Due Date Oracle.
Estimate your delivery timeline, monitor trimesters, and track biological milestones.
Biological Inputs
Current Progress
Biology & The Temporal Map
Pregnancy is calculated based on the first day of your last menstrual period (LMP). While the average human gestation is 280 days, individual variation based on cycle length is common. Use this oracle to map your trimesters.
Milestone Benchmarks
Trimester 1: Week 1 to 12. Critical development phase.
Trimester 2: Week 13 to 26. Growth and movement.
Trimester 3: Week 27 to 40. Final maturation.
Accuracy Note
This "oracle" provides an estimation based on Naegele's rule. Clinical confirmation via ultrasound remains the gold standard for definitive dating.
Pregnancy Due Date Calculation Methodology.
The Calculation Branch
Industrial Standards.
Naegele's Rule (the medical standard since 1812): add 1 year, subtract 3 months, and add 7 days to the LMP date. Equivalently, add 280 days. This assumes a 28-day menstrual cycle and ovulation on day 14. Women with longer or shorter cycles may have different conception dates. Ultrasound dating (crown-rump length at 8–13 weeks) is more accurate than LMP when available.
In-Depth Analysis & Reference Data
Pregnancy milestones by week: Week 4 — positive pregnancy test possible. Week 8 — heartbeat detectable by ultrasound. Week 12 — end of first trimester, miscarriage risk drops significantly. Week 20 — anatomy scan ultrasound, sex determination. Week 24 — viability threshold (survival possible with intensive care). Week 37 — considered full term. Week 42 — post-term, typically when induction is considered. Most spontaneous deliveries occur between 38–41 weeks.
Registry Questions & FAQ.
How accurate is a pregnancy due date?
Only about 5% of babies are born on their exact due date. Approximately 80% of births occur within 2 weeks of the due date (weeks 38–42). First-time mothers tend to go past their due date more often than those who have had previous pregnancies. Ultrasound dating at 8–12 weeks has an accuracy of ±5–7 days, which is generally more accurate than LMP-based calculation.
What is the difference between gestational age and fetal age?
Gestational age counts from the first day of the last menstrual period — this is 2 weeks before conception typically occurs. Fetal age (embryonic age) counts from the actual date of conception. Healthcare providers use gestational age as the standard because LMP is a known date while conception date is rarely known precisely. A 40-week pregnancy is 38 weeks of fetal development.
All metrics verified against ISO/ASTM benchmarks.