If you suspect you may be pregnant, you may be experiencing a lot of uncertainty. Having a baby is a major life change, whether it is your first or your fourth. Simply being pregnant may mean making significant changes to your lifestyle, by giving up smoking, alcohol, or simply cutting back on your workload. The sooner you know whether you are pregnant or not, the sooner you can begin to adjust and prepare for these changes.
Definition
HCG, or Human Chorionic Gonadotropin, is a hormone produced when a woman becomes pregnant. It preserves the uterine wall and prevents her from having periods during the pregnancy. HCG also causes the nausea and vomiting that is typical of early pregnancy.
HCG Levels
HCG levels rise exponentially during the first trimester, then fall during the second and third trimesters. An HCG of less than 5 mIU/ml indicates that you are not pregnant. By three weeks after your last menstrual period, or about 10 days post ovulation, HCG levels will be between 5 and 50 mIU/ml, depending on when conception occurred. Every pregnancy is different, and some women produce HCG faster than others. High or rapidly rising HCG levels can be an indicator of multiple births, while low or slowly rising HCG levels can indicate problems with the pregnancy.
Home Pregnancy Tests
Home pregnancy tests are accurate at a wide range of HCG levels. The earliest tests can detect as little as 20 mIU/ml, while others do not detect HCG until concentrations reach 150 to 250 mIU/ml. The most sensitive tests can detect HCG seven to 10 days post ovulation, if your body is producing at least 20 mIU/ml of HCG by that time.
Factors Affecting HCG Detection
There are several factors that affect whether a pregnancy test can detect HCG. The most important factor is when the egg implanted in the uterine wall, setting off the production of HCG. If the egg implanted quickly, your body will have had more time to produce HCG by the first day of your missed period, and your levels will be higher than a woman whose egg implanted later.
Most home pregnancy tests recommend that you test with the first urine of the morning, or wait several hours after consuming large amounts of liquid to avoid false negatives due to diluted urine.
False Negatives
In approximately 10 percent of pregnancies, the egg does not implant until a few days after the missed period. In these cases, HCG levels will not be high enough to detect until up to a week after you miss your period. If you suspect that you might be pregnant and take an early detection test that reports a negative result, wait a few days to see if you miss your period. If your period is late, take another test. You may have gotten a false negative on the first test.
