by Do you have a few days late on your period, maybe some suspicious symptoms? Or are you looking for a child and are you eager to know if the last attempt was successful? To solve the problem, beyond any doubt, it is necessary to take a pregnancy test.
At the pharmacy, without a prescription, you can buy DIY sticks that measure the concentration in the urine of human chorionic gonadotropin (hCG), a hormone released into the mother’s body by the embryo from the moment it nests in the wall of the uterus and the pregnancy actually begins. “The reliability of these devices, if used according to instructions, is 97%”, says Mario Fadin, gynecologist in Milan. Let’s see how the pregnancy test is done correctly.
How does the DIY stick work?
The stick is an elongated plastic device with a handle and, at the opposite end, an absorbent tip that is usually protected by a cap. To use it, remove the cap and immerse the tip for a few seconds in the jet of urine, or in the urine collected in a container.
The device contains an antibody that reacts to the presence of hCG and detects even small amounts of hCG. If the test is positive, i.e. if there is a pregnancy in progress, a colored line will appear in a small window 3-5 minutes after the tip is immersed. Some sticks also have a control window where a second colored strip appears to certify correct execution. Some of them show two or more coloured strips depending on the concentration of the hormone in the urine and, therefore, depending on the week of pregnancy in progress. “But this is a poorly reliable approximation,” warns Mario Fadin.
Warning, however: if you wait more than 5 minutes after using the stick, the colored line that announces a positive result may appear even if there is no pregnancy. The reading, therefore, must be carried out within the time provided by the instructions, then the stick can be thrown away because it no longer provides reliable information.
When can I do it?
From which day of the cycle does it make sense to do the pregnancy test? “The products on the market today are extremely sensitive and can be used as early as four days before the date on which menstruation is scheduled to begin,” says the gynaecologist. “But they are most reliable if used on the first day of missed menstruation, since in the first weeks of waiting the concentration of hCG in the woman’s body increases continuously, doubling every 48-72 hours.
Since the first urine in the morning is more concentrated, if you decide to use the pregnancy test before the expected date of menstruation, when the concentration of the hormone is still low, you should use the morning urine. In the following days, the test can be done at any time of the day. “Better, however, to avoid drinking a lot in the previous hours, because the urine may be too diluted,” explains Fadin. “In case of cystitis, if the urine contains protein or blood, the result of the pregnancy test could be a false positive.
Pregnancy tests: on pharmacy shelves
A pregnancy test in a pharmacy costs an average of 7-10 euros if the package contains a single stick, 20-25 euros if the package is from two sticks. “It is often found in packs of two, not because it is necessary to repeat it twice, but for commercial reasons,” says the gynecologist. “It is actually better to repeat it one week after the first attempt when the result of the first attempt is negative but the menstruation continues to be delayed, or if the first attempt was made before the expected date of menstruation and gave negative results or, again, if for some reason the outcome was confused.
Caution: Pregnancy tests have an expiration date that must be carefully considered. Expired tests are no longer reliable and can give false negative results. It is better, therefore, not to keep them aside at home, but to buy one when needed.
Blood test: in which cases is it performed?
As an alternative to urine testing, human chorionic gonadotropin can be dosed into the bloodstream. To carry out the pregnancy blood test, it is necessary to go to a diagnostic clinic, at the cost of the ticket with the prescription of the family doctor, if the clinic is public or affiliated.
“The blood test is earlier than the urine test,” explains the gynecologist. “It can be successful seven days before the scheduled start of menstruation. Usually, it is prescribed in the case of assisted reproduction, to verify in a short time the success of the implantation of the embryo, or when there is a diagnostic doubt, for example if the urine test was successful but the embryo is not visible to the ultrasound.
The blood test not only gives a positive or negative response, but also measures the concentration of the beta portion of the hCG. In case of diagnostic doubt, the doctor prescribes two examinations 48 hours apart, to assess the increase in concentration. “If the value doubles, the pregnancy is evolutionary, i.e. it progresses normally”, says Fadin. “If it increases but does not double in 48-72 hours, it could be an ectopic pregnancy, i.e. the embryo may have taken root in a different position from the mucous membrane of the uterus, for example in a tuba. If the concentration decreases with the time, it is a sign that the evolution of the pregnancy has stopped”.