The average menstrual cycle is about 28 days. Many of us think of our cycle in just two parts. The five or so days we bleed, and the rest of the month when we don’t. For those wanting to learn more about their body, knowing when your luteal phase occurs is important.
The menstrual cycle is actually broken down into four distinct phases. Being aware of each phase, as well as what is or isn’t normal in each phase, is a vital part of understanding your reproductive health.
Some people want to understand their cycle better for trying to conceive, trying to avoid pregnancy or just trying to figure out why they aren’t feeling well.
The more you understand your menstrual cycle, the sooner you might be able to conceive if desired or notice reproductive health concerns. Understanding each phase, including the luteal phase, is a great way to be an active participant in your healthcare.
The four phases of the menstrual cycle
It’s easy to think of our menstrual cycle in just in terms of when you have your period and when you don’t. However here are the four distinct phases:
- Menstruation – Period
- Follicular Phase
- Ovulation
- Luteal Phase
For those trying to conceive, understanding ovulation and the luteal phase (which make up the second half of your cycle) are usually their focus. This chart provides an easy breakdown for each phase of your menstrual cycle.
Be sure to read Menstrual Cycle – Stages, Phases and What To Expect to learn more about each phase.
What is the luteal phase?
The luteal phase is the last phase in the menstrual cycle. This is the stage which occurs after ovulation and before your period (or positive pregnancy test).
The only way to know for sure you’re in this phase is by tracking your cycle. You can also make an educated guess based on your average cycle. If your cycle is about 28 days long, you’re likely to be in the luteal phase sometime between cycle day 13 and 16. Of course, there are lots of variables in timing.
Ovulation occurs as a result of the the pituitary gland releasing follicle stimulating hormone (FSH). This stimulates the development of approximately 5-12 follicles, which produce estrogen. As a result of the increasing estrogen, Luteinizing hormone (LH) surges and the most dominant follicle is released, and begins its journey down the fallopian tubes.
What happens during the luteal phase?
After ovulation occurs, you’re in the luteal phase.
For those trying to conceive, this phase is also often referred to as the “two week wait” because it’s around two weeks from ovulation until finding out if you’re pregnant.
For women trying to conceive, those with endometriosis or PCOS, or those just wanting to learn more about their bodies, plenty of attention tends to go into this phase.
Once you ovulate, your hormones continue to fluctuate. The corpus luteum releases progesterone and some estrogen, causing the uterine lining to thicken in preparation for a fertilized egg to implant.
The egg, fertilized or not, will continue its journey from the fallopian tubes into the uterus. If there is a healthy fertilized egg, it will begin to implant about 6 days into your luteal phase. Many track days as ‘post ovulation’ rather than the day of their luteal phase.
As you see above in the chart, if the egg is fertilized, the cells will continue to split and eventually form a blastocyst. A blastocyst then implants into the uterine wall at which point you have conceived. If the pregnancy progresses, the pregnancy hormone hCG (human chorionic gonadotropin) will rise in your system. This is the hormone pregnancy tests detect.
If you do not conceive, your estrogen and progesterone levels will continue to rise for much of the luteal phase until it realizes you haven’t conceived. Then both hormones will gradually drop which triggers your period. This is the shedding of the thickened uterine lining.
Luteal phase symptoms
Typically, women don’t notice many symptoms in the luteal phase unless they’re prone to PMS (which could be the result of a hormonal imbalance). Then they may experience common PMS symptoms in the days leading up to the start of a new cycle.
If you conceive in a cycle, some experience very early pregnancy symptoms during the luteal phase. It’s rare to experience notable symptoms this early into a pregnancy, but some may experience:
- Light cramping
- Spotting/implantation bleeding
- Changes in vaginal discharge
- Nausea and other digestive changes
- Increased sense of smell
- Sore breasts
- Fatigue
- Mood swings and changes
They may also experience a variety of other signs, similar to PMS. Some women wonder about symptoms as early as 3 days post ovulation. Generally, however, you’ll simply have to wait and see whether your luteal phase ends with a positive pregnancy test or new cycle.
What is the corpus luteum?
If you’re looking into the luteal phase, chances are you’re wondering about a lot of reproductive terminology. The previous section describes the basics of the luteal phase. With that base information, the corpus luteum is easier to understand.
The released egg is also known as the corpus luteum. The corpus luteum is responsible for making sure your estrogen and progesterone levels continue to rise to thicken your uterine lining.
You may have also heard about corpus luteum cysts. These can be common, especially in the first trimester of pregnancy.
When the egg isn’t fertilized or it doesn’t implant, it allows your estrogen and progesterone levels to drop. As mentioned above, this hormonal drop triggers your uterine lining to shed, causes your period and begins a new cycle.
How long is the luteal phase?
The average luteal phase is about 14 days. A normal luteal phase is about 11 to 17 days. This can vary cycle to cycle, but most women only notice if they’re charting their cycle. The exact length of your luteal phase isn’t typically concerning. As long as it falls within the normal range, variation cycle to cycle is fine.
Reproductive health specialist Dr. Andrew Orr says, “A paper in the British Medical Journal says that statistically, ovulation is more likely to occur between days 18-28. There is 10% probability of being in your fertile window during days 10-16, which is commonly known as the fertile window. Around 70% of women are fertile outside of these times. There’s even a 1-6% chance of being fertile during your menstrual cycle!”
So, you don’t need to get hung up on length. Dr. Orr has had patients ovulate around cycle day 26 and it wasn’t an inherent concern.
You would be more concerned if you experienced signs and symptoms of endometriosis or PCOS during the luteal phase than simply experiencing varying phase lengths.
For women who choose to chart their menstrual cycles for an extended period of time, it isn’t unusual for them to notice slight variations cycle to cycle. Causes for concern would be changes in your symptoms, pain, irregular bleeding, etc., in which case you would want to contact your midwife or physician.
Luteal Phase Defect
In online fertility support groups it’s common to hear about something called a luteal phase defect. The information regarding defects varies. If your luteal phase is consistently under 10 days, some providers may call it a luteal phase defect.
Other providers aren’t overly concerned about the length of each stage in your cycle. A recent study concluded:
“Although an isolated cycle with a short luteal phase may negatively impact short-term fertility, incidence of infertility at 12 months was not significantly higher among these women.”
Some women opt to try a variety of supplements, dietary changes and progesterone support to lengthen their luteal phase. There’s some small studies regarding supplements as well as a variety of information regarding progesterone supplementation.
Vitex may help progesterone and estrogen levels
A small but double blind study including 30 women found the supplement Vitex improved both progesterone and estrogen levels during the luteal phase. They also found an increased incidence of pregnancy among the women taking the vitex for five months.
If you opt to use progesterone, it’s important to work with a qualified maternity care provider. One who can monitor if you’ve conceived, and if you should continue the progesterone or if the supplements can be stopped to start a new cycle.
It’s not unusual to be concerned if you don’t conceive within a couple months of trying to get pregnant with a short luteal phase. However, around 50% of fertilized eggs don’t implant properly. Typically, this isn’t indicative of problems, just a normal process to ensure healthy, fertilized eggs implant into the uterus.
It could take up to 12 months for a healthy couple to conceive
It’s common for healthy couples to take 6-12 cycles to conceive. In each cycle, there’s around a 20% chance of pregnancy occurring.
If you’re over 35 and have been trying unsuccessfully for 6 months, especially if you note cyclical irregularities, many recommend seeing a fertility specialist. If you’re under 35 and have been trying for 12 months, it’s recommended to see a provider. If you have a know reproductive health diagnosis, such as endometriosis, and you’re experiencing a short luteal phase, you should reach out as soon as you’re concerned.
