Setting aside the cost of eight to 15 bucks, what downsides are there—if any—to a little prenatal over-enthusiasm for taking a pregnancy test? From how long to wait to what time of day is best to what can cause a false positive, here's what you need to know.

"It is never too early to take a pregnancy test, in my opinion, especially since many women do not know that they are pregnant early in the course of their pregnancy, and outcomes are much better for fetal and maternal health if they do," said Brynna Connor, M.D., a family medicine physician in Austin, Texas and healthcare ambassador at NorthWestPharmacy.com.

"However, for more accurate results on a home pregnancy test [using urine], it's a good idea to wait about 10 days after sex to take a home urine pregnancy test," Connor advised.

"It's too early to take urine pregnancy tests less than one week after missing your period," cautioned Daisy A. Ayim, M.D., a triple-board-