1.2. Antenatal Care and Screening - Ultrasounds

Question 1

What is the First Ultrasound Sign of Pregnancy?

Answer 1

Thickening of the Lining of the Womb

Question 2

What happens at 4.5 weeks Gestation?

Answer 2

A Fluid-Filled Intrauterine Gestational Sac appears

Question 3

What happens at 5 weeks Gestation?

Answer 3

A Yolk Sac Apprears within the Uterus

Question 4

When is the (Tiny) Foetal Pole visible?

Answer 4

About 5.5 Weeks

Question 5

When is a Foetal Heart Pulsation visible?

Answer 5

By week 6, after the last Menstrual Period

Question 6

What happens once the Foetal Pole is identified?

Answer 6

A Crown Rump Length (CRL) measurement is made

Question 7

What is a Crown Rump Length (CRL) measurement?

Answer 7

It is made from one end of the Embryo to the other

Question 8

What does the Crown Rump Length (CRL) of the Embryo correlate with?

Answer 8

1. Gestational Age of the Pregnancy, which allows for an Estimated Due Date
2. Diagnose Miscarriage
3. Identify Multiple Pregnancy
4. Exclude Abnormalities of Early Pregnancy - Hydratidiform Mole / Ectopic Pregnancy
5. Identify Major Structural Abnormalities - Anencephaly

Question 9

What is Anencephaly?

Answer 9

A type of Neural Tube Defect in which the Vault of the Skull fails to develop, leading to the Foetal Brain matter being unprotected and worn away
Note - this condition is not compatible with Extra-Uterine Life

Question 10

What is the most common Chromosomal Abnormality which is screened for?

Answer 10

Down’s Syndrome (Trisomy 21)

Question 11

What is the main factor which increases the risk of Down’s Syndrome?

Answer 11

Age of Pregnancy:
1 in 1667 at aged 15
1 in 30 at age 45

Question 12

When is the Combined Ultrasound and Biochemical (CUB) screening test carried out?
Note - this is in Grampian

Answer 12

11-14 weeks
Note - if a patient books after this then they can have a Second Trimester screening, in the form of a blood test for Serum Markers

Question 13

What tests are offered to those at a risk of the Child having Down’s Syndrome?

Answer 13

1. Nuchal Translucency (with Crown Rump Length)

2. Amniocentesis (if at High Risk)

Question 14

What is screened for, other than Chromosomal Abnormalities?

Answer 14

Neural Tube Defects (Spina Bifida)

Question 15

What is measured in the Second Trimester Screening, which is useful for Identifying Neural Tube Defects?

Answer 15

Alpha Feto-protein (AFP) - a Foetal Glycoprotein produced sequentially by the Yolk Sac, Foetal G.I. tract, and Liver
A maternal serum of AFP > 2.0 is considered abnormal - 85% of all open Neural Tube Defects

Question 16

When is the Second Trimester Ultrasound carried out?

Answer 16

20 weeks

Question 17

What is the Second Trimester Ultrasound looking for?

Answer 17

Structural Abnormalities of the Fetus

Note - this has a limited role in detecting chromosomal abnormality

Question 18

What can Major Abnormalities lead to?

Answer 18

Possible decision to terminate the Pregnancy

Question 19

With an Ultrasound Scan in the Second Trimester, how is a baby scanned?
What is being looked for?

Answer 19

Systematically from top to bottom:
1. Head - Cerebellum / Ventricles
2. Neck - Cystic Hygroma
3. Diaphragm - Hernia
4 - Stomach - Double-Bubble
5. Kidneys - Dilated Renal Pelvises

Question 20

What is the Normal / Abnormal presentation of a Baby’s head, with an Ultrasound Scan in the Second Trimester?

Answer 20

Normal - Dumbbell Shaped

Abnormal - Frontal Bossing / “Lemon” shaped Skull

Question 21

What is a Cystic Hygroma associated with?

Answer 21

Chromosomal Abnormality

Question 22

How is a Diaphragmatic Hernia diagnosed, via an Ultrasound Scan in the Second Trimester?

Answer 22

Finding Abdominal Organs in the Chest

Question 23

What is the “Double-Bubble” Sign typical of?

Answer 23

Duodenal Atresia - absence / closure of the Duodenum

Question 24

Other than in Neural Tube Defects, when can Alpha Feto-Proetin (AFP) be elevated?

Answer 24

1. Gestational Age
2. Multiple Pregnancy
3. Bleeding in Pregnancy
4. Foetal Death
5. Abdominal Wall Abnormalities

Question 25

What is the Function of the Ultrasound in the Third Trimester?

Answer 25

Ensure Foetal Wellbeing

Note - There is no routine ultrasound performed

Question 26

When are Ultrasound Scans in the Third Trimester indicated?

Answer 26

1. If the baby feels Large / Small

2. A Reason to believe there may be a problem

Question 27

What, other than an Ultrasound Scan, can be used in the Third Trimester?

Answer 27

1. Liquor Volume - Fluid around the Baby

2. Placental Site - Place of the Afterbirth in the Womb