Early Pregnancy Test

Last Updated: December 15, 2016

Definition - What does Early Pregnancy Test mean?

An early pregnancy test is a test that is able to detect lower levels of human chorionic gonadotropin (hCG) hormone. A more sensitive home pregnancy test does not necessarily translate to an accurate answer faster because of the variability of how hCG levels build up in a pregnant body.

The most sensitive home pregnancy tests can detect 20 mIU/hCG.

Blood pregnancy tests are able to accurately confirm pregnancy status 99% of the time 6-10 days following ovulation.

FertilitySmarts explains Early Pregnancy Test

Five to six days after fertilization, the blastocyst implants into the uterine wall. Increased levels of hCG start to produce, generally doubling every 72 hours and level out around 8-10 weeks. Pregnancy tests work by detecting hCG levels.

The hCG hormone is measured in milli-international units per milliliter (mIU/ml). A reading of above 25mIU/ml is considered positive. An hCG level of less than 5mIU/ml is considered negative for pregnancy.

How effective an early pregnancy test is can depends on how quickly levels of hCG build up in a woman's system.

Averages levels of hCG found in pregnant woman from last menstrual period (LMP) are:

Last Menstrual Period Approximate Gestation hCG Level
3 weeks 1 week 5-50 mIU/ml
4 weeks 2 Weeks 50-500 mIU/ml
5 weeks 3 weeks 100-10,000 mIU/ml
8-10 weeks 6-8 weeks 1080-30,000 mIU/ml
14 weeks 12 weeks 3500-115,000 mIU/ml

Women who are not pregnant have less than 5.0 mIU/ml.

Urine Tests

A home pregnancy test use the "pee on a stick" method of testing to analyze hCG levels in a woman's urine. The most sensitive home pregnancy test generally available is sensitive enough to detect 20 mIU/hCG.

Pregnancy tests are generally designed to detect 50 mIU/hCG, the amount of hCG typically experienced towards the 4 weeks after LMP.

The most accurate time to take any home pregnancy test is one week after the first day of a missed period, at which point the results are nearly 98% reliable. A pregnancy test taken too early may return a false-negative result. Women who receive negative results on a test taken prior to a missed period should retake the test at a later date.

Blood Tests

A blood pregnancy test is conducted in a doctor's office. The blood pregnancy tests also measures hCG, but is able to detect smaller levels at an earlier date. 6-10 days following ovulation, blood pregnancy tests are able to accurately confirm pregnancy status 99% of the time. Blood testing as a method of early pregnancy testing is more common with assisted reproductive technology (ART) treatments. ART treatments may use early pregnancy tests to track the progress of the procedure and ensure appropriate development is occurring.

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