Prenatal Development Flashcards
Length of human gestation
- 38 weeks from conception to birth
- 0 weeks = conception
- 40 weeks from pregnancy to birth
Three stages of development
- zygote
- embryo
- fetus
how many weeks is the zygote stage
0 - 2 weeks
how many weeks is the embryo stage
3 - 8 weeks
how many weeks is the fetus stage
9 - 38 weeks
when do you start counting a pregnancy
when last week of menstrual period start counting pregnancy 2 weeks before conceptions
What happens during the zygote/germinal stage
- conception
- gametes meet
- massive cell division
- potential twins
what happens during embryo stage
- stage of most rapid development
- most vulnerabilty
- cell differentation
- placenta and amniotic fluid exhange of nutrients/waste through semi-permeable membrane
What happens at 4 weeks of embryo stage
heartbeat
what happens at 5-6 weeks of embryo stage
- rapid brain development
- movement begins
What happens at 9 weeks of fetal stage
- all internal organs present
- tactile stimulation –> responsive to touch
what happens at 10 - 12 weeks of fetal stage
- heart and brain structure
- “breathing,” grasping, swallowing, sucking
what happens at 16 - 20 weeks of fetal stage
movement felt by mother
what happens at 28 weeks of fetal stage
- may survive on own if born
- external sounds
- sight –> shine a light on mother’s abdomen and get a response from fetus
taste and smell of fetus
- preference persist postnatally
- scent of amniotic fluid
what happens at 25 - 28 week of fetal stage
- hearing
- internal and external hearing
- habituation to repeated sound stimulus
- HR/pulse increase to new sounds
- HR/pulse decreased to repeated sounds
Anise Study & Carrot Juice Experiment
- mothers who had consumed carrot juice during pregnancy lead to infant liking taste of carrot juice
- mothers who had not consumed carrot juice during pregnancy lead to infants not liking the taste of carrot juice
fetuses and neonates prefer
- mother’s voice
- mother’s language
Non-nutritive sucking
- fetus’s heart rate measured for nutritive response
- sound delievered through headphones
- operantly conditioned to suck faster for mom’s voice
Cat in the Hat Study
- mother reads the cat in the hat before birth
- infants tested soon after birth on Cat in the Hat vs. another rhyming story
- variation on NNS/HAS ti measure preference
Results of Cat in the Hat Study
- for infants who had heard the cat in the hat prenatally, they sucked in the right pattern to hear it (non-nutritive sucking technique)
- controls showed no difference –> trained to suck slower for rhymes never heard before (other story)
Teratogens
agents that cause harm during prenatal development
factors that influence severity of effect
- dose
- genetic predisposition of baby and mother
- combinations
- age/timing (sensitive periods in prenatal development)
