Progesterone

Progesterone tests and levels

As progesterone levels will vary throughout the menstrual cycle, multiple measurements can be used to help recognize and manage some causes of infertility. Progesterone can be measured to determine whether or not a woman has ovulated, to determine when ovulation occurred, and to monitor the success of induced ovulation.

Progesterone is first produced by the corpus luteum of the ovary and production from this site is necessary for the first 8 weeks of pregnancy. From implantation of the embryo onwards for 40 weeks the placenta takes over the production of progesterone (see graph below).

The levels of progesterone increase dramatically all throughout pregnancy. Progesterone production is necessary for the safe maintenance of pregnancy and all pregnancies will fail if progesterone production is too low.

In early pregnancy, progesterone measurements may be used, along with hCG (human chorionic gonadotropin) testing, to help diagnose an ectopic or failing pregnancy. Progesterone levels may also be ordered to monitor a high-risk pregnancy to help evaluate placenta and fetal health. Decreased levels are seen in ectopic pregnancies and in miscarriages.

If a woman is receiving progesterone supplementation to help support her early pregnancy, her progesterone levels may be monitored on a regular basis to help determine the effectiveness of that treatment.

Guide to Progesterone levels during pregnancy:

Normal progesterone levels during a woman's menstrual cycle and during pregnancy are different.

During the first trimester of pregnancy, normal levels can range from 9 to 47 ng/ml. Most doctors like to see a minimum level of 10 ng/ml during the first few weeks of pregnancy. If a woman has low progesterone levels this can be an indication of a threatened miscarriage.

If you are concerned about your progesterone level talk to your doctor for more information.

The progesterone levels during pregnancy are crucial for the fetus's survival, correct levels will help prevent uterus contraction; and blood vessel growth is promoted to give nourishment to the developing baby during pregnancy.

• Levels of progesterone will be naturally higher during pregnancies that involve multiples (twins, triplets, etc.) than those in which there is only one fetus.
• Taking estrogen and progesterone supplements can affect results.

When progesterone supplementation is given to a mother, its half life in the blood is very short. Within minutes it begins to be excreted into the urine. The most efficient route to take the progesterone to insure the best blood levels and the longest survival of the progesterone in the blood is to use vaginal suppositories. The next best route of administration is to take injections of progesterone. The least effective is to take the progesterone by mouth.

When is a Progesterone levels test ordered?

• As part of an infertility assessment, when a woman is having trouble getting pregnant and the doctor wants to verify that she is ovulating normally. The test may be ordered a couple of times during a woman's menstrual cycle to evaluate the change in progesterone concentrations.

• To determine when ovulation has occurred and following drug therapy to induce ovulation

• When symptoms, such as abdominal pain and spotting, suggest an ectopic pregnancy or threatened miscarriage

• To monitor the effectiveness of treatment when a woman requires progesterone injections to help maintain her pregnancy

• Periodically throughout a high-risk pregnancy to monitor placenta and fetal health

• When a non-pregnant woman is experiencing abnormal uterine bleeding