Antenatal Care

Question 1

To understand the risks of drug treatment in pregnancy

Answer 1

There are many medications which carry an associated risk of teratogenicity

• Antiepileptics
• Retinoids (isotretinoin)
• Antibiotics: Trimethoprim, tetracyclines
• Warfarin
• Propanolol

Question 2

To understand the risks of substance abuse in pregnancy

Answer 2

Smoking

• CO causes the oxygen dissociation curve to shift to the left, decreasing oxygen transfers to the foetus
• Nicotine acts as a vasoconstrictor on the uteroplacental vasculature
• Smoking may affect placental structure: irregular thickening and reduced calibre of foetal capillaries
• Causes low birthweight and reduced crown-heel length

Alcohol intake

• FAS – follows maternal consumption of > 8 units/day
• Increased risk of miscarriage, congenital abnormalities, premature labout and SGA

Illicit drug use

• May of the adverse effects of illicit drug use are related to lifestyle and malnutrition
• Heroin addiction → IUGR, perinatal death, pre-term labour, neonatal withdrawal manifestations
• Amphetamine → Increased risk of miscarriage, preterm birth, growth restriction, placental abruption
• Cocaine → Cardiac arrhythmias and CNS damage in mothers, placental abruption, foetal growth restriction, preterm labour

Question 3

To understand the booking visit and routine investigations

Answer 3

Booking visit: Should take place within the first 10 weeks of pregnancy

Information

• Supplements: 400 micrograms of folate up to 12 weeks, Vitamin D
• Smoking and substance cessation
• Diet and exercise

Blood tests

• Blood group, alloantigens, rhesus D status
• FBC: ?Anaemia
• Serology: HIV, hepatitis, syphillus
• Haemoglobinopathies: Sickle cell anaemia, thalassaemia

Other tests:

• Weight and height for BMI
• BP
• Urine dip
• Urine MC&S (checking for asymptomatic urine infection)

Question 4

To be able to perform pregnancy dating and calculation of gestational age

Answer 4

Will use a date calculating wheel to do so in OSCE

Question 5

To know schedules of routine antenatal care

Question 6

To have a detailed understanding of the use of anti-D in prophylaxis of Rhesus immunisation

Answer 6

Anti-D should be provided for Rhesus-D negative mothers. Anti-D acts by binding to surface D antigens on foetal RBCs that have crossed into maternal circulation, preventing maternal antibodies against foetal cells being produced.

Maternal rhesus status is checked at booking and at 28 weeks.

Anti-D is administered to mothers at 28 and 34 weeks, or a single large dose at 28 weeks. It should also be administered within 72 hours of a potentially sensitising event in mothers of gestation > 12 weeks.

Question 7

To have detailed knowledge of the diagnosis, management and implications of hypertensive disorders of pregnancy

Answer 7

Question 8

To have detailed knowledge of the diagnosis, management and implications of gestational diabetes

Answer 8

Diagnosis:

• Investigation is required after urine dips reveals +2 glucose on 1 occasion or +1 glucose on 2 occasions
• 75g 2-hour OGTT¹ > 7.8 mmol/L
• Fasting plasma glucose > 5.6 mmol/L

Management

For fasting plasma glucose < 7.0 mmol/L: Offer a 2 week trial of diet (low glycaemic index) and exercise.

If blood sugars are not improved after this trial then metformin is indicated.

If fasting plasma glucose is > 7 mmol/L then immediate treatment with metformin is indicated.

Self-monitoring of blood sugars through capillary BMs.

Implications

• Foetal macrosomia
• Increased risk of birth trauma and shoulder dystocia due to increased foetal size
• Polyhydramnios
• Neonatal hypoglycaemia

1:Offered to mothers at risk of GD between 24 - 28 weeks gestation or immediately to those with previous GD.

