Pregnancy Myths: Fact or Fiction?

In this post, I'm going to address some of the most common myths surrounding pregnancy that I've heard, both lighthearted and more serious. If, after reading this, you think of any myths I've missed, feel free to comment and I'll do the research for you! Enjoy!

• Fetal weight estimates, both ultrasound and external palpation, are always accurate, and a supposed "big baby" is a legitimate reason for induction or c-section: FALSE
• This one makes me laugh every time. Just from my own personal experience, I can tell you that this is very, very rarely going to be 100% accurate. My OB with my firstborn did external palpation when I was about 38 weeks, and told me that my daughter would be AT LEAST 8 pounds, probably more like 8.5. She was wrong. My baby was 7lbs 1.8oz. A full pound smaller, a week later. My midwives with my second pregnancy wouldn't even guess after my 20-week anatomy scan (during which my baby was looking a touch big, but nothing abnormal, so we all brushed it off). They said that the size of the baby, in a healthy mom, doesn't matter nearly so much as positioning in relation to mom's pelvis, and they were right. My second daughter was 8lbs 6oz, and I delivered her faster and easier, with less tearing, than her big sister. As far as ultrasounds go, particularly those done after 20 weeks or so, those can be off by 1-2 (I've even heard so much as 3) pounds either way. It's pretty hard to estimate a baby's size and take any real measurements when they're all squished up inside mom. That being said, there are some pretty darned good ultrasound techs and doctors out there who are extremely accurate at guessing weight and are nearly always right, but that is not the norm, and it's still a just guess. No major decisions should be based off of a guess, no matter how educated. 
• Here are some online sources I've found on this issue: http://www.ncbi.nlm.nih.gov/pubmed/6730930 , http://journals.lww.com/greenjournal/Abstract/1970/08000/Estimation_of_Birth_Weight_by_Quantified_External.20.aspx ,  http://childbirthinternational.com/blog/?p=146 , http://www.familypracticenews.com/news/more-top-news/single-view/ultrasound-diagnosis-of-fetal-macrosomia-found-inaccurate/36fa34152d.html , http://www.theunnecesarean.com/blog/2009/10/18/can-ultrasound-really-predict-the-weight-of-my-baby.html , http://wellroundedmama.blogspot.com/2012/09/the-dangers-of-estimating-fetal-weight.html , 
• So, is there any evidence supporting inducing or scheduling a cesarean for the sole reason that your provider suspects a big baby? Nope. I've blogged about that before, but here are some sites with great evidence on the matter: http://evidencebasedbirth.com/evidence-for-induction-or-c-section-for-big-baby/ , http://www.childbirthconnection.org/article.asp?ck=10456 , http://www.pregnancybirthandbabies.com/Big_baby.htm , http://www.acog.org/About_ACOG/News_Room/News_Releases/2013/Early_Deliveries_Without_Medical_Indications

• If you have lots of heartburn in pregnancy, it means your baby will have tons of hair: PLAUSIBLE
• This was completely and totally untrue for me. I had very little heartburn in my first pregnancy, and absolutely constant, horrible heartburn in my second, and my girls were born with about the same amount of hair. In fact, my second had a bit less hair, and she was the one who gave me such awful heartburn. So in my case, this myth is totally false. HOWEVER, there have been studies done that seem to say that this myth has a scientific basis in fact. Apparently it has to do with estrogen levels causing the esophageal sphincter to relax, which causes heartburn, and estrogen also appears to be responsible for hair growth in the baby. So heartburn isn't caused by hair, or hair by heartburn, but there is a hormone present that can cause both. The only significant study I've found on this only included 64 women, and it's still not definite that if you have heartburn you'll be guaranteed to have a baby with lots of hair, but there may be a correlation between the two. 
• Here are the articles I found about this: http://www.cbsnews.com/2100-500202_162-5276102.html , http://voices.yahoo.com/pregnant-mothers-heartburn-expect-babies-451594.html?cat=25

