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Radiology
Pregnancy of Unknown Location, Early Pregnancy Loss, Ectopic Pregnancy, and Cesarean Scar Pr
Built from Obstetric Imaging
What’s inside
9 sections · 110 slides
Overview
- What this deck covers
Why the first scan matters
Pregnancy is an inefficient process, and the earliest weeks carry the highest risk of getting the diagnosis wrong.
- Early pregnancy is fragile
- Two questions every early scan must answer
- The four diagnoses in this topic
- Where an early pregnancy can end up
- Accuracy beats speed
Pregnancy of unknown location
A positive test with an empty-looking scan is a stage, not a disease.
- What pregnancy of unknown location means
- Every pregnancy starts as unknown location
- Why the scan can look empty
- Milestones of the first weeks
- Developmental Milestones of Early Pregnancy, Ultrasound Findings, and Correlation to Beta-Human Chorionic Gonadotropin Levels
- Why the hormone number alone misleads
Normal landmarks in early pregnancy
Sac, yolk sac, embryo, heartbeat - learn the order and the sizes.
- The lining thickens before anything is visible
- The gestational sac
- Chorionic sac inside a bright decidual reaction
- When the sac becomes visible
- Dating from the sac
- The look-alike: pseudosac
- The yolk sac
- Yolk sac, embryonic pole and a measured heart rate
- The embryo appears
- Measuring the embryo
- The heartbeat
- M-mode tracing of an early fetal heart rate
- The order things appear in
Working up an unknown location
Scan technique, the corpus luteum trap, and what to do while you wait.
- How these patients present
- Choosing the probe
- Doppler: useful but used sparingly
- Ring of fire around the corpus luteum
- What the scan shows in unknown location
- Where MRI fits, and what the classic picture is
- The waiting pathway when the patient is stable
- Adding progesterone to the triage
- When waiting must stop
Early pregnancy loss
Common, rarely anyone's fault, and easy to over-diagnose.
- What early pregnancy failure means
- How common it is
- Why pregnancies fail
- The other contributors
- What to tell the patient
- How a loss presents
- Matching the bedside picture to the scan
- First-trimester bleeding and early pregnancy loss: clinical findings
- First-trimester bleeding and early pregnancy loss: ultrasound findings
- Three ways a loss looks on ultrasound
- Empty sac and abnormal yolk sacs in failed pregnancy
- Sac and yolk sac clues
- Signs you can rely on
- Guarding against a false diagnosis
- Seeing a heartbeat is reassuring
- 4.5%
- When the heart beats too slowly
- Blood collecting beside the sac
- Treating incomplete miscarriage and retained tissue
- When the tissue has not passed
- Two checks before any plan
Ectopic pregnancy
A pregnancy growing outside the uterus - the diagnosis that must not be missed.
- What ectopic pregnancy means
- Where they sit and who is at risk
- Why it happens
- Four locations, four scan pictures
- Ectopic pregnancy locations: where each one sits
- Ectopic pregnancy locations: what the scan shows
- Ectopic pregnancy locations: points to remember
- A tubal ectopic pregnancy
- Interstitial ectopic pregnancy on two-dimensional and three-dimensional views
- Why the interstitial type is dangerous
- Cervical ectopic pregnancy
- How an ectopic presents
- The cervical ectopic is different
- Imaging and the classic picture
- Treating an early tubal ectopic
- Treating interstitial and cervical pregnancies
- Stable or unstable decides the route
- Balloon tamponade and the safety rule
- What the referring clinician needs to know
Cesarean scar pregnancy
Implantation on an old scar - and the earliest sign of a placenta that will not let go.
- The scar and the niche
- What a cesarean scar pregnancy is
- Is it really an ectopic pregnancy?
- How often it happens
- Why the scar is vulnerable
- One proposed route from scar to scar pregnancy
- How it presents
- How to take the picture
- Cesarean scar pregnancy on transabdominal and transvaginal scans
- Diagnostic criteria: position
- The sac that seems to climb
- Diagnostic criteria: muscle and contents
- Blood flow marks the implantation site
- Three-dimensional reconstruction of a scar pregnancy
- MRI and the classic picture
- Look-alike 1: a miscarriage passing through
- Look-alike 2: a cervical pregnancy
- Telling the two apart
- How scar pregnancies are treated
- Counselling when there is a yolk sac but no embryo
- Counselling when there is a heartbeat
- Screening the next pregnancy
- Key points on scar pregnancy
Pulling it together
What to carry away from the first-trimester scan.
- Take-home: the sequence
- Take-home: numbers worth keeping
- Take-home: the traps
- References
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- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition