How to track your cycle for conception

Top things to know about tracking your cycle for conception:

• Tracking your menstrual cycle can help you with conception

• There is a period of six days when you are most likely to conceive

• Timing sex in the peak days for conception increases the chance of conceiving by up to 75%

A menstrual cycle starts on the first day of the period and ends at the start of the next period (1). Tracking your menstrual cycle can help you time sex around ovulation, when an egg leaves an ovary (1, 2, 3). 

The day of ovulation and the five days before are the days during which you are most likely to conceive (4, 5, 1). Because sperm can live in the reproductive tract (vagina, uterus, fallopian tubes) for up to 3-5 days, having sex in the peak days for conception allows opportunity for sperm and egg to meet (6, 1). 

Timing sex isn’t absolutely necessary for conception. 

About 84-90% of people who have sex 2-3 times a week without using birth control will become pregnant within a year (7, 8). Sometimes, planning sex this often when trying to conceive can feel overwhelming or not work for you for other reasons (9). Predicting the peak days for conception can decrease the need to have sex as often (4, 9). 

Timing sex in the peak days for conception increases the chance of conceiving by as much as 75% each cycle (4). Most people who do this will become pregnant within about six cycles (10). Research shows that having sex during the two days before ovulation has the highest likelihood for pregnancy (11). 

This method requires menstrual cycles to have some predictability; there are roughly the same number of days between each period (1). Cycles that are fewer than 20 or more than 40 days make predicting the time during which you are most likely to conceive more difficult (1, 12). 

Ovulation is not perfectly predictable for anyone (13, 5). Having more or fewer days between cycles is common (14, 15). Even if a cycle typically has a predictable pattern, it is possible for ovulation or the peak days for conception to move a couple of days (13, 5). It’s important to remember this when trying to conceive.