An ultrasound examination of the length of the cervix is recommended for all pregnant women, regardless of whether they belong to a low- or high-risk group in terms of premature birth:
For high-risk pregnant women, we recommend checking the length of the cervix every 4 weeks between the 12th and 28th weeks of pregnancy.
For low-risk pregnant women (in the absence of the above risk factors), we recommend determining the length of the cervix at least once between the 20th and 24th weeks of pregnancy.
With your hand, you can only feel the part of the cervix that extends into the vagina, and the condition of the inner cervix cannot be judged, which seems to be a more important parameter in terms of the risk of premature birth. At the same time, we often meet frightened expectant mothers who are diagnosed with a shortened cervix during a manual examination, while the length of the cervix is normal with a vaginal ultrasound examination. This may be because a part of the cervix continues above the vagina, which we cannot feel with our hands.
In women who have already given birth, the external cervix may be open, but often, with a slightly more forceful examination, the examining finger can be "drilled" all the way into the sheath, giving the impression of an open cervix. Moreover, such a rough examination can even initiate premature labor.
The method is taught by the London-based Fetal Medine Foundation (FMF) in its courses and on their website (www.fetalmedicine.com) can be completed on their online course.
An examiner who meets the theoretical and practical requirements of the FMF can obtain an FMF exam and accreditation for ultrasound examination of the cervix.
The cervix is examined with a vaginal ultrasound and the following aspects must be taken into account:
Asymptomatic dilatation of the inner cervix can also be detected during a vaginal ultrasound examination. In the literature, expansion is called funneling.
When measuring the length of the cervix, you can sometimes see sediment collected at the bottom of the amniotic cavity, which we call "sludge". Literature data has proven that the risk of premature birth is high in pregnant women with such a collection of pus.
Measurement of the utero-cervical angle (measurement of the angle between the uterus and cervix)
The measurement of the utero-cervical angle (UCA) is one of the new methods of screening pregnant women at risk of premature birth. We speak of an increased risk if the utero-cervical angle increases (>105°, the risk of premature birth before the 34th week is higher). If we find an abnormal UCA value in the pregnant woman, we will discuss the most optimal therapy and set up a follow-up plan in order to reduce the risk of premature birth.
During the examination, pregnant women are classified into low (cervical length >25mm), intermediate (cervical length 21-25mm) and high (cervical length <20mm) risk groups based on medical history data and cervical length.
If we see signs of cervical shortening in the pregnant woman, we will discuss the most optimal therapy and set up a follow-up plan in order to reduce the risk of premature birth.
The international literature offers several treatment recommendations for cervical shortening in asymptomatic pregnant women, e.g. progesterone treatment, cerclage, Arabin pessary.
The measurement of the utero-cervical angle (UCA) is one of the new methods of screening pregnant women at risk of premature birth. We speak of an increased risk if the utero-cervical angle increases (>105°, the risk of premature birth before the 34th week is higher). If we find an abnormal UCA value in the pregnant woman, we will discuss the most optimal therapy and set up a follow-up plan in order to reduce the risk of premature birth.
