The importance of hormones in understanding a woman’s fertile period

Let’s look closely at the role of our hormones in the various phases of the menstrual cycle to understand all those processes that are related to fertility.

Here are the main points:

• Cervical mucus , the position of the cervix  , some ovulation tests rely on the presence of estrogen.
• The basal temperature method monitors the presence of progesterone.
• Other ovulatory tests / kits look for the presence and quantity of luteinizing hormone (LH)
• Estrogen level is elevated before ovulation
• Progesterone is high after ovulation and during pregnancy.
• Luteinizing hormone (LH) peaks shortly before ovulation and is responsible for the follicle bursting and the release of the egg at the time of ovulation.

But let’s go into the details:

Every sign of fertility that is observed is linked to a hormonal process and therefore to the presence of hormones in the bloodstream. Among the most significant are estrogen and progesterone.

Estrogens are dominant during the pre-ovulation phase (follicular phase). Progesterone, on the other hand, is secreted mainly after ovulation, during the luteal phase. Progesterone also plays a very important role in the event of a pregnancy.

Estrogens and fertility

Estrogens are a group of hormones that stimulate tissue growth and proliferation. They are necessary in the thickening phase of the uterus wall (endometrium) so that it is able to support and nourish any fertilized egg. When talking about fertility, the type of estrogen we’re referring to is estradiol .

Estrogens play a very important role in reproduction, let’s see them:

• Estrogen triggers the release of LH (luteinizing hormone), which is needed to trigger ovulation.
• Estrogens are necessary for the proliferation of the endometrium (the inner lining of the uterus), so that a fertilized egg can implant itself and find the nourishment necessary for its development.
• Estrogens affect the production of cervical mucus which is necessary for sperm to travel to the fallopian tubes where fertilization takes place.
• Estrogens cause the cervix to soften and open to facilitate the passage of sperm which can then enter and reach the fallopian tubes.

The signs of an increase in estrogen that you may observe on your body are: the presence, quantity and consistency of cervical mucus and the location and structure of your cervix. These signs are among the best indicators of your fertile window.

Progesterone and fertility

While estrogen dominates the pre-ovulatory phase, i.e. the follicular phase of the menstrual cycle, progesterone dominates the post-ovulatory phase, i.e. the luteal phase of the cycle .
Before ovulation, progesterone is only present in small amounts. After ovulation, progesterone is produced by the corpus luteum (the remains of the ovarian follicle after ovulation), and is present in significantly higher quantities.
Progesterone plays the following roles: 

• it makes the lining of the uterus soft and spongy so that a fertilized egg can latch onto and implant itself.
• Progesterone is needed to support and sustain pregnancy.
• Progesterone is responsible for changes in basal body temperature (it increases after ovulation)
• Progesterone determines the maintenance of basal body temperature at higher levels during pregnancy.

Luteinizing hormone (LH) and fertility

Luteinizing Hormone (LH) peaks just before ovulation and is the hormone responsible for triggering the rupture of that ovarian follicle which releases the egg at the time of ovulation. 

The levels of the hormone LH can be measured with ovulation sticks  which detect its presence in the urine.

Having more LH in your urine, as seen in tests, usually means you ovulate within 12-24 hours , but this can vary slightly depending on your hormonal profile.

LH is not completely released in one moment but its production curve goes from trough to peak and back to trough and takes about 24-48 hours.

LH production usually starts early in the morning while you sleep and it takes 4-6 hours for it to appear in your urine. For this reason, first morning urine is not reliable for an accurate result. Therefore it is recommended to carry out the test in the middle of the day. It is also important to follow the instructions in the Ovulatory Kit for best results.

Ovulatory tests do not pinpoint ovulation precisely , but they do indicate that ovulation is imminent. For this reason it is important to consider, in addition to the Kit, all other signs of fertility (cervical mucus, basal temperature, cervix, etc…) which offer further clues about ovulation.

These last ones are especially useful if you are describing changes in a graph .

If, on the other hand, you have irregular or very long cycles, ovulation kits prove to be quite expensive in the long run as you need to use a series of tests to be sure you are monitoring the LH surge and peak.