Calculate your estimated due date and track pregnancy progress by week. Enter last menstrual period date or current pregnancy week to see important milestones.
Human pregnancy lasts approximately 280 days (40 weeks) from last menstrual period (LMP), with due date calculated 280 days after LMP or 266 days after conception (conception occurs mid-cycle, approximately 14 days after LMP). Naegele's rule adds 280 days (40 weeks) to LMP, providing standard due date calculation. Ultrasound dating typically refines estimate within ±3-5 days. Pregnancy divides into three trimesters. First trimester (weeks 1–12) involves rapid cell division, organ formation, and establishing placental connection. Morning sickness, fatigue, and mood changes commonly occur. Second trimester (weeks 13–27) includes fetal growth acceleration, quickening (feeling fetal movement), and visible pregnancy. Energy improves, and complications decrease. Third trimester (weeks 28–40) involves continued fetal growth, brain development, and preparation for birth. Back pain, swelling, and sleep difficulties often increase. Fetal development progresses from embryo to viable fetus: 8 weeks viable organ systems present, 12 weeks normal fetal movements, 20 weeks fetal movements felt by mother, 24 weeks viability threshold (survival possible with intensive care), 36 weeks full maturity preparation, 40 weeks ready for birth. Due dates fluctuate ±2 weeks—"term" spans weeks 37–42, with delivery between these points considered normal. Pre-term (before 37 weeks) and post-term (after 42 weeks) carry specific risks requiring medical monitoring. Understanding pregnancy progression through trimesters and developmental milestones helps expecting parents prepare and monitor normal development.
Prenatal care monitoring tracks mother and fetal health throughout pregnancy. Initial appointment establishes due date, health history, and baseline measurements. Regular appointments (monthly first trimester, bi-weekly second, weekly third trimester) monitor blood pressure, weight gain, urine protein/glucose, and fetal development. Screening tests (nuchal translucency, quad screen, glucose tolerance) assess risks and normal fetal development. Ultrasounds track fetal growth, position, heart rate, and amniotic fluid levels. Normal weight gain during pregnancy ranges 11–16kg for normal-weight women, adjusted for pre-pregnancy BMI (overweight/obese women gain less, underweight women gain more). Nutrition becomes increasingly important—adequate calories, protein, vitamins (particularly folic acid, iron, calcium), and minerals support fetal development and maternal health. Exercise benefits pregnancy and labor recovery—low-impact activity (walking, swimming, pregnancy yoga) recommended 150 minutes weekly unless complications warrant restriction. Labor preparation involves childbirth education, pain management options discussion, and birth plan development. Complications requiring monitoring include gestational diabetes (temporary diabetes during pregnancy), preeclampsia (high blood pressure with protein in urine), and intrauterine growth restriction. Most pregnancies progress normally with appropriate prenatal care enabling healthy outcomes. Emotional preparation involves discussing role changes, partner support, postpartum recovery, and infant care. Understanding pregnancy timeline, attending regular prenatal care, and preparing emotionally support healthy pregnancy and delivery.
Example 1: LMP January 15. Due date October 22 (280 days later). Week 1 begins January 15. Example 2: LMP April 1. Due date December 28. Current date April 20 (3 weeks pregnant), trimester 1. Example 3: LMP July 10. Due date April 16 next year. Current date November 1 (16 weeks pregnant), mid-trimester 2.