What is gestational age?
Gestational age is the age of an unborn baby measured in weeks and days, not in months. Since the precise date of conception is seldom known, the age is based on the date of the mother’s last menstrual period. Forty weeks after the first day of the last menstrual period is the estimated due date. An early exam of your uterus and an early positive pregnancy test also help determine gestational age. The most accurate way to determine gestational age is by an ultrasound exam. The baby can be measured with ultrasound as early as 5-6 weeks after your last menstrual period. First Month In a normal pregnancy, about 5-7 days after a sperm fertilizes an egg, the egg implants in the lining of the uterus. The fertilized egg then begins to grow in the uterus. At this stage of development the baby is called an embryo. Shortly after implantation the placenta and umbilical cord begin to form. The placenta and umbilical cord provide nourishment and oxygen to your baby and carry away the baby’s wastes.
