Gestational Week Flashcards
The length of the embryo is about 0.75 cm; weight is about 400 mg.
The spinal cord is formed and fused at the
midpoint.
The head is large in proportion and represents about one third of the entire structure.
4th
The 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.
4th
The length of the fetus is about 2.5 cm (1 in.); weight is about 20 g.
Organogenesis is complete
The heart, with a septum and valves, beats rhythmically.
8th
Facial features are definitely discernible; arms and legs have developed
External genitalia are forming, but sex is not yet distinguishable by simple observation.
The abdomen bulges forward because the fetal intestine is growing so rapidly
8th
The length of the fetus is 7 to 8 cm; weight is about 45 g.
Nail beds are forming on fingers and toes.
Spontaneous movements are possible, although they are usually too faint to felt by the mother.
Some reflexes, such as the Babinski reflex, are present.
12th (first trimester)
Bone ossification centers begin to form.
Tooth buds are present.
Sex is distinguishable on outward appearance.
Urine secretion begins but may not yet be evident in amniotic fluid.
The heartbeat is audible through Doppler technology.
12th (first tri)
The length of the fetus is 10 to 17 cm; weight is 55 to 120 g.
Fetal heart sounds are audible by an ordinary stethoscope.
Lanugo is well formed.
16th
Both the liver and pancreas are functioning
The fetus actively swallows amniotic fluid, demonstrating an intact but uncoordinated swallowing reflex; urine is present in amniotic fluid.
Sex can be determined by ultrasonography.
16th
The length of the fetus is 25 cm; weight is
223 g.
Spontaneous fetal movements can be sensed by the mother
Antibody production is possible.
Hair, including eyebrows, forms on the head; vernix caseosa begins to cover the skin.
Meconium is present in the upper intestine.
20th
Brown fat, a special fat that aids in temperature regulation, begins to form behind the kidneys, sternum, and posterior neck.
Passive antibody transfer from mother to fetus begins.
Definite sleeping and activity patterns are distinguishable as the fetus develops
biorhythms that will guide sleep/wake patterns throughout life.
20th
The length of the fetus is 28 to 36 cm; weight is 550 g.
Meconium is present as far as the rectum.
Active production of lung surfactant begins.
Eyelids, previously fused since the 12th week, now open; pupils react to light.
24th(second trimester)
Hearing can be demonstrated by response to sudden sound.
When fetuses reach 24 weeks, or 500 to 600 g, they have achieved a practical low-end age of viability if they are cared for after birth in a modern intensive care nursery.
24th (second tri)
The length of the fetus is 35 to 38 cm; weight is 1,200 g.
Lung alveoli are almost mature; surfactant can be demonstrated in amniotic fluid.
28th
Testes begin to descend into the scrotal sac from the lower abdominal cavity.
The blood vessels of the retina are formed but thin and extremely susceptible to damage from high oxygen concentrations (an important consideration when caring for preterm infants who need oxygen).
28th
The length of the fetus is 38 to 43 cm: weight is 1.600 g.
Subcutaneous fat begins to be deposited in the former stringy. “little old man” appearance is lost).
Fetus responds by morement to sounds outside the mother’s body.
32nd
An active Moro reflex is present.
Iron stores. which provide iron for the time during which the neonate will ingest only breast milk after birth, are beginning to be
Fingernails reach the end of fingertips.
32nd
The length of the fetus is 42 to 48 cm; weight is 1,800 to 2,700 g (5 to 6 1b).
Body stores of glycogen, iron, carbohydrate, and calcium are deposited
Additional amounts of subcutaneous fat are deposited
36th
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
36th
The length of the fetus is 48 to 52 cm (crown to rump, 35 to 37 cm); weight is 3,000 g (7 to 7.516).
Fetus kicks actively, sometimes hard enough to cause the mother considerable discomfort.
Fetal hemoglobin begins its conversion to adult hemoglobin.
Vernix caseosa starts to decrease after the infant reaches 37 weeks gestation and may be more apparent in the creases than the covering of the body as the infant approaches 40 weeks or more gestational age.
40th(third trimester)
Fingernails extend over the fingertips.
Creases on the soles of the feet cover at least two thirds of the surface.
In primiparas (ie, women having their first baby), the fetus often sinks into the birth canal during the last 2 weeks of pregnancy. giving the mother a feeling the load she is carrying is less. This event, termed lightening, is a fetal announcement that the fetus is in a ready position and birth is nearing.
40th(third tri)
