Module 6 - Fetal Development Flashcards
Trimesters (4)
1) Development of a fetus is divided into three trimesters
2) First trimester - month 1-3
3) Second - 4-6
4) Third - 7-9
First trimester (4)
1) Body systems begin to develop
a) Nervous system
b) Cardiovascular system
2) Week 3: heart begins to beat
3) Week 6: Fetal heartbeat can be detected on ultrasound
4) Head shape is formed during this trimester but is disproportionately large
First Trimester: Neurulation (3)
1) Week 5: Formation of the neural tube from the outer folds of the ectoderm
2) Neural fold becomes the neural crest underneath the epidermis
3) Neural plate becomes the neural tube
Neural Tube Development (2)
1) Anterior neural tube becomes the brain
2) Rest of the neural tube forms brainstem and spinal cord
Spina Bifida (3)
1) Occurs if neurulation does not completely close the neural tube
2) Varying levels of sensory and/or motor disability
3) Depends on the region of malformation
4) It is recommended that pregnant mothers and females trying to conceive take supplemental folic acid to prevent neural tube defects
End of First Trimester (4)
1) End of week 8: Embryo called a fetus
2) Arms, legs begin to form
a) Fetus begins movement but is too small to be felt by the mother
3) Eyes, ears and nose begin formation, but not yet in correct location on head
4) Week 13: Fetus has moveable joints, fingers, toes
Second Trimester (3)
1) Eyes, ears, nose move to correct position on the face
2) Head, body grow to correct proportions
3) Week 16:
a) Eyes are developed enough to detect light and dark
b) Unique fingerprints develop
Second Trimester - Weeks 18-21 (4)
1) Fetal movement able to be detected by mother
2) Lanugo - fetal hair
a) Develops on the fetus’ body to help regulate body temperature
3) Develops sleep/wake cycles
4) Heart beats in a regulated pattern
Third trimester (5)
1) Continued development of systems already in place
2) Fetus increases in weight, fat develops under the skin
3) Males: testes descent into the scrotum
4) Week 32: Sucking reflexes begin to develop
5) Week 36: Lungs fully matured
Typical full term baby size
1) 19-22 inches long, 6-10 lbs
End of third trimester (2)
1) Usually around 40th week of pregnancy, but normal pregnancies vary from 38-42
2) Ends in birth through three stages:
a) Dilation of the cervix
b) Delivery of the baby
c) Delivery of the placenta
Dilation of the Cervix (stage 1) (5)
1) Time it takes for mother’s cervix to dilate to 10 cm
2) Uterus contracts, pushing baby’s head against cervix, causing dilation
3) Longest stage of labor, average is 6-10 hours
4) Oxytocin released from posterior pituitary stimulates contraction in the uterus
5) Contractions continue until baby is born (6-10 hours)
Delivery of the baby (5)
1) Time it takes for the baby to be pushed out of the birth canal
2) After full dilation has been accomplished
3) Mother uses abdominal muscles to aide uterine contractions to push baby through cervix and vagina
4) Time is much shorter
a) 50 minutes on average for first delivery
b) Shorter in later deliveries
5) Once baby is born umbilical cord is tied and cut
Delivery of the placenta (4)
1) Placenta is expelled from birth canal
2) Afterbirth
3) Normally occurs within 15 minutes after birth of child
4) Entire placenta needs to be delivered or removed or uterine bleeding continues
Delivery positions (3)
1) Typical is head first
2) Breech: buttocks first
3) Cesarean section: baby delivered through surgical incision in the abdominal and uterine walls
a) Used in many breech births or deliveries with complications