• if you lose your mucous plug and/or start dilating in late pregnancy, you're about to go into labor RIGHT NOW: FALSE
• Now, no one's saying that dilating, effacing, and losing your mucous plug aren't signs that labor is imminent. They just can't tell you when labor will start. I lost my mucous plug, both times, about 2-3 weeks before going into active labor, and I dilated early. Perfectly normal. Some don't dilate, efface, have any show, or lose their mucous plug prior to the start of active labor. That's normal too. So if you notice that you're passing stringy, pink or brown tinged mucous (or the whole plug at once), it's a great sign that you're dilating and preparing for labor, but it's no reason to rush to the hospital (unless it's bright red, in which case you should call your doctor/midwife).
• Again, references:  http://thebirthteacher.blogspot.com/2009/04/mucous-plug-not-for-faint-of-heart.html , http://babyfit.sparkpeople.com/articles.asp?id=754 , http://www.justmommies.com/articles/mucous-plug.shtml , http://www.webmd.com/baby/labor-signs

• Pegnant women are ticking time bombs for a million problems, no matter how healthy they are: FALSE (sort of)
• In a healthy, low-risk mom, it is extremely unlikely that she will encounter any complications in her pregnancy and birth. To treat symptoms that aren't there "just in case" they pop up is more likely to cause problems than prevent them. According to the WHO (World Health Organization), only about 15% of pregnancies worldwide really need emergency obstetrical care because of "risks that are difficult to predict." That means that you have at least an 85% chance of nothing at all going wrong, no matter where in the world you give birth. In a developed nation, with access to good prenatal care, your chances of a having successful, healthy pregnancy and birth can do nothing but increase.
• All that being said, problems can arise in the best of situations, so this is why it's good to be cared for by a doctor or midwife. Keeping an eye on your health, in the unlikely event something should go wrong, is different from insisting on test after test, policy after policy, for women who show no signs of needing them. Assuming the worst will happen does nothing but create fear. But trusting nature isn't enough; nature isn't perfect. Good prenatal care, with a watchful eye there to catch any legitimate issue before it becomes an emergency, is what's needed.

• You can't/shouldn't exercise in pregnancy, and sex while pregnant is dangerous: FALSE, and FALSE
• Maintaining a healthy exercise regimen in pregnancy is absolutely beneficial to both mother and baby! It's especially beneficial to do exercises that tone the abdominal and pelvic floor muscles, because those are the pivotal muscles in childbirth (for contractions and pushing). Exercise helps you sleep better, improves your mood, improves posture, reduces backaches, regulates your heart rate, may even help baby's heart development, and helps to keep your body aligned and in optimal shape for labor. 
• Some references on exercising while pregnant:  http://www.acog.org/~/media/For%20Patients/faq119.pdf?dmc=1&ts=20130812T1541231199 , http://www.webmd.com/baby/features/exercise-during-pregnancy-myth-vs-fact , http://pregnancy.familyeducation.com/prenatal-health-and-nutrition/exercise-and-weight-management/35963.html , http://www.livescience.com/13628-exercise-pregnancy-baby-heart-benefits-cardiovascular-disease.html 
•  Sex while pregnant is the same way. Unless you have any health concerns/problems like bleeding, premature labor, incompetent cervix, etc., there is no reason you shouldn't be able to have sex while pregnant if you want to. Also, the prostaglandins in semen may help "ripen" your cervix for labor toward the end of pregnancy, and the oxytocin released in the female orgasm can stimulate contractions. So if you're looking for a natural way to start labor, why not have some fun with it, right?
• Again, references. There were a lot of them for this one, but here are some of the best I found:  http://www.mayoclinic.com/health/sex-during-pregnancy/HO00140 , http://www.webmd.com/baby/pregnancy-sex , http://www.marchofdimes.com/pregnancy/sex-during-pregnancy.aspx

• "Eating for two": FALSE
• Nope. Just no. You may need to consume 300-500 extra calories per day (which is the equivalent of one extra small meal) later in your pregnancy, but do you know how tiny your baby is in the first trimester? Even mostly through the second? And the third? They mostly get what they need from you, and they don't need much. It's more about the quality of food, and making sure you're getting adequate vitamins and nutrients and liquids, than upping your food intake much at all.
• Articles and references: http://www.webmd.com/baby/features/pregnant-eat-for-two-right , http://www.fitday.com/fitness-articles/nutrition/healthy-eating/myth-or-fact-during-pregnancy-women-need-to-eat-for-two.html , http://www.metrohealth.org/body.cfm?id=4483 , http://www.mommydocs.com/2013/03/pregnancy-eating-for-two-myt/

