How to avoid preterm labor?

I'm due in a month and I have a baby shower next weekend. I'm afraid that I'm going to have her early and I don't want her to because I still don't have everything for her yet and the place where I'm having the shower is far away from the hospital. Is there any natural ways I can just make sure she stays in there till after the shower? I work a full time job and my maternity leave is only 6 weeks so I don't want to take off from work early until she's actually here. Please help!!