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.
Per me using math... Divide 40 weeks of gestation by 3 = 13.33 per trimester! Week 1 to 13.33 weeks is 1st Trimester. 13.34 weeks to 26.67 weeks is 2nd Trimester and 26.68 to 40.00 Weeks is 3rd Trimester.