Ovarian and Foetal Imaging Flashcards
Dating of ultrasound scans in pregnancy is done using the LMP/Date of conception
LMP
Week __ of a pregnancy scan will correlate with conception/ovulation
2
By week 6-7 of pregnancy scanning what structures are you expecting to see?
- Gestation sac
- Yolk sac
- Embryo
A normal gestation sac should lie just under the ___ and be positioned slightly ___
Endometrium
Eccentric
If the developing baby hasn’t doubled in size by weeks ___ the pregnancy is considered failed
6-7
What is a threatened abortion?
bBeeding and cramping in the first 20 weeks of a pregnancy
If there foetal cardiac activity is absent by a CRL of > __mm this is considered pathologic
7
If the embryo is absent by a MSD (mean sac diameter) of ___mm this is considered pathologic
25
What is a normal embryonic heart rate?
140-150 bpm
What is the prognosis for a subchorionic bleed?
Unlikely to be problematic because is not where the embryo is developing
The yolk sac normally measures __mm
4
How should you refer to an anembryonic pregnancy in clinical practice?
An empty sac
Why is free-floating amnion before 12 weeks of scanning not necessarily indicative of a miscarraige?
Amnion does not stick to the chorion until around 12 weeks
Which condition causes a marked increase in likelihood of ectopic pregnancy?
Pelvic inflammatory disease
Should you only scan the uterus for an IVF pregnancy?
No - higher chance of ectopic pregnancy, need to scan outside the uterus
Is fluid around the uterus more indicative of an ectopic or ovulation?
Ecotopic
Which drug is used in the termination of pregnancy?
Methotrexate
Where does fluid due to ovulation tend to collect?
The pouch of Douglas
Ovaries are normally ___ cm in size
2.5-3cm
Ovarian follicles may rupture between ___mm
16-25
What are the ddx for fluid in the pouch of douglas and pelvic pain?
- Ectopic pregnancy
- Ovulation
- Menstruation (blood)
- PID (pus)
What causes a haemorrhagic corpus luteum?
Rupture of blood vessels on the ovary post-ovulation
Corpus luteum is responsible for hormonal control of pregnancy until ___ weeks
10-12
What is a common presentation of patients with gestational trophoblastic disease?
Severe sickness - excessive vomiting to the point of being unable to keep up with fluids
From Week 4-8 BHCG ___ every 2-3 days
Doubles
At what level of bHCG would you expect to see foetal cardiac activity?
20,000
At what level of bHCG would you expect to see a gestation sac?
> 2000
The accuracy of scanning in predicting EDD is
+/- ___ in the 1st trimester
+/- ____ 2nd trimester
+/- ____ 3rd trimester
+/- 5 days in the 1st trimester
+/- 10 days 2nd trimester
+/- 3 weeks 3rd trimester
Why do monochorionic pregnancies need to be monitored closely?
Risk of twin to twin transfusion
All of the embryology has formed by___ weeks. You are not altering develop at ~ 20 weeks
12
Why can bHCG not be used for dating?
To variable between patients
The patient’s LMP was only 3 weeks ago. Why should I do an ultrasound scan when an ectopic pregnancy does not manifest until 5 weeks after the LMP?
- Cannot assume this was actually her LMP
- Need to do a pregnancy test
