If a woman has intercourse on the day of ovulation, she has the highest chances of getting pregnant. However, having unprotected sex up to four days before ovulation can still result in pregnancy because sperm can survive for as long as six days in the reproductive tract.
The fertility-detecting watch, which has been approved by the U.S. Food and Drug Administration, works by detecting levels of a number of salts in a woman's sweat, including chloride, which change during the menstrual cycle. Chloride levels are at low when the cycle starts and peak three times during it.
The Daily Mail quotes Health Watch Systems as saying, "For women, knowing the days before ovulation not only lowers stress levels, but it increases her chances of getting pregnant."
By working out the normal chloride level for each user, the fertility watch then predicts ovulation. It is capable of detecting the rise in chloride levels in three ways. It measures the monthly estrogen levels three days of its peaks, four days before the increase in luteinizing hormone (which helps regulate the menstrual cycle and egg production) and five days before ovulation.
A woman who desires to conceive has to wear the watch on her wrist while she sleeps and can program it for cycles ranging from 20 days to 39 days. A woman's reproductive age declines with age, but if she has regular unprotected intercourse, there is a 94 percent chance that women aged 35 and above can get pregnant within three years of trying.