Risk factors for the development of GD should be assessed for: BMI > 30 kg/m², previous GD, FHx of diabetes, previous macrosomic baby > 4.5 kg, majority ethnic family origin with a high prevalence of diabetes

Question 9

To have a detailed knowledge of the diagnosis, management and implications of antepartum haemorrhage

Answer 9

Question 10

In normal pregnancy demonstrate understanding of preconceptual care, use of lifestyle changes, folic acid and nutritional requirements

Answer 10

Pre-conceptual care

• Folic acid should be taken prior to conception (400 micrograms or 5 mg for high risk)
• If trying to conceive then certain medications should be ceased prior to this
• Ensure good health: Exercise, diet, smoking cessation, alcohol intake

Lifestyle changes

• Smoking cessation and no alcohol consumption
• 30 minutes of moderate exercise a day
• Certain foods should be avoided: Unpasteurised milk/cheeses, mould ripened and soft blue cheeses, raw/uncooked meats, pate, liver, eggs without the british lion on, uncooked fish/shellfish, no more than 200mg of caffeine per day,

Folic acid

• Should be taken up to 12 weeks gestation

Nutritional requirements

Question 11

In normal pregnancy, to demonstrate understanding of the basics of genetic inheritance and include examples of common inherited disorders, e.g. cystic fibrosis, haemoglobinopathies

Answer 11

Question 12

Understand screening for foetal abnormality, including chromosomal

Answer 12

• Combined test at 10-14 weeks: Uses bloods (PAPP-A and hCG) and USS (nuchal transluency) to identify any abnormalities suggestive of Down syndrome, Edward’s (18) or Patau’s (13)
• Anomaly scan at 20 weeks: Checking for any structural abnormalities e.g. renal agenesis, cardiac malformations etc.
• Quadruple test at 14 - 20 weeks: May be performed if the combined test was not feasible (i.e. nuchal translucency couldn’t be assessed). Serum levels of hCG, AFP, inhibin A and uE3 are analysed.
• If the above tests provide reason to suspect an increased risk of abnormality amniocentesis (15-20 weeks) or CMV (< 15 weeks) can be performed, acting as diagnostic testing

Question 13

To be aware of the risks and management of multiple pregnancy

Answer 13

Risks:

• Preterm birth
• Foetal growth restriction
• Increased risk of chromosomal abnormalities
• Increased risk of perinatal death

​Further risks for monochorionic twins:

• Twin-to-twin transfusion syndrome (TTTS)

Further risks for monoamnioic twins:

• Cord entanglement

Maternal complication also present with an increase incidence: Anaemia, hyperemesis gravidarum, hypertension, pre-eclampsia, placenta praevia, antepartum and postpartum haemorrhage, operative delivery and maternal mortality

Management:

• ?Consultant led care
• Chorionicity should be determined at the 12 week scan (as it most accurately determined before 14 weeks)
• Increased serial growth scans (exact schedule dependent on whether dichorionic or monochorionic)
• Finalise the mode of delivery at 32 weeks. C-section is offered for all twin pregnancies.
• Pregnancies should not be allowed to progress beyond 37-38 weeks gestation
• Intrapartum care: CTG monitoring, syntocinon may be administered to aid delivery of the second twin, syntocinon after delivery is recommended due to increased risk of postpartum haemorrhage (because of the enlarged uterus)

Question 14

To be aware of the risks and management of breech presentation

Answer 14

Risks:

• Cord prolapse
• Entrapment of the head following delivery of the body
• Increased risk of mortality
• Birth trauma

Management:

• ECV
  
  • ​To be offered at 37⁺⁰ (or 36⁺⁰ in nulliparous women)
  • 50% success rate. Can be painful
  • Tocolytics (betamimetics) may be administered to increase the likelihood of success
  • Electronic foetal monitoring and testing for fetomaternal haemorrhage (in Rhesus negative mothers) should be performed following the procedure
  • Risks include placental rupture, uterine rupture and pre-term labour
  • Contraindications: Foetal compromise, multiple pregnancy, PV delivery prevented e.g. placenta praevia, ruptured membranes, recent antepartum haemorrhage
• PV delivery:
  
  • ​> a third of PV delivery attends end in emergency C-section
• Elective C-section:

Types of breech presentation: Frank, complete, footling

Question 15

To be aware of the risks and management of prolonged pregnancy

Answer 15

Risks:

• Increased risk of intrauterine foetal death
• Growth restriction due to placental insufficiency
• Foetal macrosomnia:
  
  • Increased risk of shoulder dystocia, obstructed labour, instrumental delivery, perineal trauma, prolonged labour, birth trauma
• Increased risk of meconium aspiration
• Neonatal seziures/encephalopathy/acidaemia

