Inclusion Criteria:  Informed Consent signed by the subject Pregnant woman Singleton pregnancy 18 years or older  Exclusion Criteria:  Lack of informed consent Placenta praevia totalis with haemorrhage (irrespective of severity) Severe vaginal bleeding Rupture of membranes before 34 weeks (to be excluded with pH test) Visible tissue scarring at 12 o'clock position on cervix Light bleeding (if the bleeding can be stopped, it is no longer an exclusion criterion) Cervical dilation ≥ 3 cm Cerclage or pessary in place