Early Positive Pregnancy Tests: Are You Really Pregnant?

Early pregnancy tests are designed to detect pregnancies early. Learn how they differ from standard pregnancy tests.

Early pregnancy tests are designed to tell you whether you're pregnant five days before you miss your period. These sensitive tests aim to detect a hormone produced during pregnancy earlier than standard ones. But do they really work? Learn about these tests and how they compare to regular pregnancy tests.

How Is Pregnancy Detected?

First, a pregnancy test primer: Whether it's a blood test or a urine test done at a healthcare provider's office or in your own bathroom, a pregnancy test is positive when it detects the hormone human chorionic gonadotropin (hCG)—a hormone produced by placental cells during pregnancy—in your system, according to The American Pregnancy Association.

The production of even a small amount of hCG means the fertilized egg has been successfully implanted in the uterine lining.

At-Home Pregnancy Tests vs. Commercial Tests

The variance between at-home pregnancy tests is the amount of hCG they can detect, with early pregnancy tests detecting lower levels of the hormone.

"The commercial pregnancy tests range from 20 to 50 mIU/mL. Since hCG levels double every two to three days, some tests may detect hCG two to three days earlier—so there may be some benefit to using a more sensitive test," said Seth Guller, PhD, the director of the Gyn/Endocrine Laboratory at the Yale School of Medicine.

Guller added a surprising caveat: Any benefits of early pregnancy detection should be balanced by the fact that the majority of pregnancies ending in miscarriage—or sudden pregnancy loss before 20 weeks—occur very early.

The Push for an Early Pregnancy Test

Living well is important while pregnant, but the "healthier lifestyle" that pregnancy test companies promote seems like a marketing tactic. People trying to conceive have to take reasonably good care of their bodies in preparation for a potential pregnancy in the first place.

This could include making lifestyle changes, getting vaccinations, and ensuring a healthy weight, according to the Centers for Disease Control and Prevention (CDC).

And, according to Charles Lockwood, MD, the chief of obstetrics and gynecology at Yale-New Haven Hospital, "the risk of exposure to agents causing birth defects doesn't start until two weeks after conception."

But there is no denying that trying to conceive is suspenseful. This is why a person might want to know about pregnancy as soon as possible—despite the emotional risk of learning about brief chemical pregnancies, which are miscarriages that occur within the first five weeks.

Are Early Pregnancy Tests Accurate?

There are biological factors that may affect the results of these tests. These super-sensitive tests claim to identify a pregnancy a full week before a missed period, but embryos can fully implant (and start producing hCG) at different times. So, even if you're using the most sensitive test, your embryo may not produce a positive pregnancy test right away. In fact, it may take several days.

"Embryo implantation is a process that unfolds over a number of days rather than a single event," said Hugh S. Taylor, MD, the chief of reproductive endocrinology and infertility at the Yale School of Medicine.

It takes about six days after implantation for the blastocyst (a fertilized egg containing rapidly dividing cells) to hatch and then strengthen its attachment—which can last between one to four days.

"Embryos do grow at different rates; they can vary by about one day prior to implantation," Dr. Taylor said. "Pregnancy tests vary by the growth rate of the embryo and because of maternal body size and hydration status."

So every person may test positive on a different day, regardless of how fancy the test may be. Ultimately, it's up to you to decide if waiting to find out works for your situation or not.

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