We get a lot of questions about fetal development at ACPC Women’s Clinic. Our patients are usually anxious to figure out their due date and to see what their baby actually looks like. A woman is usually about 4 weeks along before she even realizes she is pregnant. There can be some confusion around determining the due date. Here’s why:
Most women are surprised when the nurse says she is already 4 or 5 weeks along even though she had just missed her period within the last couple of days. This is because obstetricians count weeks of pregnancy from the first day of a woman’s last period (LMP – Last Menstrual Period). They do this because there is no way to determine exactly when conception occurred. To determine the age of your unborn child since fertilization (conception), use this table and just subtract two weeks.