The Biggest Pregnancy Myths Debunked

There are all kinds of crazy things people claim to know about pregnancy. Do some foods help you induce labour? Is it really possible to know the sex of your child based on the shape of your belly?

Linda Geddes, award-winning journalist and science reporter, explores the most common baby myths and questions from parents-to-be in the new book Bumpology: The Myth-Busting Pregnancy Book for Curious Parents-To-Be, out this month from sister company Simon & Schuster.

Here are the top five pregnancy myths debunked to help calm any parent-to-be.

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The shape of your bump can predict the gender of your child

Women who carry high and all upfront are expecting boys, while a low, wide bump is a sign of a girl – or so says the folklore. But when Janet DiPietro of Johns Hopkins University investigated this old wives tale she found no correlation between the shape of a woman's bump and the gender of the child developing inside it. Indeed, in most cases the pregnant woman and the investigator couldn't agree on what shape the woman's bump should be classified as. But not all old wives tales surrounding the baby's gender are so easily dismissed. For example bad morning sickness can provide a clue – women whose morning sickness is so bad that they have to be admitted into hospital (a condition called hyperemesis gravidarum) are statistically more likely to be carrying a girl.

You can't exercise during pregnancy

Many women give up exercising once they discover they're pregnant, but this is usually unnecessary. Indeed, when Andrew Satin also at Johns Hopkins University asked heavily pregnant women to walk or run on a treadmill until they reached the point where they could go no further, he found that the babies were just fine. You can even do certain stomach exercises when you're pregnant. Exercises such as the plank are safe, as are pelvic tilts. You should avoid full sit-ups or abdominal crunches during late pregnancy however, because these can cause the central abdominal muscles to pull apart.

Don't eat peanuts during pregnancy

Currently both the American Academy of Pediatrics and the UK food standards agency say that it's fine to eat peanuts during pregnancy (even though both previously advised against it, if there was a history of allergy or asthma in the child's immediate family). It's true that a handful of studies have suggested an indirect link between eating peanuts during pregnancy and childhood allergy, but others have found just the opposite: that eating peanuts may protect infants against allergies. In 2008 the UK's Committee on Toxicology reviewed a whole bunch of human and animal studies and concluded that there aren't enough high-quality studies to support the idea that eating peanuts is bad for the unborn child. A recent review by the American Academy of Pediatrics reach the same conclusion. That doesn't necessarily mean peanuts have the all clear, but until more good quality research is done, there's no particular reason to worry about eating peanuts.

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Eating spicy food and pineapple, or drinking raspberry leaf tea can bring on labour

Sex, curry, raspberry leaf tea – there are a multitude of home remedies for kick-starting labor. Unfortunately, there is little evidence that any of them work. The only home-remedy that might work is nipple stimulation. Stimulating the breast triggers the release of oxytocin, one of the hormones responsible for driving contractions in labor. A scientific review of six trials found that more than a third of women who stimulated their breasts during late pregnancy were in labour within 72 hours, compared to just 6 percent of those who didn't.

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Caesarean sections make it harder to bond with your baby and make breastfeeding more difficult

Some obstetricians have suggested that because women undergoing a planned Caesarean section don't experience labor, they have less of the hormone oxytocin circulating in their bodies. As well as driving labor, oxytocin plays a role in bonding, so the theory is it will be harder for these women to bond with their babies. There is scant direct evidence to support this, however. A study published in 2008 suggested that c-section moms were less responsive to their baby's cries than moms who delivered naturally, but the study looked at just 12 women a few days after birth, and used brain imaging rather than looking at how the women and babies interacted in real life. It also didn't follow-up the women to see how their relationships developed over time.

As for breastfeeding, it is true that more women who deliver by Caesarean section end up bottle feeding, but this doesn't have to be the case. Increasing evidence supports the idea that skin to skin contact in the first minutes or hours after birth is crucially important for establishing the breastfeeding relationship. Historically women undergoing a Caesarean section have been separated from their babies during these hours, but this is increasingly becoming the exception rather than the rule.

Linda Geddes is a London-based magazine journalist, who writes about biology, medicine and technology. She has worked as both a news editor and reporter for New Scientist magazine, and recently contributed to Dorling Kindersley's The Human Body. She has received numerous awards for her journalism, and was also shortlisted for the Paul Foot Award in 2011 and the Press and Periodicals Association's Writer of the Year award in 2009 and 2011. Her new book, Bumpology: The Myth-Busting Pregnancy Book for Curious Parents-to-Be, is out this month from Simon & Schuster, a CBS Company.