Prenatal Care ✅ Flashcards
What does routine prenatal screening include?
- Maternal blood sampling
- US scanning
- Attendance at antenatal clinic
What should maternal blood be tested for prenatally?
- Blood group
- Antibodies for rhesus (D) and other red cell incompatibilities
- Hepatitis B
- Syphilis
- Rubella
- HIV
- Haemaglobin electrophoresis
Why should haemoglobin electrophoresis be done in prenatal checks?
Identify thalassaemia and sickle cell traits
What should be tested for with hepatitis B screening at prenatal checks?
Surface and e-antigen
When are ultrasounds normally done in pregnancy
Late first trimester and mid-trimester
What is the purpose of the initial USS in pregnancy?
- Allows gestational age estimation
- Can identify multiple pregnancy
What is the purpose of the second USS in pregnancy?
- Identify structural abnormalities
- Identify abnormalities in amniotic fluid volume
What can be done if fetal growth or other problems are identified?
Monitoring with serial scans
What does antenatal clinic attendance allow for?
- Identification of pre-existing maternal medical conditions or obstetric risk factors
- Facilitation of monitoring for pregnancy complications
What is the purpose of prenatal screening for disorders affecting mother or fetus?
- Reassurance when disorders not detected
- Optimal obstetric and neonatal management to be planned, and parental counselling provided when problems detected
- Interventions for limited number of conditions with fetal medicine or surgery
- Option of termination of pregnancy to be offered for severe disorders affecting fetus or compromising maternal health
What is the limitation of using screening to as a method of reassurance?
Many abnormalities which are detected on USS are not confirmed on repeat or more expert scanning, or are transient or minor, but may cause significant anxiety
What is required when termination of pregnancy is being considered due to severe disorders affecting the fetus or compromising maternal health?
Accurate, rapid medical advice and counselling to help them make this difficult decision
How can pregnancies at increased risk of genetic disorders be identified?
Prenatal or antenatal screening
When might trisomy 21 first be suspected?
On first trimester USS
How can Down’s syndrome potentially be identified on first trimester USS?
Nuchal translucency measurement
What can nuchal translucency measurement be combined with to determine the likelihood of Down’s syndrome?
Maternal serum biochemical screening
What is non-invasive prenatal testing?
Where cell-free fetal DNA is obtained from maternal blood
What can non-invasive prenatal testing be used for?
- Identification of fetal gender
- Fetal genotyping
- Exclusion of common aneuploidy
Why might it be useful to determine fetal gender by non-invasive prenatal testing?
For X-linked disorders
Why might it be useful to do fetal genotyping by non-invasive prenatal testing?
Look for rhesus antigens
Which common aneuploidy in particular might non-invasive prenatal testing be used to exclude?
Trisomy 21
What is the advantage of non-invasive prenatal testing?
Avoids risk of miscarriage with invasive testing procedures
What is the limitation of non-invasive pre-natal testing?
There are technical, ethical, and financial issues
What does invasive prenatal testing require?
An invasive test in pregnancy with the aim of collecting fetal cells
What can invasive prenatal testing be used for?
- Cytogenic analysis
- Molecular analysis
- Biochemical analysis
What is the purpose of cytogenetic analysis in invasive prenatal testing?
Look for chromosomal abnormalities
When is molecular analysis used in invasive prenatal testing?
In the case of known genetic mutation
When is biochemical analysis done in invasive prenatal testing?
In the case of a defined disorder with a suitable prenatal biochemical test
What is the limitation of invasive prenatal testing for families already affected by a genetic condition?
It is only possible where the genetic mutation in the family is known
When is prenatal biochemical or enzyme testing possible?
In a small number of disorders, mainly metabolic, when the diagnosis has been confirmed in a family member
What are the types of invasive pre-natal testing?
- Amniocentesis
- Chorionic villous sampling
- Fetal blood sampling
What can amniocentesis be used for?
