The majority used to confirm their pregnancy with the help of home pregnancy kits. And when you meet your gynecologist, they will also suggest you participate in a blood pregnancy test. There are numerous reasons for prescribing a blood pregnancy test, but when you expect to become pregnant, you need to have a urine pregnancy test kit with you. In this article, I try to explain the blood pregnancy test and how it deviates from the usual urine pregnancy test.
What is a pregnancy test?
A pregnancy test can be used to determine whether a woman is pregnant. The results of the pregnancy tests are given depending on the presence of certain hormones in your blood or urine. A hormone called human chorionic gonadotropin (HCG) is produced by the placenta. The placenta initiates its hormone production after the embryo completes its implantation in the uterus.
HCG hormone can be detected within the pregnant woman's urine and blood after a certain period. Pregnant women can do a urine pregnancy test at home. It can only detect whether there is an elevation of the HCG level. But a blood pregnancy test can be more accurate and detailed, providing further details regarding your pregnancy.
What is a blood pregnancy test?
A blood pregnancy test is a quantitative test that can provide accurate details regarding a pregnancy before the next estimated menstruation date. But in practice, a blood pregnancy test is conducted to confirm the test results you obtain from a home urine pregnancy test.
Using sterile techniques, a blood sample will be obtained after venipuncture. The amount of HCG hormone in your venous blood will be tested to provide the quantitative date. This accurate test provides 99% of valid data when the procedure is done according to the guidelines.
Blood pregnancy test vs. home pregnancy test
Blood pregnancy tests always provide more information related to your pregnancy. But HCG hormone takes more time to reach your circulation, appearing early in the urine. So few more days are needed to raise your blood HCG level. But a urine pregnancy test can detect your pregnancy early compared to a blood pregnancy test.
The urine test kits cannot detect very low HCG levels. So the test will not show positive results in the initial days of your pregnancy. But blood pregnancy tests can detect even the lower HCG levels in non-pregnant women.
| Blood pregnancy test | Home pregnancy test |
| More sensitive than a urine HCG test | Less sensitive, need a bit more HCG level to detect. |
| Provide quantitative results | Provide qualitative results |
| It can be used to observe the HCG elevation with time. | Cannot detect the HCG elevation |
| The results can be accurate even before you miss your period. | Results will be accurate a week after the missing period. |
Why are blood HCG tests used?
Usually, a home pregnancy test is enough to confirm the pregnancy in healthy women. But with other risk factors and complications, a blood pregnancy test is used as it is more sensitive and provides quantitative data.
When a woman is a risk of pregnancy and has undergone fertility treatments, are advised to undergo a blood pregnancy test. When a physician suspects miscarriages and ectopic pregnancies, a blood pregnancy test is essential for them to confirm the situation.
The blood HCG level will double after every 48hours with a viable pregnancy. The HCG level declines and becomes half after every 48hours following a miscarriage. The HCG level does not double during the 48hours if the pregnancy is ectopic.
Evaluation of blood pregnancy test results
The quantitative HCG results confirm that the HCG level rises within the first trimester and starts to deviate after completing ten weeks. When your pregnancy reaches 16weeks, it keeps a constant HCG level and stabilizes. Abnormal HCG levels that deviate from the normal rangings will be due to other reasons.
What can you expect if the blood HCG level is higher than average?
- Malignancies and infections inside the uterus.
- Multiple pregnancies (Twins, triplets)
- Benign tumors within the uterus
- Cancer of ovaries
- A normal pregnancy with false gestational age
What can you expect if the blood HCG level is lower than average?
- Ectopic pregnancy
- Miscarriage
- Fetal death
What is the risk associated with the blood pregnancy test?
As venous blood samples are taken for the test, there is a risk of experiencing pain and bruising after venipuncture. The pain is subjective. Some women may experience more pain and faintishness after a single venipuncture. In rare cases, there is a risk of introducing germs to the bloodstream, causing infection.
But remember blood pregnancy test is a simple procedure as a routine blood test. It does not risk your life, and all these procedures are ordered to ensure the safety of you and the fetus.
Summary
Blood pregnancy tests are used to evaluate the quantitative data of your pregnancy. A hormone called HCG is measured during the blood test. The pattern of elevation and lowering of blood HCG levels are used to detect the complications and the status of your fetus. A healthy pregnancy can be confirmed with a urine pregnancy test. But a risk and complicated pregnancies need blood HCG test for further treatments.
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