Duration of pregnancy

When is a term pregnancy?

A normal pregnancy lasts 40 weeks according to the usual rules. The due date of the last menstrual full stop is calculated on this basis. According to the Neagelli rule, 1 year is added to the first day of its duration, 3 months are subtracted and 7 days are added. This applies to women who menstruated regularly and whose cycle lasted 28 days. For longer or shorter cycles, an additional number of days is added or subtracted, as appropriate.

By definition, a term pregnancy lasts 37 weeks. This means that at the end of the 37th week (known as 37+0), the pregnancy is considered term and the baby is not considered preterm at the time of birth. From this point on, the newborn is no longer at risk of the most serious complications associated with preterm birth. However, in some situations, it may need respiratory support or additional medical measures.

Duration of pregnancy – the signs of birth

Although the calculated duration of pregnancy has already expired, most women give birth in the following weeks. Many give birth after the estimated due date, which is determined on the basis of menstruation or the length of the vaginal seat in the ultrasound of the first trimester.

Towards the end of pregnancy, usually from the 37th week, symptoms can appear that announce the birth. These include cramps in front of the vagina, pain in the loins or a characteristic lowering of the abdomen associated with pushing the baby into the birth canal. In addition, other symptoms may occur, such as vomiting, diarrhoea or detachment of the mucous membrane. These symptoms do not mean that the expectant mother has to go to hospital immediately. It is best to visit the chosen facility as soon as the amniotic fluid has drained, regular contractions have started or worrying symptoms such as bleeding or decreasing movements of the baby appear. If the pregnancy is normal and labour has not yet started at 41 weeks, most hospitals will admit the woman to the maternity hospital for induction of labour.

Premature birth – consequences

For expectant parents and gynaecologists, the most important goal during pregnancy is to prolong it as long as possible until the 40th week and especially until the time of delivery, in order to avoid the consequences of premature birth. If the pregnancy is not completed, the baby is at risk of a number of possible complications. These include retinopathy of prematurity, respiratory problems, and necrotising enterocolitis or persistent ductus arteriosus. In addition to the consequences that occur immediately after birth, premature babies also have to deal with complications in the following years of life.