How do you know if and how long have you been pregnant?

Early symptoms, pregnancy tests, ultrasound and estimating how far along you are based on your menstrual cycle are all possible ways to find out

Most individuals determine that they are pregnant if they are sexually active and have missed a period. Nausea, breast soreness and fatigue are also common symptoms in early pregnancy. Ultrasound or pregnancy tests are the only ways to immediately be sure that you are pregnant.

You can do a pregnancy test from the first day of your missed period. Before that, the level of hormones produced by the pregnancy is too low to show up on the test and the test might give you a false negative.

If you do an ultrasound, the doctor can tell you exactly how long you have been pregnant. A pregnancy test is not as accurate. The ultrasound, however, will only show the pregnancy from about a week after you missed your expected period.

You can make an approximate calculation of how long you have been pregnant by calculating from the first day of your last menstrual period (LMP) to the present. You can also use our pregnancy calculator here.

The calculation of the pregnancy length (from LMP) is less secure if you have had irregular menstruation during the last 3 months before getting pregnant, during breastfeeding, and while using hormonal contraceptives like oral contraceptive pill/ -patch / -ring, injection, implant, hormonal IUD. In those cases it is advised to have an ultrasound.

More information:

Research has shown that individuals can calculate the length of their pregnancy by themselves. In a study conducted by C. Ellertson et al., out of 100 individuals, 98 in the U.S. and 87 in India were able to estimate how long they had been pregnant. Everyone was given calendars and worksheets to help them with their calculations. Approximately 9 out of 10 persons could estimate the lengths of their pregnancies accurately enough to use Mifepristone and Misoprostol on their own. The researchers concluded: “The vast majority of women seeking first-trimester abortion in this study could accurately calculate pregnancy duration within a margin of error clinically inconsequential for safe use of unsupervised medical abortion.” Most of the estimates were within 1 week of the actual length of their pregnancy.