Your little embryo is 1/16-1/18 of an inch long from crown to rump this week! Right now, baby is made up of three layers, the ectoderm, mesoderm and endoderm. The ectoderm will develop into baby’s brain, spinal cord, nerves, vertebra, skin, hair, nails, mammary and sweat glands and tooth enamel. The mesoderm will develop into your baby’s heart and circulatory system, muscles, cartilage, bone and subcutaneous tissue. The innermost layer, the endoderm will develop into baby’s lungs, intestines, urinary system, thyroid, liver and pancreas. Mom may begin to have some symptoms this week, common in the first trimester. The most frequent are sore or tender breasts, fatigue, frequent urination and nausea.
This week, baby is about the size of a Sesame Seed!