ovulation

When Did I Conceive? Understanding Conception Dates and Calculations

When Did I Conceive? Understanding Conception Dates "When exactly did I get pregnant?" Whether you're curious about that romantic getaway, need to know for medical reasons, or are simply piecing together your pregnancy timeline, determining your conception date is a common question. The answer involves a bit of biology and math. Quick answer: Conception typically occurs about 14 days before your next expected period, or roughly 2 weeks after the first day of your last menstrual period (LMP) for those with 28-day cycles. From your due date, you can calculate backwards: conception occurred approximately 266 days (38 weeks) before your due date. A worked example shows how close these calculations can get with good cycle data. Take an LMP of January 3rd with cycles averaging 30 days, tracked with OPKs that showed a positive surge on cycle day 17. Working backwards from an 8-week ultrasound dating, the estimated conception date...