Gone are the days when gender prediction meant taking the word of the wise old lady in the village. Ultrasounds have increased hugely in quality and accuracy over the past 30 years and – unlike other areas of the world, such as Europe (where scans are rarer), or India and China (where gender detection is banned), now the doctors are generally happy to scan you to your heart’s content.
But although your baby’s XX (female) or XY (male) combo of chromosomes is determined from the moment of fertilization, his or her genitalia does not even begin to develop in a visible way until about nine weeks. You’re also likely to have to wait until about 20 weeks for the detailed anatomy scan in order to find out his or her sex with the most accuracy (which is still only 98% and not guaranteed if bubs isn’t playing ball position-wise).
This four-month waiting period can spark a lot of curiosity and excitement in expectant parents, prompting random guesses from friends and family about whether or not the shape of your tummy or the glow of your skin could mean you’re nurturing a baby girl or baby boy.
Most of these guesses stem from folklore dating back centuries to when sex prediction wasn’t medically possible – although interestingly, some of them do contain strands of what we now know to be truth in them. We spoke to Pranjul Tandon, Childbirth educator and newborn care coach at Wombandbeyond.info, to help us do a fact check and discover the truth behind these theories…
Myth: If the fetal heart rate is above 140 beats/minute, it’s a girl. If it is lower, it’s a boy.
Fact: Although this might sound scientific, several studies have been done to compare fetal heart rates between genders during pregnancy, with no significant correlations or contrasts found. “In reality fetal heart rate only depends on the health, age and activity levels of the fetus,” explains Pranjul. In general an embryo’s heart rate starts at about 75 beats per minute, which then accelerates each day during the first month until it peaks at about 180 beats per minute, and then reverses so that by the middle of pregnancy the average rate is between 120 to 160 beats per minute. Intriguingly a 1999 study did find that female fetuses having a significantly higher heart rate during normal labour than male fetuses, but the reasons for this are unknown.
Myth: If your bump is protruding like the shape of a ball, it is a boy. If your bump’s weight is more spread out around your middle, it’s a girl.
Fact: This is one of folk wisdom’s favourite ‘facts’, prompting anyone from your co-workers to strangers on the street to declare they have special insight into the gender of your growing baby. While boy babies do tend to be slightly heavier than girl babies, this would only affect the size, rather than the shape, of your bump. “In fact, the appearance of a woman’s pregnant stomach is entirely dependent on her body shape and the weight and position of the fetus,” says childbirth educator Pranjul Tandon.
If a baby is positioned with its back pressed up against the mother’s front then the mother’s tummy will protrude outwards, whereas if the baby is positioned against the mother’s back her tummy will look flatter. The baby’s position has nothing to do with the baby’s gender – nor does the abdominal strength of the mother’s stomach, or how many children she’s had before, both of which can also affect whether she appears to be carrying her bump ‘high’ or ‘low’.
However, some scientists say that it’s the shape of the breasts rather than stomach that you should be looking at in order to guess the gender. According to a 2015 Polish study, a woman’s breast volume is likely to increase more during pregnancy if she is carrying a baby boy rather a girl, which is thought to be due to a male infant’s increased lactation demands.
Myth: Women with more severe morning sickness are expecting a girl.
Fact: There is actually potentially some truth to this one. A study of over a million pregnancies in Sweden between 1987 and 1995 showed there was a greater risk of the serious morning sickness condition known as hyperemesis gravidarum in the first trimester for women who were carrying a female child. These findings have been backed up by multiple other studies, including one by the University of Washington in 2004, as well as Lancet research, and a 2017 small-scale study by Ohio State University, among others.
It’s still uncertain what causes morning sickness, but some scientists believe it may be connected with the hormone human chorionic gonadotropin, which is produced by the placenta after implantation, while others conjecture that the increased likelihood of morning sickness in mothers of girls could be connected to higher levels of oestrogen.
Meanwhile, the recent Ohio study found that there’s a greater pro-inflammatory response in the immune cells of women carrying a girl, meaning they might be more susceptible to illness than women carrying boys. Nevertheless, although there may be some link between morning sickness and your baby’s gender, it’s by no means a surefire way of predicting the sex; no better than ‘tossing a coin’ according to one of the researchers in the Swedish study.
