PRENATAL DEVELOPMENT (Conception – Birth)

CONCEPTION

FIRST MONTH OF PREGNANCY – Fertilisation occurs Zygote plants itself in the lining of the uterus Rapid cell division occurs Embryonic stage lasts from 2 weeks to 8 weeks Nervous systems begins to develop Embryo is ½ inch long

SECOND MONTH OF PREGNANCY – Heart and blood vessels form Head area develops rapidly Eyes begin to form detail Internal organs grow, especially the digestive system Sex organs develop rapidly and gender is distinguished Arms and legs form and grow Heart begins to beat faintly Embryo is 1 inch long and weighs 1/10 ounce

THIRD MONTH OF PREGNANCY – Head growth occurs rapidly Bone formation begins to grow rapidly The digestive organs begin to function Arms, legs and fingers make spontaneous movements Foetus is 3 inches long and weighs 1 ounce

FOUR MONTHS OF PREGNANCY – Lower parts of the body show rapid growth Bones are distinct in X-Rays Reflex movement becomes more active Heartbeat detected by physician Sex organs are fully formed Foetus is 7 inches long and weighs 5 ounces

FIFTH MONTH OF PREGNANCY – Mother begins to feel reflex movement A fine, downy fuzz covers the entire body Ears and nose begin to develop cartilage Fingernails and toenails begin to grow Foetus performs thumb sucking, kicking and hiccups Foetus is 14 inches long and weighs 12 ounces

SIXTH MONTH OF PREGNANCY – Eyes and eyelids fully formed Fat is developed under the skin Foetus is 14 inches long and weighs 2 pounds

SEVENTH MONTH OF PREGNANCY – Cerebral cortex of brain develops rapidly Vernix is present over the entire body Foetus is 17 inches long and weighs 3 pounds

EIGHTH MONTH OF PREGNANCY – Fingernails reach beyond the fingertips Foetus is 17 inches long and weighs 5 pounds

NINTH MONTH OF PREGNANCY – Organ systems function actively Foetus settles into position, ready for birth Neonate is 21 inches long and weighs 7 pounds

ULTRA SOUND

GERMINAL STAGE – Begins from conception to the implantation of the zygote The zygote moves towards the uterus due to the contraction of the lining and the movement of cilia in the fallopian tube The zygote divides through the process of mitosis A mass of cells (morula) enters the uterus and the cells begin to specialise into brain, spinal cord, etc A mass of cells (blastocyst) moves around the uetrus for two to four days and then becomes attached to the uterine lining (endometrium) The blastocyst produces enzymes that digest a small section of the endometirum and facilitates implantation The hormone progesterone softens the endometium and allows the blastocyst to implant

EMBRYONIC STAGE – From week 4 to week 10 Main body structures begin to form through differentiation and specialisation of cells Placenta is formed for the exchange of nutrients, oxygen and waste products. The placenta also produces hormones that maintain the pregnancy The embryonic period is when there is greatest susceptibility to teratogens Nervous system, heart and kidneys form Spine and eye sockets form, followed by face and limbs Brain and spinal cord development continues and limb buds form Heart starts to pump blood, circulating it through out the babies body Stomach and kidneys start functioning Cartilage begins to develop All main organs are formed by week 10

FOETAL DEVELOPMENT – From week 11 to week 40 Rapid growth and development of the body organs and systems that have been formed during the embryonic period Increases in sized and complexity of body systems Brains growth continues In males, the testes descend Fat is deposited under the skin Nutrients stores increase Activity levels decrease as the growing foetus takes up space Lung development increases Iron is stored in the liver The head moves down into position ready for birth

FunctionMaternal/Foetal System Temperature control Placenta – heat can be exchanged between the mother and the foetus via the bloodstream Umbilical cord – transport blood into the foetus Amnion – The amniotic fluid completely surrounds the baby. It acts as a controlled temperature regulator Respiration Placenta – exchange for respiratory gases. Oxygen defuses from the maternal circulatory system across the membranes into the foetal circulatory system Umbilical Cord – transports oxygenated blood from placenta to foetus Excretion Placenta – foetal wastes of carbon dioxide and nitrogenous wastes move in a concentrated form across the membranes into the maternal blood where they will be processed and excreted Umbilical Cord – transports wastes to the capillary network in the placenta Amnion – The amnion moves in and out of the foetus’ lungs. The foetus urinates small amounts into the amnion FUNCTIONS OF THE FOETAL SYSTEMS –

Lifespan StageImportant Nutrients FunctionsFood Sources Prenatal Protein Calcium Folate Iron Vitamin A Vitamin C B group vitamins Protein – growth of foetal and maternal tissue Calcium – Foetal skeletal formation Iron – red blood cells for extra maternal and foetal blood Vitamin A – development of bones, teeth and good vision Vitamin C – formation of collagen Folate – DNA synthesis B Group Vitamins – energy release for growth Protein – meats, eggs, dairy products, soy Calcium – dairy Iron – red meats, legumes Folate – green leafy vegetables Vitamin A – dairy, green leafy vegetables NUTRITONAL REQUIRMENTS IN PRENATAL STAGE -