertilized egg will signal the corpus luteum to continue producing progesterone. This will cause a sustained high temperature. The endometrium is not expelled and the egg can implant into it. Levels of hCG will be measurable on early tests (Wondfo, Dollar Tree, and First Response Early Response test for example) approximately two days after implantation. A test may show a first positive between 9 and 12 days after ovulation. Though some women get their first positive outside of that range.

Troubleshooting (talk to your doctor if):

  • You start bleeding less than ten days after ovulation -This can indicate a hormone imbalance, infertility, anovulation, PCOS, or something else.
  • You do not start bleeding by 20 days after ovulation for multiple months. - This can indicate anovulation, PCOS, or something else.
  • Your moods or pain adversely affect your life or you experience suicidal thoughts. - This can indicate PMDD or something else.
  • You have pain while on the toilet, whether urinating or having a bowel movement. - this can indicate endometriosis or something else.
  • You have pelvic pain or pain during sex - this can indicate PCOS, endometriosis, or something else.
  • You have any other side effect that causes disruptions in your daily activities.

Fertility awareness:

Reliable

-Basal body temperature (BBT): For the first three months, or if your cycle does not have an obvious pattern, you should take your BBT during the entire week. Your temperature should stay high for most of this week, dropping just before the beginning of your next cycle. It is possible that you will get a second temperature spike at around 11 days after ovulation (tri-phasic). This may indicate pregnancy but can happen in non-pregnant cycles as well.

-Cervical mucous/discharge: For the first three months, or if your cycle does not have an obvious pattern, you should record your mucus for the entire week: volume, color, consistency, etc. This will help you see your hormonal pattern and see changes that could indicate pregnancy or health problems. Week four should see mucus becoming more sticky and dry until drying almost completely up, or whatever is normal for you.

Not as accurate

-Cervix: For the first three months, or if your cycle does not have an obvious pattern, you should check the feel and placement of your cervix during this week. During week four your cervix should become harder, lower, and be slightly open, or whatever is normal for you. A cervix that remains high and soft and is closed can be an indication of pregnancy, but is by no means an accurate pregnancy test. This can happen in non pregnant cycles as well.

Without much evidence

-Ferning: For the first three months, or if your cycle does not have an obvious pattern, you should check your ferning patterns this week. During week four ferning should not be present. There can be an estrogen spike just before the beginning of the next cycle which would cause a second ferning event.

NOTE: The estrogen spike at the end of the cycle can also cause a second positive on an OPK, although sometimes it doesn’t, this (and cost) is why we do not suggest testing with OPKs through the entire cycle.