Misconception: Ovulation On Day 14

MYTH: Ovulation occurs on day 14 of your menstrual cycle.

FACT: If the female reproductive cycle were this predictable, pinpointing the timing of ovulation would be a total no-brainer. You’d simply pull out your calendar and circle your date with destiny with a big, juicy, fertile “O” (as in ovum, ovulation, orgasm—the usual midcycle words).

Unfortunately, Mother Nature is a bit more mysterious than that. Rather than using your current menstrual cycle to determine the timing of ovulation, she ties that all-important date to your next menstrual cycle—counting backward from the day your next period starts to determine when you ovulated.

Exactly how many days to count backward varies somewhat from woman to woman. The second half of the menstrual cycle is called the luteal phase, and while it’s often 14 days long, it can range from 11 to 16 days. Here’s an example of the menstrual math: A woman with a regular 30-day cycle and a 14-day luteal phase would ovulate on day 16. If her luteal phase were 11 days long, she’d ovulate on day 19.

Of course, even women with generally regular cycles sometimes experience an occasional hiccup, losing or gaining a day. And unless you use a fertility monitor or track your basal body temperature, there’s really no way of knowing how long your luteal phase is. That’s why doctors often advise couples trying to conceive to have intercourse every day or every other day for the few days during midcycle, to try and ensure that sperm comes in contact with egg close to ovulation.