Intrapartum ultrasonography may improve operative vaginal delivery outcomes in Canada
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* Daniel J. Kiely

I read the *CMAJ* article on maternal and neonatal trauma after operative vaginal delivery (OVD) with interest and congratulate the authors on their work.1 They state that their results “raise questions about the choice of instrument, obstetrician training in OVD use and the potential ability to recognize patients who would benefit from a cesarean delivery earlier in labour.”1 I propose that developments in intrapartum ultrasonography may have the potential to improve the training and practice of OVD in Canada.

Intrapartum ultrasonography allows a more objective assessment of fetal head position and station through parameters such as angle of progression, midline angle, head–perineum distance and head direction.2,3 The International Society of Ultrasound in Obstetrics and Gynecology recommends that fetal head position and station be assessed by transabodominal and transperineal ultrasonography, respectively, before OVD.3 Further, the Royal College of Obstetricians and Gynaecologists’ guideline now recommends ultrasonography before OVD if the clinician doubts fetal head position after digital examination.4

Further research in this area is urgently needed. Randomized controlled trials have not yet shown a definitive benefit to intrapartum ultrasonography, but observational studies have shown promising results that suggest intrapartum ultrasonography may lead to improved decision-making regarding best mode of delivery, including OVD.5 To date, most work on intrapartum ultrasonography has taken place outside of Canada, but hopefully Canada will contribute to research in this area and develop training modules, if benefit can be confirmed.

## Footnotes

*   **Competing interests:** None declared.

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## References

1.  Muraca GM, Boutin A, Razaz N, et al. Maternal and neonatal trauma following operative vaginal delivery. CMAJ 2022;194:E1–12.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo4OiIxOTQvMS9FMSI7czo0OiJhdG9tIjtzOjIxOiIvY21hai8xOTQvNy9FMjYxLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.  Dupuis O, Ruimark S, Corinne D, et al. Fetal head position during the second stage of labor: comparison of digital vaginal examination and transabdominal ultrasonographic examination. Eur J Obstet Gynecol Reprod Biol 2005;123:193–7.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1016/j.ejogrb.2005.04.009&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=15925438&link_type=MED&atom=%2Fcmaj%2F194%2F7%2FE261.atom) 

3.  Ghi T, Eggebø T, Lees C, et al. ISUOG Practice Guidelines: intrapartum ultrasound. Ultrasound Obstet Gynecol 2018;52:128–39.
    
    

4.  Murphy DJ, Strachan BK, Bahl R, et al. Assisted vaginal birth: Green-top Guideline No. 26. BJOG 2020; 127:e70–112.
    
    

5.  Ghi T. Intrapartum ultrasound and evidence-based medicine: a necessary but challenging marriage. Am J Obstet Gynecol MFM 2021;3:100428.