Maternal and foetal wellbeing Flashcards
What are the main causes of birth defects?
Most commonly, aetiology is unknown (approx. 50%) Multifactoral inheritance (approx. 25%) Environmental agents, drugs and viruses Mutant genes Chromosomal abnormalities
When are embryos most susceptible to defects?
Approx. weeks 3-14 (when a lot of women don’t know they are pregnant)
What is the difference between a structural and functional abnormality?
Structural = physical problem with body part (e.g. cleft lip) Functional = problem with the function of a system (e.g. developmental disabilities)
What are the common symptoms of pregnancy in the first trimester?
Morning sickness caused by rising hCG
Increased frequency micturition due to the vascularity of of the bladder - lasts until approx. week 16 when the gravid uterus rises out of the pelvic girdle
What is Hyperemesis Gravidarum?
Severe morning sickness - present in 3.6% of pregnancies
What symptoms are common later in pregnancies?
Heartburn Constipation Vaginal discharge (leucorrhoea) Skin changes (hyperpigmentation of pregnancy) Backache (caused by loosening of ligaments and altered posture) Symphysis Pubis Dysfunction Leg cramp Carpal Tunnel Syndrome
What causes constipation in pregnancy?
Increased progesterone causes reduced gastric motility
What is leucorrhoea?
White, non-irritant, non-offensive discharge
What is gravidity?
Total number of pregnancies, including current pregnancy (twins etc. count as one)
What is parity?
The number of livebirths or stillbirths after 24 weeks gestation (each child counted individually in cases of multiple births)
What needs to be done to minimise risk of prematurity or stillbirth?
Monitor growth - identify intrauterine growth restriction
Identify anomalies
Prevent/ intervene/ deliver/ preparation
What pharmacological management can be used if there is a risk of prematurity?
Magnesium sulphate (neuroprotectant - reduces risk of cerebral palsy) Steroids (e.g. Betamethasone) - stimulates synthesis of surfactant and prevents bleeding in baby's brain and lowers risk of necrotising enterocolitis
What are biometric and biophysical tests useful for?
Biometric tests predict foetal size at point of gestation - periodically can indicate growth but not foetal wellbeing
Biophysical tests (e.g. Doppler) can predict foetal wellbeing but not growth
What foetal biometric parameters can be used to predict foetal size?
1st trimester = crown rump length
2nd trimester onwards = head circumference, abdominal circumference, femur length
What are the potential risks of intrauterine growth restriction?
Stillbirth Low birth weight Decreased oxygen levels Hypoglycaemia Hypothermia Less resistant to infection Difficult vaginal delivery Foetal tachycardia
What is type I intrauterine growth restriction?
All foetal biometrics are less than expected
Usually presents earlier than type II
Usually caused by infections or chromosome abnormalities
What is type II intrauterine growth restriction?
Disproportion between diameters
Typically affects abdominal circumference
Increased brain-liver ratio (foetal head sparing)
Usually caused by placental insufficiency or pre-eclampsia
What is biophysical profiling?
Combines a non-stress test with an ultrasound to check health of foetus - measures foetal heart rate in response to foetal movement as well as assessing breathing, movement, tone and amniotic fluid volume
Usually carried out in 3rd trimester
What are the functions of amniotic fluid?
Surrounds foetus for mechanical protection and to provide a moist environment
What is amniotic fluid composed of and how does this differ throughout pregnancy?
During early pregnancy: ultra filtrate of maternal plasma
2nd trimester: addition of extracellular fluid which diffuses through foetal skin - becomes foetal plasma
After 20 weeks: addition of foetal urine
How does amniotic fluid aid development of the GI tract in a foetus?
Amniotic fluid swallowed by foetus - movement of fluid in GI tract enhances growth and development of the GI tract
What forms meconium?
Swallowed amniotic fluid and gut debris
How is the foetal urinary system monitored?
Foetal kidney number, size and structure
Amniotic fluid volume
Bladder activity
What is polyhydramnios?
Too much amniotic fluid
What is oligohydramnios?
Too little amniotic fluid
Why is pressure higher in the right side of the heart in utero?
Lungs are fluid-filled so high pulmonary vascular resistance
More blood enters the right atrium compared to left and blood is shunted through the foramen ovale
What circulatory adaptations occur after birth?
Onset of breathing - pulmonary vascular resistance decreases
Increased blood flow to lungs - increases volume of pulmonary venous return to left atrium thus increasing pressure to above that of right atrium
Foramen Ovale closes and Ductus Arteriosus begins to constrict
At what age should the Ductus Arteriosus and Ductus Venosus close?
In full term baby, DA will functionally close within 1 day (and permanently close within several weeks)
Ductus Venosus remains partially open until 2-3 months
What is a normal foetal heartrate?
110-160 bpm
How does oxygenated blood arrive at the foetus from the placenta?
Umbilical vein
What foetal structures allow blood to bypass the lungs in utero?
Foramen Ovale (allows shunting of blood from right to left atrium) Ductus Arteriosus (allows shunting of blood from the pulmonary artery to the descending aorta)
