1.2. Antenatal Care and Screening - Ultrasounds Flashcards
What is the First Ultrasound Sign of Pregnancy?
Thickening of the Lining of the Womb
What happens at 4.5 weeks Gestation?
A Fluid-Filled Intrauterine Gestational Sac appears
What happens at 5 weeks Gestation?
A Yolk Sac Apprears within the Uterus
When is the (Tiny) Foetal Pole visible?
About 5.5 Weeks
When is a Foetal Heart Pulsation visible?
By week 6, after the last Menstrual Period
What happens once the Foetal Pole is identified?
A Crown Rump Length (CRL) measurement is made
What is a Crown Rump Length (CRL) measurement?
It is made from one end of the Embryo to the other
What does the Crown Rump Length (CRL) of the Embryo correlate with?
- Gestational Age of the Pregnancy, which allows for an Estimated Due Date
- Diagnose Miscarriage
- Identify Multiple Pregnancy
- Exclude Abnormalities of Early Pregnancy - Hydratidiform Mole / Ectopic Pregnancy
- Identify Major Structural Abnormalities - Anencephaly
What is Anencephaly?
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
What is the most common Chromosomal Abnormality which is screened for?
Down’s Syndrome (Trisomy 21)
What is the main factor which increases the risk of Down’s Syndrome?
Age of Pregnancy:
1 in 1667 at aged 15
1 in 30 at age 45
When is the Combined Ultrasound and Biochemical (CUB) screening test carried out?
Note - this is in Grampian
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
What tests are offered to those at a risk of the Child having Down’s Syndrome?
- Nuchal Translucency (with Crown Rump Length)
2. Amniocentesis (if at High Risk)
What is screened for, other than Chromosomal Abnormalities?
Neural Tube Defects (Spina Bifida)
What is measured in the Second Trimester Screening, which is useful for Identifying Neural Tube Defects?
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
When is the Second Trimester Ultrasound carried out?
20 weeks
What is the Second Trimester Ultrasound looking for?
Structural Abnormalities of the Fetus
Note - this has a limited role in detecting chromosomal abnormality
What can Major Abnormalities lead to?
Possible decision to terminate the Pregnancy
With an Ultrasound Scan in the Second Trimester, how is a baby scanned?
What is being looked for?
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
What is the Normal / Abnormal presentation of a Baby’s head, with an Ultrasound Scan in the Second Trimester?
Normal - Dumbbell Shaped
Abnormal - Frontal Bossing / “Lemon” shaped Skull
What is a Cystic Hygroma associated with?
Chromosomal Abnormality
How is a Diaphragmatic Hernia diagnosed, via an Ultrasound Scan in the Second Trimester?
Finding Abdominal Organs in the Chest
What is the “Double-Bubble” Sign typical of?
Duodenal Atresia - absence / closure of the Duodenum
Other than in Neural Tube Defects, when can Alpha Feto-Proetin (AFP) be elevated?
- Gestational Age
- Multiple Pregnancy
- Bleeding in Pregnancy
- Foetal Death
- Abdominal Wall Abnormalities