• There's no need to worry about forming a birth plan and/or discussing it with your care provider till you start approaching your due date: FALSE 
• This could not be more untrue. An integral part of ensuring that you receive evidence-based care that is tailored to you, and achieve the birth experience you want, is first knowing what you want, and having a supportive care provider! How are you going to know if you have a supportive care provider if you don't talk to them about your wishes before it becomes an issue? The last thing you want is for them to pull a bait-and-switch on you at the last minute, so check their c-section/induction/etc. rates, ask them about their birth philosophy, educate yourself on how to best achieve what you want out of your pregnancy and labor, and make sure you and your doctor are on the same page before you reach a critical point. This is why you interview doctors. You re hiring them to perform a service for you, and if you are not comfortable with them for any reason, or your birth philosophies don't match up, you need to know that ahead of time, before you get in too deep. No references are needed for this; it's just common sense.

• You're overdue if you go past 40 weeks, and your due date is a deadline that is set in stone: FALSE, and FALSE
• You are not overdue, or "postdates," until you reach 42 weeks. Got that? Let me emphasize it: 42 WEEKS; NOT 40. 40 weeks is an average, not a deadline. The length of the average pregnancy is anywhere from 37/38(sources vary)-42 weeks, with 40 being, as I said, the mid-point. It is rare for babies to actually be born ON their due date, and the average for most first time moms is around 41 weeks 3 days. Every woman's cycles are different, and the 40-week due date (or Naegele's Rule) is based on the assumption that you have 28-day cycles and ovulate on day 14. If that is not true for you, then the 40-week due date calculations are far less likely to apply to you, and any suggested inductions for "postdates" could end in disaster due to a miscalculated due date (and a baby who is subsequently born too early). Also, no two women will gestate for the same amount of time, as a rule. I "cook" my babies faster, and they have both come early (39+1 and 38+6). I've heard of some women not going into labor till as late as 43, 44, and even 45 weeks, and having perfectly healthy babies! If "40 weeks" was a definite rule, that wouldn't be happening. It's an estimate, that is all. ACOG has actually come out with publications containing guidelines that state that providers should discourage elective (non-medically indicated) inductions before 39 weeks, due to the risk of premature birth, because due dates are so unreliable and are not a good enough indication of when each individual baby is ready to be born.
• This one definitely needs some good references, methinks: http://givingbirthwithconfidence.org/2012/03/finding-your-most-accurate-due-date/ , http://www.parents.com/pregnancy/giving-birth/labor-and-delivery/the-truth-about-due-dates/ , http://birthwithoutfearblog.com/2010/11/17/estimated-due-dates-are-as-accurate-as-a-crystal-ball/ , http://www.parenthood.com/article-topics/how_accurate_is_the_pregnancy_due_date.html , http://www.mdfpcases.org/ob/articles/postdates.pdf , http://voices.yahoo.com/the-lie-edd-why-due-date-isnt-you-1958162.html?cat=25