- Chromosome/microarray and DNA analysis
- Look for fetal infection
How can amniocentesis be used to look for fetal infection?
PCR for CMV, toxoplasmosis, rubella, and parvovirus
What can chorionic villus sampling be used for?
- Chromosome/micro-array and DNA analysis
- Enzyme analysis of inborn error of metabolism
What can fetal blood sampling be used for?
- Fetal haemoglobin for anaemia
- Fetal infection serology
- Fetal blood transfusion
What other diagnostic techniques can be used in fetal medicine?
- Further imaging
- Pre-implantation genetic diagnosis
What further imaging be can done in fetal medicine?
- High definition USS
- Fetal MRI
Why might further imaging be done in fetal medicine?
Identification and deliniation of fetal abnormalities
When can pre-implantation genetic diagnosis be performed?
In IVF patients
What happens in pre-implantation genetic diagnosis?
Genetic analysis of cells from a developing embryo before transfer into the uterus
What fetal therapies may be used?
- Glucocorticoid therapy
- Digoxin or flecainide
- Fetal blood transfusion
- Intrauterine intravenous immunoglobulin or platelet transfusion
What is the purpose of glucocorticoid therapy before preterm delivery?
Accelerate lung maturity and surfactant production
When might digoxin or flecainide be used in fetal medicine?
To treat fetal supraventricular tachycardia
How is digoxin or flecainide given to the fetus when used to treat fetal supraventricular tachycardia?
It is given to the motehr
When might fetal blood transfusion be required?
In rhesus or other isoimmunisation causing severe anaemia and hydrops fetalis (oedema and ascites)
How can hydrops fetalis be monitored?
Fetal middle cerebral artery Doppler USS
When might intrauterine IV immunoglobulin or platelet transfusion be indicated?
Perinatal isoimmune thrombocytopenia
What causes perinatal isoimmune thrombocytopenia?
Antiplatelet antibodies crossing the placenta
What is the purpose of treating perinatal isoimmune thrombocytopenia with intrauterine IV immunoglobulin or platelet transfusion?
Prevent intracranial haemorrhage, which occurs in up to 25%
Give 6 examples of fetal surgery
- Catheter shunts
- Fetoscopic laser therapy
- Intrauterine shunting for urinary outflow obstruction
- Fetal endoscopic tracheal occlusion
- Spina bifida surgical correction by hysterostomy
- Surgery for sacrococcygeal teratoma
How are fetal catheter shunts inserted?
Under USS guidance
What is the purpose of the insertion of fetal catheter shunts?
To drain fetal pleural effusions
What often causes fetal pleural effusions?
- Chylothorax
- Congenital cystic adenomatous malformation of the lung
What is it called when catheter shunts are used to drain fetal pleural effusions?
- Pleuro-amniotic shunts
Where do pleuro-amniotic shunts drain fluid to and from?
From chest to amniotic cavity
What is the purpose of pleuro-amniotic shunts?
Reduce risk of fetal death from hydrops and pulmonary hypoplasia
What is the purpose of fetoscopic laser therapy?
Ablate placental anastomoses that lead to twin-twin transfusion syndrome
What can cause intrauterine urinary outflow obstruction?
Posterior urethral valves
What is the limitation of intrauterine shunting for urinary outflow obstruction?
Results have been disappointing in reducing morbidity and death because of pre-existing renal damage
What is fetal endoscopic tracheal occlusion (FETO) used to treat?
Congenital diaphragmatic hernia
How does FETO work?
As fetal tracheal obstruction promotes lung growth, this is replicated in utero by inflating a balloon in the trachea
At what gestation is spina bifida surgical correction by hysterostomy performed?
22-24 weeks gestation
What is the limitation of spina bifida surgical correction by hysterotomy?
It may precipitate preterm delivery, and its benefit remains uncertain
What complication is reduced with spina bifida surgical correction by hysterotomy?
Hydrocephalus requiring shunting
