Raspberry leaf tea??

I'm 30 weeks and wanted to start drinking this to just help tone my uterus-  I have been told that it can help make for a shorter labor, just wondering what some of your experiences have been with it and if it works- also, I know it needs to build up in your system so eventually I'll move up to two cups a day and then three- how early should I make the move up to two? I don't want to induce labor TOO early... Hopefully he shows up at 38 weeks 😊anyway, thanks ladies!!