Hi guys, Dr Nana K here. Once again. Now a lot of people have been asking me exactly what's the rationale behind how we calculate the fertile window. So just a little explanation. All right. So usually, a man's sperm can survive for about 5 days inside a woman's body before it dies. What that means is that if you have sex today, a man's sperm can survive for the next five days. So if you overlay to the next five days, there's a high chance of you getting pregnant. 

All right, now immediately after sex, it can take between 30 minutes to up to 12 hours for the sperm to reach the tube where the egg is released. And normally when a woman releases an egg, it lasts for 12 to 24 hours at the most. Okay, so that is why after the day of ovulation, we say that day and the next day is the woman's fertile period. Now, sometimes we add an extra day to the day because maybe sometimes you may ovulate a day later, and there's no way to be very very sure that the woman exactly ovulated on that day.  So once the sperm can reach the Fallopian tubes, then it's able to fertilize the egg and then after that, the fertilized egg travels into the womb for it to be implanted to develop into pregnancy.  

So if you're trying to get pregnant, don't be worried if it doesn't happen straight away. Okay. I know it's a bit challenging sometimes but it may take up to a year for most couples to get pregnant. But if you're over the age of 35 when you've been trying for six months or longer to get pregnant and it's not coming, please see a doctor. Please see a gynecologist.  You have to make sure that you're having at least sex at least three times a week. That's what's recommended for most people and then sometimes after having sex, make sure you lie down for about 15 minutes. Don't be in a hurry to get up to go and use the bathroom or anything like that. 

Also, try and avoid using any lubricants that may damage the sperm that the man releases inside. So don't worry, be relaxed when you're too anxious normally pregnancies don't come. All right, so, this is just how we calculate the fertile periods.