Management:

• Induction offered from 41⁺⁰
  
  • ​Membrane sweep
  • Vaginal prostaglandins
  • Amniotomy
• If induction is refused then there should be twice weekly CTG and estimation of maximum amniotic fluid pool from 42⁺⁰ weeks

Question 16

To be aware of the principles of foetal monitoring

Answer 16

• Assess foetal growth
• Assess for congenital abnormalities/genetic conditions
• Assess placenta flow and amniotic fluid pool

Question 17

To be aware of the implications of pre-existing disease in pregnancy

Answer 17

Can cause an increased risk of complications, dependent upon the pre-existing condition.

*See separate topics

Question 18

To demonstrate knowledge on the diagnosis, management and implications of preterm labour/rupture of membrane

Answer 18

Diagnosis:

• History: PV fluid, abdominal pain/contractions
• Examination:
  
  • Speculum and PV examination to look for amnioitic fluid
  • Abdominal palpation to check foetal position
• Investigations:
  
  • Foetal fibronectin test
  • TVS to assess cervical effacement
  • High vaginal swab for infection¹ (via speculum), CRP
  • CTG

Management:

• If presenting between 24-34 weeks steroids should be administered, +/- tocolytics to allow for administration
• Antibiotics if in comfirmed labour and infection detected
• C-section if indicated

Implications:

• Increased risk of neonatal mortality and morbidity
• Complications associated with prematurity: RDS, NEC, CP

1: Chorioamnionitis presents with abdominal pain, fever, tachycardia, uterine tenderness and coloured/offensive liquor

Question 19

To demonstrate knowledge of the diagnosis, management and implications of anaemia

Answer 19

Diagnosis

• FBC and serum ferritin levels performed at booking and at 28 weeks
• Hb level < 110 g/l in the first trimester or < 105 g/l in the second and third trimester indicates anaemia
• Maternal symptoms may be experienced, such as fatigue, dyspnoea, pallor, weakness, headaches

Management

• Oral iron supplementation
  
  • Parenteral may be considered if there is no improvement
• Tranfusion

Implications

• Maternal implications: Reduced immune function
• Effects on the foetus: Increased risk of iron deficiency anaemia in the first 3/12 of life

Question 20

To demonstrate knowledge of the diagnosis, management and implications of rhesus isoimmunisation

Answer 20

Diagnosis:

• Unsensitised women are diagnosed antenatally through routine screening at the booking appointment (10-14 weeks) and tested again at 28 weeks
• Bloods taken for rhesus status, blood group and antibodies
• Rhesus negative mother
• Mother may have been previously sensitised, in which case anti-D

Management:

• Administration of Anti-D to the mother, as either one dose at 28 weeks or 2 doses (28 and 34 weeks)
  
  • Anti-D acts to bind the foetal RBCs that have crossed into the maternal circulation, preventing the synthesis of maternal antibodies against the rhesus positive cells
• Anti-D should also be administered within 72 hours of any potentially sensitising events such as aborption, intrapartum haemorrhage, ECV and CVS/amniocentesis
• At birth, the neonates blood group should be checked. If the neonate is rhesus positive then an additional dose of anti-D should be given to the mother and a kleihauer test performed, to see if any additional ‘mop up’ anti-D is required

Implications:

• Neonatal haemolysis → neonatal jaundice
• Haemolytic disease of the newborn
• Hydrops foetalis
  
  • ​In utero transfusion or early delivery required

Question 21

To demonstrate knowledge of the diagnosis, management and implications of infections in pregnancy.

