If you think you could be pregnant, it’s best to know when you can take a pregnancy test. The best time to take an early pregnancy test depends on what type of test you are taking.
There are two types of pregnancy tests, a blood test and a urine test. Both look for the pregnancy hormone called Human Chorionic Gonadotropin, usually referred to as hCG, which is only found in a woman’s body if she is pregnant. The hCG hormone is made by the early cells of the pregnancy called the trophoblast, and these will later become the placenta.
The difference between the two tests is when they can detect hCG. Blood testing can detect hCG about eight to ten days after ovulation and in most cases urine testing (home pregnancy tests) detect hCG about two weeks after ovulation. The level of hCG is measured with a blood test known as a quantitative test, usually called a “quant beta” by doctors. The urine test is a yes or no version, and is called a qualitative test.
hCG Measurement — “Quant Beta”
The hCG hormone is measured by its concentration in the blood or urine, and is reported in milli International Units per milliliter, or mIU/ml. A thousand milliunits equals one unit, so a milli IU is one-thousandth of a unit. A milliliter is one-thousandth of a liter. The term cc is also used sometimes instead of ml. One cc is one cubic centimeter, and is equivalent to one milliliter (one ml.).
Pregnancy tests with a sensitivity of 20 mIU/ml are more sensitive than tests with a 50 to 100 mIU/ml detection. Manufacturers will display how sensitive their tests are using mIU as the standard unit of measure.
Test sensitivity walks hand in hand with early detection. The lower the number, the sooner a test can detect pregnancy. The most sensitive pregnancy tests can detect hCG levels as low as 20 mIU, which occurs about eight days following implantation of the egg.
There are many benefits to taking a home pregnancy test—they are cheap, easy, and more important, private. By taking the test privately, you are able to take the test when you are ready and you can react however you want to. Nobody needs to know you have taken it, including your spouse, friends, parents, or other family members.
The urine test should be done with the first urination of the morning, as hCG is at its highest level at that time and is easiest to detect. If you are unsure about your results, you should make an appointment with your doctor so he or she can confirm the results with a blood test. Urine tests just show positive or negative. They cannot tell you how far along the pregnancy is.
Home pregnancy tests, if done correctly, can be 99 percent accurate. However, many women test too early in their cycles, not allowing enough time for hCG to build up in the system. It’s best to take the test after you have missed a period, or 14 days after ovulation. Testing any earlier can give you false negative results.
If you believe you are pregnant but get a negative result, take it again a few days to a week later (that is if you have still not started your period). At that point, if you get a negative result but are still unsure about it, visit your doctor.
Most women do not know exactly when they ovulate. Ovulation is the key ingredient in the conception formula. A woman can only get pregnant when she ovulates. When a woman says “my period is late,” she actually means her ovulation date is late.
The timing of the menstrual cycle timing can vary from one woman to the next; we know that every woman starts her period almost exactly 14 days after she ovulates. That’s why pregnancy tests should not be taken too early. If you have a long cycle, you might have conceived after the “textbook” day 14 date of ovulation associated with a 28-day cycle.
When an egg is fertilized after you ovulate, it takes about a week to travel through the fallopian tube to the uterus and implant. It’s only after a fertilized egg implants in the uterus that your body starts producing hCG. Even then, it takes time to build up the levels of hCG in your body. If you did conceive but you test too early, you might receive a negative result because the fertilized egg hasn’t had time to become implanted.
Have you ever heard the expression, “you can’t be a little bit pregnant”? Well this is not exactly true. Now that we have sensitive tests for hCG, we have learned something about early pregnancy that we never knew before. Yes, you can be “a little bit pregnant” and not ever know. This is called a chemical pregnancy.
If an hCG test is done before the period is late and comes back positive, sometimes the menstrual period will still show up at the expected time, or perhaps a couple of days late. This is a normal process that takes place in a woman’s body, and we have no idea how often it occurs. This is the problem with doing a pregnancy test too soon. You might get a positive test result, with all the associated emotional implications (good or bad or who knows), and yet in just a few days your period shows up. This is a chemical pregnancy.
This phenomenon is normal and common. Doctors do not call this a miscarriage. No treatment is required. We do not add it to your pregnancy score. Did you know that doctors count how many times a woman has been pregnant? We call it the G score. G stands for gravida. There is also a P score, which stands for para. Any pregnancy, whether it leads to a birth, a miscarriage, or termination, adds 1 to the G score.
If you are pregnant for the first time, you are a G1, P0. After you have a baby you are a G1 P1. A chemical pregnancy is not counted toward this score. So yes, you can be a little bit pregnant and never know it. This is why physicians normally advise women to do a pregnancy test after they are late for their period. Try to be patient, and you may save yourself from the emotional experience of a chemical pregnancy.
BG edit 4/25/16