• You should  never eat sushi, cold cuts, mayo, etc., or have ANY caffeine or alcohol, while pregnant: FALSE(ish)
• The general rule is "everything in moderation." Yes, there are fish you should avoid while pregnant (and in childbearing years) due to the risk of high mercury levels. However, pregnant women in coastal and island nations have been eating raw fish since their cultures began, and they give birth to perfectly healthy babies. Should you be sure that your fish is fresh? Yes. Are there precautions you can take to protect yourself and your baby? Absolutely. Should you avoid sushi altogether with no exception? No. Want a personal story about it? I ate almost nothing but sushi throughout my second and third trimesters with my first baby (can you say cravings?), and she's just fine. Does that mean everyone will be? No. It just means that it's not a definite issue. Like anything in life, exercise caution.
• Reference: http://www.babymed.com/food-and-nutrition/how-safe-it-eat-sushi-or-raw-fish-during-pregnancy
• The same goes for mayo, cold cuts, and most anything else food-wise you hear about during pregnancy. The risks people talk about are still present when you're not pregnant, and they are so small that if you simply make sure your food is fresh and properly stored, you really don't have much of anything to worry about. Now, you probably should avoid unpasteurized cheeses and such (bacteria), but really, there are far more important things to be concerned with during pregnancy. Again, a personal story: I ate both mayo and cold cuts while pregnant with both girls, and again, both are fine. Be safe, be smart, be hygienic, and you've probably got nothing to worry about.
• Then we come to the caffeine debate. Most experts agree that 150-300mg a day of caffeine won't have much of an effect one way or another, and is safe during pregnancy. My story? I drank coffee and sodas with caffeine while pregnant. Every now and then, I might have had a little more than the "recommended" amount. And my girls are fine. Everything in moderation, as I said before. 
• Reference: http://americanpregnancy.org/pregnancyhealth/caffeine.html 
• And last, but not least, alcohol. There is no amount that is agreed upon by medical professionals to be "safe," but 1 in 8 women in a recent CDC study admit to drinking a little during pregnancy. I did it myself, very rarely and moderately, and once again, my girls are perfect. Do I think that automatically makes it okay for everyone? No. I was very healthy, with no real complications that could have been worsened by 1/4 a glass of wine once a month. It was my choice. It really comes down to that: mother's choice and extreme moderation, in this case.
• References for this: http://www.medicalnewstoday.com/articles/262063.php , http://www.theguardian.com/lifeandstyle/2013/jun/18/drinking-moderation-pregnancy-baby-development , http://www.cbsnews.com/8301-204_162-57589867/moderate-drinking-during-pregnancy-may-not-harm-babys-neurodevelopment/ ,  http://americanpregnancy.org/pregnancyhealth/alcohol.html , http://www.sciencebasedmedicine.org/alcohol-and-pregnancy/

• You should stay away from microwaves and x-rays while pregnant: PLAUSIBLE
• There have been studies that show slight risks associated with both microwave exposure and x-rays on a developing baby. Are they a terrible, scary, big deal? Not really. Your biggest concern with x-rays is if they need to take images of your abdomen and/or pelvis, and the risks involved with microwaves usually occur in a broken microwave. So if yours is fully functional, relatively new, and in good working order, you're more than likely fine. To emphasize these points: I broke my foot while 5 weeks pregnant with my second, and had to have an x-ray done. We took precautions (those lead aprons rock), and you know what? She's just fine. And I used microwaves while pregnant, and again, no side effects. Just use common sense.
• Here are some of my references:  http://pregnancy.about.com/od/isitsafeinpregnancy/qt/microwave.htm , http://rhrealitycheck.org/article/2011/08/08/pregnant-women-need-avoid-microwaves/ , http://www.intelihealth.com/IH/ihtIH/c/9273/35323/412440.html?d=dmtHMSContent , http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm142632.htm , http://americanpregnancy.org/pregnancyhealth/xrays.html , http://www.aafp.org/afp/1999/0401/p1820.html

• Stress is "bad for the baby," and your mood directly affects baby's development: PLAUSIBLE
• Everyone know that stress is bad for you. In anyone, it can cause anxiety, depression, and any number of physical symptoms. Of course that's going to affect a pregnant woman, whose hormones are insane anyway, even more. Some studies suggest that babies of moms who experienced extreme stress while pregnant may have a higher chance of asthma and allergies, so it is plausible that your stress can have an effect on your growing baby. Ask your friends and family to respect your condition and not stress you out, try to remove as much stress as you can from your life (easier said than done, I know), and take time every day to do something just for you.
• References for this:  http://www.naturalnews.com/023611_stress_pregnancy_asthma.html , http://www.medicinenet.com/script/main/art.asp?articlekey=51730
•  It also seems likely that severe moodswings can indeed have an effect on babies in the womb, too. Hormonal changes from these intense shifts in emotion can reach baby, apparently. Common sense again comes into play here. If you are under intense stress or experiencing moodswings, try to make time for yourself every day. Don't forget to indulge, because you matter, too. And while you are your baby's home, you (and your emotional state) are of utmost importance. Do I think this means that you should be as serene as a pond on a day without wind at all times? Um, no. I've been pregnant twice. That is utterly impossible. Just try to relax when you can.
• Some sites with more information:  http://news.bbc.co.uk/2/hi/health/1517520.stm , http://www.world-science.net/othernews/111117_depression.htm , http://www.livescience.com/17126-pregnancy-mothers-mental-state-baby-development.html

