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The Luteal Phase & IVF

The Luteal phase and IVF treatment

If you’re planning to undertake an IVF cycle, it helps to understand your body’s luteal phase. This phase of your cycle plays a critical role in helping your body prepare for pregnancy. During the luteal phase, your body produces progesterone to thicken the lining of your uterus to make it hospitable to an embryo. However, if your luteal phase is too short or too long, it can affect the outcomes of your IVF, so it’s crucial to speak to your doctor about your concerns.

What is the Luteal Phase?

The luteal phase is one phase of your menstrual cycle. But to really understand your luteal phase, you need to understand all four phases, which each have their own function and purpose. 

  1. Menstruation – Your cycle starts on Day 1 – the day you get your period. When you don’t fall pregnant, your uterus sheds its thickened lining.
  2. Follicular Phase – This phase overlaps with menstruation – it occurs when your egg follicles (egg-releasing sacs) begin to grow on your ovaries. While you start off with many follicles, one becomes larger than the others and releases an egg.
  3. Ovulation – Ovulation occurs when your ovarian follicle releases a mature egg.
  4. Luteal Phase – After you ovulate, you enter your luteal phase, finishing with your next period.

This entire cycle typically takes between 24 – 32 days. Your luteal phase does not tend to shorten as you age. If your cycle is consistently shorter or longer than this, consult with your doctor to investigate the reasons.

How long should your Luteal Phase be?

Your luteal phase is the number of days between your ovulation and menstruation. Most women have a normal luteal phase that lasts somewhere between 11 to 17 days, with 12 – 14 days being the most common. If your luteal phase falls below ten days in length, it’s considered short.

If you have an 11-day luteal phase, 10-day luteal phase, or 9-day luteal phase, 8-day luteal phase (or even lower), book an appointment with your doctor to discuss.

What happens during your Luteal Phase?

During your luteal phase, the empty follicle that just released the egg shuts down and turns yellow. This empty egg sac becomes an entirely new structure called the corpus luteum and starts releasing oestrogen and progesterone. These hormones, particularly the progesterone, thickens the uterine lining and helps encourage blood vessel growth. Ideally, your uterine lining becomes thick and enriched with blood to provide the embryo with nutrients and oxygen.

What happens if you get pregnant?
If an embryo successfully implants in your uterine wall, you will begin to produce a hormone called human gonadotropin (hCG). This hormone will enable your corpus luteum to continue to produce progesterone until you are around ten weeks pregnant. At that point, the placenta will be developed enough to take over progesterone production.

As your pregnancy continues, your body will continue to produce more and more progesterone.

  • First trimester: 10 to 44 nanograms per millilitre (ng/mL) of progesterone
  • Second trimester: 19 to 82 ng/mL
  • Third trimester: 65 to 290 ng/mL

What happens to your corpus luteum if you don’t get pregnant?

If you don’t fall pregnant after ovulation, your corpus luteum shrinks, and eventually all that is left is a small amount of scar tissue. Your progesterone levels drop, signalling to your body that it’s time to shed your uterine lining. Finally, you menstruate, and the whole process begins again.

How to Track Your Luteal Phase

To track your luteal phase, you’ll need to start by monitoring your entire menstrual cycle on a calendar. There are plenty of free apps online that can help you do this. However, ignore their default ovulation dates. You’ll need to track your own ovulation to get an accurate understanding of your luteal phase. Even if your entire cycle consistently falls within the ‘normal’ range of 24 – 32 days, your luteal phase may still be short.

There are a few main methods of tracking your ovulation.

Ovulation strips – These strips read the level of luteinizing hormone (LH) in your urine.

Basal body temperature charting – With BBT charting, you take your temperature in the morning every day and monitor its rise before ovulation.

Cervical mucus – Check your cervical mucus for an ‘egg-white’ consistency.

Wearable devices – Bracelets and insertable devices that track your BBT

By charting all of this information, you can get an accurate prediction of your luteal phase. It’s essential to do this for at least three months, as your cycle can vary by up to 9 days from month to month. Over time, you can get an average, and notice important trends.

Can You Get Pregnant During the Luteal Phase?

Technically, you cannot get pregnant during the luteal phase. By definition, the luteal phase occurs between ovulation and menstruation, and once ovulation is over, it is no longer possible to get pregnant.

