babybumpkit publishes free pregnancy and fertility calculators and the guides that go with them. This page explains who writes them, where the information comes from, how pages are checked, and how to tell us when something is wrong.
Who writes the site
The site is written by Larson, D., its founder. He is not a clinician, and the site does not present itself as written by one. His background and reasons for building the site are on the author page.
Where the information comes from
Medical statements on this site come from published guidance and research: the American College of Obstetricians and Gynecologists (ACOG), the NHS, the Mayo Clinic, the CDC, the National Institutes of Health and peer-reviewed studies indexed on PubMed. Each page lists the sources it relies on, with links, so you can read them yourself. Where guidance differs between countries or bodies, the page says so rather than choosing the tidier answer. We do not invent statistics, and a figure we cannot source does not go on the page.
How the calculators work
Each calculator applies a standard formula from that guidance, such as Naegele's rule for due dates or the Institute of Medicine's ranges for weight gain. The formula and its source are shown on the calculator page. Calculations run in your browser; the dates you enter are not sent to us. Every result is an estimate based on averages, which is why each calculator carries a medical disclaimer.
How articles are written
Our calculators, week-by-week guides and topic articles are written and edited by people, and checked against the guidance they cite.
Blog articles are drafted with the help of AI tools, working from a fixed editorial brief. Before a blog article is published it must pass automated checks: it has to cite at least two sources, and those sources can only come from a list of ACOG, NHS, Mayo Clinic, NIH and CDC pages that we maintain by hand, so a citation here is never one an AI made up. Drafts that claim a result is guaranteed or “100% accurate”, or that fail the structure and length checks, are not published.
We also check new topics against pages we already have, and merge pages that cover the same question so there is one clear answer instead of two partial ones.
Dates and updates
Every page shows when it was last updated. We update pages when guidance changes, when a source moves, or when we find a better or clearer way to answer the question.
Advertising and independence
The site is free. If it carries advertising, advertisers have no say over what we write, and ads are never placed above a calculator.
Corrections
If you think something on the site is wrong, out of date or unclear, email hello@babybumpkit.com with the page and what you noticed. We read every message and correct errors as soon as we can confirm them.
Not medical advice
Nothing on this site replaces your midwife, doctor or other healthcare provider. If something here disagrees with what they tell you, follow their advice. The medical disclaimer explains this in full.