How do doctors determine the day you concieved?

There are a few different ways that doctors can determine the day you conceived.

* Last menstrual period (LMP). This is the first day of your last menstrual period. It's important to note that this is not the same as the day you ovulated. Ovulation typically occurs 14 days before the start of your next menstrual period.

* Ultrasound. An ultrasound can be used to measure the size of the fetus and determine how far along you are in your pregnancy. This can help to pinpoint the day of conception.

* Blood test. A blood test can be used to measure the levels of certain hormones, such as progesterone, that can help to determine how far along you are in your pregnancy. This can also help to pinpoint the day of conception.

In most cases, doctors will use a combination of these methods to determine the day you conceived. This can be important information for a variety of reasons, such as planning for your pregnancy or making decisions about prenatal care.