Mama, ang pinkish discharge at frequent tightening ng tyan mo at 39 weeks, these are signs na dapat i-check agad ng doctor, lalo na since you're so close to your due date. Please call your OB or go to the hospital para ma-assess kung ano na talaga ang status mo, okay?
A few of us moms in our circle experienced similar things near the end, pero bawat pregnancy is different, at kailangan mo ng proper check-up para malaman if you're in early labor or if something else is happening. Hindi mo dapat maghintay, mama, go now and let them examine you properly. Praying for you!