If you have been trying to get pregnant or have had a few miscarriages your doctor might recommend that you receive a shot of pregnancy hormone hCG. The hormone, called human chorionic gonadotropin, is responsible for keeping the fertilized egg from being shed with a woman's monthly period and helps maintain the embryo in the first trimester of pregnancy. For women who are having difficulty conceiving or maintaining a pregnancy, the hCG shot might keep the growing fetus alive until other hormones take over in the second trimester of pregnancy.
HCG is a naturally occurring hormone that exists in very small quantities in both men and women. During a normal pregnancy levels of hCG rise rapidly following conception and usually double every 48 hours during the first trimester. The hormone keeps the corpus luteum, which stimulates placental growth, active after conception. Some women with low levels of hCG lose their fertilized egg every month with their menstrual cycle, necessitating hormone replacement therapy as a means of helping an early pregnancy along.
HCG shots are commonly administered to trigger ovulation and may also keep the growing embryo intact. Some doctors will prescribe the hCG shot for the first trimester of a woman's pregnancy if she has a history of first trimester miscarriage. According to BabyCenter obstetricians Joyce and Marshall Gottesfeld, hCG shots are sometimes given during the first trimester of pregnancy in order to stimulate the production of the hormone progesterone. Doctors may prescribe hCG instead of progesterone directly because progesterone is made from synthetic ingredients, although neither has been scientifically proven to prevent miscarriage.
The hCG shot contains pregnancy hormones and as such is responsible for some early pregnancy symptoms such as tender breasts, nausea and soreness. According to "Getting Pregnant and Fertility Drugs: Human Chorionic Gonadotropin," if the hCG shot is administered around ovulation you have increased odds of becoming pregnant with multiple fetuses. Other symptoms of hCG treatment include fatigue, headache, irritability, abdominal discomfort and water retention. You may also notice soreness at the injection site for the drug.
If you have had the hCG shot due to a luteal phase defect or other fertility problem, keep in mind that the injection may cause a false positive pregnancy test result (a pregnancy test that says you are pregnant when you are not). The shot contains the hormone that is measured in home pregnancy tests and in blood tests. According to the website BabyHopes.com, approximately one half of the hCG hormone disappears from your body every 28 hours so the time it will take for a pregnancy test to be accurate will depend on how much of the hormone was taken. Doctors normally recommend waiting 14 days after a 10,000 IU injection, 10 days after a 5,000 IU injection or seven days after a 2,500 IU injection. You also can have your doctor take two quantitative hCG tests for pregnancy after the shot--if the level rises from the first to the second, you are likely pregnant.
The hCG shot can increase the risk of blood clots and you should call your doctor immediately if you experience pain, warmth, redness, numbness or a tingling sensation in your arms or legs. Women receiving the hCG shot for the first time may develop a condition called ovarian hyperstimulation syndrome or OHSS. You should call your doctor if you have symptoms of OHSS such as shortness of breath, severe pelvic pain, swelling of the hands or legs, diarrhea, nausea or vomiting.