“If you’ve confirmed that you’re pregnant by either missing your menstrual period or having a home pregnancy test and you go in to see your doctor, your doctor will likely confirm your pregnancy with another urine pregnancy test that potentially is more accurate than the pharmacy and/or a blood test that will detect pregnancy hormone in your blood. And it’s important at that stage to know when your last menstrual period was. So if you’re trying to get pregnant, it’s really important to be tracking your menstrual periods so that you know the first day of your last menstrual period, because that’s like looking back in time. And sometimes we forget that. So if it’s tracked on the calendar the first day of every menstrual period, your healthcare provider will be able to look back and say, that’s the first day of your last menstrual period. Therefore, the embryo that is now potentially growing is a certain age or stage.
And that’s the best way for us to tell the age or stage of the growing baby, which at this phase is called an embryo. Now the first trimester lasts about 14 weeks. And another thing your healthcare provider may do, if you’re uncertain of your dates, or he or she wants to confirm the gestational age or the age of that embryo, they may order what’s called a dating ultrasound. Now a dating ultrasound is done specifically to determine the length or the size of that growing embryo and compare it or cross reference it with your menstrual period that lasts the first day of your last menstrual period. And putting those pieces together, determine exactly how old or big or what the gestational age is of that growing embryo, and that will be added to determine when your due date is.”