FETAL DEVELOPMENT 1 ST TRIMESTER First Trimester The

FETAL DEVELOPMENT 1 ST TRIMESTER First Trimester The first 3 months of pregnancy is a critical time. It is a period of rapid growth and development. By the end of the 1 st trimester, all of the organs will be formed and functioning. Day 1 The sperm and ovum unite Day 7 -10 The fertilized ovum attaches to the lining of the uterus. The placenta begins to form. 2 weeks The baby, called an embryo, is now a layered disc on the uterus wall. A woman will miss her menstrual period. 4 weeks The beginning of the embryo’s eyes, ears, nose, spine, digestive tract and nervous system are present. The tube for the future heart starts beating. 8 weeks The embryo, now called a fetus has all the organs a full term baby will have. The heart is functioning. Bones begin to form. 12 weeks Tooth buds are present. Fingernails and toe nails are forming. Immature kidneys secret urine into the bladder. External genitalia are forming. The fetus can now move in the amniotic fluid but these movements cannot be felt. The heartbeat may be heard using ultrasound equipment. Province of British Columbia. (2012). Baby’s best chance: parents’ handbook of pregnancy and baby care. Ministry of Healthy Living and Sport. Victoria: BC. Illustrations from Government of Canada. (2011). The sensible guide to pregnancy. Retrieved from: http: //www. phac-aspc. gc. ca/hp-gs/pdf/hpguide-eng. pdf © 2015 teachingsexualhealth. ca