Version User Scope of changes
Jul 12 2008, 4:57 PM EDT (current) pg255pg255 75 words added
Jan 14 2008, 9:47 AM EST ePregnancy.com 5 words added

Changes

Key:  Additions   Deletions

Determining your due date


You can calculate your own due date, or your doctor or midwife will do it for you at your first prenatal care visit. Your due date is an estimate and will be approximately 40 weeks from the first day of your last menstrual period.

Even though your baby is not conceived until about two weeks after you start your period, week one of your pregnancy is considered to be the week of your menstrual period.

Your first trimester lasts until the end of week 13, the second trimester lasts from week 14 to the end of week 26, and your third trimester is from week 27 until birth. Most babies are born between weeks 38 and 42.

Advanced algorithms are available which try to increase the accuracy of due date prediction based on computing a number of different variables (e.g. here). This is potentially important as a marked discrepancy between the due date predicted from the date of conception / ovulation and the date predicted from ultrasound raise the possibility that the discrepancy is due to fetal growth problems and hence the need for closer attention.

See also:

Due Date Calculator, redbabybook.com

Due Date Calculator, Medical College of Wisconsin

Due Date Calculator, ePregnancy.com