Sources of indoor pollution include. 1  Mold and pollen. 2  Tobacco smoke. 3  Household products and pesticides. 4  Gases such as radon and carbon monoxide. 5  Materials used in the building such as asbestos, formaldehyde and lead.
After conception, your baby begins a period of dramatic change known as the embryonic stage. This stage runs from the 5th through the 10th week of the first trimester of pregnancy. During this stage, the baby is called an embryo. Your babyâs penis or vagina is visible at the end of the embryonic period, but it's not yet possible to tell on an ultrasound if your baby is a girl or a boy. 2  Muscles and movement. 3  Muscles develop and the embryo begins to move.
Within three weeks, the blastocyte cells ultimately form a little ball, or an embryo, and the baby's first nerve cells have already formed. Your developing baby is called an embryo from the moment of conception to the eighth week of pregnancy.y the end of the second month, your baby is about 1 inch long and weighs about 1/30 of an ounce. At about 6 weeks, your baby's heart beat can usually be detected. After the 8th week, your baby is called a fetus instead of an embryo. Month 3. Your baby's arms, hands, fingers, feet, and toes are fully formed.