I don't think cm/ discharge is a reliable indicator of pregnancy either way. If you look up early preg signs in books/internet, you wont see cm/ milky discharge as a sign. (After ovulation discharge is normally creamy or sticky) I dont think theres such a thing as pregnancy discharge either...leukkorhea usually happens in later months. A climbing temp would be a better indication of preg than cm- so I would watch your temps as well as other standard preg signs, such as sore breasts, tiredness etc.
But, they DO mention it.
Besides bleeding, a woman may notice a white, milky discharge from her vagina. That's related to the thickening of the vagina's walls, which starts almost immediately after conception. The increased growth of cells lining the vagina causes the discharge.
https://www.webmd.com/baby/guide/pregnancy-am-i-pregnant
White milky vaginal discharge is occasionally the first pregnancy sign and symptom noticed by many women. - See more at: https://www.babymed.com/pregnancy-s...-and-symptom-pregnancy-0#sthash.36cvIptf.dpuf
Symptoms: Sticky white or pale yellow discharge can be constant during pregnancy, leaving you feeling in frequent need of new undies.
https://www.parenting.com/article/weird-pregnancy-symptoms
#9. Pelvis: Increased Cervical Fluid
Many women notice more cervical fluid (vaginal discharge) than normal during early pregnancy. This is normal. It can be white and creamy (like lotion) or wet and slippery.
https://www.countdowntopregnancy.com/early-pregnancy-symptoms/top-10-early-pregnancy-symptoms.php
More vaginal discharge? You're not imagining it. What you're noticing is probably leukorrhea the odorless (or mild-smelling) milky discharge that you occasionally found in your underwear before you were pregnant. There's just a lot more of it now, partly because of increased estrogen production and greater blood flow to the vaginal area.
https://www.babycenter.com/0_12-icky-pregnancy-side-effects_10312447.bc#articlesection3
I can go on.