At which cervical dilation points can the plateau phenomenon occur?

The plateau phenomenon refers to a stage during labor where cervical dilation slows or ceases temporarily, even though contractions continue. This can lead to extended periods of time where there is no progression in cervical opening.

The plateau phenomenon is particularly noted during the active phase of labor, which typically spans from around 4 cm to 7 cm of dilation. At 4 cm and 7 cm, the cervix is still making the transition to full effacement and dilation, areas where some women may experience a plateau before the next stage of dilation occurs. Additionally, it is also known that transitions leading up to full dilation (10 cm) can sometimes have moments of stagnation, particularly around 9 cm, contributing further to this phenomenon.

Therefore, the correct answer identifies key points in labor where this plateau may reliably occur, aligning with the understanding of labor progression dynamics. The other options do not include the most recognized stages where this phenomenon is likely to manifest.