23 weeks- change of discharge

Olivia

So my discharge has changed over the last few days. I am 23 weeks and 2 days and my discharge used to be like clear and stringy. It is now white-yellowish and thick, I’m not having any burning or itching as if it’s a yeast infection either. I called my office and they said they wouldn’t worry about if it was a mucus plus and it could be a change of discharge. I wanted to ask what exactly a mucus plug looks like and if it’s been happening the past 3 days that other symptoms would have gotten worse by now? Just always worried about preterm labor.