Pregnancy Myths in Latin America: What Science Says

Grandmothers, aunts, neighbors, coworkers. If you’re pregnant, you’ve probably built up an impressive collection of unsolicited advice by now. Some of it sounds reasonable. Some sounds questionable. And a lot of it leaves you with pregnancy myths that Google can’t quite settle.

The truth is that many of these beliefs have deep roots in our culture. They come from generations of women who cared for other women with the resources and knowledge they had. They deserve respect. But we also deserve to know what current evidence says, so we can make informed choices.

Let’s go through the most common myths from our region, one by one.

Myths that science couldn’t confirm

We’ll start with beliefs that, based on available evidence, don’t have scientific support. This doesn’t mean anyone who follows them is doing something wrong; it simply means that science hasn’t found a real connection.

”An eclipse will harm your baby”

This belief originates in Nahuatl (Aztec) mythology: the Aztecs believed that something “bit” the moon during an eclipse, and if a pregnant woman witnessed it, her baby would be born with a cleft lip. This is where the tradition of wearing a red ribbon on the belly or pinning a safety pin (“segurito”) to your clothes comes from.

UNAM (Mexico’s National Autonomous University) and IMSS (Mexican Social Security Institute) have confirmed in multiple statements that eclipses have no effect on the health of either mother or baby. Cleft lip results from incomplete tissue fusion during fetal development at weeks 6-10, a process entirely unrelated to astronomical events.

If staying indoors during an eclipse makes you feel calmer, that’s fine. But there’s no need to worry if you forgot the red ribbon.

”Your belly shape reveals the baby’s sex”

“Pointy belly, it’s a boy. Round belly, it’s a girl.” You hear this across all of Latin America, and someone has probably told you this in the checkout line.

Belly shape depends on factors like your abdominal muscle tone (it tends to be firmer in a first pregnancy, which is why the belly looks more “pointy”), the baby’s position, your uterus shape, and your body type. The baby’s sex doesn’t influence any of these factors.

”More babies are born during a full moon”

One of the most deep-rooted beliefs: the full moon triggers labor. It’s so popular that a large percentage of delivery floor nurses believe it too.

But the data tells a different story. A study by Arliss et al. published in the American Journal of Obstetrics & Gynecology (2005) analyzed 564,039 births across 62 lunar cycles. The result: no significant differences in birth frequency, delivery type, or complications between any lunar phase.

The belief persists because of confirmation bias: when a birth coincides with a full moon, we remember it. When it doesn’t, we forget.

”Pineapple causes miscarriage”

Pineapple contains bromelain, an enzyme that in concentrated supplement form can break down proteins. But bromelain is concentrated in the core of the pineapple, not the flesh we eat.

A 2011 study found no correlation between pineapple consumption and the risk of miscarriage or preterm labor. A normal serving of pineapple is safe during pregnancy and provides 30 mcg of folic acid per cup. What you should avoid are concentrated bromelain supplements, which aren’t approved for use in pregnancy.

”Spicy food harms the baby”

Capsaicin (the compound that makes chili peppers spicy) doesn’t cross the placenta in amounts that could affect the baby. According to MotherToBaby, a teratology resource from the NCBI (updated in 2024), no human studies have shown increased risk of birth defects, miscarriage, or preterm delivery from capsaicin consumption. The FDA classifies it as GRAS (Generally Recognized As Safe) for food use. The UK’s National Health Service (NHS) also does not include spicy food on its list of foods to avoid during pregnancy.

The only real effect: it can worsen heartburn, which is already common in the second and third trimesters. If you love spicy food and it doesn’t cause you discomfort, there’s no medical reason to give it up.

”Unfulfilled cravings leave marks on the baby”

Cravings are very real. A study published in Nature Metabolism in 2022 (University of Barcelona) discovered that pregnancy hormones alter the brain’s reward system: the same area that makes you feel pleasure when you eat something you love becomes more reactive during pregnancy. That’s why certain foods, especially sweet and calorie-dense ones, feel almost irresistible. It’s not a lack of willpower: it’s your brain responding to hormonal changes.

But birthmarks (hemangiomas or vascular marks) are caused by clusters of blood vessels or melanocytes under the skin. They have no connection to the mother’s food cravings, whether fulfilled or not.

”Sweet cravings mean a girl, salty cravings mean a boy”

No study has found a correlation between the type of craving and the baby’s sex. As we saw, cravings respond to hormonal changes in the brain’s reward system, not to the baby’s chromosomes.

Myths with some truth

Not everything is black and white. Some popular beliefs turned out to have a partial basis when researchers put them to the test.

”Severe nausea means it’s a girl”

There’s some truth here, but not much. A study published in The Lancet (1999) and another in the journal Birth (2020, with 4,320 pregnancies) found that women hospitalized for severe nausea (hyperemesis gravidarum) had girls between 53% and 56% of the time, compared to 49% in the general population.

The proposed mechanism: hCG levels (the hormone that causes nausea) tend to be higher in pregnancies with female fetuses. But the difference is only a few percentage points, and it only applies to severe nausea. Mild or moderate nausea doesn’t predict anything.

”Lots of heartburn means a hairy baby”

It sounds like a tale, but a study from Johns Hopkins University (Costigan et al., 2006, published in Birth) with 64 pregnant women found a statistically significant correlation: 82% of women with moderate to severe heartburn had babies with abundant hair, and 83% of those without heartburn had babies with little or no hair.

