Strengths and Limitations
The main strengths of this study were the high number of women included, the completeness of the data collection and the very small amount of missing data. This resulted in a solid database that allowed us to obtain significant results from various analyses, including the multivariate analysis.
One limitation of our study is the monocentric design. In our obstetrics department, 80 % of OVDs are conducted with vacuum assistance, and mid-cavity OVDs account for 35 % of all operative deliveries. The overall rate of C-section is approximately 15 %. These characteristics allowed us to obtain a large study population, but they may affect the external validity of our study. Thus, the implementation of our score is possible in teams who regularly practice VAD. The use of this score implies the presence of an experienced obstetrician from the outset for all attempts at mid-cavity VAD.