Symptoms may not start for 6 to 12 hours after exposure to the ultraviolet light. Symptoms include: 1  A feeling that something is in the eyes (foreign body sensation). 2  Sensitivity to light (photophobia). 3  Tearing.
It is divided into three stages, called trimesters: first trimester, second trimester, and third trimester. Conception to about the 12th week of pregnancy marks the first trimester. The second trimester is weeks 13 to 27, and the third trimester starts about 28 weeks and lasts until birth.
The First Trimester (Weeks 1-13) The first trimester is typically the shortest for you, because the first 3-4 weeks or more of your pregnancy, you do not even know you are pregnant. In fact, weeks 1-2 are the week of your last normal menstrual period, and when you ovulate. Most mothers won't be able to take a pregnancy test until around week four, and some are even later than that. This first trimester sees an incredible shift in your baby.