1. The two most commonly listed symptoms of early pregnancy are "fatigue" and "nausea". Fatigue is NOT the correct word in my opinion. Fatigue is a MASSIVE understatement of what happens in the first trimester, because to me fatigue means "I need a nap". My first trimester was closer to what you get at the end of finals, when you haven't slept more than 3 hours a night for the last two weeks and not at all for the last 48 hours and you're running on caffeine and cold pizza, and you are literally so sick and horribly exhausted that you're shaking and you're going to need to sleep for roughly a week to make up for this abuse to your body. THAT is the level of "fatigue" I experienced the first trimester. You'd wake up after a nap and feel like you haven't slept at all.
2. They call it "morning sickness". This is also a misnomer. Its all day, all night, puking so hard it feels like it comes from your toes sickness.
3. I NEVER EVER expected pregnancy to be the single best diet I've been on in years. In fact, I was deeply concerned that since I was already plus-sized, about what the physical effects of the added weight of a baby would do to my joints etc. Instead I have slowly but steadily lost weight my entire pregnancy. I've now lost over 25 pounds. According to my doctor apparently my metabolism really DOES suck that bad (ie- normally I can eat less than anybody else and STILL gain weight) and the baby has rev-ed up my metabolism to the same level of as that of a normal person so now I'm dropping weight.
4. I've heard of women who get dark lines up the center of their belly when pregnant. I've even seen some that got hair up their belly, I never expected freckles. No lines and no hair but lots of freckles. Between about 6 & 7 months I have gotten a BUNCH of new freckles. Almost all of them are in places that NEVER see the sun. I showed the doctor and she says that its totally normal.
5. I've decided that any woman who claims she "didn't know she was pregnant" when she gives birth is either lying or has some variety of psychiatric issue. Being poked from the INSIDE is a VERY strange sensation. But it gets progressively stronger and more insistent and really does feel like somebody just elbowed you, only from the inside. There isn't ANY WAY a normal person could mistake these sensations for any normal bodily function.
6. I forever misspelled the word "pregnant" before I got pregnant. ;) Now I know how to spell it.
7. I thought the reason pregnant women are known for being constipated was because the baby was some how sitting on things and slowing them up. So I was surprised when this happened when the kid was the size of a peanut. I also didn't know that pregnant women are prone to gas. Somehow they neglected to mention these two lovely facets of pregnancy. Apparently pregnancy causes the smooth muscle tissue to relax, in part to slow down your digestive processes so that you can more completely absorb the nutrients in your food. The downsides to this is that your foods' extended stay in your bowel allows more time for the creation of gas and also dries the stool more which causes the constipation. Drinking obscene amounts of water can help to fend of this situation. Lots of fiber is of course vital as well.
8. I didn't know that your blood volume nearly doubles when you're pregnant. Most of the reason for this is to buy you grace when you deliver so you don't bleed to death but also to allow surplus circulatory capacity for the two people your organs are now providing for. Your kidneys ALSO kick into high alert AND for the first trimester the baby's kidneys are not yet functional so your kidneys are cleaning up for both you AND baby - which is why frequent urination is such a problem in the first trimester.
9. I knew pregnancy was divided into 3 trimesters. I always figured that it was because 9 months divides evenly by 3. I didn't realize the pregnancy really divides its self into three in terms of symptoms and development. People didn't do it, Mother Nature did. It's really true that you do the exhausted/pukey bit the first 3 months, then you feel pretty good the second 3 months, and then you go back to exhausted and very sore for the last 3 months. And his development goes a lot the same - everything is pretty much THERE by the end of the first trimester. It gets bigger and develops more fully the 2nd and the third is almost totally dedicated to weight gain.
10. I didn't know that every lubricant on the market (except one that claims otherwise) is basically sperm killer. When trying to conceive the doc says not to use lube because even if it doesn't actually kill the sperm outright with its happy chemicals, it makes things thicker so the sperm get stuck in it and die before they achieve their purpose.