The myth of “eating for two” endures partly because it kind of makes sense, but mainly because it is so appealing. In a survey of 2,100 women, the National Charity Partnership (NCP) found that two-thirds of women did not know how many extra calories they needed during pregnancy (a measly 200 a day – something like, the charity says, two pieces of wholegrain toast with olive-oil spread – and only in the third trimester). Being overweight in pregnancy carries increased risks to the woman and baby; the myth, said the Alex Davis, head of prevention for the NCP, is “very unhelpful”. Other myths are just annoying – and at no other life stage will a woman be subjected to so much rubbish.

Eat red meat or salty food if you want a boy; eat sweets if you want a girl

The idea that there are boy foods (strong, meaty) and girl foods (light, sugary) is basically sexist, but food may influence the sex of the baby. In 2008, scientists found women who had a high-calorie diet prior to conception were slightly more likely to give birth to a boy. Not that wolfing down the calories is recommended (see above).

You can tell the sex of the baby from the shape of the bump ...

The only thing the bump might tell you, bearing in mind that women love to be stared at and commented on, is if it’s a woman’s first pregnancy – in subsequent pregnancies, stomach muscles may be weaker and the baby may be carried lower. The shape of the bump is determined by the size and position of the baby and the body type and muscle tone of the woman.

… and from what you are eating

Again, women are supposed to crave sweet things if they are expecting a girl, and savoury things if it’s a boy. There’s no evidence for this, but how much you eat may be a predictor. Boys tend to be around 100g heavier than girls at birth. In one study of 304 women, those who went on to have male babies had about a 10% higher energy intake during the pregnancy.

Heartburn means you will have a hairy baby

This tale may have some truth in it. In a study of 64 women, researchers found most women who reported moderate or severe heartburn had babies with luxuriant hair, while those reporting no heartburn were more likely to have baldies.

Playing Mozart to your bump means you’ll have a brainy baby

The evidence is scant, but it may have other beneficial effects. In her book Bumpology, Linda Geddes suggests it may relax you, and playing the same music after the baby is born could also ease its “transition into the outside world by providing it with something familiar.”

Curry/pineapple/sex induces labour

One survey found 18% of women thought eating a hot curry could help bring on labour. Others believe pineapple can speed things up – it contains an enzyme, bromelain, that is thought to soften the cervix, although how much you would have to eat for it to have any effect isn’t known (a huge amount, probably). The idea of sex bringing on labour is loosely based on science. Semen contains prostaglandin, a hormone used medically to induce birth. Nipple stimulation, the release of oxytocin and orgasm-related contractions are also thought to stimulate the uterus. But the evidence is mixed.