How Can Pregnancy Due Calculators Help Determine Gestational Age?

When a mother finds out she is pregnant she's eager to know when the little 'bundle of joy' will arrive. She is usually told a due date by her midwife or doctor, but often she's calculated her due date already, maybe using an online pregnancy due date calculator. So she knows about when the baby is due, and her care provider hopefully explained that the due date is only an approximate date of delivery – she need not show up at the hospital on that day, expecting that the baby knows how to read a calendar! As for the actual delivery date, anything within the window of two weeks before to two weeks after that magic "due date" is considered to be "on time."

What Is Gestational Age?

Gestational age is the age of the unborn baby from the first day of the woman's last menstrual period. This is including the two weeks before the egg is even fertilized. It is not the beginning of pregnancy – which causes confusion for many expectant mothers.

Gestational age is different from fertilization age – also called conventional age or developmental age – because the fertilization age is counted from when the egg is fertilized, and that is usually two weeks later than the gestational age. When the periods of time during the pregnancy are referred to – first trimester, second trimester, third trimester – they are referring to gestational age.

What Affects The Accuracy Of The Gestational Age?

Despite whatever the pregnancy due date calculator tells a woman about how old her baby is, there are several things that can affect the accuracy of the gestational age. First, if the mother knows the date that the sexual intercourse took place, that helps. That date can be used to more accurately determine the date of conception.

Mothers who are in tune with their body, and keeping track of their fertility – particularly in an attempt to become pregnant – these mothers are more likely to notice the fertility signs that are related to ovulation. They would know if they tend to ovulate sooner or later than the average mother, and they might be able to tell when they last ovulated.

During pregnancy, some mothers are given an ultrasound, where some of the baby's body parts can be measured to more accurately determine how old the baby is. These determinations can help validate the date achieved with the pregnancy due date calculator.

After birth – particularly if the baby is born premature – the doctor or pediatrician can recognize the physical traits that the baby has and relate them to a part of the gestational period. This is helpful in determining the age to which the baby had matured prior to birth. These involve things like skin tone, presence of linugo, and limb flexibility.

Using a pregnancy due date calculator can help a mother know approximately when to anticipate her newborn's arrival. That date can be changed based on further information that the doctor feels affects the pregnancy due calculator.