How birth control works

How exactly does contraception work? What contraceptive methods are available? And what exactly do they do to your hormones? In this blog post, we'll tell you more about the hormones involved in your cycle and how contraception works.

We discuss:

The 4 most important fertility hormones

• Estrogen
• Progesterone
• FSH and LH

What contraceptive methods are there and how do they work?

• The pill
• The spiral
• The hormonal coil
• The copper coil
• Other hormonal contraceptive methods
• Natural contraception

Your menstrual cycle can be divided into two phases: the phase before ovulation (follicular phase) and the phase after ovulation (luteal phase).

Between these two phases, ovulation occurs. When you ovulate, you are at your most fertile.

The 4 most important fertility hormones

There are 4 hormones that play a major role in your fertility:

🔸 Estrogen

In the first half of your cycle, the follicular phase, estrogen plays a dominant role. Estrogen causes the lining of the uterus to thicken, transforming it into an ideal environment for the fertilized egg.

As ovulation approaches, you produce more estrogen, which is accompanied by a thin, slippery, cloudy-white discharge. This is called cervical mucus. This sperm-friendly mucus makes it easier for sperm to swim to the egg and survive longer in the cervix.

🔸 Progesterone

In the second half of your menstrual cycle, after ovulation, progesterone plays an active role. Estrogen levels then decrease and progesterone levels increase.

Progesterone is produced in the ovaries after ovulation. This hormone promotes the implantation of a potentially fertilized egg and also prepares the uterine lining for its growth. If the egg isn't fertilized, progesterone production decreases. This causes the uterine lining to break down. This is the start of your menstrual cycle.

🔸 FSH and LH

In addition to the 'well-known' hormones estrogen and progesterone, there are two other hormones that are less well-known, but play a major role in your cycle: follicle-stimulating hormone and luteinizing hormone.

The follicle stimulating hormone (FSH)

The pituitary gland (a gland in the center of your head, just below your brain, responsible for producing many hormones) produces follicle-stimulating hormone (FSH). As the name suggests, this hormone stimulates the follicles—the sacs where eggs that aren't yet fully developed—will develop.

In short, this means that this hormone helps your ovaries prepare your eggs. Several follicles develop, and after a while, one follicle becomes "dominant." This is the follicle that develops into an egg and will travel to the uterus.

The litheinizing hormone (LH)

Luteinizing hormone increases after estrogen levels rise in your body. This increase in luteinizing hormone causes the follicle to rupture, releasing the mature egg. From the ovary, the egg travels down into the fallopian tube. This process is called ovulation.

Your most fertile days coincide with this LH surge. The surge lasts only one or two days, and you can track these fertile days with an ovulation test.

What contraceptive methods are there and how do they work?

Different contraceptive methods each work differently. The two most common hormonal contraceptive methods are the pill and the hormonal IUD.

In addition, as a woman you can choose a contraceptive method without hormones: the copper coil.

Finally, we briefly discuss a method that does not involve any hormones or 'instruments': the natural contraceptive method.

🔹 The pill

The pill is a well-known method of contraception, requiring you to take one pill daily. It releases artificial hormones (estrogen and progestin), which prevent eggs from maturing and suppress ovulation.

The artificial hormones in the pill inhibit the release of LH and FSH and ensure that no egg is released.

And if a woman doesn't ovulate, fertilization can't occur. No ovulation also means your body doesn't have to "clear out" an egg, which is why you don't actually have a period when you're on the pill.

The monthly bleeding during the week you stop taking the pill is therefore artificial. During the six or seven days you stop taking the pill, there is no absorption of artificial hormones, and the small amount of uterine lining that has built up breaks down again. This is called withdrawal bleeding.

The hormone also causes changes in the cervical mucus. The mucus becomes thick and cloudy, making it harder for sperm to penetrate.

The negative effects of the pill:

The pill is the most commonly used contraceptive among women in Belgium. However, there are negative side effects associated with the pill, which are thankfully receiving increasing attention lately. The pill can decrease your sexual desire (your libido) because you take a form of progesterone daily.

