Pregnancy & Baby Guides
Clear, no-fluff answers to the questions that come up most while you're pregnant or trying to conceive — written to pair with our free calculators.
Our calculators give you a fast, specific answer — a due date, a fertile window, an estimated percentile. These guides go a level deeper: the reasoning behind that number, the assumptions it depends on, and what to do when your own situation (an irregular cycle, an unexpected ultrasound, a changed estimate) doesn't fit the textbook case the calculator assumes. Each guide cites recognized sources — ACOG, the CDC — and links back to the calculator it pairs with, so you can move between the explanation and the tool as you need to. We'll keep adding guides as new questions come up often enough to be worth a proper answer.
How Is Your Due Date Calculated?
A clear explanation of how due dates are calculated from your last period or conception date, why 40 weeks is the standard, and how ultrasounds can adjust the estimate.
Can Your Due Date Change?
Why due dates get revised, how early ultrasounds affect your estimate, and what it means if your doctor moves your date.
How to Calculate Ovulation With Irregular Periods
Tracking ovulation when your cycle length varies month to month — what signs to watch for and how to estimate your fertile window without a predictable calendar date.
Signs of Ovulation: How to Recognize Your Fertile Window
The physical signs of ovulation — cervical mucus changes, basal body temperature, mild pelvic twinges — and how to combine them with cycle tracking.