Nucleotides and the double helix. DNA, or deoxyribonucleic acid, is the heritable material found in all cells. DNA provides the instructions to build, maintain, and regulate cells and organisms and is passed on when cells divide and when organisms reproduce.
Calculating Conception. Gestational age, or the age of the baby, is calculated from the first day of the motherâs last menstrual period.Since the exact date of conception is almost never known, the first day of the last menstrual period is used to measure how old the baby is. Use our Pregnancy Calculator to calculate these dates for you.he baby can be measured as early as 5 or 6 weeks after the motherâs last menstrual period. Measuring the baby using ultrasound is most accurate in early pregnancy. It becomes less accurate later in pregnancy. The best time to estimate gestational age using ultrasound is between the 8th and 18th weeks of pregnancy.
How is my due date calculated? Your due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle). Note that your menstrual period and ovulation are counted as the first two weeks of pregnancy. If you deliver on your due date, your baby is actually only 38 weeks old, not 40.