Antenatal Care

Question 1

What is the normal duration of pregnancy?

Answer 1

Normal duration of pregnancy: 40±2 weeks

Question 2

How to calculate the expected date of delivery (EDD)?

Answer 2

EDD (expected date of delivery, end of 40th week) = LMP + 9 months 7 days
• Naegele’s rule: assume 28D cycle, patient ovulates on D14

Question 3

How to calculate the period of amenorrhoea?

Answer 3

Period of amenorrhoea: no. of weeks from LMP

Question 4

List the definitions for the following:

(a) 1st trimester
(b) 2nd trimester
(c) 3rd trimester
(d) Post-date pregnancy
(e) Post-term pregnancy

Answer 4

1st trimester: up to 12 weeks
2nd trimester: 13-27 weeks
3rd trimester: 28 weeks onwards
Post-date pregnancy: > 40 weeks
Post term pregnancy: > 42 weeks

Question 5

What is done for each routine antenatal visit?

Answer 5

Components
• History
• PE: inc weight, BP, abdominal/pelvic examination
o Abdo exam: SFH, fetal lie and presentation, auscultate fetal heart
• Urine dipstick test: sugar, protein, acetone

Question 6

What is the frequency of antenatal visits for each trimester?

Answer 6

Frequency of visits
• 1st trimester: 2-4 weekly
• 2nd trimester: 4-weekly
• 3rd trimester: 2-weekly till 35 weeks, weekly from 36 weeks onwards (more frequent visits due to the increase in likelihood of getting cx)

Question 7

What is carried out during the booking appointment?

Answer 7

Booking Appointment
• Check for risk factors for GDM
• Check for risk factors for PE
o Age ≥ 40 years, BMI ≥ 30, nulliparity, family hx of PE, PMH of PE, HTN, renal dx, multiple pregnancy
o Requires more frequent BP monitoring if present
o Start on PO aspirin to reduce risk of PE
o Seek immediate advice if PE symptoms are present:
 Severe headache, visual problems (BOV, flashing before eyes), vomiting, sudden swelling of face/hands/feet, severe abdominal pain
• Start on 400 mcg daily of folic acid supplementation
o To decrease the risk of neural tube defect
o Before conception till 1st 12 weeks of pregnancy

(?counsel about flu vaccination)

Question 8

What is the purpose of starting a pregnant lady on folic acid supplementation?
What is the dose of folic acid supplementation?

Answer 8

Purpose:
o To decrease the risk of neural tube defect
o Before conception till 1st 12 weeks of pregnancy

Dosage: 400 mcg daily before conception till 1st 12 weeks of pregnancy

Question 9

What are the benefits of having a flu vaccination for pregnant ladies?

Answer 9

Flu vaccination
• Pregnant women are more likely to develop flu complications
• Can decrease the risk of serious cx like pneumonia in later stages of pregnancy
• ↓ risk of miscarriage, premature birth, stillbirth, neonatal death
• Helps protect baby  will continue to have some immunity to flu for the 1st few months of life

Question 10

What is required for the 1st trimester antenatal care?

Answer 10

• Diagnosis of pregnancy
• Confirm gestational age
• Maternal AN screening blood test
• Identification of high-risk pregnancies
• Coping with pregnancy changes/symptoms
• Fetal Down syndrome screening (optional)

Question 11

What are the common symptoms of pregnancy?

Answer 11

N/V, heartburn, constipation, backache

Amenorrhoea, breast tenderness

Question 12

What are the common signs of pregnancy?

Answer 12

Breast changes, uterine enlargement and softening, increased vascularity of breasts and pelvic structures

Question 13

What are the investigations conducted to diagnose pregnancy?

Answer 13

Urine HCG, U/S

Question 14

How to calculate the gestational age (GA)?

Answer 14

• LMP
• Vaginal examination: uterine size estimation in 1st trimester; accuracy ± 1 week
• Abdominal palpation (2nd & 3rd trimesters): unreliable; accuracy ± 3-4 weeks
• Ultrasound
o 1st trimester: crown rump length measurement (CRL); accuracy ± 3-4 days
o 2nd trimester: biparietal diameter, head circumference, femur length; accuracy ± 1-2 weeks
o 3rd trimester: no method

Question 15

What should you look out for when doing the viability/dating scan (1st trimester)?

Answer 15

• Where is the pregnancy? Intrauterine pregnancy or ectopic pregnancy?
• How many babies? Singleton or twin pregnancy?
• Is the fetal heart seen? To check if pregnancy is viable
• How far (no. of weeks) is the pregnancy? Done by measuring the CRL (head to buttocks)
• Any other masses seen?

Question 16

What is the viability of pregnancy for resuscitation?

