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Pregnancy Week Calculation:
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The Pregnancy Week Calculator determines the current gestational age by calculating the number of weeks and days between the last menstrual period (LMP) and the current date, providing week-by-week tracking with developmental information.
The calculator uses the standard pregnancy dating formula:
Where:
Explanation: Pregnancy is typically calculated from the first day of the last menstrual period, with full-term pregnancy being approximately 40 weeks (280 days).
Details: Accurate week-by-week tracking is essential for monitoring fetal development, scheduling prenatal appointments, performing appropriate tests, and preparing for delivery. Each week brings significant developmental milestones.
Tips: Enter the first day of your last menstrual period and the current date (or any date you want to check). The calculator will determine exactly how many weeks and days pregnant you are at that point in time.
Q1: Why is pregnancy calculated from LMP instead of conception?
A: LMP is used because it's typically easier to recall than the exact conception date, and it provides a standardized method for healthcare providers worldwide.
Q2: How accurate is LMP dating?
A: LMP dating is generally accurate within 1-2 weeks. Early ultrasound dating (before 14 weeks) can provide more precise gestational age if LMP is uncertain.
Q3: What if I have irregular periods?
A: With irregular periods, LMP dating may be less accurate. An early dating ultrasound provides the most reliable gestational age assessment.
Q4: When should I see week-by-week pictures and information?
A: You can check weekly updates throughout pregnancy to follow fetal development, physical changes, and prepare for each stage of pregnancy.
Q5: What are the three trimesters of pregnancy?
A: First trimester: weeks 1-13, Second trimester: weeks 14-27, Third trimester: weeks 28-40+. Each trimester has distinct developmental milestones.