Repro: Fetal growth and development Flashcards
What is the purpose of the fetal period?
Growth and physiological maturation of the structures created during the embryonic period. Preparing the fetus for independent life after birth
How does the composition of the fetus change throughout pregnancy?
Embryo - very little weight gain, placental growth most significant
Early fetus - protein deposition
Late fetus - adipose deposition for body temp regulation
How can fetal wellbeing be assessed?
Mothers recalling fetal movement, gets to learn patter
Measuring symphysis-fundal height
Ultrasound scan
What is the purpose of the 12 and 20 week ultrasound scans?
12 week scan - used to calculate age, rule out ectopic and count the number of fetuses, can mearure HR (bradycardia sign of imminent death)
20 week scan - assess fetal growth, look for abnormailities (all major body systems present), determine the sex of the baby
How can the pregnancy be dated?
Biparietal diameter - the distance between the parietal bones. Used in T2 and 3
Abdo circumference and fetal length
What are some general reasons for a low birth weight?
- they are premature
- they are just small
- they have suffered growth restriction (increased risk of morbidity and mortality)
How does the respiratory system develop during the fetal period?
The embryonic period only develops the bronchopulmonary tree so functional specialisation occurs in the fetal period.
week 8-16: bronchioles being to form
16-26: budding from the bronchioles however still no gas exchange membrane
26-term: terminal alveoli begin to bud. Differentiation of type 1 and 2 pneumocytes so surfactant produced
How does the fetus prepare the breathe independently?
The fetus practices breathing movement to condition the respiratory musculature.
The lungs are fluid filled which is crucial for normal development - amniotic fluid contains growth factors
At what stage is the fetus viable?
When the lungs have entered the terminal sac stage of development >24 weeks
What is respiratory distress syndrome?
Occurs in premature babies where there is inadequate surfactant production.
If pre-term delivery is unavoidable the mother needs to be given glucocorticoids to drive the development of type 2 pneumocytes
When is the fetal heart rate achieved?
15 weeks
What is the role of the fetal urinary system?
Fetal kidney function begins at week 10 and plays a large role in amniotic fluid production
What is the clinical relevance of oligohydramnios and polyhydramnios?
Oligohydramnios: caused by either placental insufficiency meaning their is fetal renal impairment, or fetal renal impairment alone
Polyhydramnios: can be idiopathic or may suggest the fetus has an inability to swallow (can be anatomical or neurological cause)
When does myelination of the brain occur?
Bwgins in the 9th month, therefore is incomplete at birth. Thats why there is increasing infant mobility in the first year
What is quickening?
Maternal awareness of fetal movements (usually from 17 weeks onwards)