While you tend to have between 5-7 fertile days each month, this is because sperm can live inside the body for up to 5 days. That means you can have intercourse five days before ovulation (which usually lasts around 36 hours) and still get pregnant. However, once ovulation is over, it’s over.

That said, you will encounter stories of people who claim to have fallen pregnant during their luteal phase. The likely explanation for this is that they ovulated at a different time than they thought.

Giving yourself the power with fertility testing

Testing your fertility in the comfort of your home

Progesterone test

At home Progesterone test to confirm if ovulation has occurred on day 21 of a menstrual cycle with online results in 5 days.

Are you thinking of starting a family and want to check you are ovulating normally? Or have you been trying for a baby?

Do you want to be proactive about checking your fertility status so that you can seek help if you need it? If so, this simple at-home ovulation test which includes advice from a qualified doctor, is an important first step in understanding your fertility.

Ovulation tracker

FertilTime Ovulation test is a simple to use home screening test that enables women to determine the 2 best days to conceive.

This fast and reliable test works by detecting raised levels of Luteinising Hormone (LH) in urine – an indication the ovulation is about to occur. The test is greater than 99% accurate.

FertilTime allows women to test their best chances of conception discreetly in the comfort of their own home.

PCOS fertility test

Polycystic Ovary Syndrome (PCOS) is a condition in women that affects the ovaries resulting in the development of cysts on the ovaries which can become enlarged. This test is for any woman who is experiencing any PCOS symptoms and wants to investigate further. Our doctors will interpret your results and let you know what action you should take next.
Our PCOS Blood Test includes tests for testosterone, sex hormone binding globulin (SHBG) and the free androgen index (FAI) to indicate the amount of available androgens circulating in the blood. It also measures luteinising hormone (LH) and follicle stimulating hormone (FSH); a high LH/FSH ratio of between 2:1 or more may indicate PCOS.

Luteal Defect

If your luteal phase is fewer than 10 days in length, you may have a condition called luteal phase defect (LPD). With LPD, your ovaries don’t produce enough progesterone, and/or your uterine lining doesn’t respond and thicken to the progesterone. This condition can cause fertility problems and miscarriages.

However, not all doctors believe that LPD can be a standalone cause of infertility, as there is no definitive way to test for the problem. The American Society for Reproductive Medicine’s position is that it is not an issue on its own. Instead, they have found that it is connected to irregular ovulation, short menstrual cycles, endometriosis, PCOS, and lifestyle factors.

So, again, it’s a good idea to speak with a trusted doctor about your concerns. They may suggest progesterone testing or an endometrial biopsy, though both of these tests are controversial for LPD.

Having a Long Luteal Phase Length

While we typically think of a shortened luteal phase as a problem for IVF and fertility in general, having a long luteal phase length can also pose problems. If your luteal phase is too long, it lengthens your overall cycle and gives you fewer chances to get pregnant each year. This can add additional stress to an already stressful situation.

In most cases, a long luteal phase is caused by hormonal imbalances, such as polycystic ovary syndrome (PCOS). PCOS lengthens your cycle in general due to heightened amounts of male hormones in the body, but it can be treated and managed.

Having a Short Luteal Phase Length

In addition to LPD, there are a few lifestyle factors that can shorten your luteal phase. Smoking has been correlated with short luteal phases, as it reduces your body’s natural ability to produce oestrogen and progesterone. Being significantly overweight has been correlated with a short luteal phase, as have eating disorders and low body weight.

It’s important to note that not all women with a short luteal phase experience fertility problems or miscarriage.

How to Lengthen Luteal Phase

If you are worried that your luteal phase is too short, it’s crucial to speak to your doctor about tested for Luteal Phase Defect (LPD). But there are a few things that you can do to improve your lifestyle that may also lengthen your luteal phase.

  • Quit smoking
  • Maintain a healthy weight
  • Have your thyroid tested
  • Seek treatment for eating disorders

Understanding your Luteal Phase can help your IVF success

Learning more about your body, tracking your ovulation, and understanding your luteal phase can help you fall pregnant naturally or have success with your next round of IVF.
If you are planning a round of IVF, be sure to pay attention to the length of your luteal phase over the course of three or more months. If you have any cause for concern, be sure to share this information with your doctor, and they can consider it when designing your treatment plan. Good luck!

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With thanks to the fantastic experts at Clinica Tambre