Many of the most dramatic prenatal developments occur during the first couple weeks of pregnancy There are three periods of prenatal development these are NOT the same as the trimesters 1 Period of the zygote begins with conception when the egg is fertilized in the fallopian tube until the newly merged sperm and egg are implanted in the uterine wall about 12 14 days post conception Once it sticks to the wall it is an embryo a The new mass of cells starts dividing quickly and quickly forms a little ball of cells known as blastocyst About 4 days after conception there should be 100 hollow cells in the blastocyst b The cells are totipotent meaning they contain a germ disk the cells that actually become the baby s body c Other germ disks go into the placenta the support structure 2 Period of the embryo begins just after implantation and continues until a recognizable organism has formed about 8 weeks a There are three layers of pluripotent undifferentiated cells meaning they could be any part of the embryo Ectoderm becomes hair skin and nervous system innermost Mesoderm becomes hair and bones middle Endoderm becomes lungs and digestive system innermost b Eventually they become differentiated unipotent meaning they specialized in one type of cell not many c The embryo grows inside out proximodistal and head to toe cephalocaudal which is why the head is so fucking big 3 Period of the fetus begins at 9 weeks once all major organs are fully formed a The placenta has differentiated into the chorionic villi which separates the mother s blood from the babies blood the umbilical cord which connects the fetus to the placenta and the amniotic sac a salt water bag that cushions the baby from harm b Placental barrier is where all food nutrients and toxins pass through c Cerebral cortex fingernails and sex specific parts d Fetus is covered in a waxy substance called vernix which prevents the fetus 1 Amniotic sac breaking water breaking only in 20 of cases and fecal matter happens from chapping ABC s of childbirth with it 2 Blood around the vagina 3 Contractions Stages of childbirth 1 Stage 1 12 24 hours is the contraction period where we need to get contractions to 10 cm 2 Stage 2 1 hour is the actual childbirth This is most risky if the placenta detaches before the birth it can choke the baby leading to anoxia lack of oxygen and a 20 chance of c section occurs here 3 Stage 3 10 15 min is the afterbirth which is short but necessary where the baby support structure is ejected Many diseases AIDS syphilis Rubella genital herpes etc that target the placenta and the heart so if the mom has it the child might Amniocentesis where fluid is tested from amniotic sac to make sure baby is health CVS where blood is tested from chorionic villi to make sure baby is healthy Ultrasound sound waves to see what it looks like APGAR appearance pulse grimace reflex activity and respiration an after birth test on a scale of 0 2 for five categories 1 Appearance we are looking for a healthy baby that is pink all over 2 Pulse should be over 120 3 Grimace baby should cry 4 Activity want a baby who is moving 5 Respiration baby should be breathing Rooting reflex Sucking reflex Blink reflex Pupillary reflex Palmar grip reflex Moro reflex Babinski reflex Stepping reflex babies turn their head to the nipple if you stroke their cheek babies suck on nipple babies blink if you shine bright light babies pupils dilate babies hold to anything you place in their hands babies throw their hands to catch stuff babies spread toes when bottom of foot is stroked babies try to step forward if held above the floor Teratogens anything that puts newborn at risk when consumed by pregnant women They are time and dose dependent Any alcohol is going to have some small effect on the baby Lots of damage is done during the 3 8 week period after that not so much 1 in 7 women report risk drinking during pregnancy drinking more than 7 times a week Three other risks 1 Stress 2 Low birth weight 3 Age of mother Maternal stress can lead to premature births This is not cause for concern on it s own but when paired with a low birth weight it can be scary and they are at greater risk for stuff like sudden infant death syndrome which while unknown in cause occurs more when babies are asleep face down 6 months 10 inches eyes formed taste buds can inhale and cry can t live 7 months viable but breathing is shallow 7 months to birth living is possible breathing is better How teratogens influence development 1 Depends on the genotype 2 Influence changes over development 3 Affects specific aspects of development Pregnant mothers should increase eating by 10 20 and they should expect to gain 25 30 pounds baby fat more blood Right before labor a week or so the baby starts dropping We might see false contractions which is the body essentially practicing for real labor We might also see vaginal discharge losing a few pounds a dull backache loose bowel movements or nesting a sudden burst of energy before labor