To be perfectly honest, my relationship with my mother-in-law isn't awesome. It never has been. From the moment we met she had it in for me. Then, when my husband and I got married and I got pregnant, our relationship took a turn for the worst. There's something about having grandchildren that makes mothers-in-law do and say the most passive aggressive, rude, judgmental things. Over the years I've learned how to deal with toxic family members, though, and there are so many things this mom with a difficult mother-in-law wants pregnant women to know.
Sometimes I really do think (and hope) my mother-in-law means well. After all, she wants what's best for her child and grandchildren. For the most part, she probably thinks she is being helpful when she tells me how I should raise my children. Unfortunately, sometimes what my mother-in-law thinks is best and what I know is best are two entirely different things. And to make matters worse, my mother-in-law makes comments about how long she breastfed, how her "natural birth" is better, how easy parenting was back in her day, and how lazy moms are today. She came to visit me in the hospital, at home, and while I was trying to recover from childbirth at the most inopportune and surprising times, always with a subtly shaming comment about my housekeeping or cooking. It really sucked, and I knew my spouse felt stuck in the middle.
In the end, it is often up to you, as the mother, to set boundaries, say no, and even cut off contact if your mother-in-law gets too difficult. Above all, remember that you can't control what other people do and say, and that don't have to let a toxic person push you around, even if you're related to them through marriage.