Maternity leave question

I am curious to hear what the earliest someone started their maternity leave was. I am looking for women who voluntarily began maternity and not women who were medicallt recommended to. I am due Jan 6th, was going to work up to Xmas eve then begin leave and quit at end of leave. But now I am seriously considering taking me leave Thanksgiving week because my childcare job has become too much now that I am 31 weeks pregnant and near the end. Also does anyone have experience with quitting after maternity leave? My reason will be I have no childcare for my own child in able to return.