Pregnancy Myths Debunked: Common Old Wives’ Tales vs Facts (and What’s Actually True)

Pregnancy is a time when everyone suddenly has an opinion. From well-meaning relatives to strangers in supermarket queues, pregnant women are often bombarded with a lot of advice. Sometimes this is helpful, sometimes a little outdated, and some rooted firmly in old wives’ tales rather than medical science.

So how can you know what to really trust? We’ve rounded up the most common pregnancy myths and explained what’s fact and what’s fiction, and a few practical tips you can actually use on your pregnancy journey too. Hopefully this post will give you some of the answers to the questions you sit up Googling at 3am, asking “is this normal?!”

We’ll look at what’s true vs myth, why these tales exist in the first place, and when it’s time to stop listening to Aunt Susan and start listening to your healthcare provider.

Why pregnancy myths are everywhere

Pregnancy myths have survived for generations because pregnancy used to be mysterious, poorly understood, and often dangerous. Before modern prenatal care, people relied on observation, coincidence, and storytelling to make sense of what was happening inside the womb.

Throw in a more than a few hormonal changes, dramatic bodily shifts, and the fact that no two pregnancies are the same, and it’s no wonder myths still thrive, especially during early pregnancy and the first trimester, when symptoms can feel intense and unpredictable.

And that’s not to mention the fact that advice on pregnancy and babies changes over time according to the most recent and best research. So while your mum might have put you to sleep on your tummy as a baby, that’s not considered safe sleep nowadays based on a wealth of research, so her advice in this situation is outdated.

Myth #1: Morning sickness only happens in the morning

The myth

​If you’re feeling sick all day, something must be wrong.

The facts

Despite the name, morning sickness can happen at any time of the day, or for some of us, all day long.

Nausea is linked to rising pregnancy hormones and tends to peak during the first trimester, though some women experience it into the second trimester or beyond. For some, it’s mild. For others, it’s relentless. 

If you’re experiencing sickness a lot of the time or if you’re losing weight in your pregnancy because of it, speak to your midwife as you may be experiencing hyperemesis gravidarum and may need further treatment.

Tip: Small, frequent meals with whole grains, staying hydrated, and managing blood sugar can help with normal pregnancy sickness. If sickness is severe or affecting your mental health, speak to your family physician or midwife.

Myth #2: You’re “eating for two”

The myth

​You need to double your calories.

The facts

Most pregnant women only need extra calories later in pregnancy, and even then, it’s usually around 200–300 calories per day during the third trimester, not a full second meal.

What matters more than total caloric intake is quality: a well-balanced diet with adequate protein, fibre, healthy fatty acids, and key micronutrients like iron, folate, and iodine.

Overeating can increase weight gain, raise the risk of gestational diabetes, and make it harder to maintain a healthy weight.

Myth #3: Spicy foods cause labour (or harm your baby)

The myth

​Spicy foods will trigger labour or upset the unborn baby.

The facts

​​Spicy foods don’t affect fetal development or your baby’s digestive system.

They can, however, worsen heartburn or reflux, especially later in pregnancy when your growing uterus puts pressure on your stomach. That discomfort is about you, not your baby.

Is this a good reason to skip them? Only if you feel uncomfortable as they won’t affect everyone in the same way.

Another similar old wives’ tale says that if you experience heartburn, your baby has a lot of hair!

Myth #4: Hot tubs and warm baths are always dangerous

The myth 

Pregnant women must avoid all hot water.

The facts

Hot tubs are discouraged because they can raise core body temperature due to the sustained temperature of the water, which may increase the risk of complications, especially in early pregnancy.

However, warm baths (not too hot) are generally fine and can be great for relaxation, muscle aches, and stress relief. Warm water is often used as pain relief during labour!

Myth #5: Stretch marks can be prevented with cocoa butter

The myth

​Cocoa butter will stop stretch marks.

The facts

​Stretch marks are mostly genetic and linked to skin elasticity, weight gain, and growth rate.

