What Is a Beta Pregnancy Test?
Pregnancy tests are a massive industry, as women wonder after each cycle, whether they will be listening to that pitter-patter of tiny feet. Will it be this month? Next month? Do we need to start looking at infant car seats, or maybe pick up a few gender-neutral onesies on the way home from work? Are we comfortable growing and raising a tiny human being? Do we have what we need to be good parents? Will we be like our mom? Is that a good thing or a bad thing?
This is exciting and terrifying at the same time. Your mind flits between desperately wanting to see a positive test result, and being desperately terrified that you might actually see a positive test result!
A beta pregnancy test is a blood test for hCG. Doctor’s offices and hospitals use this type of test (as you know, home pregnancy tests are urine tests). Beta pregnancy tests come in two types: qualitative and quantitative.
Qualitative tests offer a simple yes or no; pregnant or not answer. The cut-off for a “yes” verdict is similar to many urine tests – 25 mIU of hCG. These tests will confirm a positive urine test that a woman takes at home or tests a woman for pregnancy if she hasn’t already tested herself.
Most pregnant women hit the 25 mIU mark in their 3rd to 5th week of pregnancy (measured since their last menstrual period), and there can be a wide variance of hCG levels from woman to woman. Remember that a negative qualitative test does not mean that you are not pregnant; it means that your body has not produced enough hCG to register on a pregnancy test.
Quantitative tests show the amount of hCG in the woman’s blood. These tests are useful for women who are taking fertility treatments or who have a history of miscarriage. Knowing how much hCG in a woman’s blood is beneficial because it shows if hCG levels are increasing. During the first weeks of pregnancy, hCG levels double every 48-72 hours. If a woman is undergoing fertility treatments, she will likely be taking several of these blood tests to ensure that her hCG levels are increasing and that her pregnancy is developing typically. If the levels are not doubling at the expected rate, she may not have a viable pregnancy.
hCG Levels During PregnancyWhen tracking your pregnancy's progress with blood pregnancy tests, you will want to see an increase in the level from one test to another. hCG typically doubles every 48 to 72 hours in a healthy pregnancy. If an hCG result is 100 on Tuesday, a second blood test should show a result of 200 on Thursday or Friday.
hCG levels During Early Pregnancy:hCG levels in weeks from LMP (last menstrual period):
|3 weeks LMP:||5 - 50 mIU/ml|
|4 weeks LMP:||5 - 426 mIU/ml|
|5 weeks LMP:||18 - 7,340 mIU/ml|
|6 weeks LMP:||1,080 - 56,500 mIU/ml|
|7 - 8 weeks LMP:||7, 650 - 229,000 mIU/ml|
|9 - 12 weeks LMP:||25,700 - 288,000 mIU/ml|
|13 - 16 weeks LMP:||13,300 - 254,000 mIU/ml|
|17 - 24 weeks LMP:||4,060 - 165,400 mIU/ml|