Repro 9.2 Fetal growth and development. Flashcards
What is the main function of the embryonic period?
To lay the foundations for the future systems of the body.
At this point though, they are immature.
What is the main function of the fetal period?
The growth and maturation of the systems and structures created in the embryonic period.
Prepares the fetus for life after birth,
How long does the fetal period last?
~30 weeks
What patterns of growth occur during the embryonic period?
- organogenetic period (large growth and activity)
- absolute growth is very small
- weight gain is small
- placental growth of most significance
what patterns of growth occur in the fetal period?
Both growth and weight gain accelerate.
early fetus- protein deposition (for muscle growth, results in a lot of weight gain)
late fetus- adipose deposition (for regulation of body temperature)
What is CRL?
Crown- rump length.
When is CRL most significant?
increases rapidly during the preembryonic, embryonic and early fetal periods.
most signifcant in early fetal period, until around 20 weeks when it is visible
With regards to body proportions, what is seen at arounf week 9?
The head is half of the crown-rump length
At birth, approximately what proportion of the neonates length is made up by the head?
1/4
Ante-natally, how can you assess fetal well-being?
- asking the mother (she will be aware of what is ‘normal’ for that child and can report any changes)
- USS
- Measurements of uterine expansion by palpating for the sympehsis-fundal height.
Why is the USS the investigation of choice and what is it used for?
It is SAFE for the fetus, no radiation is involved,
- can be used in early pregnancy to etimate age
- can be used to look for any fetal abnormalities
When is an USS routinely carried out?
Why at this time?
At around 20 weeks.
By this point all systems are present so the doctor can make an assessment.
What are some methods of estimating fetal age?
- last menstrual period
- devleopmental criteria (using USS)
- crown-rump length
- bi-parietal diameter
- abdomen circumference and femur length
Why is using the LMP to estimate the fetal age not that good?
-prone to innaccuracys (women aren’t always regular, there may be a small amount of breakthrough bleeding during implantation at around day 14 which can lead to some confusion.
When is the best time to use CRL to estimate fetal age?
Between weeks 7 and 13.
What is the first antenatal scan in pregnancy used to look for?
- CRL to estimate the age of the neonate and EDD
- to check for the number of embryos
- to check for ectopic pregnancys
- check for viability (heart beat present, is it bradycardic?)
What is the bi-parietal diameter and how is it used?
The space between the 2 parietal bones of the fetal skull,
used alongside abdominal circumference and femur length to date age of fetus in the late fetal period.
What is the use of 3/4D USS?
- Relatively new
- shows the fetus in real time, so can see suckling, or breathing etc
- used as a complimentary tool to standard USS
- nice for the parents to have