Answer 16

24 weeks

Question 17

What are the maternal screening tests for the 1st trimester?
Include the rationale of the investigations and relevant f/u care

Answer 17

• FBC ± thalassemia screen
o FBC: to assess for anemia (Hb < 11 g/dL)  to consider Fe supplementation if present
• Blood group and Ab: Type and Screen
o Routine antenatal anti-D prophylaxis is offered to all non-sensitised pregnant women who are RhD -ve
o Partner is offered testing to determine if anti-D prophylaxis is necessary
o Screen for alloantibodies in early pregnancy and again at 28 weeks, regardless of RhD status
o Dosage: 100 µg anti-D IgG at GA 28 and 34 weeks
• Hepatitis B, VDRL, HIV and rubella screening
o Syphilis: congenital infection and anomalies, IUGR, preterm birth, stillbirth, neonatal death
o Rubella: to identify women not immunised in childhood
 Identifies women at risk of contracting rubella infection and enables vaccination at postnatal period to protect future pregnancies

Question 18

What are the risk factors for high-risk pregnancies in the 1st trimester?

Answer 18

Maternal
 PMH (HTN, DM, anemia, heart dx), previous LSCS, uterine surgery
 Pregnancy: PIH, GDM, anemia, APH, malpresentation

Fetal
 AMA, fetal abnormalities, exposure to teratogens
 IUGR, threatened premature labour, PROM, abnormal fetus, multiple pregnancy, persistent breech presentation after 34 weeks

Question 19

Provide some advice for pregnant patients who are in their 1st trimester

Answer 19

• Nutrition
o ↓ risk of listeriosis: drink only pasteurised milk, X eat uncooked or undercooked ready prepared meals
o ↓ risk of salmonella: X raw/partially cooked eggs or meat
• Lifestyle adjustments
o X smoking
o Consequences of recreational drug use and alcohol consumption in pregnancy (fetal alcohol syndrome)
o Exercise: potential dangers of certain activities, e.g. contact sports, high-impact sports  risk of abdo trauma and falls
• Travel
• Coitus
• Medications: use prescription meds as little as possible, inc OTC meds
• Common minor complaints

Question 20

What are the common complications during the 1st trimester?

Answer 20

• Common ones: N/V, pelvic discomfort, PV bleed

* Miscarriage, hyperemesis (excessive vomiting), ectopic pregnancy

Question 21

What is the name of the Down syndrome screening conducted in the 1st trimester?

What does it comprise of?

When is the Down Syndrome screening done?

What is the result of the screening?

Answer 21

• Down syndrome combined screening: maternal blood and U/S assessment
o Nuchal translucency (NT), free B-HCG, PAPPA (pregnancy-associated plasma protein A)
o Called the First Trimester Screen (FTS)
• Done: 11+4 weeks to 13+6 weeks
• Computerised estimation of risk of Down syndrome: Low/High risk (high risk: risk ≥ 1 in 300)

Question 22

What is done during the 2nd trimester?

Answer 22

• Clinical fetal monitoring
• Maternal counselling
• Triple test for Down syndrome screening: 16-20 weeks (optional)
• U/S screening scan: 20-22 weeks (Mentor: be clear over which scan is being used! Screening scan vs bedside ultrasound scan)

Question 23

What is the name of the U/S screening scan done in the 2nd trimester? What is its purpose and elaborate.

Answer 23

• Recognize presence of fetal abnormalities, diagnose multiple pregnancies, identify low lying placenta, detect other pregnancy cx: uterine abnormalities, pelvic tumour
o U/S detection rate of malformation: up to 60-70%
o Importance of detecting fetal abnormalities
 Certain fetal abnormalities are associated with chromosomal abnormalities and not compatible with life (–> option of TOP)
 Perinatal/multidisciplinary care, may need transfer to tertiary centres
 Mental preparation
o Types of structural abnormalities: anencephaly, cystic hygroma, omphalocele, AVSD, Ebstein anomaly, talipes (club foot)
• Uterine blood flow waveform assessment
o Uterine artery resistance (uterine artery supplies the uterus)
 Routine use is controversial
 Elevated uterine artery resistance ± notching
• Increased risk of IUGR, preeclampsia, placental abruption, and intrauterine death
• If uterine arcuate resistance index > 0.62  commence patient on aspirin 100 mg daily till 35 weeks GA (if NKDA to aspirin)
o To lower risk, to improve blood flow

Question 24

When is the screening for gestational DM done during pregnancy?

Answer 24

• Recommended at 24-28 weeks GA in patients with risk factors for GDM
• 1st trimester screen for GDM: offered to patients with significant risk factors
o Risk factors: BMI > 30, GDM, baby > 3500g in prior pregnancy, family hx of DM in 1st degree relatives
• Check for risk factors at booking appointment

Question 25

What is the management for GDM?

Answer 25

o 85% women with GDM respond to changes in diet and exercise
o 15% need oral hypoglycaemic agents or insulin therapy if diet and exercise X effective
o If GDM X detected and not controlled  increase in risk of birth cx like shoulder dystocia

Question 26

What should you counsel the patient during the 2nd trimester?

Answer 26

• General advice: diet, supplements, exercise, and rest
• Antenatal classes
• Breastfeeding advice