Early pregnancy tests

October 8, 2007 7:49 PM

Are those early pregnancy tests reliable?

I'm thinking about taking one of those at-home early pregnancy tests- you know, the ones that you can take 5 days before a missed period. Does anyone have experience with these? Mainly, have you taken one, had it give you a negative result and then found out a week later you were actually pregnant? Or vice versa? I'm just wondering if I should bother, or if 5 days early really is too early.
Thanks!

posted by anonymous to health & fitness (7 comments total)

False negatives can happen, but false positives are really rare from what I've read.
FWIW, I learned I was pg with my daughter using a test that was advertised as an early result test, and it gave me a positive result a couple days before Aunt Flo was due.
posted by missuswayne at 7:57 PM on October 8, 2007 [1 favorite has favorites]

have you taken one, had it give you a negative result and then found out a week later you were actually pregnant?

Yup. With both of my pregnancies. I took a bizillion tests each time and didn't get a positive until I was good and late.
posted by jrossi4r at 8:09 PM on October 8, 2007 [1 favorite has favorites]

I used a non-US brand about four days before my period and got a negative. Baloney. I was sure I was pregnant (lots of other signs and I was charting/tracking). Maybe it was too soon for it to be picked up, maybe it was a dodgy product. Sure enough, four days later I tested positive with a major brand.

Do you have any other physical changes or signs?
posted by cocoagirl at 8:11 PM on October 8, 2007

Whatever test you choose, make sure you take it with your first pee of the morning. The hormones will be more concentrated then.
posted by sugarfish at 8:43 PM on October 8, 2007

The sensitivity of the tests will vary wildly between different manufacturers; it's amazing that the industry isn't more regulated.

A personal story: Earlier this year, while impatiently waiting to see if I was knocked up yet, I went through a bunch of tests (one of the expensive "early" brands that would show a plus or minus) almost every day starting from about five days before the day my period should have started to about two days after (it still hadn't started), when I got what I thought was maybe a very weak plus sign -- that is, there was maybe a vertical line running through the ever-present horizontal line. But I couldn't be sure if I was just imagining the very faint color change. Frustrated, I went out to the drugstore right away and grabbed a cheapo no-name brand off the shelf, one possibly made in Mexico (I live in Southern California), brought it home, and tested with it. Positive, clear as day.

So no, the early tests really aren't worth it.

False negatives can happen, but false positives are really rare from what I've read.

Ditto that. The instructions that come with the test will tell you the same.
posted by Asparagirl at 9:13 PM on October 8, 2007

I took a generic pregnancy test 5 days before my period was due and got a positive when I was pregnant with my daughter.

The brand is less important than the sensitivity of the test. The sensitivity of early pregnancy tests is determined by the amount of HcG (pregnancy hormone) that they can detect; the more sensitive they are, the earlier they can give you a positive result. The ones that advertise that they work 5 days early are able to detect 25 mIU/mL of hCG or less, which is the average that could theoretically be detectable at 9 days past ovulation or so (5 days before the average missed period). However, every pregnancy is different, so they may or may not be accurate that early. Fertilized eggs take about 6-12 days to implant in your uterus and another day or two to start secreting the hormone the test detects; if the egg hasn't had time to implant and secrete the hormones it needs to yet, the test won't be positive even if you are pregnant. The later in your cycle you test, the more likely the result is to be accurate, because it is more likely to have had that time.

peeonastick.com is a great resource for finding out more about this stuff if you're interested. They also have a list of how sensitive and reliable all the brands of tests are.

Incidentally, some of the most sensitive tests on the market are sold at Dollar Tree for a dollar; at that price you can afford to take two.
posted by streetdreams at 9:16 PM on October 8, 2007

peeonastick.com - what a great domain name.
posted by junesix at 1:49 AM on October 9, 2007