[header] How to induce labour [title] Have sex. [step] This is a popular recommendation from midwives, though firm research on its effectiveness is lacking. The theory is that the woman's orgasm can trigger labor, as well as prostaglandins in semen coming into contact with the vagina (so plan your activities accordingly! ). 
[substeps] There's one caveat: don't resort to this remedy if your water has already broken. Once the amniotic sac has ruptured, you run the risk of infection.