It's possible you're just reacting to the weather changes. A hot shower works wonders on noses. I find relief whether .I'm congested or runny.
Make sure the tissues you're using are super super soft (i prefer the ones with lotion) keep something warm on hand whenever possible like hot cocoa or soup. And if you don't feel like getting wet (might sound weird to some of you, but I for one hate getting wet especially when it's cold) just run the hot water in the shower and sit on the toilet with the seat down. The steam will work wonders, hon.
I can't give an answer about your mother's condition during her pregnancy, but these are a few drug-free methods I used during my pregnancy and again just a few weeks ago. Hope they help a bit!