MILESTONES OF FETAL GROWTH AND DEVELOPMENT Flashcards
length of the embryo is about 0.75 cm, weight is about 400 grams
spinal cord is formed and fused at the midpoint
head is large in proportion and represents about ⅓ of the entire structure
rudimentary heart appears as a prominent bulge on the anterior surface
arms and legs are bud-like structures
rudimentary eyes, ears, and nose are discernible
i. end of 4th gestational week
length of the fetus is about 2.5 cm (1 inch), weighs about 20g
organogenesis is complete
heart with septum and valves beats rhythmically
facial features are discernible + legs and arms have developed
external genitalia are forming but sex is still indistinguishable
abdomen bulges forward because the fetal intestine grows so rapidly
sonogram shows a gestational sac, which is diagnostic of pregnancy
urine secretion begins but may not yet be evident in amniotic fluid
heartbeat is audible through doppler instruments
ii. end of 8th gestational week
length of fetus is 10-17 cm, weight is 55-120 grams
fetal heart sounds are audible using ordinary stethoscope
lanugo is well-formed
both the liver and pancreas are functioning; fetus actively swallows amniotic fluid, demonstrating an intact but uncoordinated swallowing reflex
urine is present in amniotic fluid
sex can now be determined thru an ultrasound
iii. end of 16th gestational week
length is 25 cm and weighs about 223 grams
spontaneous fetal movements can be felt by the mother; antibody production is possible; hair, including eyebrows, forms on the head + venix caseosa begins to cover the skin
meconium is present in the upper intestine
special fat that aids in temperature regulation begins to form behind the kidneys, sternum, and posterior neck
passive antibody transfer from the mother to the fetus begins
definite sleeping and activity pattern are distinguishable as the fetus develops biorhythms that will guide sleep/wake patterns throughout life
iv. end of 20th gestational week
length of fetus is 28-36 cm, weighs 550g
meconium is present in as far as the rectum
active production of lung surfactant begins
eyelids, previously fused since the 12th week, now opens
hearing can be demonstrated by response to sudden sound
v. end of 24th gestational wee
length of fetus is 35-38 cm, weighs 1,200g
lung alveoli are almost mature, surfactant can be demonstrated in amniotic fluid
testes begin to descend into the scrotal sac from the lower abdominal cavity
blood vessels of the retina are formed by thin and extremely susceptible to damage from high oxygen concentrations (important consideration when caring for preterm infant)
vi. end of 28th gestational week
length is 38-43cm, weighs 1,600 g
subcutaneous fats begin to be deposited
fetus responds by movement to sounds outside the mother’s body
active Moro reflex (natural reaction of a baby when startled) is present;
iron stores are beginning to be built
fingernails reach the end of the fingertips
vii. end of 32nd gestational week
length of fetus is 42-48 cm, weight is 1,800g
body stores of glycogen, carbohydrates, iron, and calcium are deposited
sole of the foot has only one or two crisscross creases compared with a full crisscross pattern evident at term
amount of lanugo begins to diminish
most fetuses turn into a vertex (head down) presentation during this month
viii. end of 36th gestational week
length of the fetus is 48-52 cm, weighs 3,000g (7-7.5lbs)
fetus kicks actively, sometimes hard enough to cause the mother discomfort
fetal hemoglobin begins its conversion to adult hemoglobin
<SIDE NOTE: LIGHTENING: the fetus settles on the pelvic bone, relieving the mother of some of the fetus’s weight>
ix. end of 40th gestational week
