Antenatal care Flashcards
what is the rate of congenital rubella syndrome occurring in fetuses when maternal rubella is contracted
- between conception and 11 weeks
- between 12- 16 weeks
- after 20 weeks
Congenital rubella syndrome occurs when maternal rubella is contracted before 20 weeks.
- upto 11 weeks = 90% of fetuses affected
- 12 to 16 weeks = 20% of fetuses affected
- No published case reports of CRS after 20 weeks’
incubation period of rubella
Incubation period 12-23 days (average 14 days)
Symptoms of congenital rubella syndrome
Congenital rubella infection teratogenic with poor prognosis and significant complications (sensorineural deafness, cataracts and cardiac abnormalities most common)
what proportion of pregnancies does Pre-eclampsia effects?
3%
What can be used in high risk patients to lower the risk of pre-eclampsia
Aspirin 75mg OD
Associated with 17% reduction in developing pre-eclampsia when used in at risk groups.
Aspirin mechanism of action
Inhibits cyclooxygenase isoenzymes COX1 and COX2
Blocks the formation of thromboxane A2 n platelets(which promotes platelet aggregation)
Blocks prostacylin formation in endothelial cells (which inhibits platelet aggregation)
Platelets lack a nucleus so cannot upregulate thromboxane production but endothelial cells can. so the overall effect is to inhibit platelet aggregation
NICE advice on Aspirin in Pre-eclampsia
75mg OD from 12 weeks until birth
if more than one moderate risk factor for pre-eclampsia
or one high risk factor for pre-eclampsia
High risk factors for pre-eclampsia
that warrant Aspirin 75mg OD
- hypertensive disease during a previous pregnancy
- chronic kidney disease
- autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome
- type 1 or type 2 diabetes
- chronic hypertension
Moderate risk factors for pre-eclampsia
2+ warrant Aspirin 75mg OD
- first pregnancy
- age 40 years or older
- pregnancy interval of more than 10 years
- body mass index (BMI) of 35 kg/m² or more at first visit
- family history of pre-eclampsia
- multiple pregnancy
When is the fetal anomaly scan offered
18-20+6 weeks
what does the fetal anomaly scan screen for?:
- anencephaly
- open spina bifida
- cleft lip
- diaphragamtaic hernia
- gastroschisis
- exomphalos
- serious cardiac abnormalities
- bilateral renal agenesis
- lethal skeletal dysplasia
- Edwards’ syndrome (T18)
- Patau’s syndrome (T13)
Breech complicates what % of term deliveries?
Breech complicates 3-4% of term deliveries
What is External cephalic version?
External cephalic version (ECV) is defined as manipulation of the fetus via the abdomen into a cephalic presentation
Rate of spontaenous version of a breech baby in nulliparous women after 36 weeks
Spontaneous version rates in nulliparous women: 8% after 36 weeks
What is the success rate of ECV?
ECV successful in approximately 50% of cases
40% for nulliparous, and 60% for multiparous
What is the rate of reversion to breech after successful ECV?
Revert to breech after successful ECV <5%
Fetal loss rate for pregnant women with appendicitis
Fetal loss in simple appendicitis is 1.5%
Fetal loss in appendicitis with peritonitis 6%
Fetal loss with perforated appendix 36%
How many weeks on average does a rescue cerclage delay delivery?
Rescue cerclage may delay delivery by 5 weeks.
Also associated with a two-fold reduction in the chance of delivery prior to 34 weeks.
Who should be offered cervical cerclage?
History-indicated cerclage = women with 3+ previous preterm births and/or second-trimester losses
Ultrasound-indicated cerclage = history of mid-trimester loss or preterm birth AND cervical length 25 mm or less before 24 weeks of gestation.
Features of Congenital CMV infection
Sensorineural Hearing Loss Visual Impairment Microcephaly Low Birth weight Seizures Cerebral Palsy Hepatosplenomagaly with jaundice Thrombocytopenia with petechial rash
Diagnosis of fetal CMV infection
Amniocentesis
at least 6 weeks after maternal infection and not until the 21st week of gestation
Management of a pregnancy where fetal CMV confirmed by amniocentesis
Cerebral MRI indicated at 28–32 weeks of gestation.
It may need to be repeated.
Serial ultrasound examination of the fetus every 2-3 weeks until delivery.
What is the most common cause of an acute surgical abdomen in pregnancy?
Appendicitis
Most commonly presents in the second trimester.
Classic presentation of appendicitis in pregnancy
Central abdominal pain that localises to the right iliac fossa.
Associated with fever, nausea, diarrhoea and urinary symptoms.
Management 1st or 2nd trimester Acquisition of Genital Herpes
Initial episode treated acicolvir 400 mg TDS for 5 days
Daily suppressive aciclovir 400 mg TDS from 36 weeks
reduces HSV lesions at term and the need for caesarean section
Does epilepsy carry a risk of teratogenicity?
Epilepsy increases risk of teratogenicity
4% not on medication
6-8% on treatment
All AEDs carry an increased risk of teratogenic effects.
