Uy, 1cm pa lang talaga kaya medyo maaga pa for labor signs, pero good na ginagawa mo ang primrose oil as advised ng OB mo! A few of us tried it too around that time, and honestly it does help soften the cervix gradually, just make sure consistent ka talaga every night para may effect. Besides the primrose, try walking pa rin, pelvic exercises, and staying hydrated kasi lahat yan nakakatulong; one of my mum friends swears na pag consistent sa lahat ng ito, bumilis talaga ang dilation when labor actually comes. Keep monitoring din kung may other signs of labor na, contractions, water breaking, discharge changes, and definitely check in with your OB next visit para makita kung may progress na, especially since malapit ka na sa due date!