How accurate is the due date calculation?

The estimated due date is accurate to within ±2 weeks in most cases. An early ultrasound (before 13 weeks) is the most accurate method and is recommended to confirm the due date.

What if my cycle is not 28 days?

Naegele's rule assumes a 28-day cycle with ovulation on day 14. If your cycle is longer or shorter, conception likely occurred on a different day. An early ultrasound measurement is more accurate in these cases.

What is a full-term pregnancy?

Full-term is 39–40 weeks. Early term is 37–38 weeks. Late preterm is 34–36 weeks. Preterm is before 37 weeks. Post-term is 42+ weeks, which may prompt medical intervention.

When should I start prenatal care?

Start prenatal care as soon as you know you're pregnant, ideally in the first 8 weeks. Early prenatal care significantly improves outcomes for both mother and baby.

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