What is Amenorrhea?
Amenorrhea is a medical condition defined by the absence of menstruation in women of reproductive age. There are two amenorrhea types:
- Primary amenorrhea occurs when a girl has not gotten her first period by age 15 or within five years of the first signs of puberty.
- Secondary amenorrhea is more common and occurs when a woman who had regular periods stops getting her period for at least three months, or for six months if it was previously irregular.
Amenorrhea causes may vary and there can be many of them. Here we can find some examples:
- Pregnancy or breastfeeding is the main cause of secondary amenorrhea.
- Hypothalamic amenorrhea: occurs when a woman stops having her period because her brain is not sending the signals to her ovaries that would cause her period to start. This is often because of stress, extreme exercise (athletes’ amenorrhea) or extreme weight loss.
- Amenorrhea and PCOS: Polycystic Ovarian Syndrome can cause amenorrhea by creating a hormonal imbalance in a women’s body making the menstrual cycle be unpredictable.
- Contraceptive amenorrhea: caused by birth control pills, which prevent ovulation from happening. This type of amenorrhea is usually safe, and it is a quite common side effect of contraceptive pills.
- Anatomic causes: for example, congenital female reproductive tract anomalies.
Hormonal Influence on Bleeding: Comparing Different Types of Oral Contraceptives
Contraceptive pills can cause amenorrhea, but whether someone will develop amenorrhea depends on many factors, one of which is the type of oral contraceptive they use, Combined Oral Contraceptives (COCs) or Progestin-Only Pills (POPs).
But first, let’s explain in a simple way the cause of menstrual bleeding. Each month, the body prepares for a possible pregnancy by thickening the lining of the uterus, also called endometrium. Estrogen plays a key role in thickening the endometrium, while progesterone stabilizes it. In other words, estrogen stimulates the growth of the lining and progesterone maintains it to make it suitable for a fertilized egg.
If pregnancy does not happen, the production of estrogen and progesterone drops, the body understands that it does not need the lining and sheds it. This shedding of the lining is what makes up menstrual blood (click here for more information).
Now let’s see what happens when taking contraceptive pills.
On the one hand, Combined Oral Contraceptives (COCs) contain both estrogen and progestin. This type of contraceptive method will usually include some “rest days”, which are days without hormones, in the following combinations:
- 21 days of hormone treatment followed by 7 hormone-free days
- 24 days of hormone treatment followed by 4 hormone-free days
- 84 days of hormone treatment followed by 7 hormone-free days
During the hormone-free days, withdrawal bleeding may occur. This bleeding is like a menstrual period but is typically lighter and shorter. It happens because the sudden drop in hormone levels causes the lining of the uterus to shed, which is what results in bleeding. When taking hormonal contraceptives, your body doesn’t produce as much estrogen and progesterone, and these hormones are provided by the COC. In this case, the endometrium has grown and stabilized due to the consistent intake of both estrogen and progestin during the hormone days. This is a normal and expected response when using COCs in this way.
Therefore, with COCs combinations where there are “rest days”, it is less likely for amenorrhea to occur. However, in cases where COCs are taken continuously (without “rest days”), because there is no drop in hormone levels, amenorrhea is a lot more frequent.
On the other hand, Progestin-Only Pills (POPs) contain just progestins, which can be a synthetic or natural form of progesterone. Progestins works by suppressing the hormonal signals from the brain that stimulate the ovaries to produce eggs and hormones, including estrogen. This suppression leads to lower estrogen levels, resulting in a very thin uterine lining that cannot build up enough to shed, leading to no menstrual bleeding. Because of this, amenorrhea occurs even if “rest days” are included when taking POPs. However, this effect may vary among women.
Therefore, usually, POPs cause amenorrhea more often than COCs and have more irregular bleeding.
Contraceptive amenorrhea is a normal response to hormonal contraceptives and is not harmful. However, if amenorrhea persists after stopping the contraceptive treatment, it is referred to as post-pill amenorrhea, which may require further evaluation by a healthcare provider.
Benefits of Induced Amenorrhea
While Combined Oral Contraceptives (COCs) and Progestin-Only Pills (POPs) are indicated for use as a contraceptive method, induced amenorrhea can be considered a beneficial effect, especially when managing certain health conditions, and does not indicate a problem with the contraceptives themselves.
Below, we will explain how some of those benefits work.
- Endometriosis
Endometriosis is a condition in which women experience pelvic pain, heavy bleeding, infertility, and fatigue, among other symptoms. It is defined as the presence of endometrial tissue outside the uterus, resulting in inflammation and damage to these areas. As we have seen previously, estrogen promotes the growth of the endometrium, including the tissue outside the uterus in people with endometriosis. Therefore, endometriosis is an estrogen-dependent disease, meaning that high levels of estrogen can make symptoms worse, which is why progestins are often used to reduce estrogen levels. Thinning the uterine lining with progestin can help relieve symptoms of endometriosis, making induced amenorrhea a beneficial side effect.
- Polycystic Ovary Syndrome (PCOS)
PCOS is a hormonal disorder caused by the excess production of androgens (male hormones) by the ovaries and is characterized by multiple cysts on the ovaries. Main symptoms include irregular periods, excessive hair growth and acne.
Induced amenorrhea using estrogen/progestin pills helps reduce androgen levels by suppressing the ovaries’ production of these hormones. This reduction in androgens can improve symptoms like acne and excessive hair growth.
- Heavy Menstrual Bleeding
Induced amenorrhea, often achieved through POPs, reduces the thickness of the uterine lining. A thinner lining results in less tissue to shed during menstruation, leading to lighter or absent bleeding.
- Stress Reduction
Induced amenorrhea can help reduce stress by eliminating menstrual-related symptoms, stabilizing hormone levels, and providing psychological relief. This can lead to a more stable emotional state and improved quality of life.
Amenorrhea during contraceptive use can sometimes lead a patient to believe they might be pregnant. However, if the contraceptive has been used correctly, the likelihood of pregnancy is very low. Nonetheless, if there is any doubt, it is advisable to take a pregnancy test and consult with a primary care doctor for confirmation and further guidance.