Moisturising with cocoa butter or oils can help with itching and skin comfort, but it won’t change your underlying skin structure. The root cause isn’t dryness, it’s stretching.

Myth #6: You can tell the baby’s gender by the bump

The myth

​High bump = baby girl. Low bump = boy.

The facts

Bump shape is influenced by muscle tone, body shape, whether it’s your first pregnancy, and the position of the baby, not the sex of the baby.

Similarly unreliable techniques for figuring out a baby’s sex are:

• Wedding ring on a string
• Baby’s heart rate
• Food cravings
• Whether you’re carrying “wide” or “neat”

They’re fun gender prediction tests, but they’re not science. (We’ve covered more of these in detail in our popular old wives’ tales blog post)

Myth #7: Hair dye harms the baby

The myth

​Hair dye affects the developing fetus

The facts 

Research shows minimal absorption of hair dye chemicals through the scalp. Most experts consider occasional use safe, especially after the first trimester.

If you’re cautious, highlights or semi-permanent dyes are great options.

Myth #8: Exercise is dangerous in pregnancy

The myth

You should rest and avoid physical activity

The facts

​For a normal pregnancy or uncomplicated pregnancy, staying active is encouraged.

Safe activities include:

• Walking
• Swimming
• Prenatal yoga (not hot yoga)

Avoid contact sports, strenuous exercise, and anything with a high risk of falls. Exercise supports mental health, circulation, and can help manage blood sugar and sleep. Always tailor exercise to your own activity level and follow medical advice.

We have a blog post all about safe exercise in pregnancy here.

Myth #9: Caffeine is completely off-limits

The myth

You can’t drink coffee while pregnant.

The facts

Moderate caffeine intake is considered safe. Most guidelines suggest staying under 200mg per day, that’s roughly one 12-ounce cup of coffee.

Remember caffeine is also found in soft drinks, chocolate, and tea.

Myth #10: You shouldn’t eat fish at all

The myth

​All fish is dangerous to eat while pregnant.

The facts

Fish is actually excellent for baby’s brain development thanks to omega-3 fatty acids.

The advice is to avoid high-mercury fish like king mackerel and raw options (raw fish), and to limit fish like tuna, but low-mercury types of fish like salmon and sardines are beneficial.

Myth #11: Soft cheeses are always unsafe

The myth

All soft cheeses are banned during pregnancy.

The facts

Pasteurised soft cheeses are safe. The risk comes from unpasteurised products due to listeria, which can affect the umbilical cord and placenta. Make sure to check labels and ask for advice when eating. In general, many UK cheeses are pasteurised.

Our guide on healthy eating during pregnancy has more information on what you should avoid and what you should aim to eat.

Myth #12: Your due date is exact

The myth

Babies arrive exactly on their due date.

The facts

A due date is an estimate based on weeks of pregnancy, not a deadline. Only around 4-5% of babies arrive on their exact due date day!

This is why pregnancy is sometimes described as closer to 10 months than 9!

When myths become harmful

Some myths go beyond harmless fun and can delay proper care, especially if they cause pregnant patients to ignore symptoms like:

• Vaginal bleeding
• Reduced fetal movement
• Severe pain or dizziness

Always contact your healthcare provider if something feels wrong. No myth overrides professional guidance.

Myth vs real life

Pregnancy is full of quirks, contradictions, and an overwhelming lot of information. Some myths persist because they’re entertaining. Others stick around because they once filled a gap before modern women’s health knowledge and prenatal visits were widely accessible.

Use myths as conversation starters and fun activities for baby showers like guessing the sex of your baby not decision-makers for a healthy pregnancy.

For anything related to your health or your new baby, rely on evidence-based guidance from your care team and trusted sources such as national guidance or organisations like the American College of Obstetricians and Gynecologists.

And if you want the real truths, the emotional ones, the messy ones, the postpartum realities nobody warns you about, we’ve got those covered too.

Because pregnancy isn’t about being perfect. It’s about being informed, supported, and trusting yourself just as much as the science.