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Baby Zodiac Signs by Due Date: What Sign Will Your Baby Be?
Your due date lands your baby in one of 12 zodiac signs — until it moves. Here are the exact date ranges our calculator uses, the cusp windows where two signs are still in play, and why an estimated date can change the answer.
BMI Before Pregnancy: Why It Matters and What It Changes
Your pre-pregnancy BMI is the input that sets your recommended weight gain, and it follows you through the whole pregnancy. Here's how the BMI bands map to the IOM targets, and where a single height-and-weight number stops being useful.
Caffeine During Pregnancy: How Much Is Safe? (The 200 mg Rule)
Almost every guideline lands on the same ceiling: under 200 mg of caffeine a day in pregnancy. Here's what that is in real mugs, cans and squares of chocolate — and how strong the evidence behind the number really is.
How Due Date Calculators Work (And Why They're Just Estimates)
Most people who Google "due date calculator" want their EDD in 10 seconds. Here's what's actually happening when you punch in a date — and why your provider's first-trimester ultrasound is the only date that really counts.
How Much Water Do You Need During Pregnancy?
ACOG says 8 to 12 cups a day, and the IOM sets an adequate intake of 3.0 L of total water for pregnancy. Here is where those numbers come from, and why your body weight, your activity and the weather matter more than your trimester.
Ovulation 101: When You Are Actually Fertile
Your fertile days are a six-day window that closes on the day you ovulate. Here is where those days fall, how cycle length moves them, and what cervical mucus, LH tests and basal body temperature each actually tell you.
Pregnancy Weight Gain: How Much Is Right for You (IOM Targets by BMI)
There is no single right number for pregnancy weight gain — there are four, and the one that applies to you depends on your BMI before you conceived. Here are the IOM 2009 ranges, the weekly rates behind them, the separate twin numbers, and what the evidence actually says about gaining more or less.
The Chinese Gender Predictor: Fun Tradition or Real Science?
The Chinese gender chart turns two numbers — lunar age and lunar conception month — into a boy-or-girl answer. Two large studies say it lands at chance. Here is the real math, and the two tests that actually tell you.
The Mayan Gender Predictor: How It Works and Whether It Is Accurate
The Mayan gender predictor compares the mother's age at conception with the month she conceived, then calls boy or girl on whether both numbers share the same parity. Here is the arithmetic, the folklore behind it, and what actually determines your baby's sex.
Twin Pregnancy Weight Gain: The IOM Targets by BMI
Twin pregnancy weight gain has its own targets, and they are not the singleton numbers doubled. Here are the IOM 2009 provisional ranges by pre-pregnancy BMI, why there is no range at all for underweight women, when in the pregnancy the gain actually matters, and what the research since 2009 shows about gaining below or above them.
When Did I Conceive? Reverse Due Date and Conception Date Explained
Subtract 266 days from your estimated due date and you have your most likely conception date. Here is why that number is 266 and not 280, why conception means ovulation rather than the night you remember, and how wide the honest answer really is.
Your Twin Due Date Is Really Week 37: How Twin Due Dates Work
A twin due date is calculated the same way a singleton's is — last period plus 280 days. What changes is the week your team plans delivery for: 37 weeks for twins with a placenta each, 36 for twins sharing one, earlier again for mo/mo twins. Here is where both numbers come from.