In addition, the pill alters your body's vitamin and mineral intake. This can cause all sorts of symptoms, such as lethargy or even depression.

Studies have shown that the pill (or other artificial contraceptives) robs your body of vitamins and minerals (such as B vitamins, folic acid, zinc, and magnesium).

🔹 The spiral

The IUD is a small, a few centimeters long device inserted by a doctor or gynecologist. It is inserted only once and lasts between 5 and 10 years. With an IUD, the egg cannot implant in the uterus.

You can choose between a hormonal IUD or a copper IUD.

The hormonal coil

A hormonal IUD releases the hormone levonorgestrel (progesterone). This hormone acts primarily on the uterine lining and thickens the cervical mucus. This makes it harder for sperm to penetrate the mucus of the cervix. In addition, ovulation is sometimes suppressed, making the uterine lining unsuitable for the implantation of a potentially fertilized egg.

Only a small portion of these hormones reach your body. However, women can still experience symptoms from these hormone releases (acne, mood swings, bloating, loss of libido).

The most well-known hormonal coil is the Mirena coil.

The contraceptive effect of Mirena is based on the following effects*:

• The mucus in the cervical canal becomes thicker, making it more difficult for sperm to pass through.
• The release of the hormone levenorgestrel in the uterus prevents sperm from moving and functioning normally. This reduces the chance of fertilization.
• The uterine lining is barely formed. This means that even if fertilization does occur, a fertilized egg cannot implant.
• The presence of a foreign object in the uterus may prevent an egg that may have been fertilized from implanting.
• In some women, ovulation is suppressed. If no egg is released, fertilization cannot occur.

*source

The copper coil

A copper IUD doesn't contain any artificial hormones, so ovulation does occur and you do have a period. A copper IUD is a reliable method of contraception and reduces the risk of pregnancy. The copper IUD works in two ways:

• Copper is toxic to male sperm, making them barely or not at all capable of fertilizing an egg.
• Copper makes the lining of the uterus unsuitable for implantation of a fertilized egg.

Unfortunately, many women experience problems with the copper IUD as it causes inflammation, resulting in severe cramps and bleeding.

🔹 Other contraceptive methods with hormones

Besides the pill and the hormonal IUD, there are other contraceptive methods that use hormones. These include the injection, the contraceptive patch, the NuvaRing, and the contraceptive implant. These methods work the same way as the pill and the hormonal IUD.

🔹 Natural contraception

Besides the well-known methods using hormones or an instrument, there are also natural ways to avoid pregnancy. These are better known as natural fertility methods or contraceptive methods (Natural Family Planning/Sensiplan). These methods don't involve the use of medications or artificial hormones, and they don't involve insertion.

These methods can be used both for contraception and when trying to conceive.

The best known and most efficient method works in 2 ways:

• You measure your basal body temperature
• You analyze and check your cervical mucus

Measuring your temperature:

When you ovulate, your body temperature rises. On average, your temperature after ovulation is about 0.2 to 0.3 degrees higher than before ovulation. A rise in your temperature, therefore, indicates ovulation.

You measure this increase in the morning with a thermometer with 2 decimal places (your temperature will then be seen as 37.43 instead of 37.4, for example).

You keep track of this data in a curve or app.

Checking your cervical mucus:

Your discharge changes throughout your cycle. In the days leading up to ovulation, mucus is thicker, thinner, and clear. During the rest of your cycle, it's sticky and cloudy.

You can easily recognize the slime once you know what to look for.

You can also double-check when you're most fertile with an ovulation test. This works with urine, which detects luteinizing hormone.

With this contraceptive method, it's recommended to use reliable methods to track your temperature increase. Popular apps include Natural Cycles , or you can seek guidance from a certified Sensiplan Coach.

We hope this blog has been helpful. Have any questions? Chat with us ; we're here to listen.