Answer 21

Diagnosis

• Antenatal screening at booking for HIV, hepatitis and syphilis
• UTI may present as abdominal pain and intrapartum haemorrhage
• Maternal symptoms/exposure/known recurrences (e.g. HSV)

Management

-

Implications

• If there is maternal immunity to the infection (IgG present) then the foetus will not be affected by the disease
• Toxoplasmosis: Chorioretinitis, intracranial calcification, hydrocephalus.
• Syphilis: Vertical transmission if no maternal treatment.
• Erythema infectiosum: In early pregnancy miscarriage and stillbirth may result. Later in pregnancy infection causes foetal anaemia, which can lead to high output cardiac failure, fluid retention and oedema.
• Chicken pox: Congenital varicella syndrome, consisting of chorioretinitis, cataracts, neurological deficit and limb hypoplasia
• Chlamydia: Mucopurulent conjunctivitis
• Rubella: Congential rubella syndrome consisting of congenital glaucoma, cataracts, cardiac malformations, ‘blueberry muffin baby’, hepatosplenomegaly, developmental delay and deafness
• CMV: 90% of newborns are asymptomatic, presenting later with progressiv hearing loss. 10% present with jaundice, splenomegaly and petechiae from thrombocytopenia. Cytomegalic inclusion disease affects the neurological, ophthalmic, endocrine and haematological systems.
• HSV: Neonatal HSV infection sees chorioretinitis, neurological problems and vesicular skin eruptions

Question 22

To demonstrate knowledge of the diagnosis, management and implications of thromboembolic disease.

Answer 22

Diagnosis

• Deep vein: Swelling, tenderness, redness, unilateral oedema in the affected area
  
  • Compression duplex US
• PE: Sudden onset dyspnoea, ECG changes
  
  • ECG, CXR, +/- CTPA
• D-dimer should not be used in pregnancy

Management

• Anticoagulants: LMWH
  
  • Baseline blood tests are required prior to administration - FBC, coagulation screen, U&Es and LFTs
• Treatment should be continued for the rest and pregnancy and at least 6/52 post-partum, until 3/12 of treatment has been given. May consider LMWH or warfarin, both can be used when breastfeeding
• Graduated compression stockings and elevation of the affected limb

Implications

• Risk of the thrombus dislodging and travelling to the cerebral circulation, where it may cause a stroke

Question 23

To understand the legal rights of and provisions for pregnant women

Question 24

In complicated pregnancies, to be aware of how to perform diagnostic tests for fetal abnormality.

Answer 24

Screening tests to assess risk:

Combined test at the dating scan (10-14 weeks): Nuchal translucency on USS and bloods (PAPP-A and hCG)

Quadruple test (15-20 weeks): Bloods

Diagnosis:

Amniocentesis (15-20 weeks) or CVS (< 15 weeks): Allows for diagnosis

• Risks: Discomfort, pain, bleeding¹, miscarriage (1/200 miscarry)

​1: More common following transvaginal CVS

Question 25

To be aware of antenatal causes of maternal mortality and morbidity.

Answer 25

• Cardiac disease is the most common cause of indirect death (M
• Thromboembolism and thrombosis are the most common direct cause of death
• Post-partum and antenatal haemorrhage
• Amniotic fluid embolism
• Sepsis

Question 26

To be aware of the causes of stillbirth and perinatal morbidity/mortality.

Answer 26

Stillbirth: Foetal death in utero after 24 weeks gestation. Absent foetal heart beat on real-time ultrasound is necessary to definitively diagnose stillbirth.

*Approximately 60% of stillbirths are associated with placental pathology

Question 27

To be aware of the implications of the small-for-dates baby.

Answer 27

Small for gestational age: Measurement below the 10^th centile for abdominal circumference and/or estimated birth weight. Serial US for growth are indicated, if growth remains below the 10^th centile then SGA is diagnosed.

Implications:

• Increased risk of poor neurodevelopmetal outcomes compared to peers
• Increased risk of metabolic and cardiovascular diseases
• Prone to precocious pubarche, earlier menarche and faster progression of puberty
• SGA due to IUGR: After birth complications such as asphyxia, meconium aspiration, persistent pulmonary hypertension, hypothermia, hypo/hyperglycaemia, hypocalcaemia, polycythaemia, jaundice, feeding difficulties, feed intolerance, NEC

IUGR: Growth of the baby slows or ceases during intrauterine life. Tends to be discordant growth, such that the head circumference growth is maintained and abdominal circumference growth velocity falls.

Question 28

To be aware of the implications of the large-for-dates baby.

Answer 28

• Obstructed labour
• Shoulder dystocia
• Instrumental delivery
• Birth trauma: Brachial nerve plexus
• GDM associated macrosomia: Hypoglycaemia, hypothermia, polycythaemia