Pregnancy and the Home Pregnancy Test Pregnancy occurs when a sperm from the male penetrates an egg from the female. This is called fertilisation. A home pregnancy test looks for the presence of the hormone, Human Chorionic Gonadotrophin (HCG), in the urine, which is produced in the placenta soon after the embryo attaches itself to the uterine lining. What are the symptoms of Pregnancy? Some of the most common symptoms of pregnancy include: - Missed menstrual periods;
- Nausea, with or without vomiting;
- Tiredness;
- Breast changes and breast tenderness;
- Frequent urination.
Nausea can affect many women, particularly in the first three to four months of pregnancy. Tiredness usually occurs within the first and third trimester (months 1 to 3 and months 6 to 9). How does a home pregnancy test work? A home pregnancy test measures the presence of the hormone HCG (Human Chorionic Gonadotrophin) in your urine. HCG is produced in the placenta shortly after the embryo attaches to the uterine lining. This hormone then builds up rapidly in your body in the first few days following implantation. Normally, HCG can be detected by a home pregnancy test 7-10 days after conception. A pregnancy test is usually capable of detecting pregnancy as early as the first day after you miss a period. The further into the pregnancy you are, the higher the levels of HCG in your urine. The concentration of HCG in non-pregnant women is normally 5.0mIU/ml. At the time of the last missed menstrual period, urine HCG levels are about 100mlU/ml with peak levels of 100,000 to 200,000mlU/ml seen at the end of the first trimester (three months). How soon will a pregnancy test work? Most pregnancy tests state that they work as soon as a period is late, i.e. one day or any time after that. Generally, women do not continue to have normal periods when pregnant but some may experience lighter/shorter periods. For women who do not have a regular cycle, it can be difficult to know when a period is due. It is best to take the pregnancy test three weeks after having unprotected sex (as this is roughly how long it will take for the hormone levels to show up on the pregnancy test). If the pregnancy test is negative (i.e. you are not pregnant) but the period still doesn't arrive a week later, another test should be taken. Periods can be late for other reasons including stress, change of diet or other health conditions. Women should seek medical advice if they are concerned. When should a pregnancy test be taken? The pregnancy test can be taken at any time of the day. However, it is recommend that you take the pregnancy test first thing in the morning when your urine is most concentrated or at least four hours from last urinating. If you drink large volumes of fluid to try to increase the volume of urine for the pregnancy test, this could dilute the urine, which would make the hormone HCG more difficult to detect in the pregnancy test. How accurate is a home pregnancy test? The home pregnancy test has proved to be greater than 99% accurate in laboratory and consumer studies. How long will it take before I can read the result? The results of the pregnancy test can be read after just 5 minutes. What is the difference between a home pregnancy test and those done by a doctor? Many doctors and clinics use the home pregnancy test to verify the results, in which case they are exactly the same. Occasionally, some women may be given a blood test, but they aren’t very different from home pregnancy tests either. Both types look for the presence of HCG in your body. What should I do with my results? If your pregnancy test results are positive, you should consult your doctor to discuss your pregnancy and what steps and precautions should be taken next. In addition, if your pregnancy test is negative and you still suspect you may be pregnant, you may want to confirm your pregnancy test results with another home pregnancy test a few days later. If you test too early, you may get a negative result because not enough of the HCG hormone has built up in your system. Can anything affect the results of these pregnancy tests? Alcohol, painkillers, oral contraceptives, antibiotics and other common drugs will not affect the result of these tests. Only medicines that contain HCG can produce a false positive result. If you are unsure about your result or your period has still not arrived, you should see your doctor for advice. |
