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.
Hereâs what you need to know about how many weeks, months and trimesters there are in a pregnancyâand where you fit in. There are 40 weeks (or 280 days) in a pregnancy, starting from the first day of your last menstrual period. Keep in mind, however, that only about 30 percent of pregnancies last 40 weeks.