Flashcards in Repro Deck (311)
What occurs in the fetal period (breifly)
Growth and maturation of structures developed in embryonic period
Early = protein deposition
Late = adipose desposition
LMP vs weeks post fertilisation?
LMP = fert +2
When does the CRL increase rapidly?
Pre to early fetal
Ante-natal assessment of fetal well being?
Mother and fetal movements
Uterine expansion - symphysis fundal height
Uses of Obstetric ultrasound scan (USS)?
Check age in early pregnancy
Fetal abnormalities and growth
Purposes of a 7-13 week scan?
Estimate from CRL the EDD and the time of cenception
Check location, number and viability
Uses of the biparietal diameter
Used to date pregnancies in T2/3 in combination with other measurements e.g. abdominal circumference and femur length.
Also used for anomaly detection (more AC and FL)
Describe the classification of birth weights
4500 maternal diabetes - macrosomia
Stages of lung development?
Pseudoglandular 8-16 weeks
Canalicular - 16-26
Terminal sac stage - 26+
Describe the pseudoglandular stage
Duct system develops from the bronchopulmonary trunk
Describe the canalicular stage
Respiratory bronchioles bud off from bronchioles formed during the pseudoglandular stage
Describe the terminal sac stage
Terminal sacs bud from resp bronchioles.
Differentiation of Type 1 and 2 pneumocytes (surfactant)
What factors aid lung development?
What are the implications for pre term survival
THreshold of viability is the lungs, only possible once lungs have entered the terminal sac stage >24 weeks
What is respiratory distress syndrome?
Pre mature infants
insufficient surfactant pproduction
glucocorticoid treatment for mother as this increases surfactant
Definitive fetal HR when?
Describe development of urinary system later
Kidney function at 10 weeks
Not neccessary for survival but without there is oligohydramnios
Desribe the development of the nervous system
Myelination of brain begins at 9 months and finishes after birth
Coordinated voluntary movement develops at 4 month
What is quickening
at 17 weeks, increase in fetal awareness
way of antepartum surveilance
Describe O2 supply to fetus
Incre pO2 in mother and low in fetus (4kPa).
Hb 70% sat at 4kPa - more hb than adults
Double bohr effect in both fetal and maternal blood??
Describe CO2 and the fetus
Cannot tolerate CO2
Lower maternal CO2
Prog stimulates maternal hyperventilation
Sat of blood and to the brain in fetus
Blood shunted to brain- bypass liver via Ductus venosus (70-65% with IVC) - bypass lungs via foramen ovale (directed by crista dividens- part of septum secundum, joins pulmonary flow in LA 65-60%) and ducuts arteriosus
SVC tends to go to RV as is superior to RV
Describe functions and secretions of amniotic fluid
10ml at 8 weeks
1l at 38 weeks
300ml at 42 weeks.
Constant turnver - early maternal secretion and diffusion with embryo ECF. late - fetal production.
Production of fetal urine
100ml a day at 25 weeks to 500ml hypotonic.
Constantly swallows amniotic fluid forming meconium
Fetus and bilirubin
Fetus cannot conjugate and thereofore remove bilirubin so crosses the placenta - may get jaundiced as a neonate if conjugation does not establish quickly
Describe rhythms in the fetus
Breathing movement and HR.
Function of cytotrophoblast
Function of the syncytiotrophoblast
Invades maternal epithelium and lacunae to establish utero-placental blood flow.
Allows for diffusion - multi nucleated sheet