Fact or Fiction: can you tell the sex of a baby by the shape of the bump?

«Your bump’s really low. Definitely a boy!» – you may have heard this yourself during your pregnancy. Or how about this piece of wisdom: «Your belly’s growing wide, so it’s probably a girl.» Did these predictions turn out to be true in the end?

There’s many a myth surrounding the shape of baby bumps. Pointy ones are said to be carrying boys, as do ones that are low down. Wide bellies and those that are quite high up, on the other hand, are said to mean it’s a girl. These theories are persistent and have been around for thousands of years. According to the German newspaper Süddeutsche Zeitung (article in German), they go back to ancient times. It’s likely they’re based on the assumption that boys are carried in the right of the womb and girls on the left.

However, this would mean a separation down the middle of the belly, which would only be visible on the side and not influence the shape of the bump. Who knows, maybe it’s a case of ancient Chinese whispers: the longer the message is passed on, the more it’s distorted.

In any case, it doesn’t matter anyway. Why? Because all belly shape theories are rubbish. Experts agree on this today.

Belly shape myths debunked

Scientists at Johns Hopkins University in the US disproved the myth in 1999 in a study. 104 pregnant women who did not know the sex of their baby were asked to guess it using a traditional method: using folk wisdom such as the shape of the belly, their dreams or their premonitions. They were right in only 55 per cent of cases, so they might as well have taken a blind guess.

Interestingly, dreams and feelings scored better (71 per cent), at least in women with a higher level of education. Sounds even more off the wall than the belly shape theory. What’s more, the scientists were unable to explain it. «Although predictions of the middle-class group were statistically better than chance, individual women who feel sure of their baby’s sex before birth should not be painting the nursery blue or pink just yet,» lead study author Janet DiPietro said at the time.

Factors that influence the shape of the abdomen

The only reliable method of determining gender is at around week 14 of pregnancy by means of a medical check involving ultrasound, invasive diagnostics or a blood test.

The shape of the belly, however, depends on the baby’s size, the amount of amniotic fluid and the mother’s body shape and muscles. And how the child is positioned. If it’s lying upside down, for example, this often results in an egg-shaped belly. If the child is «sitting» in breech presentation, the abdomen tends to widen.

Incidentally, heartburn, cravings and blemished skin don’t indicate whether the child will be a boy or a girl. In other words, appearance has absolutely nothing to do with the baby’s sex. Presumably, these myths are so persistent because there’s a 50 per cent chance the prediction will be correct. Not bad, I suppose.

In the series Fact or Fiction, I get to the bottom of wacky wisdom about babies and bizarre pregnancy theories. Other articles: