A pregnancy test is all about detecting the presence of the pregnancy hormone called hCG (Human Chorionic Gonadotrophin). hCG is produced by the placenta on the first day the embryo implants in the uterine wall. Concentrations of hCG varies from woman to woman.
During pregnancy, both the blood and urine will contain the hCG. A blood test, though more invasive than a urine test, is a more accurate and sensitive test, able to measure low levels of hCG. A blood test can be done 7-10 days post-ovulation.
Early signs or pregnancy include missed period, lighter than usual period (due to implantation bleeding that occurs the same time as the period), swollen breast, breast tenderness, prominent veins on the breast, vaginal discharge, nausea, constipation, pass urine more often and a metallic taste in the mouth.
A pregnancy test kit (PTK) uses monoclonal antibodies to detect the presence of hCG. It is an indicator stick with a strip that has an absorbent wick. When hCG in the urine is detected, a chemical reaction occurs and the result is revealed on the indicator screen as a ‘+’ sign or a colored circle/bar. Results will take about 3 minutes.
Over-the-counter PTKs provide privacy and fast results and are, on average, 99% accurate. Read and follow the instructions on the kit carefully.
If test results are negative and if mensturation does not start within a week, test again. Consult a gynaecologist if pregnancy symptoms are there but test results show otherwise. PTKs can be used on the first day of a missed period.
Do not drink excessive amounts of liquid in an attempt to produce more urine because the urine can become diluted, making hCG undetectable. Use urine that has been in the bladder for more than 4 hours.
Chapter: Pregnancy :: 5 June 2007
