Antenatal Care Screening and Diagnosis

Question 1

How many appointments are there for uncomplicated nulliparous vs parous women?

Answer 1

For uncomplicated nulliparous women – 10 appointments

Uncomplicated parous women 7 appointments

Question 2

When are SFH and presentation and lie checked from?

Answer 2

From 24 weeks symphysis fundal height

From 36 weeks check presentation and lie

Question 3

When should the booking visit ideally occur?

Answer 3

Ideally 8-12 weeks

Question 4

Who should be on which supplements?

Answer 4

Vitamin D – 10ug especially those with darker skin or who cover their skin for cultural reasons and in obesity (continue whilst breastfeeding).

Folic acid – 400mcg daily from preconception to 12 weeks, some may need higher dose (5mg) for those on antiepileptics, previous affected child, diabetes, obesity > 35 BMI, sickle cell and demonstrated folate deficiency.

Question 5

What diet and lifestyle advice should be given at a booking visit?

Answer 5

Diet and lifestyle: food hygiene including what to avoid, smoking and alcohol cessation and assessment of drugs. Food: pasteurised milk only, avoid ripened soft cheese (e.g. brie, camembert and blue veins cheeses), no pate, be wary of undercooked or non-cooked meat (all due to listeriosis) and avoid raw or partially cooked eggs, and poultry (due to salmonella).

Question 6

What general education and warnings are given during the booking visit?
What are the flying rules?

Answer 6

Education about pregnancy e.g. baby growth, exercise (fine but avoid high impact sports), breast feeding and mental health. Inform about maternity leave and check what their job is. Singleton low risk pregnancies – no flying after 37 weeks, uncomplicated multiple pregnancies no air travel after 32 weeks.

Question 7

Which examinations and investigations take place during the booking visit?

Answer 7

Examination
Identify high risk pregnancies from history and examination
BMI
BP
Dipstick
Breast and pelvic examination not recommended except in FGM
Signs of domestic violence

Investigations:
Blood disorders – haemoglobinopathies, thalassaemia and clotting
FBC for anaemia
Blood grouping for Rhesus status and red cell alloantibody status
Infection screening – HIV, Hep B, Rubella and syphilis
Urinalysis – glycosuria, proteinuria, haematuria and asymptomatic bacteraemia

Question 8

Which two conditions should mother be assessed for risk factors for in the booking visit?

Answer 8

Assess risk factors for Gestational diabetes: BMI >30, previous macrosomic baby, family history of diabetes or gestational diabetes, and family origin – south Asian, black Caribbean and middle eastern are all high risk.

Assess risk factors for pre-eclampsia: BP and urinalysis first then: Age >40, nulliparity, pregnancy interval of > 10y, family or previous personal history, BMI >30, hypertension, renal disease and multiple pregnancy.

Question 9

When is the dating scan and when is the down’s syndrome screen?

Answer 9

10-13+6 weeks – Dating Scan - CRL used unless > 84mm then Head circumference used. Most accurate between 8 and 13 weeks. After BPD (biparietal diameter) and femur length can be used.
11-13+6 weeks – Down’s syndrome screening

Question 10

What happens at the 16 week antenatal appointment?

Answer 10

16 weeks – review results for Down’s test and any anomalies, supplementation of results if needed and BP/urine, Often iron supplements if Hb < 11g/dl.

Question 11

When does the first anomaly scan take place?

Answer 11

18-20+6 weeks – anomaly scan including placental location, may be repeated at 32 weeks

Question 12

What happens at the 25 week antenatal appointment for nulliparous women only

Answer 12

25 weeks (only nulliparous) – glucose tolerance test if indicated
Routine care: BP, Urine dip and SFH

Question 13

What happens at the 28 week antenatal appointment?

Answer 13

28weeks – Second screen for anaemia and atypical red cell alloantibodies. If Hb < 10.5g/dl consider iron. First dose of anti-D prophylaxis to rhesus negative women.
Routine care: BP, Urine dip and SFH

Question 14

What happens at the 31 week antenatal appointment for nulliparous women only

Answer 14

31 weeks (nulliparous only) – Routine care: BP, Urine dip and SFH

Question 15

When does the detailed anomaly scan take place if required and what does it look for?

Answer 15

3rd Trimester – optional 32-week detailed scan to assess growth, viability, liquor volume, anatomy, placental location, and soft markers for aneuploidy: nuchal fold, short femur, choroid plexus cysts, echogenic focus of heart, dilated renal pelvis and talipes.

Question 16

What happens at the 34 week antenatal appointment?