Myth: Suffering from heartburn during pregnancy can indicate that the baby is a girl with lots of hair.
Fact: Heartburn is a common pregnancy complaint, which happens when the growing uterus pushes the stomach, causing stomach acids to travel to the esophagus. Another cause can be changing levels of hormones, which interfere with the stomach and digestion system. But although scientists have long thought that the connection between heartburn and fetal hair was nothing but folklore, a 2006 John Hopkins study shocked the scientific community by proving that there actually is a connection. How could this be?
The researchers theorized that there may be a shared biologic mechanism involving a dual role of pregnancy hormones in both the relaxation of the lower esophageal sphincter and the modulation of fetal hair growth. However, although there may be a link between heartburn and hair, this is no indication that you’re having a girl – baby boys can be just as hairy as baby girls!
Myth: If the Linea Nigra runs above the belly button, it’s a boy and if it runs below the belly button, it’s a girl.
Fact: This Latin term translates literally to ‘black line’ and refers to the dark line that often runs from the pubic bone to below or above the navel of a pregnant women’s belly. A type of skin hyperpigmentation that roughly 75% of pregnant women will experience, it’s believed to be caused by fluctuating hormones and is more prominent in mothers with darker skin. While there’s no evidence that it has anything whatsoever to do with the gender of your baby, experts speculate that its evolutionary purpose was to help guide a newborn up towards their food source, the nipple – the skin of which usually also darkens in pregnant women.
Myth: Dangling the wedding ring with a string on a pregnant belly can predict the gender.
Fact: “Perhaps the most fun and the most ridiculous old wives’ tale about gender prediction, which has been around for centuries,” says Pranjul. “The only thing a wedding ring may predict is the wealth of the unborn baby’s parents.”
Myth: If a pregnant women prefers sleeping on her right side, she will have a girl, and if she prefers the left side, she will have a boy.
Fact: This old wives’ tale is so spurious that scientists haven’t even bothered to look at the link between sleeping position and baby’s gender (spoiler alert: there’s no connection). Far more important is the fact that doctors recommend that expectant mums should sleep on their sides, rather than their backs, which has been associated with a heightened risk of still birth. “Sleeping on your left side is considered most favourable than on the right side as it increases blood circulation and flow of nutrients to the baby,” says Pranjul.
Myth: Craving for salty/spicy/sour foods indicate a boy, whereas craving sweets and dairy products indicate a girl.
Fact: Food cravings are one of the most mysterious and misunderstood aspects of pregnancy. While countless women will swear by their insatiable pregnancy desire for pickles and ice cream, the jury is still out in the scientific community on whether pregnancy cravings really actually exist at all, or if they’re simply psychological (although pregnancy ‘Pica’ – the urge to eat inedible substances such as charcoal and chalk – is a recognized condition).
There’s been a lot of research on what could cause cravings during pregnancy, although there’s no definitive evidence yet. Some theorize that it could be down to varying hormone levels, some that it could be due to the body’s nutritional deficiencies, while some have investigated the cultural impact of pregnancy. Either way, there is no current evidence that cravings are in any way an indication of the sex of the unborn baby.
Myth: There are all sorts of theories about how your baby can impact your appearance, many of which are directly contradictory. For instance, some say that if the Mum-to-be’s skin is radiant and soft, it’s a girl, and if it is dull and dry, it is a boy. Meanwhile others say the opposite: that a baby girl will steal her mother’s beauty, while a baby boy will boost it.
Fact: Pregnancy almost always brings about skin changes due to varying hormone levels, but these affect every individual differently. They may cause your oil glands to secrete more sebum, which could either manifest itself in the renowned ‘pregnancy glow’ or, if you’re less lucky, in recurrent acne and chin spots.
Additionally, the increased blood volume in pregnancy brings more blood to your vessels, resulting in skin that can look flushed. Of course, good nutrition and plenty of hydration play a major role in how a mother’s skin looks – but, unfortunately, the sex of the baby you’re carrying does not. #KhabarLive