The proposed explanation: pregnancy estrogens relax the lower esophageal sphincter (causing heartburn) and simultaneously stimulate fetal hair growth. In other words, it’s not the baby’s hair causing your heartburn, but rather the same hormone that causes heartburn also happens to make the baby’s hair grow. It’s a small study that needs replication with more participants, but the correlation was clear.

”The postpartum cuarentena is necessary”

La cuarentena (40 days of rest after birth, supported by female family members) is a deeply rooted tradition across Latin America. What does the science say?

A qualitative review of 51 studies across more than 20 countries (Dennis et al., 2007, published in Women’s Health) found that 21-to-40-day postpartum rest periods exist in nearly every culture studied. The documented benefits include better mental health, stronger bonds with the baby, and greater breastfeeding success.

Myths that turned out to be true

Some things that seemed like superstition ended up having solid scientific backing.

”Pregnancy brain” is real

For a long time it was dismissed as an excuse or exaggeration. But a study published in Nature Neuroscience in September 2024 (Chrastil et al., UC Irvine) confirmed it with MRI scans: gray matter decreases by an average of 4% across 80% of brain regions during pregnancy.

If you’d like to learn more, we have a full article on pregnancy brain and how to manage forgetfulness.

”If something feels off, talk to your doctor”

Worries during pregnancy are normal, and the vast majority of the time everything is fine. But science found something interesting: when a mom feels a persistent concern about her baby’s health, that feeling deserves attention. An international study published in ScienceDirect showed that maternal intuition about a baby’s wellbeing has a real basis, as the body may be picking up on subtle signals before they become obvious.

This doesn’t mean every worry is a red flag. Most aren’t. But if something gives you a nagging feeling that won’t go away, don’t keep it to yourself: mention it to your OB-GYN at your next visit, or call sooner if you feel it’s needed. That’s what your medical team is there for.

Traditional remedies: what you need to know

Some traditions deserve a special section because they can carry real risks.

Rue (ruda, Ruta graveolens)

Used as a home remedy in several Latin American countries (Mexico, Guatemala, Peru, Argentina, Uruguay). It contains compounds with potential effects on the uterus, but the effective dose and the toxic dose are unpredictable and vary between individuals.

Documented adverse effects include severe gastric pain, vomiting, liver damage, kidney damage, anemia, and in extreme cases, maternal death. If the pregnancy continues, fetal skeletal malformations have been documented in animal studies.

Sobada (traditional abdominal massage)

Practiced by midwives in Mexico and Central America, the sobada serves both diagnostic (checking fetal position) and therapeutic purposes. Research by Quattrocchi (2006, SciELO) described this practice as rooted in Maya medicine, serving an important cultural role.

However, there are no clinical trials evaluating its safety. Medical professionals have raised concerns about the risk of placental abruption if too much pressure is applied. If you choose to have sobadas, make sure it’s with someone experienced and trustworthy, and mention it to your OB-GYN.

Summary: what science says about each myth

Myth	Verdict
Eclipse harms the baby	False
Belly shape predicts the sex	False
Full moon triggers labor	False
Pineapple causes miscarriage	False
Spicy food harms the baby	False
Unfulfilled cravings leave birthmarks	False
Sweet cravings = girl, salty = boy	False
Severe nausea = girl	Partially true (53-56% vs 49%)
Lots of heartburn = hairy baby	True (small study, n=64)
Postpartum cuarentena is necessary	Partially true (real benefits)
Pregnancy brain is real	True (Nature Neuroscience, 2024)
Maternal intuition about baby’s wellbeing	True (supported by studies)

Frequently asked questions

Are pregnancy myths only a Latin American thing?

No. Research has found similar myths in Asia, Africa, Europe, and North America. The belief in the moon’s influence on labor, for example, exists across cultures worldwide. What changes are the specific details and associated traditions.

Is it bad to follow traditions like la cuarentena?

No. La cuarentena has aspects that science supports: rest, companionship, and emotional support are beneficial. What helps is distinguishing between the parts that help you (resting, letting yourself be cared for) and those that might limit you without medical reason.

How do I handle unsolicited advice from family?

With patience and firmness. Thanking someone for their advice without feeling obligated to follow it is a skill you can practice. If a piece of advice raises doubts, write it down and ask your OB-GYN at your next appointment. Keeping everything noted down helps you remember.

Is maternal intuition always right?

Not always. Maternal intuition about the baby’s sex is correct only 51% of the time (essentially a coin flip), according to a study published in PMC (2019). But intuition about the baby’s wellbeing did show significance in studies. The difference is that in the second case, the body may be processing real physical signals. When in doubt, always check with your doctor.

Are any myths actually dangerous?

Yes. The most concerning is the hot-cold belief system (documented in communities in Chiapas, Mexico, among others), which classifies foods and medicines as “hot” or “cold.” According to a study published in SciELO, some women reject iron supplements from health clinics because they consider them “excessively hot,” which can contribute to maternal anemia, a condition affecting 20-39% of pregnant women in the region (WHO/FAO, 2023).

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Our traditions are part of who we are. It’s not about discarding them, but about adding updated information so every mom can make decisions with confidence.

If between the cravings, the doctor’s appointments, and everyone’s advice, you feel like things are slipping through the cracks, Memobebe helps you keep everything organized in one place.

For more information on pregnancy nutrition, read our nutrition guide for Latin American moms. And if pregnancy brain is getting to you, we have a dedicated article on that. Explore more in our pregnancy section and nutrition section.