When is a pregnant woman due? Does a pregnancy last 38 or 40 weeks? Sometimes it proves difficult to calculate when a woman is going to give birth. This has to do with a difference in the calculation of gestational age. In general, a gestational age of 40 weeks is used in the Netherlands and Belgium.

How long does a pregnancy last?

A human pregnancy lasts 38 weeks. Yet 40 weeks are often said, which is also correct. This causes quite a bit of confusion. It is quite easy to explain:From fertilization, i.e. the fusion of egg and sperm, it takes another 38 weeks until the baby is fully grown and is born. However, in practice it often proves difficult to determine when fertilization took place. Since fertilization usually takes place two weeks after the first day of the last menstrual period, these two weeks are also included for convenience. Pregnancy therefore begins on the first day of the last menstrual period, although in practice there is no pregnancy yet.

How to calculate?

There are many useful calculators available on the internet that show exactly when the expected delivery date is. All these calculators are based on the first day of the last menstrual period: enter this as well. To calculate it yourself: take the first day of the last menstrual period. Add exactly 40 weeks to this. The outcome is the expected delivery date.These calculations assume a cycle duration of 28 days. Sometimes a woman has a shorter cycle : for example 25 days. Then subtract 3 days from the delivery date (28-3=25). If the cycle lasts longer, for example 35 days, add 7 days to the delivery date (28+7=35).

4th week of pregnancy: what does that mean?

When people talk about the 4th week of pregnancy, it does not mean that the woman is four weeks pregnant, but is in her 4th week. She will then be 3 full weeks pregnant and on her way to 4 weeks of pregnancy. Only in the 5th week of pregnancy, she is 4 full weeks pregnant. This can also sometimes cause some confusion.

Born late or premature

A baby born earlier or later than the expected delivery date is not necessarily a premature or late baby. Because the moment of fertilization can never be determined exactly, the delivery date may differ slightly in reality. It may also happen that one baby is ready to be born earlier than the other. This may also depend on the rate of growth of the baby and external influences such as use of medication, over or underweight of the mother, smoking and alcohol.It is generally stated that a baby born between 38 weeks and 42 weeks of pregnancy is born on term. It is safe to give birth at home from 37 weeks of pregnancy. After 42 weeks of pregnancy, it is determined whether labor should be initiated. Continuing too long with a full-term pregnancy is not healthy and safe for the baby: the amniotic fluid decreases and the placenta begins to die.

Date of birth

The date of birth is not the day the mother is due, but the day the baby is born. In most countries this is also the child’s birthday. In some cultures, a birthday is calculated from the day of conception. For example, in this culture a person is always nine months older than his or her birthday.Sometimes a birth takes place just around the turn of the day: at twelve o’clock at night. It is important to pay close attention to the exact delivery time. This makes the difference of being one day older or younger if proper care is not taken.

Gestational age of humans versus animals

Humans are nine months pregnant, or 40 weeks. This is comparable to that of a cow: it is also pregnant for an average of 40 weeks. An elephant has the longest gestation period: 18 to 22 months. A hamster has the shortest gestation period: 16 days. Generally speaking, the gestation period depends on the life expectancy of the species. A hamster lives on average 1 to 3 years: not enough time to carry a 9-month pregnancy to term.However, this is not always the case: elephants live an average of 30 to 40 years and yet have a much longer pregnancy period than humans. An elephant cub develops in the womb for so long that its brain is fully developed. This enables a young elephant to recognize the group immediately after birth and to provide itself with food through its trunk. This significantly increases the chance of survival of an elephant cub.