Conception Day Calculator

How do I calculate when I got pregnant?

Simply enter the date of the first day of your last period to calculate when ovulation may have occurred. The system uses a 28-day menstrual cycle to make the estimates. If your menstrual cycle is very different the result will not be reliable.

Is it possible to know the exact day of fertilization?

If your question is “when did I get pregnant?” know that it is not possible to say exactly on what day the fertilization occurred. This is because the fertile period is relatively long. As the sperm can survive for up to 5 days, sexual intercourse 5 days before ovulating can produce a pregnancy. The egg is viable for about 24 hours, so it is possible to get pregnant up to one day after ovulation.

In addition, women ovulate APPROXIMATELY 14 days after menstruation, when the cycle is 28 days. If the cycle is longer or less, ovulation may occur before or after. So it is difficult to say the exact day of fertilization, but it is possible to have an idea.

To be as accurate as possible, use in our calculation the same method that your doctor uses to calculate your gestational age, be it the date of the last menstruation, the probable date of delivery or the gestational age estimated by your first ultrasound exam.

How long after the relationship does the conception occur?

Between intercourse and conception there is an interval of about 24 hours. That is, the sperm can take about 1 day to find the egg and fertilize it.

How to find out the date of conception by ultrasound?

Knowing the gestational age, just subtract two weeks and you will have the number of weeks in which the conception occurred. To avoid having to do the calculations in your head, just put the date on which the exam was performed and the gestational age estimated on our calculator. We recommend that you also read our post on how to calculate gestational age.

How do I know who my child’s father is?

If you had a relationship with two different people during your fertile period, it is not possible to determine clinically precisely who the child’s father is. In case of doubt, talk to your doctor about the paternity test that can be performed after the child’s birth.

Can the paternity test be done during pregnancy?

Collecting material for the paternity test can put your baby at risk. Following the opinion of CREMESP we recommend that the collection be made only after birth.