1. What is the Last Period Date Pregnancy Calculator?

The Last Period Date Pregnancy Calculator estimates the due date of pregnancy based on the first day of the woman's last menstrual period (LMP). This is the most common method used by healthcare providers to estimate due dates.

2. How Does the Calculator Work?

The calculator uses Naegele's rule:

Where:

• LMP — First day of last menstrual period
• 280 days — Average length of human pregnancy (40 weeks)

Explanation: The calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The calculator also shows current gestational age based on today's date.

3. Importance of Due Date Calculation

Details: Knowing the estimated due date helps monitor fetal development, schedule important prenatal tests, and prepare for delivery. Only about 5% of women deliver on their exact due date.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period (LMP) in the format YYYY-MM-DD. The calculator will estimate your due date and current gestational age.

5. Frequently Asked Questions (FAQ)

Q1: What if my cycles aren't 28 days?
A: The calculation may be adjusted for longer or shorter cycles. Consult your healthcare provider for a more accurate estimate.

Q2: How accurate is this calculation?
A: It's a general estimate. Ultrasound measurements in early pregnancy provide more accurate dating.

Q3: What is considered full term?
A: Between 37 weeks and 41 weeks, 6 days. Babies born before 37 weeks are preterm, after 42 weeks are post-term.

Q4: Can I calculate conception date from this?
A: Conception typically occurs about 2 weeks after LMP, but this varies based on cycle length.

Q5: What if I don't remember my LMP?
A: An early pregnancy ultrasound can estimate gestational age and due date.