Uterine notch refers to decreased blood flow in one or both uterine arteries. A phenomenon which, if it is too important, can harm the proper development of the baby. What is it due to? What are the consequences for mother and baby? Highlight with Dr Véronique Beaudoux, gynecologist-obstetrician at the University Hospital of Angers.
The uterine notch corresponds to the sudden decrease in blood flow in one or both uterine arteries which have the role of supplying the uterus during pregnancy. However, a slowing down of this flow can, if it is too great, prove to be problematic for the fetus and harm its development. Its presence is assessed by a Doppler echo uterine arteries, performed in the fifth month of pregnancy, only if intrauterine growth retardation (IUGR) has been detected or if the mother has risk factors.
A uterine notch is said to be bilateral when it concerns the two arteries supplying the uterus.
' The uterine notch is quite common during pregnancy, it is a physiological phenomenon, related to the anatomy of the uterine arteries. Its presence may be normal up to the fifth month of pregnancy . This is the reason why there is no systematic screening, except in patients who present one or more risk factors. On the other hand, if it is discovered during the first ultrasound, it will be necessary to control its disappearance after 24 weeks of amenorrhea. “, says Dr. Véronique Beaudoux.
The causes of uterine notch remain poorly understood. However, the cardiovascular risk factors of smoking, high blood pressure, high cholesterol, diabetes, and obesity increase the risk of uterine notch. 'Certain autoimmune diseases in which vascular involvement is possible, such as anti-phospholipid syndrome or lupus , may cause a uterine notch. It can, however, be present even in the absence of these risk factors “, adds the gynecologist.
Uterine notch does not cause any particular symptoms . Most often, it is discovered when the fetus has a growth retardation unexplained (IUGR) or low weight for gestational age (PAG) on second trimester ultrasound, known as morphological ultrasound. A Doppler ultrasound is then performed to measure the blood flow in the uterine arteries.
'If a uterine notch is observed on one or both uterine arteries after 24 weeks of amenorrhea, this raises the suspicion of uteroplacental insufficiency, i.e. a lack of blood supply to the uteroplacental level which could cause growth retardation or fragility in the fetus since it is no longer nourished properly' , details the specialist.
There is no treatment for uterine notch . If the baby is growing normally, simple monitoring will be put in place. Conversely, if the uterine notch is associated with one or more risk factors in the mother, she should rest as much as possible. Depending on the term of the pregnancy, a induction of labor may be offered.