An endometrial thickness greater than 10mm on ultrasound following a dilation and curettage or spontaneous abortion suggests retained products of conception (RPC) which is 80% sensitive. A thickness of 11mm or 14mm after a medical termination of pregnancy indicates an 18% or 50% chance respectively that a patient may require surgical intervention to fully terminate the pregnancy. There is no clear cutoff for thickness or volume on ultrasound to differentiate between RPC and decidua alone following a miscarriage. A thickness of 11.25mm or more has the best diagnostic performance for detecting RPC after a first trimester spontaneous abortion.

1. Endometrial thickness and
RPOC
Radiology Tips
RADIOLOGY TIPS

2. RADIOLOGY TIPS
Retained products of conception can be suspected on ultrasound if the endometrial
thickness is >10mm following dilatation and curettage or spontaneous abortion (80%
sensitive).
REF- Retained products of conception Dr Dalia Ibrahim and Radswiki et al. Radiopaedia
https://radiopaedia.org/articles/retained-products-of-conception?lang=gb

3. Measurement of endometrial width after medical termination of pregnancy (TOP)
Using a cutoff of 11 mm during the follow-up visit after medical TOP, 18% of the patients may
need dilatation and curettage to complete the pregnancy termination, and if it is 14 mm, half
of them may need surgical intervention.
There is no difference between 11 and 14 mm regarding the risk of surgical intervention
after medical TOP.
REF- Zeev Blumenfeld, William Abdallah, Dalia Kaplan and Ori Nevo Reproductive
Endocrinology, Dpt. of Ob/Gyn, RAMBAM Health Care Campus and Rappaport Faculty of
Medicine, Technion—Israel Institute of Technology, Haifa, 31096, Israel.
(Endometrial Thickness- a Practical Prospective Marker for the Risk of Surgical Intervention
after RU486 Induced Abortion)
Clinical Medicine: Reproductive Health 2008:2 25–30
RADIOLOGY TIPS

4. RADIOLOGY TIPS
Among the patients, 109 (85%) had evidence of chorionic villi on histology, whilst
decidua was only found in the remaining 19 (15%). There was no identifiable cut-off
for endometrial thickness or volume that could be used to differentiate between
retained products of conception and decidua.
Conclusion- Measurements of endometrial thickness or volume on ultrasound scan
are not good tests for diagnosing an incomplete miscarriage.
REF-The value of measuring endometrial thickness and volumeon transvaginal ultrasound scan for the
diagnosis of incomplete miscarriage E. SAWYER*, E. OFUASIA*, D. OFILI-YEBOVI*, S. HELMY*, J. GONZALEZ† and
D. JURKOVIC**Early Pregnancy and Gynaecology Assessment Unit, King’s College Hospital, and Dental Institute,
Kings College London, London, UK
(Ultrasound Obstet Gynecol2007;29: 205 – 209)

5. RADIOLOGY TIPS
An endometrial thickness of 11.25 mm or more detected by sonography had the best
diagnostic efficacy, considering the heterogenecity with the thickness of the
endometrium, 13.5 mm had the best performance criteria for detection of RPOC following
first trimester spontaneous abortion.
REF-Can Ultrasound Predict the Presence of Retained Products of Conception Following
First-Trimester Spontaneous Abortion? Z Zare1 *, M Shadman Zijerdi1 1Department of
Radiology, Shiraz University of Medical Sciences, Shiraz, Iran
IRCMJ 2010; 12(2):187-189 ©Iranian Red Crescent Medical Journal