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Pregnancy dating, explained
Clear, sourced articles on how due dates and pregnancy weeks are worked out — and what the numbers can and can’t tell you.
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BlogHow Is a Due Date Calculated?
The 280-day convention, the assumptions behind it, and how conception, IVF and scan dates fit in.
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BlogWhat Does EDD Mean in Pregnancy?
What “estimated due date” means, and why the word “estimated” matters.
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BlogHow Accurate Is a Pregnancy Due Date?
What research shows about how often babies arrive on their estimated due date.
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BlogUltrasound vs LMP: Which Due Date Should You Use?
How a dating scan and your last period are used together to set a due date.
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BlogHow Many Weeks Pregnant Am I?
How weeks and days of pregnancy are counted, and why they start before conception.
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BlogHow to Calculate Your Conception Date
How a conception date is estimated by convention, and why it can’t be exact.
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BlogDue Dates With Irregular Periods: What Changes?
Why the standard calculation assumes a regular cycle, and what that means if yours isn’t.
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BlogPregnancy Due Date FAQ
Short, sourced answers to common questions about due dates.
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