• Cocoa butter prevents stretch marks: FALSE
• This comes down more to your genetics than anything. If you have very dry skin (like me), you're more likely to develop stretch marks in pregnancy than someone with more elastic skin. Stretch marks are caused by the skin being stretched quickly, giving the skin insufficient time to adjust, and so the marks form. Here is a good article that details the science of stretch marks. 
• As far as cocoa butter goes, well, it can't hurt, right? Using lotions, bio-oils, and such can help improve your skin's elasticity and ability to stretch, but some women are just doomed to sport the marks. I'm one of them. I applied high-quality cocoa butter, gifted to me by my grandmother (who herself gave birth to 5 children), at least twice a day while pregnant with my first. It didn't help. I still developed huge, red marks, mostly on the lower left side of my belly where my daughter most liked to rest herself. I didn't get very big in my first pregnancy, so I didn't get a lot of the marks. The second time around, however ... It was bad. I still used my cocoa butter, mostly to ease the terrible burning and itching of my skin as it stretched, but I still got awful stretch marks all over my belly and thighs (I got bigger the second time around, which is totally normal). There were times when I thought my daughter was going to burst out of my belly, the skin just couldn't stretch anymore! So no, cocoa butter won't "prevent" them if you're genetically predisposed to them (ask your mom about hers, for some insight into what yours might look like), but hey, it's not going to do any harm, so you might as well give it a shot.
• Here are a couple of articles on the matter:  http://www.foxnews.com/story/2008/08/06/sorry-ladies-cocoa-butter-does-not-prevent-stretch-marks/ , http://www.foxnews.com/story/2008/08/06/sorry-ladies-cocoa-butter-does-not-prevent-stretch-marks/

• Ultrasounds are perfectly safe and have no adverse side effects or risks: FALSE (to a point)
• Ultrasound scans are made up of high frequency sound waves, used to create an image of something within your body. It's sound; shooting sound waves at a tiny baby in your womb. If you really think about it that way, it makes sense that there might be some risks involved. What are those potential risks? Studies say that prolonged ultrasounds can cause neurological damage, that the thermal aspect of ultrasounds (sound waves that don't bounce off the baby and are instead absorbed) can heat up fetal tissue dangerously, and, well, they're loud! The noise level of an ultrasound, as perceived by the growing baby, has been compared to that of a train. Not exactly pleasant, that's for sure. Both of my girls wriggled away from the "wand" they use to perform the ultrasound, as if they didn't like it. I always thought that they just didn't like the prodding, but now that I've done more research into what ultrasounds are and how they work, it's gotten me thinking.
• Now, this isn't to say that all ultrasounds are inherently dangerous and you should always avoid them, no matter what. The point being made is that you should avoid unnecessary ultrasounds when possible, because they are not risk-free. If the risks outweigh the benefits (suspected serious problems that need to be checked out), that's a different case entirely. But begging your OB/midwife for extra ultrasounds so you can see the baby more often, or going to one of those "clinics" that does keepsake ultrasounds, probably isn't the best idea. Not only are the people in those clinics not adequately medically trained, but any unnecessary exposure, even at the hands of a certified ultrasound technician, is too much. Just as you would try to avoid an x-ray while pregnant unless it was necessary due to the potential risks, the same discretion should go for ultrasounds.
• Here are a few of the sources I found on this: http://www.greenhealthwatch.com/newsstories/newslatest/latest0701/ultrasound-hurt.html , http://www.midwiferytoday.com/articles/ultrasoundwagner.asp?q=ultrasound , http://www.midwiferytoday.com/articles/ultrasoundrodgers.asp , http://contemporaryobgyn.modernmedicine.com/contemporary-obgyn/news/modernmedicine/modern-medicine-now/fetal-ultrasound-how-put-safety-first

