Dictionary TryingPregnancyDue Date Due Date Last updated: November 9, 2023 What Does Due Date Mean? A due date is an estimation of when a baby is most likely to be born. Typically, a pregnancy lasts 40 weeks from the day of conception, however, not many people are aware of the exact date they conceived. Determining a due date plays a key role in helping doctors to determine how far along a pregnancy is, what tests need to be performed at specific milestones, and when to schedule check-ups to ensure that the baby is growing healthy. Advertisement FertilitySmarts Explains Due Date There are several calculations which can help to give an approximate due date: Last menstrual period (LMP): Add 40 weeks or 280 days from the first day of your last period. Date of ovulation: 38 weeks or 266 days from the date of ovulation. IVF transfer: Date of embryo transfer plus 266 days, minus the age in days of the embryo at transfer. Ultrasound: A first-trimester sonogram, where measurements are taken of the fetus, is the most accurate way to determine the due date. One study found that only 4% of women deliver at the 40-week due date, while an estimated 70% deliver within 10 days of the estimated due date. A person’s due date is a bit of a waiting game, and it is hard to correctly identify because the triggers for labor are not completely understood. Advertisement Share This Term> Related Terms First-Morning Urine Egg Activation Related Reading 14 Onesies that Celebrate IVF Babies IVF Pregnancy Announcements Fertility Podcasts Relatable Words After a Miscarriage Let’s Stop Arguing About Whether or Not Stress Causes Infertility Books About Infertility Tags Trying Pregnancy Trending Articles Pregnancy IVF Pregnancy Announcements Egg Retrieval From Eggs to Blastocysts: Understanding IVF Attrition Cervical Mucus Identifying Stages of Cervical Mucus Artificial Insemination (AI) Implantation Calendar: What is Happening During the Two Week Wait?