During a pregnancy, it is important to understand why and how the progesterone levels fluctuate, as well as how low progesterone can affect the mother and fetus. The progesterone hormone is crucial for conceiving in addition to carrying out a full-term pregnancy. Causes of low progesterone levels may be external or internal, and the symptoms of low progesterone are important to recognize in order to prevent any problems during pregnancy.
So, what is progesterone? Progesterone is a sex hormone that regulates the menstrual cycle and prepares the uterus for a pregnancy. Irregular levels may lead to infertility or miscarriage.
This hormone is produced by the adrenal glands, ovaries, and the placenta. Progesterone is also essential for the development of breasts, and plays a key role during lactation.
Understanding Low Progesterone Levels
Progesterone levels fluctuate throughout the menstrual cycle. In the first few days, known as the follicular phase, the progesterone levels are low. These levels slowly increase during the 10- to 18-day ovulation phase and rise to a high level during the luteal phase, shortly before the start of the period.
Progesterone levels will stabilize with a pregnancy. It is during the first seven to nine weeks that the placenta becomes the progesterone producer. This causes the progesterone levels to rise throughout the pregnancy and decrease after birth once the placenta is delivered.
The levels of progesterone are measured by nanograms per milliliter. Normal ranges depend on the health of the individual and the predictors of the testing laboratory.
During the menstrual cycle, the progesterone levels are measured as less than one nanogram per milliliter for the first 14 days. Levels can range from two to 25 nanograms per milliliter over the next 15 to 28 days.
Pregnancy levels of progesterone are measured based on the stage of the pregnancy. In the first trimester, levels range from 10 to 44 nanograms per milliliter. The amount ranges from 19.5 to 82.5 nanograms per milliliter during the second trimester, and finally, levels peak from 65 to 290 nanograms per milliliter during the third trimester.
[REFERENCE RANGES FOR PROGESTERONE]
While high progesterone levels may be linked to a traditional pregnancy, a molar pregnancy, adrenal or ovarian cancer, or excessive hormone production of the adrenal glands are also possible factors.
A progesterone deficiency is often seen with a miscarriage or ovulation problems. Low levels may also be present in postmenopausal women.
What Are the Signs of Low Progesterone?
1. Difficulty Getting Pregnant
Trying to conceive can be a struggle for many women. A low progesterone level may make it difficult to become pregnant.
A drop in progesterone levels occurs without fertilization of an egg. This will hinder the immediate chances of conceiving as the lining of the uterus does not thicken as required.
Progesterone levels may need to be evaluated if a woman has a hard time becoming pregnant after several months of attempting.
2. Difficulty Staying Pregnant
Once pregnancy is confirmed, the risk of keeping the fetus alive depends on a balanced progesterone level. Throughout pregnancy, the placenta produces progesterone to support the fetus under normal circumstances.
Without sufficient levels, the lining of the uterus begins to thin and a miscarriage may occur. Progesterone supplements are sometimes used to increase necessary levels.
This being said, increasing the progesterone levels with supplements does not guarantee a healthy pregnancy.
One reason may be due to the difficulty in measuring the appropriate dosage, timing, or route of the supplement required in relation to the possible exchange of hormones, as researchers noted in a review published by the Current Opinion in Obstetrics and Gynecology journal in 2005.
For decades, there has been a concern that using progesterone supplements to prevent miscarriages may actually cause the fetus to be spontaneously aborted. University of Birmingham researchers studied the effects of the hormone replacements on women with a history of multiple miscarriages with no reasonable explanation. The results, published in 2015, showed that those who received progesterone supplements in the first trimester of pregnancy were not less likely to suffer a miscarriage than those who did not.
The study further reports there were no findings of harmful effects on the fetus of these same women with a successful pregnancy.
3. Bleeding and Abdominal Pain
While there are many reasons for severe abdominal pain or bleeding during pregnancy, having low levels of progesterone could be an underlying cause. This is seen in cases where the lining of the uterus begins to thin and weaken.
Spotting and moderate blood loss may indicate a miscarriage, as referenced in a report published in the Nigerian Medical Journal. This 2012 review further suggests the bleeding and any accompanying symptoms may be alleviated by higher progesterone levels.
For those women who are not pregnant, progesterone levels may be measured by several symptoms and a change in their menstrual cycles.
Some of the signs and symptoms to watch for with low progesterone levels include significant changes in mood, extreme depression or anxiety, migraines, severe headaches, hot flashes, and a decrease in sexual desire.
Menstruation-related signs of a low progesterone level may include:
- Shortened menstrual cycles: A menstrual cycle lasting only up to 26 days between starting dates may indicate low progesterone levels. This should primarily be seen in pre-menopausal periods as the body naturally reduces its production at this time. It can also be seen in some cases among young women.
