SAS#9 Flashcards
measured from the time
of ovulation
OVULATION AGE
▪Length of pregnancy- from 1st day of LMP
(gestational age)
•Ovulation age & gestational age measured
in
lunar months (4-week periods) or
trimesters (3-month periods
•Pregnancy =
10 lunar months (40 weeks or
280 days)
•Fetus grows in utero for
9.5 lunar months
or 3 full trimesters (38 weeks or 266 days)
▪ Length: 0.75 to 1 cm
▪ Weight: 400 mg
▪ Spinal cord formed & fused at midpoint
▪ Lateral wings forming body are folded forward to fuse at
midline
▪ Head folds forward, prominent, 1/3 of entire structure
▪ Back is bent so head almost touches tip of tail
▪ Rudimentary heart bulges on anterior surface
▪ Arm and leg buds
▪ Rudimentary eyes, ears, nose are discernible
END OF 4TH GESTATIONAL WEEK
▪ Length: 1 inch
▪Weight: 20g
▪ Organogenesis complete
▪Heart, with septum & valves, beats
▪Discernible facial features
▪Arms and legs developed
▪ External genitalia present but cant be discerned by
simple observation
▪ Primitive tail regressing
▪Abdomen is large because fetal intestines are growing
rapidly
▪ UTZ shows gestational sac (diagnostic of pregnancy)
▪END OF 8TH GESTATIONAL WEEK
•Length: 7 to 8 cm
•Weight: 45 g
•Nail beds on fingers & toes forming
•Spontaneous movements possible but too
faint to be felt
•Some reflexes present like the Babinski reflex
•END OF 12TH GESTATIONAL WEEK
(1ST TRIMESTER)
•Bone ossification centers forming
•Tooth buds present
•Sex distinguishable by outward
appearance
•Kidney secretion begins but urine not
yet evident in the amniotic fluid
•Heartbeat audible through DOPPLER
technology
•END OF 12TH GESTATIONAL WEEK
(1ST TRIMESTER)
▪ Length: 10 to 17 cm
▪Weight: 55 to 120 g
▪ Fetal heart sounds audible with ordinary
stethoscope
▪ LANUGO is well formed
▪ Liver & pancreas functioning
▪Actively swallows amniotic fluid demonstrating
intact though uncoordinated swallowing reflex
▪ Urine is present in amniotic fluid
▪ Sex can be determined by ultrasound
▪END OF 16TH GESTATIONAL WEEK
▪ Length: 25 cm
▪ Weight: 223 g
▪ Spontaneous movements felt by the mother
▪ Antibody production possible
▪ Hair forms, including eyebrows and hair on the head
▪ Meconium present in the upper intestine
▪ BROWN FAT, a special fat insulator deposits behind the
kidneys, sternum & posterior neck
▪ Vernix caseosa begins to form
▪ Definite sleep/wake patterns (developed biorhythms)
▪ END OF 20TH GESTATIONAL WEEK
▪ Length: 28 to 36 cm
▪ Weight: 550 g
▪ Passive ab transfer begins by 20th week, established by 24th
week
▪ Meconium present as far as the rectum
▪ Active production of lung surfactants begins
▪ Eyebrows/eyelashes well-defined
▪ Eyelids now open
▪ Pupils capable of reacting to light
▪ 24 weeks or 601 g- low-end age of viability if cared for in a
modern NICU
▪ Hearing can be demonstrated by response to sudden sound
▪ END OF 24TH GESTATIONAL WEEK (2ND
TRIMESTER)
•Length: 35 to 38 cm
•Weight: 1,200 g
•Lung alveoli begin to mature, surfactant
present in amniotic fluid
•Testes begin to descend in scrotal sac
from the lower abdominal cavity
•Blood vessels of retina are thin &
susceptible to damage from high O2
•END OF 28TH WEEK OF
GESTATION
▪ Length: 38 to 43 cm
▪Weight: 1,600 g
▪ Subcutaneous fat begins to be deposited( the
former stringy, “little old man” appearance is lost)
▪ Fetus responds by movement to sounds outside
mother’s body
▪Active Moro Reflex
▪ Birth position (breech or vertex) is assumed
▪ Fe stores beginning to be developed
▪ Fingernails grow to reach end of fingertips
▪END OF 32ND WEEK OF GESTATION
• Length: 42 TO 48 CM
•Weight: 1,800 to 2,700 g (5 to 6 lbs)
• Body stores of glycogen, Fe, CHO & Ca are deposited
•Additional amount of subcutaneous fat are deposited
• Sole of foot has only 1 or 2 crisscross creases (full
crisscross pattern at term)
• Lanugo begins to diminish
•Most babies turn into a vertex or head-down position
during this month
•END OF 36TH GESTATIONAL WEEK
