Our section arrives: Ask the midwife With one of the questions that moms and dads looking for a safe child have been asked on occasion. Midwife Marina Fernández collaborates with Babies and more and every week answers a question related to pregnancy, childbirth, postpartum or breastfeeding that our readers leave for her. This week we are going to talk about the pregnancy tests.
Marina Fernandez She is a midwife, specializing in home birth, a lactation consultant and an expert in complementary therapies. She is a member of the Professional Association Born at Home and a founding partner of Multilacta.Each week he will collaborate with Babies and more by answering a question from our readers. You can know her better on her Marina Matrona page.
The matron Marina Fernández answers a question today which is common to find in our Answers section and for which you can find here answered in detail. So Matron Marina Fernández explains to us what a pregnancy test is.
What exactly is a pregnancy test?
"A pregnancy test is a method that allows, with a high margin of safety, to know if a woman is pregnant.
For this the human chorionic gonadotropin hormone is sought; hCG for its acronym in English. This is found in both blood and urine. The levels increase exponentially over time, after implantation and decrease in the 2nd trimester of pregnancy, so at this time if a pregnant woman takes the pregnancy test, it can be negative. "
How is a pregnancy test done?
"There are two ways to do pregnancy tests: in blood and urine.
The blood tests are the most sensitive and reliable, they are performed in a laboratory and the results are usually within a few hours, they allow to know how many weeks of pregnancy have passed through a study of the concentration of hormones and if this pregnancy continues in its development or there is a problem such as an abortion, an ectopic pregnancy, or an egg egg also called an anembryonic pregnancy, or another alteration that increases the HCG hormone. They have a 99% reliability from 15 days after ovulation.
Urine pregnancy tests are acquired in pharmacies, without a prescription, consist of chemically prepared bands or strips that react to the hCG hormone in the urine. It usually takes two or three minutes to give a result. They have a reliability of 75 to 97% when they give a negative result. All positive results will be 99% reliable.
The chances of false positives are remote. To be able to detect pregnancy with a minimum of reliability, we must resort to chemical tests and they need at least fifteen days from fertilization to be able to detect pregnancy. Rushing could cause a false negative.
Some tests can detect the hormone shortly after implantation, which can happen between six and twelve days after ovulation. However, the usual thing in urine tests is that it takes three or four additional days for the hormone levels to be high enough to be detected by these methods.
In case the negative test, but doubts persist, it can be repeated three to seven days after the first one, so that hCG levels increase over time. A test can be performed at any time, but hCG levels are higher between seven and twelve weeks of pregnancy, when it reaches maximum levels.
Regardless of what type of test is used, it is not recommended to drink plenty of fluids before performing it. When the hormone is diluted in a larger amount of fluid, it is difficult to detect by tests in the first weeks of pregnancy. It should be done with the first urine in the morning, after 5 or 6 hours without urinating.
It is very important to take into account several factors when carrying out a pregnancy test. The first thing to check is that the test has not expired and is in good condition. You should read the instructions for use and do it correctly. Avoid exposing it to any substance, especially those that may impregnate or damage it.
You should only come into contact with the device, the urine of the woman who is performing the test. Once the urine has been contacted with the device in the correct way, it should not be shaken, dried or altered. The appropriate thing will be to let it rest in a stable place until the necessary time elapses, which is a few minutes. If the test does not yield any results, it is likely that it was performed incorrectly. "
How accurate are the tests if you do them just the day your rule should have started?
"Most home pregnancy tests claim to have" greater than 99 percent accuracy "and suggest that you can do them the first day you miss the period. However, a study published in 2004 in the American Journal of Obstetrics and Gynecology states This is not the case. Some tests can detect the hormone in your urine at that time and give you a positive result, but most are not accurate enough to guarantee an accurate result.
Researchers at the University of New Mexico evaluated digital and manual tests from three different manufacturers and found that only one brand of tests (both digital and manual) was 97% correct when detecting pregnancy on the first day of lack of the period (the amount of hCG in the urine at this time can vary greatly from one woman to another). The other brands detected the pregnancy half of the times tested.
In short: you have a much better chance of getting a correct result if you wait for the test one week after the scheduled date for your period. "
How can I know which are the most sensitive tests?
"It is not easy. New products are constantly appearing and brands can improve home tests at any time. Some brands provide information about the sensitivity of a test, that is, they report the lowest concentration of hCG (in International Units). per milliliter of urine) that is capable of detecting the test. For example, a pregnancy test that claims to detect hCG at 20 mIU / ml should theoretically be more sensitive than one that claims to detect it at 50 mIU / ml. "
How to interpret the results?
"The tests also vary according to the way of making the results known: some show pink or blue lines on the test strip, while others display a positive or negative red sign in a window (that is, a + symbol o).
Some brands have a digital screen where you read if you are pregnant or not. Most have a control indicator (usually a second line or symbol) that is supposed to indicate whether the test is valid. If this control indicator is not marked, the test may not be valid. "
Is it possible to get a false negative?
"If the test shows a negative result, or an unclear positive result, wait a few days or a week and repeat it, if the rule has not yet come to you. If you ovulated in your cycle later than thought, it may happen that You have done the test too early to get a positive result.
Anyway, do not assume that a negative result means that you are not pregnant. Have a little patience, do not be distressed and try to be relaxed.
Also, it can be an ectopic pregnancy (which can be negative or positive) if you notice severe pain in the lower abdomen, dizziness, or abnormal bleeding; you should see your doctor to see what is happening.
Another situation in which you should see your doctor is if you have been without the period and with negative results in the pregnancy test for more than 3 months, to investigate the cause of amenorrhea. "
Is it possible to obtain a false positive result?
"False positives when the test says that you are pregnant but in reality you are not are uncommon, but they can occur.
It can occur in the following circumstances; if you had an abortion, spontaneous or voluntary in the last eight weeks; if you have taken a medication to increase fertility that contains hCG; if you have a tumor that secretes hCG; if it is a defective test; if you have a chemical pregnancy or an ectopic pregnancy. Don't despair and ask for professional help. "
What are the symptoms of pregnancy?
The symptoms of pregnancy are:
- Absence of menstruation. The most common sign of pregnancy is usually amenorrhea.
- Although its causes are varied, the lack of menstruation is one of the first symptoms and the reason par excellence to resort to home pregnancy tests.
- Abnormal bleeding may be a slight "implantation bleeding" around the date you should have the period. It is a slight spotting rather than bleeding.
- Sickness. Usually in the morning, nausea and vomiting are other celebrities
- signs during the first weeks.
- Breast tenderness The accelerated multiplication of hormones after fertilization causes physical changes in women; one of them is breast enlargement, which becomes much more sensitive.
- Unstable bladder Hormonal changes, increased flows in the lower areas and inflammation of the uterus after conception affect the bladder making it unstable and increasing the frequency with which we go to the bathroom.
- Fatigue. The increase in hormone levels, the production of the placenta, and the energy provided to the ovule for its development are factors that increase body fatigue and the need to increase sleep hours is noted.
I hope I have resolved the doubts about how and when to do the pregnancy test and know how to interpret the result of it. "
We remind you that you can consult all the answers that matron Marina Fernández has given here and also send your questions so that she can answer them in the future in our section: Ask the midwife.
