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Pregnancy Calculator Formula:
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A pregnancy calculator estimates the due date of a pregnancy based on the last menstrual period (LMP) using standard obstetric calculations. It helps healthcare providers and expectant parents track pregnancy progress and plan for delivery.
The calculator uses Naegele's Rule:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle and adds 280 days (40 weeks) to the first day of the last menstrual period to estimate the due date.
Details: Accurate pregnancy dating is essential for monitoring fetal development, scheduling prenatal tests, determining gestational age, and planning for delivery. It helps identify potential complications and ensures appropriate prenatal care timing.
Tips: Enter the first day of your last menstrual period in the date field. The calculator will automatically compute your estimated due date based on standard obstetric calculations.
Q1: How accurate is this calculation?
A: Naegele's rule provides a good estimate, but only about 5% of women deliver on their exact due date. Most deliveries occur within 2 weeks before or after the estimated date.
Q2: What if my menstrual cycle isn't 28 days?
A: For women with irregular or longer cycles, the calculation may need adjustment. Ultrasound dating in early pregnancy often provides more accurate gestational age.
Q3: When should I confirm my due date with a doctor?
A: It's recommended to schedule your first prenatal appointment within the first 8 weeks of pregnancy to confirm dating and begin proper prenatal care.
Q4: Can the due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements, which are most accurate in the first trimester.
Q5: What are the three trimesters of pregnancy?
A: Pregnancy is divided into three trimesters: First (weeks 1-13), Second (weeks 14-27), and Third (weeks 28-40+), each with distinct developmental milestones.