Updated 31 August 2016

Early pregnancy tests may not be reliable

If you think you might be pregnant, you probably want to know as soon as possible, but are pregnancy tests reliable?


There's a good chance you'll need to wait until just after you've missed your period - not three days before it's expected.

Doctors say so-called early-result pregnancy tests are a waste of time and money.

False negatives
Studies on the packaging of such kits say 48 percent of women get a "false negative" result when they test three days before their expected period. In other words, the test told nearly half of the women they weren't pregnant when, in fact, they were.

"It's a waste of money, and it's a waste of time," says Dr Shari Brasner, an ob-gyn at Mt. Sinai Hospital in New York City. "I can't really think of a scenario in which it's so critical to know four days earlier."

One American manufacturer gives the statistic of the chances of a false negative rate on the back of the pack. The company's tests also found 31 percent of women will get a false negative two days before their period and 14 percent one day before.

But other manufacturers claim that putting the false negative in the fine print is misleading because many women never bother to read it.

When to take the test
Ninety percent of those surveyed at the American College of Obstetricians and Gynaecologists meeting in Los Angeles recently said the best time for a women to take a home pregnancy test is after she has missed her period. Nearly four out of five said they preferred women to use a home pregnancy test up to four days before their expected menstrual period.

Pregnancy tests measure the level of human chorionic gonadotropin (hCG), a hormone produced by the placenta during pregnancy, in the urine. The rate at which hCG is generated varies among women, Brasner says.

She does not recommend a particular brand of pregnancy test to her patients.

"All of the over-the-counter tests today are very sensitive," she says. "I do not routinely recommend that women come in for blood tests anymore to confirm pregnancy because the tests are such a fabulous tool. I rely on them."

She does, however, say women should save their money and wait until after their period to test.

"They will know soon enough," she says. "You avoid this whole discussion of 'Maybe it's a false negative. Maybe I am really pregnant.' If it's done appropriately, there is an overwhelming good chance that a positive is a true positive and a negative is a true negative." - (HealthDay News)


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