• Worse morning sickness means that you're having a girl; carrying high means you're having a girl, carrying low means a boy; fetal heart rate indicates gender: FALSE
• With myths like this, you have about a 50/50 chance of being right, but they are not supported by science.
• The way a mother is carrying her baby is more about her shape, the way the baby is lying, and genetic factors like that, than gender. I know my girls would go from low-slung to riding-high within a matter of minutes if they wanted to. Due to my shape, you couldn't even tell I was pregnant from behind. Other than that, I carried them very differently, and they were both girls. 
• Some more references: http://www.uamshealth.com/?id=895&sid=1 , http://www.everydayfamily.com/six-pregnancy-myths-revealed/
• The same thing goes for fetal heart tones. The myth is that a heart rate below 140bpm means the baby is a boy, and above 140bpm means a girl. I'll admit, it was true for me, as both my girls' heartbeats were high, but there is no science that backs this up. 
• Sources: http://www.in-gender.com/Gender-Prediction/Fetal-Heart-Rate.aspx , http://pregnancy.about.com/od/genderpredictions1/ss/genderfht.htm , http://www.nytimes.com/2008/01/15/health/15real.html?_r=0

• You can't refuse anything your doctor suggests. Anything you doctor says is absolutely set in stone. You don't call the shots, and all prenatal tests are mandatory. Blind trust in doctors and just "being a good patient" is the best way to go: FALSE
• This. Could. Not. Be. More. False.
• You have the right to refuse any tests or procedures your doctor suggests. If you have to sign an AMA (against medical advice) form to get them to stop pestering you, so be it. It is your body, and your baby, and you call the shots. If it were anything other than pregnancy, this would not even be in question. Doctors cannot perform any procedures on an unwilling patient, period. You may have to look into laws in your area if it comes to more serious issues like VBAC and RCS, but the right is still yours.
• Blind trust in doctors has gotten us a cesarean section rate of over 30%. It got us twilight sleep, thalidomide, a 1 in 3 induction rate, and 2 out of 3 women receive drugs to artificially start or augment their labor. (See this previous blog post of mine.) You don't have to be a "good patient" to get good, evidence-based care. You just have to find a care provider whose views on pregnancy and birth are in harmony with yours. Easier said than done, but as I've said before, you are hiring them, not the other way around.

• You can't switch care providers after (x) weeks of pregnancy: FALSE
• Well, this might have a little basis in truth. Some care providers won't accept new clients after they reach a certain point in pregnancy, but that is not the norm. It is never too late to shop around and see what your options are, if for any reason you become dissatisfied with your current care provider.

• Cravings have nutritional meaning/significance: BOTH TRUE AND FALSE
• If you're craving ice cream, it means you want ice cream. If you're craving fried eggs, you probably just want to eat fried eggs. The same goes for pineapple, icees, sushi, french fries with copious amounts of ketchup, and anything other food or drink you might crave during pregnancy (yeah, all of those cravings I listed were some of mine ...). They do not indicate a nutritional need in your diet. Craving red meat doesn't mean you need iron. Craving fruit doesn't mean that you need more sugar. During pregnancy, it more than often means that you find those foods comforting, or maybe they're just the only things you find palatable (yeah, I completely understand that). If cravings were tied to dietary needs, you'd never crave anything unhealthy.
• Sources on the matter: http://www.webmd.com/diet/features/cravings-why-they-strike-what-to-do , http://hypnosishealthinfo.com/food-cravings-nutritional-deficiency/ , http://www.prevention.com/food/healthy-eating-tips/heath-news-roundup-do-food-cravings-indicate-nutritional-deficiency , http://www.huffingtonpost.com/2012/10/08/food-cravings_n_1940299.html
• HOWEVER, there is a serious condition that you can develop (and not just in pregnancy) that involves craving non-food items like chalk, dirt, or paint. If this happens, tell your doctor immediately, as it can be a serious condition.
• More PICA information: http://americanpregnancy.org/pregnancyhealth/unusualcravingspica.html , http://www.webmd.com/mental-health/mental-health-pica

