When I wrote my post on things I want to try next time I'm pregnant to keep my babies from being "too big," I forgot to mention Vitamin D. I have no idea how or why it works to keep your baby small, but here's a couple of things I've learned about it recently.
It might make gestational diabetes easier to control. At least the Navelgazing Midwife says so (maybe anecdotal experience?). Anyway, it's worth a shot.
It might make labors shorter and less painful. Again, the Navelgazing Midwife says so. That would be awesome, although short or long, I maintain that labor is going to be hard work and a little scary, no matter what way you slice it. At least on this side of Eden, anyway.
Some mothers and therefore their breastfed babies are deficient. It's the reason that pediatricians recommend breastfed babies receive D-Vi-Sol or some other vitamin D supplement. Also, my husband tells a funny story about a conversation that he had with one of my doctors once. When I was breastfeeding my son, age 7 months, I had some blood drawn. My vitamin D was low and my endocrinologist reported the results to my husband over the phone. He apparently spent a long time trying to impress upon my husband the severity of the national epidemic. OK, maybe it's only funny if you know my very serious, earnest, well-meaning, and apparently (though not truly) naive endocrinologist from St. Louis.
It may prevent the development of Type I diabetes in my children. See this post by my cousin. I'm just not seeing any downside to vitamin D at this point!
I asked a maternal-fetal specialist about Vitamin D when my levels came up low again at the beginning of the third trimester of my second pregnancy. She said that OBs don't recommend vitamin D above 400 IU (the daily recommended dose for non-pregnant women) because there's evidence that at REALLY high levels (40,000 IU) it hurts you. Or something like that. Well, I've seen a lot of recommendations and I don't know who really knows what level between those two extremes is the best. I take 4,000 IU daily, and my vitamin D levels are now clinically normal but on the low end.