When a mother has a large fetus that is not engaged in the pelvis, what might be observed at around 6 cm dilation?

When a mother has a large fetus that is not yet engaged in the pelvis, the observation at around 6 cm dilation can often be an arrest of labor. This situation occurs because the engagement of the fetal presenting part into the pelvis is crucial for the progression of labor. When the fetal head is not engaged, it may lead to insufficient pressure exerted on the cervix, which is necessary for further dilation and progression through the stages of labor.

In this scenario, as the contraction patterns may not be effective in promoting engagement, it can result in a prolonged or stalled labor, characterized by an arrest. It's important to monitor the labor closely, as an arrest may necessitate intervention to assist with the labor process. The significant size of the fetus can lead to increased difficulty in descent due to its head being larger than the pelvic inlet, further contributing to the likelihood of an arrest.