The day 28 thing over ovulation was a definite mistake originally had a day 21 column. The Thomson Reuters Trust Principles. The ultra sound showed heart activity, so I am guessing that it is normal?!? This is very obviously incorrect but people are buying it. The Arizona legislature used this method of dating as a definition, deliberately ignoring that they should have used gestational age as the definition.
In cases where the date of conception is known precisely, such as with in vitro fertilization, the EDD is calculated by adding days to the date of conception.
Due Date Calculator
The gestational age would, therefore, be at least 3 to 4 weeks at the time of a reliable hCG pregnancy test. Int J Gynaecol Obstet. Find Your Due Date. Implantation happens days after conception, which would mean that conception would have taken place between the 11th and 14th. Chorionic gonadotropin secretion by human embryos in vitro. But even if you're one of the lucky ones who's able to get pregnant when she really wants to, just remember that you probably won't be able to map out exactly when you'll give birth to the day or even the week or month!