By Joanne Stone, Keith Eddleman, Mary Duenwald

Pregnancy has a certain mystique. Millions of women have been through it, yet predicting in detail what any one woman’s experience will be like is difficult. Perhaps that’s why so many myths have formed (and survived) over the centuries, most of which are designed to foresee the unknowable future. Here are 12 tales that, alas, are really nothing but nonsense:

  • Old Heartburn Myth: If a pregnant woman frequently experiences heartburn, her baby will have a full head of hair. Simply not true. Some babies have hair; some don’t. Most lose it all within a few weeks, anyway.

  • Mysterious Umbilical Cord Movement Myth: If a pregnant woman lifts her hands above her head, she will choke the baby. People used to think (and, alas, some still believe) that the mother’s movement could cause the baby to become tangled in the umbilical cord, but that’s just not true.

  • Curse Myth: Anyone who denies a pregnant woman the food that she craves will get a sty in his eye. Nope. This myth doesn’t mean that someone who stands between a pregnant woman and her craving is in the clear, though: He will most certainly be subjected to threats, name-calling, or icy glares, but no sties.

  • Heart Rate Myth: If the fetal heart rate is fast, the baby is a girl, and if the heart rate is slow, the baby is a boy. Medical researchers actually looked into this myth. They did find a very slight difference between the average heart rate of boys and that of girls, but it wasn’t significant enough to make heart rate an accurate predictor of sex.

  • Ugly Stick Myth: If a pregnant woman sees something ugly or horrible, she will have an ugly baby. How could this possibly be true? There’s no such thing as an ugly baby!

  • Java Myth: If a baby is born with café au lait spots (light-brown birthmarks), the mother drank too much coffee or had unfulfilled cravings during her pregnancy. Nope. Drinking 150–200 mg caffeinated beverages/day is considered safe (about 1–1/2 cups coffee/day — but not Starbucks Trenta). Higher consumption of caffeine has been linked to miscarriage and low-birth weight.

  • Myth of International Cuisine: Eating spicy food brings on labor. It doesn’t, but it may be an effective marketing tool: One Italian restaurant advertises its Chicken Fra Diavolo as a sure-fire labor-inducer. The dish may be delicious, but it simply can’t bring on labor. Nope. Niet. Nunca. Nein. Non.

  • Great Sex Myth: Having passionate sex brings on labor. What got you into this mess will also get you out? That’s just wishful thinking, but go ahead and try it (if you feel like it when you’re nine months pregnant). It’s likely to be worth the effort.

  • Round Face Myth: If a pregnant woman gains weight in her face, the baby is a girl, and if a woman gains weight in her butt, the baby is a boy. Neither statement is true, obviously. The baby’s sex has no influence whatsoever on the way the mother stores fat.

    Another related myth is that if the mother’s nose begins to grow and widen, the baby is a girl. The so-called reasoning here is that a daughter always steals her mother’s beauty. Strange concept — and quite untrue.

  • Moon Maid Myth: More women go into labor during a full moon. Although many labor and delivery personnel insist that the labor floor is busier during a full moon (police say their precinct houses are livelier then, too), the scientific data just doesn’t support the idea.

  • Belly Shape Myth: If a pregnant woman’s belly is round, the baby is a girl, and if the woman’s belly is more bulletlike, it’s a boy. Forget about it. Belly shape differs from woman to woman, but the child’s sex has nothing to do with it.

  • Ultrasound Tells All Myth: Ultrasound can always tell the baby’s sex. Nope, not always. Often, by about 18 to 20 weeks’ gestation, seeing a fetus’s genitalia on ultrasound is possible. But being able to determine the baby’s sex depends on whether the baby is in position to give you a good view.

    Sometimes the sonographer can’t see between the uncooperative baby’s legs and, therefore, can’t determine the sex. Sometimes, too, the sonographer may be wrong, especially if the ultrasound is done very early in the pregnancy. So even though you can find out the baby’s sex through ultrasound in most cases, it’s not 100 percent guaranteed.