The development of your baby in the womb is a wonderful process. During pregnancy, your future child will develop at an astonishing rate. This is an important time to make sure you are eating a healthy diet, taking your prenatal vitamins, and getting good prenatal care. These three steps can help reduce the chance of birth defects and set your baby on the right path to a healthy life. The average pregnancy lasts for 38 weeks from the date you conceive (this is called conception). However, doctors usually date your pregnancy from the first day of your last menstrual period — that is the day your last period started. Using this method a pregnancy is said to last 40 weeks (280 days). Your due date is usually calculated as 40 weeks from the first day of your last period. However, fertilization of your egg by sperm happens a day or 2 after ovulation, which occurs in the middle of a 28-day cycle, and then it is a couple of days before the fertilized egg implants in the uterus, so for the first 2 weeks of the 40-week ‘pregnancy’ you are not actually pregnant at all.