Myth Registry
What the evidence
actually says.
The most common health myths — stated clearly, assessed against the clinical evidence, and categorised by how wrong they are.
"You need to eat for two during pregnancy."
ACOG is specific: most pregnant women need approximately 340 additional calories per day in the second trimester. Not a second dinner.
"You can't exercise during pregnancy."
ACOG recommends at least 150 minutes per week of moderate-intensity aerobic activity. Exercise reduces gestational diabetes risk by 38%.
"Morning sickness means a healthy pregnancy."
There is a statistical association — but 20–30% of entirely healthy pregnancies involve no nausea at all. Absence of symptoms does not indicate a problem.
"Stress causes miscarriage."
The overwhelming majority of early miscarriages are caused by chromosomal abnormalities in the embryo — genetic events that cannot be caused by emotional state.
"You should only sleep on your left side during pregnancy."
The concern is about the supine (back) position after 28 weeks — not left versus right. The 2019 meta-analysis found both sides are equally safe.
"Cocoa butter prevents stretch marks."
A Cochrane Review found no topical product has been reliably shown to prevent stretch marks. Genetics and rate of skin stretching are the primary factors.
"Spicy food induces labour."
No randomised controlled trial has shown a causal link between dietary capsaicin and uterine contractions. ACOG does not list it among induction methods.
"Heartburn means your baby will have lots of hair."
One small 2006 study found a significant correlation — and the mechanism is biologically plausible. But the sample was 64 women and it has never been replicated.
Want the full evidence, not just the verdict?
The Knowledge Base goes deeper — cited, verified, and updated when the research changes.