Which Pregnancy Myths Are Actually True?

If you have heartburn when you're pregnant, it means that your baby will have a lot of hair when it's born. Really? This is Dr. Kirtly Jones from Obstetrics and Gynecology at University of Utah Health, and this is The Scope of Some Myths About Pregnancy, on The Scope.

Pregnancy is mysterious, and what is going on in there is mostly unseen and to my biological eye, magical. There are outcomes that are good and some less than good, and we cannot explain all of them based on scientifically proven cause and effect. So we turn to myths and old wives' tales. Some of these exist back to before there were well-defined scientific methods, and some are new. Let's look at a few.

Belly Shape Does Not Determine Baby's Gender

One, the shape of your pregnant belly can tell you whether you're carrying a boy or a girl. If you carry your baby bulge low, it's a boy. If you carry it high, it's a girl. There is no fact to that. It is a fact that the first pregnancy, before the abdominal wall is stretched out, tends to be visually higher. As the abdominal wall gets stretched out with each new pregnancy, the uterus appears to be carried lower, but it's not the sex of the baby.

Baby's Heart Rate Does Not Predict Gender

Number two, your baby's heart rate can determine the sex of your baby. Higher heart rates are for a boy, and lower is for a girl. That's a no. There is no evidence that the heart rate is determined by the baby's sex.

Eating Spicy Foods Does Not Cause Blindness

Number three, spicy foods can cause your baby to be born blind. That's a no. However, because pregnancy hormones and the pushing of the uterus as it gets higher can cause reflux, spicy foods can be less well tolerated, but they won't make your baby blind.

Cocoa Butter Does Not Prevent Stretch Marks

Four, cocoa butter prevents stretch marks. That one is a no. But it does smell good and it makes your skin feel soft, so go for it if you like it. But it makes your sheets greasy.

Eclipse Gazing Does Not Cause Cleft Palate

Number five, looking at the sun during an eclipse will give your baby a cleft palate. That one would be hard to prove because there are few pregnant women who would be so careless as to look at the sun when they're pregnant during an eclipse, and there are a few eclipses and I don't really recommend a randomized controlled trial to test that one out.

Eating for Two Is Not Necessary

Number six, you should eat for two when you're pregnant. I don't know where that one came from except that it's usually a rationalization about how much you might want to eat. You can get enough energy to make a baby in about 300 calories extra a day, about 3 little cookies with no redeeming nutritional value, 3 tablespoons of peanut butter, notice that's not a rounded tablespoon but a flat one, ladies, or 3 glasses of reduced-fat milk, a good nutritional source of calcium and protein. So you should eat for about 1.16 persons or about 1 and a 6th.

Hair Coloring is Safe During Pregnancy

Number seven, you cannot color your hair when you're pregnant because it will harm the baby. That's a no. If it were true, there would be some serious fashion problems. It probably isn't good to introduce any new chemicals that you aren't sure about in your first trimester, but after that the amount that might be absorbed by your skin, if you do it a couple of times during your pregnancy, is unlikely to be a problem.

Dark Beer Does Not Induce Milk Production

Number eight, drinking dark beer will help your milk come in. That's a no. Really? That's my family's favorite myth. It was given to my mother in Germany by the nuns at the hospital when she delivered me. It was given to my sister and to me, and it sure seemed to bring it on. Well, actually, it doesn't make the milk be produced. However, relaxing a new mom just out of the hospital, who's worried about everything, can help the milk come down. The let-down reflex of releasing the milk stored in the ducts so the baby can nurse can be inhibited by anxiety and stress and maybe the alcohol and dark beer can work for that.

Heartburn Does Not Indicate Hairy Babies

Number nine, if you have heartburn, you'll have a baby with lots of hair. No. Well, a study from Johns Hopkins, published in 2006 in the journal "Birth," asked 64 pregnant women about their degree of heartburn during pregnancy, and an independent observer graded the amount of hair in the newborns, and there was a simple linear association between the degree of heartburn and the amount of hair. The more heartburn, the more hair, and the association was highly statistically significant. Now, I can see that there might be some racial differences in how hormones affect pregnancy and then affect the sphincter or the tight place between the stomach and the esophagus that prevents reflux and heartburn, and some racial groups have babies with more hair, and some with less. However, 90% of the women in this study identified as Caucasian. So there isn't really a good reason for this amazing statistical outcome. The author said, "Much to our surprise and somewhat to our chagrin, our application of straightforward but standard scientific methods to investigate the validity of this ubiquitous pregnancy 'myth'" -- they put quotations around the word "myth" -- "resulted in its partial confirmation." Who knew? Pregnancy is still mystifying.

If you have questions about what you've been told by your mom or your auntie, talk to your clinician and make them do their homework and look it up, and thanks for joining us on The Scope.

_{updated: May 3, 2024
originally published: March 7, 2019}