Introduction: Preterm birth (PTB) is a major obstetrical and global health issue. Pregnant women with shortening cervical length (CL) in the second trimester are at higher risk of PTB. The prophylactic use of vaginal progesterone in women with short CL reduces PTB rate by 45%. We sought to evaluate our experience with universal cervical CL screening by transvaginal ultrasound (TVUS) by determining short cervix incidence at mid-trimester anatomy scans in our tertiary care institution.
Methods: We retrospectively assessed singleton pregnancies who underwent midterm anatomy scans between 180/7-236/7 weeks’ gestation (2015-2019). Pregnancies with fetal anomalies and fetal demise were excluded. Women were categorized into two groups according to anatomy scan time: Group 1- after introduction of universal TVUS screening (April 2017–March 31, 2019) and Group 2- prior to screening (April 2015-March 31, 2017), where CL was assessed by transabdominal scans (TAS) and TVUS was only performed upon physician request or if TAS CL ≤30 mm. Data regarding short cervix incidence and follow up for CL were collected for both groups.
Results: 6200 pregnancies were included, of which 2150 have presently been analyzed and subdivided, giving 1207 women (56.1%) in Group 1 and 943 women (43.9%) in Group 2 (Figure 1). No differences were found in mean CL or gestational age at time of anatomy scan (Table 1). Women in Group 1 were significantly more likely to have TVUS cervical assessment, while in Group 2 TAS was the more frequent method (p<0.005, for both). The incidence of a short CL was 2.2% in Group 1 and 1.3% in Group 2 (p<0.08).
Conclusion: No significant differences were found in the incidence of short cervix before and after universal screening. However, incidence after screening is more similar to literature and did increase from before screening. We believe that upon completion of the database, the results may change.
Saja Anabusi– Clinical Fellow, Sunnybrook Health Sciences Centre, University of Toronto
Vasilica Stratulat– Diagnostic medical sonographer, Sunnybrook Health Sciences Centre, University of Toronto
Susan O’Rinn– Senior Project Manager – Research, Sunnybrook Health Sciences Centre, University of Toronto
Noor Ladhani– Maternal-Fetal Medicine specialist, Sunnybrook Health Sciences Centre, University of Toronto
Elizabeth Asztalos– Physician, Sunnybrook Health Sciences Centre, University of Toronto, Toronto
Kalesha Hack– Radiologist, Sunnybrook Health Sciences Centre, University of Toronto
Jon Barrett– Chief of Maternal-Fetal Medicine at Sunnybrook Health Sciences Centre, Sunnybrook Health Sciences Centre, University of Toronto
Stefania Ronzoni– MFM Specialist, Division of maternal fetal medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada