Obligatory medical device diagnostics.
- Vaginal sonography (ultrasound using an ultrasound probe inserted into the vagina)) – measurement of cervical length (length of cervix); indications:
- From the 16th week of gestation, if there is a history of spontaneous preterm birth.
- Symptomatic patients
[Pregnant women with a history of preterm birth and cervical shortening < 25 mm below 24 SSW → surgical cerclage/cervical reversal (leading to reduction in preterm and late abortion rates)]
- Cardiotocography (CTG; heart sound contraction recorder).
Optional medical device diagnostics – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Abdominal fetal sonography/ultrasound examination of the child, for further diagnosis of:
- Singleton? Multiple babies?
- Growth in time?
- Timely development?
- Amniotic fluid volume (oligohydramnios, amniotic fluid volume < 500 ml; polyhydramnios, amniotic fluid volume > 2,000 ml).
- Doppler sonography (ultrasound examination that can dynamically visualize fluid flows (especially blood flow); measures blood flow pattern in uterine arteries (uterine arteries) and fetal blood flows in arteries and veins) in the pregnant woman – to assess fetal supply/infant supply (Doppler sonography can detect impending placental insufficiency/uterine placental weakness as early as 20 to 24 weeks of gestation)
Further notes
- Cervical length measurement and fibronectin testing were of low predictive value in a large prospective observational study, including combined use:
- Preterm birth was indicated by cervical length shortening in only 8.0% (35 of 439 women) at first sonography and 23.3% (94 of 403 women) at second examination (specificities were 97.8% and 93.6%, respectively; “number needed to be screened”: 247 women would need sonography (ultrasonography) to detect impending preterm birth).
- Fibronectin testing was even less useful as a screening measure: Preterm birth was indicated in only 7.3% (30 of 410 women on the second test) and 8.1% (31 of 384 women on the third test), respectively (specificities were 96 and 96.8%; “number needed to be screened”: a fibronectin test would need to be performed in 680 women to detect impending preterm birth)
