Pregnancy is a process, which causes many fluctuations in the hormones of the woman's body. Estrogen, human chorionic gonadotropin, hCG, and progesterone hormones all increase at various points in the pregnancy. A doctor should monitor hormone levels when necessary as they may prove indicative of a possible miscarriage, twin birth or incorrectly guessed birth date.
Natural hCG Level Increases
The American Pregnancy Association says that human choronic gonadotropin, or hCG, levels rise in nearly all common pregnancies. In fact, 85 percent of normal pregnancies show a rise in hCG levels every 48 to 72 hours, and they can double every 96 hours. Low levels of the hormone are also not uncommon.
This rapid growth of hCG levels nourishes the egg after fertilization and aids attachment to the uterine wall. hCG levels peak 8 to 11 weeks after the start of pregnancy and then begin to decline again and level out for the rest of the pregnancy. The level of hCG hormones can sometimes be used to estimate the birth date. Uncommon levels of hCG also may mean a multiple birth.
Use of Fertility Medications
HCG medications used to increase fertility rates often increase the levels of hCG in the body. They are usually used prior to pregnancy to cause ovulation or treat infertility, and may also be used to increase sperm count in males. Human chorionic gonadotropin has brand names like Novarel, Ovidrel, and Pregnyl, according to Drugs.com. Other medications like antibiotics or oral contraceptives should not affect hCG levels in pregnant women. If the woman's hCG levels have risen it may indicate a serious problem, such as a molar pregnancy.
HCG Levels in Molar Pregnancy
The American Pregnancy Association categorizes a molar pregnancy as an abnormality of the placenta. When the egg and sperm join in fertilization, it may cause a molar pregnancy in about 1 in every 1000 pregnancies. A molar pregnancy produces no baby. Though hCG gets produced, an ultrasound will clearly show that only the placenta appears.
Natural Increase of Estrogen
During pregnancy, high estrogen levels are common. Pregnancy can cause the levels to rise; this rise may lead to side effects of headaches, breast tenderness and in rare cases even cancer. Generally, these side effects frequently occur in women with menopause or pre-menopause.
Increased Levels of Progesterone
During pregnancy, increased levels of progesterone are viewed as a good thing. Too little progesterone can indicate a possible miscarriage. A doctor may check the woman's level of progesterone early in the pregnancy. HCG maintains the corpus luteum--what remains of the follicle after ovulation--which actually proves responsible for the increased levels of progesterone.
In the first trimester, progesterone is expected to rise sharply. 10 ng/ml should become evident during the first weeks of pregnancy. The American Pregnancy Association says that levels may vary greatly, however, from 9 to 47 ng/ml in the first trimester. Because of this variance in progesterone levels only a doctor can determine if the levels are healthy, and what the risk of miscarriage is.