The Cycle Day

28 days is not the magic number for all women. In order to figure out your most fertile days, Dr. Esposito suggests this calculation:"The first day of bleeding is considered to be Cycle Day 1 and the length of the cycle is from Cycle Day 1 to the next Cycle Day 1 of the subsequent cycle. In general, for women with regular cycles, the second half of the cycle -- called the luteal phase --should always be 14 days long. So, in order to figure out when a woman is ovulating she need only subtract 14 from her total cycle length to get her day of ovulation -- i.e., a woman with a 30-day cycle would subtract 14 from 30, resulting in a Cycle Day 16 as the likely day of ovulation.

Plug in your specific dates to get a customized ovulation calendar here to help you figure out your most fertile days.How do I chart my cycle?One option for charting is to keep a close eye on cervical mucus. The amount and consistency of mucous  changes throughout your cycle - typically dry for the first few days after your period, then slippery like egg white during ovulation. Look for changes throughout the month when going to the bathroom - you'll be able to notice the mucous on toilet paper.Another option is to measure basal body temperature. "After ovulation the body temperature rises by about one degree and if a woman becomes pregnant the body temperature stays up, which is due to progesterone

Dr. Esposito explains. "So upon awakening and before any activity, the woman will take her temperature first thing in the morning with a special basal body temperature thermometer. She will do this daily and record the temperatures. There tends to be a correlation between the dip in the temperature -- seen as mid cycle -- and the LH surge -- LH is the hormone causing release of the egg from the follicle at the time of ovulation -- but this timing is only accurate to within 2-3 days.

The LH surge usually occurs 24 to 36 hours prior to ovulation. The dip in temperature is believed to represent the beginning of the LH surge."Check out this cool printable basal body tempeature chart to help you keep track.Do over-the-counter ovulation predictor kits (OPKs) really work?According to Dr. Esposito, these kits can be a very helpful tool in helping a couple determine when the woman is ovulating so intercourse can be timed appropriately. "The OPK's detect LH hormone in the urine -- which is usually detected around 12 hours after it is detected in the blood," she explains.