The date of the first documented positive pregnancy test and the beta-human chorionic gonadotropin (b HCG) level may help ascertain the minimum gestational age.
In women who conceived following assisted reproduction techniques, the date of embryo transfer is known and may date the pregnancy accurately.
The estimation of pregnancy dates is important for the mother, who wants to know when to expect the birth of her baby, and for her health care providers, so they may choose the times at which to perform various screening tests and assessments,such as serum screening, assessment of maturity, and induction of labor for postdate pregnancies.
The 3 basic methods used to help estimate gestational age (GA) are menstrual history, clinical examination, and ultrasonography.
For a woman with a regular period, conception typically occurs about 11-21 days after the first day of the last period.
Your midwife may recommend an early scan at between six weeks and 10 weeks if you have experienced bleeding, pain, or problems in a previous pregnancy. If all three are different days, how do you know when to plan for delivery? I'll bet there are hundreds of pregnant women out there right now who thought they had a due date all nailed down. A couple weeks later, oh, right about inauguration day, you started "celebrating." You got caught up in all that national love and hope and, well, what do you know? You can expect a lot of women to share the same, approximate due date. Is it based on your last period, the ultrasound or the date the doctor gives you? We say a normal pregnancy lasts 40 weeks but figure that anything after 38 is "due." So, if we're basing this on a January 5th period that makes your baby due: October 12th.Gestational age, or the age of the baby, is calculated from the first day of the mother’s 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.You may have calculated the length of your pregnancy from the first day of your last menstrual period (LMP).However, conception doesn't actually occur until around 14 days after your LMP, or later if your cycle is longer than 28 days. The rhetoric of "natural" in natural childbirth: childbearing women's perspectives on prolonged pregnancy and induction of labour.Gestational age is calculated from the first day of the mother’s last menstrual period and not from the date of conception.The baby can be measured as early as 5 or 6 weeks after the mother’s last menstrual period.Measuring the baby using ultrasound is most accurate in early pregnancy. The best time to estimate gestational age using ultrasound is between the 8th and 18th weeks of pregnancy.The most accurate way to determine gestational age is using the first day of the woman’s last menstrual period and confirming this gestational age with the measurement from an ultrasound exam.