1. What is the Pregnancy Due Date Calculator?

The Pregnancy Due Date Calculator estimates the expected delivery date based on the last menstrual period (LMP) and adjusts for the woman's average menstrual cycle length. This provides a more personalized estimate than the standard 280-day calculation.

2. How Does the Calculator Work?

The calculator uses the adjusted due date formula:

Where:

• \( \text{LMP} \) — First day of last menstrual period
• \( \text{cycle\_length} \) — Average length of menstrual cycle in days
• 280 — Standard pregnancy length (40 weeks)
• 28 — Standard cycle length used in basic calculations

Explanation: For women with cycles longer than 28 days, ovulation typically occurs later, so the due date is adjusted earlier. For shorter cycles, the due date is adjusted later.

3. Importance of Accurate Due Date Calculation

Details: An accurate due date helps monitor fetal development, schedule important prenatal tests at the right times, and determine if pregnancy is progressing normally.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and your average cycle length (typically 21-45 days). The most accurate results come when LMP date is certain and cycles are regular.

5. Frequently Asked Questions (FAQ)

Q1: Why adjust for cycle length?
A: Women with longer cycles typically ovulate later in their cycle, which means conception occurs later relative to their LMP.

Q2: How accurate is this calculation?
A: The calculation is an estimate - only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after.

Q3: What if my cycles are irregular?
A: For irregular cycles, an early ultrasound provides the most accurate due date estimation.

Q4: Does this work for IVF pregnancies?
A: For IVF, the conception date is known precisely, so different calculation methods are used.

Q5: When should I see my doctor?
A: Schedule a prenatal visit as soon as you suspect pregnancy, regardless of the calculated due date.