Most of the time, you wont know the exact day you got pregnant. Your doctor will count the start of your pregnancy from the first day of your last menstrual period. Thats about 2 weeks ahead of when conception happens.

Why do doctors add 2 weeks on to pregnancy?

If your period is regular and lasts 28 days, and if ovulation generally happens on day 14 of your cycle, then conception probably took place about two weeks after the LMP. For gestational age counting, these two weeks are added to a pregnancy as a simpler method than trying to track from ovulation or fertilization.

How can I tell who the father of my baby is during pregnancy?

The first is non-invasive prenatal paternity testing, which involves sampling the DNA in your blood. This is then compared to DNA from a cheek swab taken from each potential dad. It can be carried out from seven weeks of pregnancy. The second is invasive prenatal paternity testing.

How do I know who the father of my baby is?

A DNA paternity test is nearly 100% accurate at determining whether a man is another persons biological father. DNA tests can use cheek swabs or blood tests. You must have the test done in a medical setting if you need results for legal reasons. Prenatal paternity tests can determine fatherhood during pregnancy.