What is the luteal phase?
The luteal phase is one of the four phases of the menstrual cycle and starts in the second half of your cycle, after ovulation, and ends when your next period starts.
The menstrual cycle can be split into two main phases; the Follicular phase and the Luteal phase.
We can then differentiate these phases even further into:
- Early Follicular Phase (also known as Menstruation)
- Late Follicular Phase
- Mid-Luteal Phase
- Late Luteal Phase (when PMS typically occurs)
You can find out more about the different phases in our article “The Menstrual Cycle - Phases, Hormones, and Their Functions"
What happens during the luteal phase?
After you ovulate, the corpus luteum—a structure inside the ovaries that holds a developing egg—collapses and begins to produce progesterone.
Progesterone is a female reproductive hormone that helps thicken your uterine lining so that if there is a fertilized egg, it can implant itself.
If no egg implants, the corpus luteum stops producing progesterone and your period starts after about 10-16 days, shedding your uterine lining.
Why is the luteal phase important for female health?
Why is the luteal phase important for women trying to conceive?
The luteal phase is a crucial part of the menstrual cycle. During this time, your body increases progesterone levels as well as other hormones that help prepare the uterus for pregnancy.
When we think about pregnancy, most of our minds jump straight to conception—when the sperm enters the egg. However, pregnancy doesn’t really begin until the embryo implants in the uterine lining and for that to take place, the body must make enough progesterone to build up a thick, healthy lining.
If your body isn’t making enough progesterone, your luteal phase may be on the short side. Anything shorter than 10 days can make it difficult to achieve pregnancy.
This is called a luteal phase defect.
Why is the luteal phase important for all women, even if not trying to conceive?
Even if you aren’t trying to get pregnant, your progesterone levels matter. Progesterone is crucial for building healthy bones, boosting metabolism, and long-term heart health, and helps with deep sleep.
How do I know if I’m in my luteal phase?
The increase in progesterone causes your basal body temperature (BBT) to rise slightly (0.3-0.6 degrees Celsius) and it returns to baseline once your next period starts. When your BBT rises, you’ll know you are in your luteal phase.
Moreover, some women experience ovulation pain which can also be used as an indication that a shift in phases is approaching.
How to calculate when you enter your luteal phase?
Here are 4 ways from most accurate to approximations.
- If you use an ovulation test, you’ll know when you see an LH surge that you’ll ovulate within the next 24 to 36 hours. This means you will enter the luteal phase in around 24 to 36 hours.
- Measuring your basal body temperature throughout your cycle can help you identify if you have already ovulated and entered the luteal phase.
- You can also calculate when you are entering your luteal phase with a period tracking app and using the ovulation estimate to give you rough guidance. Though not 100% accurate it’s good enough to give you an indication of where you might be in your cycle.
- Lastly, if your cycles are regular you can also calculate when your luteal phase will start by diving the length of your cycle in half.
For example, if your cycle is 28 days long, Ovulation is likely to occur on day 14, which would make the luteal start on day 15 and last 14 days.
How long should the luteal phase be?
The luteal phase should last anywhere between 12-17 days. In most cases, the luteal phase lasts between 12-14 days.
What does it mean if your luteal phase is short?
A short luteal phase is when it lasts 11 days or fewer. This means that less than 11 days pass from the moment you ovulate to your next period. The main concern with a short luteal phase is that it may not give the womb lining enough time to thicken sufficiently to be able to support the implantation of a fertilized egg.
What are the causes of a short luteal phase?
A short luteal phase might happen when your body doesn’t make enough progesterone. Some of the reasons why this might occur are:
- Excessive exercise
- Thyroid disorders
How do you know if you have a short luteal phase?
One of the ways to know if you have a short luteal phase is to use one of the methods above to calculate when you have ovulated - i.e. ovulation test pr measuring your basal body temperature - and counting the number of days between ovulation and the start of your next period. If your luteal phase is fewer than 11 days, you may have low progesterone.
What does it mean if your luteal phase is long?
Long luteal phases are defined as being longer than 17 days and may be due to hormone imbalances, such as polycystic ovarian syndrome (PCOS).
However, it could also mean that you are pregnant. If your period is delayed, it’s advisable to take a pregnancy test.
What are the symptoms in the luteal phase?
As your progesterone levels increase you may start experiencing a number of symptoms. These may become more pronounced as you approach the end of your cycle and are often referred to as PMS (pre-menstrual syndrome).
Common symptoms include:
- Mood swings
- Tender breasts
- Breakouts or spots
- Changes in appetite
- Changes in sex drive
- Change in body temperature
- Difficulty sleeping
Related articles you might be interested in:
- Female Insomnia - Causes, Symptoms, Treatment, and More
- Does the menstrual cycle impact women's muscle strength performance in resistance training? Research Review
How to ease symptoms in the late luteal phase?
- Prioritise rest and sleep: A number of these symptoms such as a change in your basal body temperature(BBT) and increased anxiety, can cause difficulty sleeping and thus perpetuate other symptoms. During this time is always advisable to prioritize rest (i.e. sleep an extra hour or two if you are feeling tired) to support energy levels.
- Magnesium: Supplementing with magnesium has been highly recommended by a number of nutritionists, menstrual cycle experts, doctors, and women’s health practitioners. Not only does magnesium support better sleep, but it also helps reduce bloating.
- Reduce your caffeine intake: It’s easy to increase intake when you are feeling fatigued, however, that will only perpetuate the problem. Instead, opt for reducing (ideally eliminating) your caffeine intake past 12 pm. That will help you sleep better and ease off
Check out our article on: What to Eat During the Luteal Phase to learn more about how to use nutrition to support your hormones.
Frequently Asked Questions on the luteal phase
Luteal phase deficiencies
Luteal Phase Defect (LPD) (sometimes referred to as Luteal Phase Deficiency or Luteal Phase Insufficiency) refers to a condition where there is an abnormality in the development of the endometrium (the innermost lining of the uterus).
To put it simply, if a woman has LPD her womb lining doesn’t thicken properly each month, making it hard for her to carry a pregnancy.
Can you get pregnant in your luteal phase?
You can get pregnant during the luteal phase. However, once you’ve ovulated the egg can only survive for 12-24 hours and so you can only get pregnant on the first day of the luteal phase.
Measuring your basal body temperature daily can help you understand when you are entering the luteal phase and your chances of getting pregnant.
Are you weaker during the Luteal phase?
Research is unclear on this one. Some studies suggest that women are stronger and able to build muscle faster during the Follicular phase over the Luteal one, however, recent studies have shown that this might not be the case. Check out a review of current studies for more information: Does the menstrual cycle impact women's muscle strength performance in resistance training? Research Review
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- Mesen TB, Young SL. Progesterone and the luteal phase: a requisite to reproduction. Obstet Gynecol Clin North Am. 42, 135-151 (2015).
- Crawford NM, Pritchard DA, Herring AH, Steiner AZ.
- . Fertil Steril. 107, 749-755 (2017).
- Ava Women - What Does Progesterone Do? The Top 8 Impacts.
- Ava Women - What Every Woman Should Know About Her Luteal Phase
- WebMD - Luteal Phase DefectSome of the typical indications are: