Low progesterone levels can be problematic during any trimester, but the impact and treatment can differ depending on when you are diagnosed and your doctor's assessment of other pregnancy factors. In fact, many women with low progesterone levels during pregnancy go on to have healthy, full-term babies even without any treatment. Understanding where progesterone comes from and how it affects your pregnancy can help you discuss a diagnosis of low progesterone levels with your doctor.
Progesterone
The corpus luteum, part of the follicle of the ovary, produces the female hormone progesterone to support the buildup of the uterine lining before conception and to sustain that lining for a short time after fertilization and implantation. About 10 weeks into pregnancy, the placenta takes over the function of producing progesterone for the remainder of the pregnancy.
Low Levels in Early Pregnancy
Low progesterone levels in early pregnancy indicates a problem with the corpus luteum. If progesterone levels fall too low during the first 10 weeks of pregnancy, the uterine lining might be unable to support the pregnancy. Miscarriage can result from low progesterone levels. According to the American Pregnancy Association, normal levels of progesterone during the first trimester typically fall between 9 and 47 nanograms/ml. If your doctor deems that your levels are too low or not rising fast enough, she might prescribe progesterone treatment to raise your levels.
Low Levels in Late Pregnancy
After the placenta has taken over the function of progesterone production, miscarriage is less likely; however, low levels during this period also can occur if the placenta does not produce normal levels of progesterone. Low levels in the second and third trimester are more likely to cause problems such as a shortened cervix, which can lead to preterm labor and birth. Normal levels of progesterone fall between 17 and 146 ng/ml in the second trimester and between 49 and 300 ng/ml in the third trimester. Progesterone gel administered to women with a short cervix can cut the risk of preterm birth.
Considerations
Progesterone levels vary widely among women and even between pregnancies in the same woman. Your doctor might be more concerned with seeing a rise in progesterone as the pregnancy progresses and less concerned about the specific measurement of your progesterone level. The effectiveness of progesterone treatment to solve the problem of low progesterone levels in pregnancy has been controversial, especially since progesterone functions differently during different trimesters. If you are unsure whether you need progesterone treatment for low progesterone in any phase of your pregnancy, talk to your doctor about your concerns.
References
- University of Maryland Medical Center; Early Miscarriage; October 2008
- American Pregnancy Association; Concerns Regarding Early Fetal Development; October 2008
- "Early Human Development"; Effect of Progesterone Treatment Due To Threatened Abortion in Early Pregnancy for Obstetric and Perinatal Outcomes; L. Duan, et al.; January 2010
- Drugs.com: Progesterone Treatment Cuts Preterm Birth Risk in Certain Women
