Usually the day of ovulation is 14 days before the expected period date. Now if the period is regular then around 14 day ovulation happen and sexual activity at that point of time helps in increasing the chances of pregnancy. One day before the period in a regular cycle it is almost impossible to get pregnant, but when the cycles are irregular then when you are expecting a period on 20th she may get her period on 30th or next month fifth or fifteen days later or 20 days later. In such a case one day before the expected date of period if you have sex there are high chances of getting pregnant because the date we do not know and we do not know the 14th day prior to the period date expected. Hence she would ovulate at any point of time. So we are not able to clearly know the date of ovulation and hence the chances of pregnancy.

свернуть