Not enough space for membrane sweep

Had my 39 week appt today. Still 1 cm dilated. Doc said while she was checking for dilation that there isn’t any room for her to do membrane sweep. What does that mean?

To clarify she was able to get her finger in to check for dilation and could reach but said there wasn’t enough space for her to do it. So doesn’t that mean baby’s head is right against my cervix?