Pregnancy occurs when an egg is fertilized by a sperm after being released from the ovary when ovulation is occuring. Signs and symptoms of pregnancy can consists of a missed period, spotting, cramps, back pain, heartburn, constipation, vomiting, and many other sick-like symptoms. A pregnancy that is full term is a pregnancy that last 40 weeks. Any baby that is born before 37 weeks is considered premature. Ways to find out if you are pregnant would be to take a pregnancy urine test or blood test. Blood test can confirm a pregnancy earlier than a urine test. Pregnancy consists of 3 trimesters. Week 1-12 is the first trimester. Week 13-36 would be the second, and 27 and up would be the third trimester. The most essential trimester of pregnancy is the first trimester because all of the fetus's functions start to form. For example, the brain, spinal cord, organs, and limbs develop.