Answer 16

34 weeks – Anti D second dose and prep for labour

Routine care: BP, Urine dip and SFH

Question 17

What happens at the 36 week antenatal appointment?

Answer 17

36 weeks – presentation of baby and ECV if indicated. Offered at 37 weeks for multiparous women. Provide information for post-partum care e.g. mental health, vitamin K prophylaxis and breast feeding.
Routine care: BP, Urine dip and SFH

Question 18

What happens at the 38 week antenatal appointment?

Answer 18

38 weeks – Routine care: BP, Urine dip and SFH

Question 19

What happens at the 40 week antenatal appointment for nulliparous women only?

Answer 19

40 weeks (nulliparous only) – discuss prolonged pregnancy 
Routine care: BP, Urine dip and SFH

Question 20

What happens at the 41 week antenatal appointment?

Answer 20

41 weeks – offer membrane sweep (to attempt to induce labour)
Routine care: BP, Urine dip and SFH

Question 21

How are pregnancies dated?

Answer 21

Last known menstrual period – simply add 41 weeks from the end of the last menstrual period. Only really works if very regular cycles and ovulation was exactly 14 days after this LMP. – known as Nagele’s rule.

Dating ultrasound scan – between 8 and 13 weeks this is the most accurate measurement. This is done by measuring the CRL

Question 22

What conditions are tested for in the maternal blood screen at the booking visit?

Answer 22

• Haemoglobinopathies, Thalassaemia’s and Sickle Cell disease
• VDLR screening (syphilis)
• AFP screening (produced in the liver and raised levels are associated with small bowl and associated with open neural defects, gastroschisis, cystic hygroma, congenital nephrosis, teratoma, foetal infection and oesophageal atresia).
• Combined Aneuploidy screening – 21, 18 and 13 (Down’s, Edward’s and Patau’s)
• Rhesus status
• HIV and Hep B

Question 23

How is Down’s syndrome screened for?

Answer 23

Down’s syndrome screening
Occurs in 1st or 2nd trimester
1st Trimester – Combined test
USS and blood test looking at Papp A (low) and hCG (high). The USS and blood test combined with maternal age and gestational age to determine risk of Down’s syndrome. Should be completed between 11-13+6 weeks

USS - Nuchal translucency (increased in Down’s, cystic hygroma, cardiac malformations, abdominal wall malformation, congenital diaphragmatic hernia and congenital infections). Scan also assesses, viability, accurate dating, twin determination and chorionicity, and detection of foetal abnormalities.

2nd Trimester serum test – Only done if women book late. Can do triple or quadruple test between 15-20 weeks
Triple: AFP (low), unconjugated oestriol(low) and hCG
Quadruple: AFP, unconjugated oestriol, hCG and inhibin A (high)

If risk of Down’s is greater than 1:150 then they are offered invasive tests

Question 24

What invasive procedures are available for testing?

Answer 24

Amniocentesis, chorionic villus sampling, cordocentesis, fetoscopy, foetal skin biopsy and aspiration of fluid filled foetal cavities.

Question 25

Describe the difference between amniocentesis and chorionic villus sampling and when they are used respectively?

Answer 25

Amniocentesis - abdominally
Indications – high risk down’s, maternal age, USS anomaly, parental translocation and maternal request.
Procedure: after 15 weeks gestation, performed under USS guidance, culture amniocytes, harvest and band. 1% risk of miscarriage, risk of preterm delivery and chronic liquor leak.

Chorionic Villus sampling - vaginally
Indications – rapid result required, assessment of genetic abnormalities and detection of viral DNA e.g. CMV. Procedure: after 10 weeks, USS guided, transabdominal/trans cervical. Risk of miscarriage = 1%.

Question 26

Should obese women lose weight during pregnancy?

Answer 26

Ideally women should lose weight before conception. Once pregnant weight loss should not be encouraged but neither should weight gain. Encourage a balanced diet and regular exercise.

Obese women should be on higher dose folic acid and Vitamin D and

Question 27

What are the risks of obesity during pregnancy?

Answer 27

PET and Diabetes
VTE
Miscarriage
Stillbirth
Cardiac Disease
IOL
Increased risk of instrumental delivery
Macrosomia 
Shoulder dystocia
3rd and 4th degree tears
Higher failure rate of VBAC
PPH 
Post-natal depression

Question 28

What extra precautions should be taken with obese women during pregnancy and labour and post partum?

Answer 28

High Risk pregnancy – consultant led care
High dose folic acid
Vitamin D
Regular screening for diabetes and PET
Mobilise early
Consider Thromboprophylaxis for 7 days post natally (definitely if BMI >40)
Serial growth scans may be needed