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Hormones 101: LH in fertility testing

LH in fertility testing – we’re giving you the science. This blog explains why we include LH in our hormone test panel.

We empower women with knowledge about our bodies. At Adia, our experts debunk myths around women’s health to give you the facts. In our “Hormones 101” series, we explain why we’ve selected certain hormones for our test panel, and how these relate to fertility.

What is Luteinizing Hormone (LH)?

The pituitary gland produces luteinizing hormone (LH). LH controls the length and sequence of your menstrual cycle. It facilitates ovulation by getting your ovarian follicles to release eggs. LH also prepares your uterus for egg implantation.

LH works with follicle stimulating hormone (FSH) in your system, to support ovulation. Both hormones also help produce oestrogen and progesterone. You can read more about FSH here

How does LH affect fertility?

LH is an important player in your menstrual cycle, with different roles to play. For example, in the first two weeks of your cycle, LH stimulates your ovarian follicles to produce oestrogen. Then, LH levels surge around Day 14 of your cycle, causing an ovarian follicle to tear and release an egg from the ovary. This is known as ovulation.

You might have noticed that we ask you to complete our test on Day 3 of your cycle. This is in part because LH levels rise naturally around Day 14.

In the latter half of your cycle, LH uses the ‘leftovers’ from your egg-releasing ovarian follicle to form what’s called a ‘corpus luteum’. This is a temporary structure in your ovary. Then, LH stimulates the corpus luteum to produce progesterone. Progesterone prepares the uterine lining for egg implantation, and is essential during early stage pregnancy. If the egg isn’t fertilized, the corpus luteum stops making progesterone and decays.

So in short, LH helps you ovulate. Once you’ve ovulated, LH helps make progesterone, and this prepares your uterus for egg implantation.

Why do you include LH in fertility tests?

LH facilitates ovulation, and ovulation is necessary to conceive. So, it’s important that your LH levels are within a ‘normal’ range, though of course some variation can be expected. LH in fertility testing gives you an important snapshot of your fertility health.

LH levels higher than what’s normal for your age can indicate fertility problems. There is no absolute predictor of fertility and LH in fertility tests can only tell you so much. However, elevated LH levels can indicate premature ovarian failure, since this signals decreased sex hormone production from the ovaries. Conditions like polycystic ovary syndrome (PCOS) can cause an imbalance in LH and FSH levels. So LH in fertility testing can tune you in to important indicators about your overall fertility health.

On the other hand, lower LH is also associated with infertility. This is because a critical level of LH is needed to support ovarian function. If LH is too low, this could affect your menstrual cycle with conditions like amenorrhea (having no periods), or stop you from ovulating.

What if my LH levels aren’t normal?

LH in fertility tests gives you limited information, so we look at this in context of FSH, AMH and other hormones on our panel. That being said, if your LH levels are imbalanced:

  • Firstly, please don’t worry. When you do a test with Adia, we send you a detailed report explaining your results. You can then discuss this report with our fertility experts.
  • Secondly, remember that knowledge is power. Having knowledge and data about your body can help you make informed decisions, such as lifestyle changes, treatment or freezing your eggs. Once you have your report, you can talk to our fertility experts about your result. You can also share your results with your GP.

Ultimately, we want to empower women with knowledge and data about our bodies. The hormone test is one part of your preconception health plan. We use this information to formulate a plan with our experts that helps you achieve your goals.

I hope this explains why we’ve included LH in our fertility test, and what LH does. Please get in touch with our experts if you have questions about this article. Join Adia to ask an expert a question.

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Read other blogs in our ‘Hormones 101’ series: