Progesterone is a hormone produced by the ovaries that is responsible for preparing the uterus for pregnancy and maintaining the pregnancy once it has occurred. Women who have low progesterone levels may have a more difficult time conceiving; they may also be at increased risk for miscarriage in early pregnancy once they do conceive. Understanding the causes of low progesterone levels and possible preventative measures that can be taken to increase progesterone can greatly increase the chances of a successful pregnancy.
Hormone levels during pregnancy are critical since they influence the growth and development of the fetus. Progesterone is the most important hormone in early pregnancy since its function is to promote growth of the blood vessels while simultaneously keeping the uterus from contracting. Women who have low levels of progesterone at the time of conception are at increased risk for miscarriage of the embryo.
Progesterone helps to thicken the lining of the uterine wall to prepare it for implantation once the egg is fertilized by the sperm. It then helps to maintain the pregnancy until birth. It is produced by the follicle from which the egg is initially released, also known as the corpus luteum, and continues during the luteal phase of a woman's cycle, approximately 12 to 16 days. Once fertilization of the egg occurs, the corpus luteum continues to produce progesterone until the placenta assumes the role at approximately 10 weeks.
Progesterone levels can vary greatly during the first trimester of a woman's pregnancy. Averaging 12 to 20ng/mL in the first six weeks, levels can range from 9 to 47ng/mL overall throughout the first trimester. Progesterone levels should consistently rise approximately 1 to 3ng/mL every two or three days until they reach their peak for the specified trimester. In situations of an ectopic pregnancy or miscarriage, progesterone levels will be low at the onset and will not increase.
Low progesterone levels in women can be linked to an underactive thyroid or adrenal gland disorders and diseases. Women who have an underactive thyroid may have a decreased amount of progesterone since it is the hormone that regulates thyroid activity. Symptoms of underactive thyroid are insomnia, dizziness, irritability, difficulty concentrating, bloating, weight gain, muscle and/or joint pain, urinary tract infections, hot flashes, changes in appetite, night sweats and vaginal dryness; symptoms of adrenal gland disorders include fatigue, insomnia, weight gain and depression. (See References 2)
Vaginal suppositories of progesterone can be used one to two times per day beginning near the time of ovulation and continuing for up to 11 weeks afterward. Also, women with a history of low progesterone or miscarriage due to low progesterone levels can use a progesterone cream. This is applied once they have ovulated in order to supplement their own naturally produced progesterone. It is important to note that progesterone supplements are unlikely to increase progesterone levels adequately if started after receiving a positive pregnancy test result.
Women who are unsure of their progesterone levels should chart their basal body temperature each month to determine if it rises consistently after ovulation. If it does not, a health-care provider should be contacted to determine if progesterone and other hormones are at the correct levels prior to conception. Progesterone cream should be used under the supervision of a doctor and dosage instructions should be followed carefully since they can prevent ovulation from occurring if used incorrectly.