In theory, you are pregnant as soon as you conceive. Having said that, there is no certain way to determine when conception occurred, health practitioners date your pregnancy according to your last menstrual cycle. So, as discussed, in order to figure out the extent of your pregnancy, keep your last menstrual cycle in mind and then make calculations from there onwards. Your last menstrual period is the first day of your pregnancy.
Calculating your pregnancy week
Some women opt for calculating their pregnancy week in line with their time of ovulation, which is approximately two weeks after your last menstrual period. That tends to provide you with an estimate of the time of conception. However, we would suggest you to go with the former technique which is accepted universally by health practitioners despite the fact that it puts you ahead in your pregnancy by about a couple of weeks. This is to avoid obfuscation since it is important to standardize the pregnancy weeks as it has repercussions on any decisions that your obstetrician has to make during the time of delivery.
Irregular menstrual cycle
Now, what if you were suffering from irregular menstrual cycle and were not sure about your last menstrual period? If that is the case, then the above techniques would not work for you. Rather, your obstetrician can use an ultrasound scan to date your pregnancy which is also called as the dating scan. This is typically performed roughly ten to thirteen weeks and six days into pregnancy. The length of the baby is measured from the head to the bottom to figure out how pregnant you are in this scan. At this point in time, the growth of most of the babies tends to be the same and the difference between your actual pregnancy week and the date determined through an ultrasound scan is generally one to two weeks. This difference increases after the first trimester when babies grow at varying rates. So, any date scanning performed after than period would not be considered correct.