There’s no better feeling than seeing those two lines pop up on your pregnancy test when you are trying to conceive! But, the disappointment you experience when the test is negative can be equally intense. Have you ever wondered what controls your menstrual cycle and the fate of your pregnancy? It’s hormones! Chemical molecules racing through your bloodstream can be tiny but mighty!
Here we will discuss the Fab Four, a group of female sex hormones that are essential for conception and pregnancy. They include :
- Follicular Stimulating Hormone (FSH)
- Luteinizing Hormone (LH)
- Progesterone (PdG)
The levels of these hormones can be estimated to find out if they are within their normal limits using lab tests for FSH, estrogen, LH, and progesterone (PdG Test).
How do we check for hormone levels in the body?
If you are trying to get pregnant and you and your doctor suspect that a hormonal imbalance may be affecting your ability to conceive, testing your hormone levels is an excellent place to start.
Traditionally female sex hormones are evaluated with a blood test. However, recently, home test kits can measure the amount of hormones in your urine and saliva. Not only are the samples easier and less painful to collect, but they also give a daily estimate of the fluctuations in your levels.
Back to Basics! What happens during your menstrual cycle?
Your cycles consist of 4 phases: menstruation, follicular, ovulation, and luteal. Different hormones play their own roles during the course of the cycle. They work together to increase the chances of conception or the onset of monthly periods if a pregnancy does not occur.
The follicular phase begins on the first day of your period and lasts till ovulation. The luteal phase begins after ovulation and lasts till the day before your next period starts.
The luteal phase lasts for 14 days for most women whereas the follicular phase can change in length.
Looking at the four fertility hormones helps to understand their contribution to the menstrual cycle.
Balance is Key! How do hormones affect your menstrual cycle?
Let’s look at each of the key hormones to find out how they affect your fertility.
1. Follicular-Stimulating Hormone
What makes FSH and LH unique is that they are both produced by the pituitary gland in the brain and work together to keep the menstrual cycle regular and to release healthy eggs in women. FSH also controls sperm production in men and plays a vital role in male and female fertility.
As FSH is released, it stimulates the growth of a few follicles in the ovaries that contain eggs during the first half of the menstrual cycle. After that, one dominant follicle per cycle will grow, and the egg inside it matures. At this point, the follicle begins to release estrogen to carry out its function in the cycle.
As the estrogen levels rise, your body sends a signal to the brain to stop releasing FSH and prevent other follicles from maturing. The rising estrogen levels also indicate that it’s time for the mature egg to break free of its follicle during the next phase of the cycle – ovulation!
After ovulation, the empty follicle, called the corpus luteum in medical terms, begins to release progesterone during the luteal phase of the cycle. As the progesterone levels rise, they also send a signal to the brain, telling it to stop releasing FSH.
If pregnancy does not occur during this cycle, the progesterone levels begin to fall causing your uterine lining to shed and thus your period begins. This indicates that the cycle is over, and your brain gets the message to start rereleasing FSH, marking the beginning of a new cycle.
When your FSH levels are either too high or too low, what does it mean?
Low FSH levels in men indicate that they may have difficulty producing sperm. At the same time, in women, it could mean that the follicles and eggs needed for ovulation are not developed, leading to infertility.
FSH levels should be high right before you ovulate. Too high levels of the hormone could indicate that the ovaries are not responding to the hormone, and the brain has to release more FSH to elicit a reaction. It could also mean that the reserve of eggs in the ovaries is running low.
As a female sex hormone, estrogen is released by the follicles as they begin to grow in the ovaries at the beginning of each cycle. When a single dominant follicle grows and its egg matures, it leads to a surge in estrogen, which prompts the release of LH from the pituitary gland in the brain.
LH is the hormone that leads to ovulation when the egg ruptures out of its follicle and travels down the fallopian tube into the uterus, ready for fertilization. Another function of estrogen is that it creates an inviting environment for the sperm so that it can survive long enough to meet with the egg and fertilize it. Even after fertilization, it prepares your body for pregnancy by thickening the inner lining of your uterus, called the endometrium, making it ready for implantation.
When your estrogen levels are either too high or too low, what does it mean?
If your estrogen levels are too low, the endometrium may not be thick enough for the egg to implant into the uterus. On the other hand, too much estrogen, also called estrogen dominance, could disrupt the menstrual cycle and decrease progesterone levels needed to sustain a pregnancy.
1. Luteinizing hormone
LH helps with reproduction in both men and women. In males, it is released from the pituitary gland to stimulate testosterone production. In females, the surge in LH occurs 14-16 days before your next menstrual cycle in response to increased estrogen levels releasing the egg from the mature follicle.
If the egg is fertilized, LH will prompt the corpus luteum or the remnants of the follicle to release progesterone, which prepares the uterus for pregnancy.
When your LH levels are either too high or too low, what does it mean?
If your LH levels are too low, ovulation may not occur, and you may have trouble conceiving. Low FSH levels usually accompany low LH levels because they have a common origin. However, if your LH levels are too high, then it may cause multiple follicles to mature and rupture triggering problems with fertilization.
LH levels can be conveniently determined using at-home ovulation kits, which will tell you exactly when you’re due to ovulate and therefore indicate which days are your most fertile days.
Progesterone is a prominent player in the reproductive cycle because it prepares the body to sustain a new pregnancy. It is released by the corpus luteum, the follicle left over after ovulation, and helps a fertilized egg to implant into the thickened walls of the uterus. As the pregnancy progresses, the placenta takes over as the primary source of progesterone.
Progesterone levels drop if the egg remains unfertilised and menstruation will start as your uterus sheds its lining, stimulating the release of FSH from the brain to begin a new cycle.
When your progesterone levels are either too high or too low, what does it mean?
Low levels of progesterone can cause infertility and lead to miscarriages. Even after the baby is born, progesterone levels are needed for breastfeeding. During pregnancy, high levels of progesterone help support the pregnancy as well as prevent ovulation. On its own or in combination with estrogen, progesterone can be taken as a method of contraception, which means it prevents ovulation and prevents pregnancy. That is why high levels of progesterone could make conception difficult.
Why do hormone imbalances occur?
Studies indicate that hormone imbalances can occur due to various factors. Some may be genetic, due to trauma, infection, injury, or cancer that affects the glands producing the hormones. In addition, lifestyle factors like age, diet, obesity, and stress play a significant role in hormone control.
When should you suspect that you have a hormonal imbalance?
If you are less than 35 years of age and you’ve been trying to conceive for more than a year, and are otherwise healthy, it may be time to investigate your hormone levels. If you are above the age of 35 years and have been trying to conceive for more than 6 months without success, then consult your gynaecologist to investigate your hormone levels. Other warning signs include mood swings, irregular periods, acne, or hot flashes.
Your body has a unique and complex system of hormones that work together toward reproduction and fertility. In addition, each hormone plays a vital role in the menstrual cycle. Understanding the delicate balance of these four hormones can go a long way in helping you plan your pregnancy journey.