Sodium Valporate has worst teratogenic profile
What is the most common invasive prenatal diagnostic procedure done in the UK?
Amniocentesis
At what gestation is most amniocentesis carried out
Gestation 15 weeks onwards
What is early amniocentesis?
Amniocentesis done before 15 weeks gestation
At what gestation is chorionic villus sampling carried out?
Gestation 11-13 weeks
By what route can chorionic villus sampling be carried out?
Transabdominally or transcervically
What does chorionic villus sampling involve?
Aspiration or biopsy of placental villi
What does amniocentesis involve?
Obtaining a sample of amniotic fluid for karyotyping
What is the additional risk of miscarriage for amniocentesis?
1%
What is the additional risk of miscarriage for chorionic villus sampling?
The additional risk of miscarriage from chorionic villus sampling is slightly higher than that of amniocentesis which is 1%
How does the miscarriage rate from transabdominal CVS compare with that of transcervical?
Almost identical miscarriage rates
What is the risk of amniocentesis before 15 weeks gestation?
Higher rate of fetal loss.
Higher rate of fetal talipes and respiratory morbidity.
What fetal abnormalities was CVS previously believed to have been linked with?
Oromandibular limb hypoplasia,
Limb disruption defects.
What are the difficulties with performing CVS before 11 weeks gestation?
Technically difficult to perform as a smaller uterus and thinner placenta.
What type of consent is required before CVS or amniocentesis.
Written consent.
Including reason for offering it, type of results available, risk of pregnancy loss, accuracy and limitations, method of communicating results, need for anti-D post procedure
What technique for needle insertion should be used for transabdoninal CVS or amniocentesis?
Needle insertion under ultrasound visualisation
Avoiding transplacental placement in amniocentesis unless it is the only safe passage.
Maximum size of 20 gauge needle.
Use local anaesthesia
What is the benefit of ultrasound guided amniocentesis?
Allows visualisation of the position of the placenta, the umbilical cord insertion and enables identification of a suitable entry point.
Benefits of continuous ultrasound visualisation during amniocentesis
Reduces blood staining (interferes with amniocyte culture.
Reduces risk of feral trauma.
Reduces risk of maternal bowel injury.
Avoid placental cord insertion
What is the risk of Down’s syndrome at maternal age 20
1 in 1500
What is the risk of Down’s syndrome at maternal age 30
1 in 1000
What is the risk of Down’s syndrome at maternal age 40
1 in 100
1 in 100 risk of down syndrome occurs at what maternal age
40yo
Can phenytoin be used in pregnancy
Should be avoided if possible.
Can cause fetal hydantoin syndrome
What anticonvulsant is usually used in pregnancy
Lamotrigine
Can phenytoin be used in breastfeeding women?
Yes. Small amounts are present in the milk but breast feeding is acceptable.
What things can increase the risk of complications in pregnant women infected with chicken pox?
Smoking Lung disease HIV On steroids / immunosuppressants 3rd trimester
Risks of smoking in pregnancy
Low birth weight. Premature labour. First trimester miscarriage. SIDS Female infertility. Earlier age of menopause. Increased risk of ectopic pregnancy. Increased risk of placenta praevia, abruption, insufficiency.
What proportion of mothers in the UK smoke during pregnancy or the 12 months before?
26%
What % of mothers continue to smoke throughout pregnancy
12%
Maternal Pregnancy related risks of smoking
Ectopic pregnancy Placental abruption Placenta praevia PROM Pre-eclampsia DVT Longer recovery from anaesthesia / respiratory infections
Fetal Pregnancy related risks of smoking
Reduced vascularisation Capillary oedema Broad basement membrane of placental villi Reduced placental function Miscarriage Still birth Low birth weight Fetal growth restriction Neonatal death Nicotine withdrawal
Long term effect on children whose mothers smoked in pregnancy
Behavioural problems incl ADHD
Learning difficulties
Respiratory problems
More likely to become a smoker
Complications of PET
IUGR Thrombocytopenia DIC renal failure CVA fetal death Maternal death
Neonatal risks of maternal IDDM
Severe hypoglycaemia Hypertrophic cardiomyopathy Hypomagnesaemia preterm labour Polyhydramnios Hyaline membrane disease Congenital heart disease Shoulder dystocia Macrosomia Sacral agenesis
Maternal risks of IDDM in pregnancy
PET
preterm labour
Polyhydramnios
Recurrent miscarriage
Maternal causes of IUGR
Smoking Alcohol Infections PET Hypertension Placental antiproton DM renal disease
Fetal causes of IUGR
Chromosomal
Anencephaly
Multiple pregnancy
Causes of vaginal discharge on pregnancy
CT GC TV BV Thrush Physiological
SFH that is large for dates may be associated with….
Twin pregnancy
GDM
Molar preg
Causes of proteinuria in pregnancy
PET UTI Acute pyelonephritis Placental abruption Chronic glomerulonephritis Diabetic nephropathy Essential hypertension
