Pregnancy is the most blissful period in a woman’s life and a life changing experience for a couple. It can be an extremely overwhelming feeling especially if you are trying it for the first time. If you notice that you have missed your periods or experiencing some weird symptoms, do confirm the conception by a Pregnancy Test before getting all emotional and planning for motherhood.
What Is A Pregnancy Test?
A pregnancy test can tell whether or not you are pregnant by checking for a particular hormone, ie., hCG in the urine or blood.
How Does It Work?
All pregnancy tests chiefly follow the principle of detecting the human chorionic gonadotropin (hCG) hormone. The hCG hormone is usually made during pregnancy in a woman's placenta after a woman has conceived i.e., when the fertilized egg implants itself in the uterus. The placenta is the sac that nourishes the egg after it’s fertilized and attaches it to the uterine wall.
Every woman has a different genetic constitution and hence even the time of ovulation in the menstrual cycle may differ. This causes the fertilized egg to get implanted in the uterus at different times. And the hCG hormone is only produced once the implantation takes place successfully. Although this usually happens about six days after the fertilization when the egg and sperm merge, but several studies show that in up to 10 percent of women, implantation does not occur until much later, i.e., after the first day of the missed period. And thereafter the amount of hCG rapidly doubles up in every 48 to 72 hours and usually reach its peak around 8 to 11 weeks after conception. Thereby, the level of hCG declines and remains steady during the rest of the pregnancy.
What Types of Pregnancy Tests Are Available?
There are two main types of Pregnancy Tests, one being the urine test and the other the blood test.
The Urine Test is often referred to as Home pregnancy test (Hpt) and can be done at home or at the doctor’s chamber. There are different types of Hpt’s and they are usually inexpensive, 97 – 99% effective and are mostly sold over the counter.
How Does It Work?
Most Home Pregnancy Tests work in the same way, i.e., they measure the level of hCG in the urine. They mostly come in the form of sticks or strips and contain specific instructions that need to be followed while trying it out. In most cases, one either has to hold the stick in the urine stream or collect the urine in a cup and then put 2-3 drops of it in the given window on the stick or just immerse the stick in the collected urine. Then the woman needs to wait for a few minutes as mentioned in the instructions. Different brands instruct the woman to wait for different amounts of time. After the time has passed, the user should inspect the ‘result window’. If the test result comes up either in the form of a plus ‘+’ sign or double lines, that means you are pregnant. Nowadays new digital tests even show the words "pregnant" or "not pregnant” on the result window.
Most home pregnancy tests also have a ‘control indicator’ in the result window which shows whether the test kit is functioning properly. In case, the control line doesn’t appear, it means your Hpt kit is faulty and may not produce conclusive results.
Sometimes, even if the line is faint, you need not worry, it might just be the case that the hCG hormone in the urine is negligible. This usually happens if you are testing before your missed period or just after a day you missed your periods. Although most Hpt’s claim to be 99 percent accurate on the first day of the missed period, yet researches suggest that most of them do not always detect the low levels of hCG usually present in early pregnancy.
You must confirm the pregnancy either by conducting another Hpt after a few days or visit the doctor’s office to get a blood test done.
Also known as the beta-hCG test, this usually measures the level of the hCG hormone present in a sample of your blood. This test is chielfy conducted by a doctor or pathologist and is often referred to as beta-hCG blood test, quantitative hCG blood test, repeat quantitative beta-hCG test, quantitative blood pregnancy test or quantitative serial beta-hCG test. While a qualitative hCG blood test just detects the presence of hCG in your blood, a quantitative hCG or beta-hCG blood test checks for its specific levels.
How Does It Work?
A beta-hCG test works by determining even smaller amounts of hCG, and can confirm or rule out a pregnancy earlier than a urine test. A blood test can usually detect pregnancy even before you've missed a period and are about 99 percent accurate.
Although there is no special preparation required to take during this test, patients must inform the doctor about consumption of any medications, vitamin or nutritional supplements, Ayurvedic or herbal preparations, or homeopathic medicines if they are taking, before going for the test.
The doctor or pathologist usually collects the blood sample from a vein in your arm using a small needle and the process generally takes less than 5 minutes. There are chiefly no side effects of a beta-hCG test apart from slight pain or bruising at the spot where the needle was put in, but it usually subsides quickly if you keep applying some pressure after removal of the needle. In very rare cases, there can be conditions such as excessive bleeding, fainting, light headedness, infection at the site of the needle, hematoma or swollen veins.
Why Is It Done?
A beta-hCG test is usually done to confirm pregnancy, determine the approximate age of the fetus, diagnose an abnormal pregnancy, for example an ectopic pregnancy, diagnose a potential miscarriage or analyze Down’s syndrome.
A quantitative blood hCG test can be conducted more than once, if the hCg levels in the first test is quite low and the doctor wants to rule out an ectopic pregnancy. An ectopic pregnancy is usually characterized by cramps or pain in the lower abdomen, low back pain, unusual vaginal bleeding and pain on one side of the pelvis.
A beta-hCg test is also done to confirm pregnancy in a woman trying to conceive if she is about to undergo certain medical procedures or exposed to X-ray to prevent any potential harm for the developing baby.
An increased level of hCG in the blood for non-pregnant women or post-menopausal women may also work as a tumor marker and indicate specific types of cancerous conditions like breast cancer, ovarian cancer, lung cancer or uterine cancer in women. Sometimes, a high level or hCG can also occur due to noncancerous conditions like ulcers, cirrhosis, and inflammatory bowel disease.
What Are The Levels Of hCG?
Once you get back your lab test, the doctor will analyze the report and mention the hCG levels in your blood. These levels are measured in milli-international units of hCG hormone per milliliter of blood (mIU/mL).
Normal hCG levels in a nonpregnant healthy women are less than 10.0 mIU/mL.
The reference range for pregnant women is as follows:
Weeks From Last Menstrual Period (LMP) Normal hCG Levels (mIU/mL)
If the levels of hCG are lower than the normal range, it could mean a miscalculation of the conception or pregnancy date, ectopic pregnancy or blighted ovum that could result in a miscarriage.
However, if the levels of hCG are higher than the normal range, it could again be due to miscalculation of pregnancy date, a molar pregnancy (a condition when an abnormal mass forms inside the uterus after fertilization instead of a normal embryo) or multiple pregnancies with twins or triplets.
None of the above-mentioned tests are 100 % accurate every time. It can give both false-negative results and false-positive results for pregnancy. However, your doctor or OB/GYN will help you figure out your results or perform follow-up testing if there’s any doubt. Do not panic if your test results don’t match the normal range, as these numbers are just estimating and you can obviously have a normal baby even if your beta-hCG levels are slightly lower or higher than the normal range.