• Bed rest is always beneficial: FALSE
• The current evidence does not support the practice of bed rest, and in fact, bed rest may cause complications such as blood clots, loss of muscle tone, weight loss, and depression. It does not improve outcomes significantly at all when it comes to preventing preterm birth, miscarriage, and the like (which are the most common reasons for prescribing it), and therefore is usually an unnecessary ordeal to put an expectant mom through, especially if she has other children, or a job, or her house, to take care of.
• Research on this matter:  http://articles.chicagotribune.com/2011-01-29/health/ct-met-bed-rest-20110129_1_bed-rest-pregnant-women-preterm , http://www.scienceandsensibility.org/?tag=bed-rest-during-pregnancy , http://commonhealth.wbur.org/2013/05/unethical-bed-rest-for-pregnant-women , http://www.webmd.com/baby/guide/bed-rest-during-pregnancy , http://www.medscape.com/viewarticle/529232

• Your doctor/midwife can know ahead of time (before a ToL) whether or not baby "will fit": FALSE
• No matter how big they think your baby is, there is no way to know if it will fit through its mother's pelvis without a ToL (trial of labor). An educated guess can, of course, be mad, but it is just that: a guess. If there are no other concerning factors, there is no reason to take any preemptive action such as a scheduled induction or c-section (which I've addressed in this post and a previous post). There are exceptions, such as a mom with a known birth defect of the pelvis, or who had an accident that injured/crushed her pelvis. But if those factors are not present, there is no reason not to give her a ToL before assuming the baby won't fit, no matter how "petite" she is or how "big" the baby seems.
• And here are some sources:  http://spinningbabies.com/baby-positions/cpd , http://www.bellybelly.com.au/birth/small-pelvis-big-baby-cpd#.Ugqx3m3wa1s , http://www.justmommies.com/pregnancy/concerns-and-complications/cephalopelvic-disproportion-what-you-should-know

• Weight gain requirements and limitations are a general rule and the same for everyone: FALSE
• First, I'll start with my stories. With my first, I lost 8lbs in my first trimester, gained those 8lbs back in my second trimester, and gained 8lbs more in my third trimester. I was only 8lbs above my pre-pregnancy weight when I gave birth. With my second, I slowly and steadily gained 16lbs. I was told, based on my height, BMI, and pre-pregnancy weight, to expect to gain 25-30lbs both times. I didn't, and my girls were born picture-perfect and I was completely healthy. I have know women who gained exactly their recommended amount, some who didn't gain anything at all, and still others who gained 50lbs or more, and all had healthy babies. What is normal for one woman or pregnancy is not going to be the same as anyone else. Genetic factors do come into play, but they, like everything else, are not a guarantee. As long as mother and baby are healthy, the mom's diet is balanced and she's exercising appropriately, baby is growing well, and everything else looks good, weight gain alone doesn't have to be much of a concern. 
• References: http://www.marchofdimes.com/pregnancy/weight-gain-during-pregnancy.aspx , http://www.acog.org/Resources%20And%20Publications/Committee%20Opinions/Committee%20on%20Obstetric%20Practice/Weight%20Gain%20During%20Pregnancy.aspx

• You will show sooner, and get bigger, in subsequent pregnancies than you did in your first: TRUE
• Yes, I am dealing with a "myth" that is (often) true! Once your body has "been there, done that," especially if your pregnancies are close together, you're probably going to start showing sooner. Your uterus has stretched and grown to accommodate a baby before, so it grows much faster and easier the second (and third, and fourth) time around. Also, your abdominal muscles may be more stretched out and lax, which allows your belly to "pop" sooner. There are exceptions, of course, such as moms who have very toned abdominal muscles, or whose pregnancies was spaced out further (which gave their bodies more time to recover), etc. But the general rule is that any subsequent pregnancies will become "visible" sooner, and you're more likely to appear "bigger" as well.
• And my sources: http://www.babymed.com/pregnancy-symptoms/why-am-i-showing-so-early-pregnancy ,  http://pregnancy.about.com/cs/secondpregnancy/a/aa051997.htm , http://pregnancy.amuchbetterway.com/your-second-pregnancy