Umbilical arterial systolic / diastolic ratio

Last revised by Yuranga Weerakkody ◉ on 9 Feb 2021

Citation, DOI, disclosures and article data

Citation:

Weerakkody Y, El-Feky M, Umbilical arterial systolic / diastolic ratio. Reference article, Radiopaedia.org (Accessed on 30 May 2023) https://doi.org/10.53347/rID-71456

DOI:

https://doi.org/10.53347/rID-71456

Permalink:

https://radiopaedia.org/articles/71456

rID:

71456

Article created:

7 Oct 2019, Yuranga Weerakkody ◉

Disclosures:

At the time the article was created Yuranga Weerakkody had no recorded disclosures.

View Yuranga Weerakkody's current disclosures

Last revised:

9 Feb 2021, Yuranga Weerakkody ◉

Disclosures:

At the time the article was last revised Yuranga Weerakkody had no recorded disclosures.

View Yuranga Weerakkody's current disclosures

Revisions:

4 times, by 2 contributors - see full revision history and disclosures

Systems:

Obstetrics

Synonyms:

Umbilical arterial SD ratio
Umbilical arterial systolic / diastolic (S/D) ratio

Umbilical arterial systolic/diastolic (S/D) ratio is a parameter used in obstetric imaging as part of umbilical arterial (UA) Doppler assessment. It is the ratio between the systolic velocity and the diastolic velocity.

Practical points

Reference range varies through the stage of pregnancy. If there is an increase in the resistance to blood flow through the umbilical artery, this is seen as an increase in systolic/diastolic (S/D) flow ratio.

S/D ratio mean value decreases with fetal age⁴