How Is Pregnancy Timeline Calculated?

This calculator estimates your pregnancy timeline using one of the following methods:

• LMP Method: Assumes a 280-day (40-week) pregnancy from the first day of your last period. Conception is estimated at 14 days after LMP.
• EDD Method: Works backward from your due date to estimate LMP and conception.
• Ultrasound Method: Uses the ultrasound date and gestational age at that time to calculate LMP, then computes the timeline.
• Conception Date Method: Estimates LMP as 14 days before conception, then calculates the timeline.
• IVF Transfer Date Method: Calculates conception date based on transfer date and embryo age, then estimates LMP and the timeline.

The calculator uses standard obstetric assumptions but may not account for individual variations.

What Does Gestational Age Mean?

Gestational age is the age of your pregnancy, measured in weeks and days from the first day of your last menstrual period. For example, at 12 weeks, you’re at the end of your first trimester. This calculator shows your current gestational age based on today’s date (April 23, 2025) and your input.

Factors Affecting Your Due Date

Several factors can influence your actual due date:

• Cycle Length: This calculator assumes a 28-day cycle with ovulation on day 14. If your cycle is longer or shorter, your due date may differ.
• Multiples: Twins or higher-order multiples often deliver earlier (around 36–38 weeks).
• Medical Conditions: Conditions like gestational diabetes or preeclampsia may lead to earlier delivery.
• Ultrasound Accuracy: Early ultrasounds can adjust your due date based on fetal measurements.

Understanding Pregnancy Trimesters

Pregnancy is divided into three trimesters:

• First Trimester (0–12 weeks): Major organs develop, and you may experience symptoms like nausea.
• Second Trimester (13–27 weeks): The baby grows rapidly, and you may feel movement.
• Third Trimester (28–40 weeks): The baby prepares for birth, and you may feel more discomfort as delivery approaches.

Limitations of This Calculator

This calculator provides estimates based on averages and assumptions:

• It assumes a 28-day cycle and ovulation on day 14, which may not apply to everyone.
• It does not account for multiples or medical conditions that may affect delivery timing.
• IVF calculations assume standard embryo ages (3-day or 5-day); variations may affect accuracy.
• For precise due dates, consult your healthcare provider, especially if you have irregular cycles or are expecting multiples.

Always discuss your pregnancy timeline with your doctor or midwife for personalized care.