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Things to know about Pregnancy Tests: Purpose, timing, and procedure

Dr. BhavikaJan 17, 2024

Gone are the days when women discovered their pregnancy through morning sickness and food cravings. Now it takes two minutes and one simple test to determine if you are pregnant. Here is a rundown of these tests and when to use them.

Contents

What is a pregnancy test?
Why take a pregnancy test?
When should you take a pregnancy test?
How do I take a Urine Pregnancy Test (UPT)?
How does a urine pregnancy test work?
How accurate is a urine pregnancy test?
Blood tests for pregnancy

What is a pregnancy test?

A pregnancy test is a modality to confirm whether you are pregnant or not. This is usually done by measuring the level of a particular hormone in the body called Human Chorionic Gonadotropin (hCG), either in blood or urine. In any woman of the reproductive age group (from the onset of menarche until menopause) who has had unprotected intercourse, the absence of a period is a possible indicator of pregnancy. This is then confirmed by testing or scanning.

Human Chorionic Gonadotropin, or hCG, is a hormone that is produced exclusively in pregnancy only. Once the egg undergoes fertilisation, it is implanted into the wall of the uterus. A structure called the placenta also starts developing. The early forms of the placenta produce hCG. The detection of hCG, either in urine or blood, is hence diagnostic of pregnancy.

While blood testing for hCG requires healthcare professionals to administer the test, the Urine Pregnancy Test (UPT) is a simpler, more accessible method of detecting pregnancy. These test kits are available over-the-counter and offer 97 to 99% accuracy. Blood tests are however more sensitive, and are able to pick up pregnancy earlier than a urine test.

Why take a pregnancy test?

You may need a test if you are attempting to conceive and want to confirm conception. You may also need to take the test in case you have missed your period, especially after a history of unprotected intercourse.

Since women typically check for pregnancy within 10 to 14 days of missing a period, it is unlikely that any symptoms are seen yet. However, you can look out for:

Frequent urination
Nausea
Vomiting
Fatigue
Enlarged breasts with tenderness
Abdominal bloating
Acid reflux

Since these symptoms are also seen in the premenstrual period they are not specific and can’t be solely used to diagnose pregnancy.

When should you take a pregnancy test?

Taking a pregnancy test too soon after a missed period may give you a false negative. If conception has occurred, it takes about 10 days for the fertilised egg to undergo implantation and for placental cells to start secreting the hCG hormone.

Generally, it is recommended to take a urine pregnancy test around ten days after your missed period. If you have had unprotected sex in the middle of your cycle or suspect that your method of contraception may have failed, you can test as soon as ten days after intercourse.

hCG concentration in the blood is much higher than in urine. Hence, it may be detected in the blood even when the urine test is negative. If you have a negative urine test, but still have missed your period, reach out to your doctor for further evaluation.

How do I take a Urine Pregnancy Test (UPT)?

Read the package instructions clearly prior to taking the test. Most UPTs come along with a small plastic dropper.

Collect a midstream urine sample.
Using the dropper, carefully put 3 to 4 drops of urine in the sample well on the test kit.
Wait for about 5 minutes to see the results.
You will see two lines marked C and S. The C line is the control. This line will always turn red. It indicates that the test is working as it should.
If the S line turns red too it indicates a positive result. Hence, two red lines mean that you are pregnant.

Make sure to:

Read the instructions on the package thoroughly prior to taking the test
Do not drink a lot of water in order to urinate more; this can dilute the urine and cause a false negative. It’s best to use the test first thing in the morning.
Certain medications can interfere with an accurate test.
Always check to see that the control line has turned red.

How does a urine pregnancy test work?

A urine pregnancy test usually has a piece of reactive paper that detects the presence of hCG in urine. On contact with urine, depending on the manufacturer, the test usually shows a double vertical line.

How accurate is a urine pregnancy test?

If used correctly, a urine pregnancy test is between 97 to 99% accurate in detecting pregnancy. If your test result is positive, make sure to reach out to your treating doctor for confirmation as well as to discuss further steps.

Blood tests for pregnancy

A blood test can also be performed in order to confirm pregnancy. This also works by detecting the levels of the hCG hormone in the blood. A blood test is more sensitive and has 100% accuracy. It also detects a pregnancy earlier than a urine pregnancy test.

There are two types of blood tests that are performed with regard to the hCG hormone:

Qualitative test: This test detects the level of the hCG hormone, and aids in the confirmation of the pregnancy.
Quantitative test: This test measures the amount of hCG in your bloodstream. This is a clinical indicator. It gives your doctor an idea about the progress of your pregnancy. They may order two tests a few days apart to see if there is an expected rise in hCG levels. This is more important in women who have had previous spontaneous abortions, fertility issues, etc.

A pregnancy test can be positive in certain other conditions as well, which occur due to non-pregnant production of the hCG hormone. These are rare in occurrence and are usually associated with other symptoms. Some conditions include:

Pituitary gland tumours
Liver disease
Diseases that affect the uterus like choriocarcinoma and gestational trophoblastic diseases
Urinary tract infections

It is very important to remember that a negative urine pregnancy test is not confirmatory. It may simply mean that you have tested too early. Sometimes if the cells have implanted outside the uterine cavity it may take longer for the test to give a positive result.

If you have missed a period and are sexually active it is always best to consult a doctor to guide you on what to do next.

Disclaimer: The content on this page is generic and shared only for informational and explanatory purposes. Please consult a doctor before making any health-related decisions.