- Irregular periods: A menstrual cycle that occurs too frequently or is spaced several months apart may also indicate that progesterone levels are low. This is often caused by an imbalance of progesterone and estrogen.
- Irregular spotting: Low progesterone levels may also cause a minimal amount of vaginal bleeding. This may occur before or after the expected menstrual cycle.
- Premenstrual syndrome: Commonly known as PMS, this monthly condition may affect the mood of a woman days before menstruation begins. It can also cause bloating, abdominal cramping, depression, and headaches. A Harvard Review of Psychiatry review reported that these symptoms may be alleviated with an adequate level of progesterone.
- Hypothyroidism: Hypothyroidism refers to an underactive thyroid. This may cause irregular menstruation, depression, severe mood swings, and extreme fatigue. A randomized placebo-controlled study analysis published in the Clinical Endocrinology journal found that the activity of the thyroid is linked to the levels of progesterone present in postmenopausal women with normal thyroid function.
- Anxiety: As the nervous system relies on progesterone for proper brain function, a low level may cause the mood to shift and anxiety may develop. The hormonal changes of the menstrual cycle may also contribute to the anxiety.
- Sex drive: Progesterone levels can have a direct effect on sexual desires. Researchers from the University of California, Santa Barbara reported that as progesterone levels increase during the menstrual cycle, the interest in sexual intercourse decreased. This 2013 study further concluded that low levels found before ovulation triggered an increase in sex drive.
It should be noted that more recent literature suggests the sex drive actually decreases with the presence of low progesterone levels.
- Fibrocystic breasts: Low levels of progesterone may result in the development of fibrocystic breast disease. Small, painful lumps may be felt in the breasts. These are usually noncancerous and can vary in size throughout the menstrual cycle.
Signs of Low Progesterone during Pregnancy
Pregnancy has its own set of signs and symptoms, many of which are normal and also may be an indication of low levels of progesterone.
- Spotting of blood
- Severe abdominal cramps
- Back pain
- Extreme fatigue
- Breast tenderness
- Low blood sugar
- Vaginal dryness
How Does Low Progesterone Affect Pregnancy?
As noted above, progesterone is essential for a healthy and successful pregnancy. A low progesterone level will affect the development of the fetus and the outcome of the pregnancy.
1. Before Pregnancy
Because progesterone is crucial in preparing the uterus to accept a fertilized egg for development, low levels may impede this process. Without sufficient amounts of progesterone, the resulting thin endometrium cannot support the egg.
2. During Pregnancy
A low level of progesterone during pregnancy may lead to a miscarriage. It is just as important during as it is before pregnancy to have ample levels of progesterone to continue supporting the fetus. The progesterone produced by the placenta is responsible for maintaining this environment after the first 10 weeks of pregnancy.
What Causes Low Progesterone?
Knowing the triggers of low progesterone during pregnancy may help to prevent the levels from dropping, thereby preventing complications.
- Stress: The most common cause of low progesterone levels is high stress levels. During a stressful time of worry and concern, such as that of pregnancy, the body produces a stress hormone known as cortisol. This hormone may prevent production and actions of the progesterone.
- Xenoestrogens: A xenoestrogen is an estrogen-like chemical compound found in many foods, cosmetics, and plastic containers. It may be synthetic or natural, but the human body cannot produce the hormone. Xenoestrogens mimic estrogen and can mistakenly lead the body to raise our own estrogen levels. This, in turn, may lower the progesterone levels as the body reduces estrogen levels.
- Excessive exercise: High-energy exercise routines have a direct and negative effect on the production of progesterone. These forms of movement increase levels of the naturally produced cortisol due to the physical strain on the body. Progesterone is then used to convert into the needed cortisol, resulting in low levels of progesterone.
- Ectopic pregnancy: Lower than normal levels of progesterone in the early stages of pregnancy may be caused by a condition known as an ectopic pregnancy. This sees a pregnancy develop within the fallopian tube as opposed to the uterus. A miscarriage or termination of the pregnancy is the end result. Severe abdominal, back, and pelvic pain, as well as nausea, dizziness, and spotting are symptoms.
Progesterone levels may be affected by the physical and emotional state of the individual. They constantly change during the menstrual cycle and particularly during pregnancy.
Low progesterone levels during pregnancy may be a common and harmless sign of the fluctuating hormonal changes experienced, depending on the stage of the pregnancy.
As progesterone levels normally rise throughout pregnancy, low levels may be linked to a serious health condition of the mom or fetus. Extreme stress and fatigue may also be the cause and, while these are preventable and treatable, constant low levels of the progesterone hormone may lead to miscarriage.
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