When to talk about term overrun?
In Western countries, more than ¾ of births occur between 37 and 39 weeks old.
Specialists consider:
that a pregnancy is prolonged beyond 41 SA,
that beyond 42 SA, it’s about term overrun.
15 % of pregnant women give birth between 41 SA and 41 SA + 6 days, while 1 % give birth beyond 42 SA.
The implications are important depending on whether it is an extended pregnancy or an outdated term because the longer the duration of the pregnancy is prolonged, the more obstetric consequences for the mother and the risks for the child increase, with maternal morbi-death fetal more important than for term births not exceeding 41 SA.
The interest of early ultrasound
Ultrasound dating of pregnancy reduces the risk of prolonged pregnancy and erroneously triggers childbirth for this reason.
According to several studies, the calculation of the normal term of pregnancy is greatly facilitated (and therefore allows you to intervene more accurately in case of overrun) by achieving the first ultrasound carried out between 9 and 11 week of pregnancy.
Thus, the term frequency exceeded is 7,5 % if the date of the last period is used as a calculation criterion, 2,5 % when an ultrasound is done before 20 weeks, and only 1 % if Ultrasound is done before 12 weeks of refurbishment.
Term overrun: what risks to the mother?
Term overrun can have consequences for the mother. Thus, studies show:
An increase in frequency of instrumental extractions and perineal tear rates of 3nd and 4rd degree beyond 42 SA.
An increased risk of hemorrhaging of deliverance starting at 41 SA.
Peripartum infections (chorioamniotites, indometritis) are also slightly more common, especially when delivery occurs after 42 SA.
Term overrun: what risks to the child?
The frequency of fetal post-maturity syndrome with macrosomy increases with prolonged pregnancy and especially term exceedance.
The main causes of fetal morbi-death are perinatal asphyxia and meconium inhalation. The presence of meconium in amniotic fluid is in itself a sign of fetal suffering. Hypoxia (lack of oxygen) can also be explained by the accelerated aging of placenta from 41 SA but also the foetal compression linked to oligoamnios (decreased amniotic fluid volume) that occurs from 41 SA and especially 42 SA. Added to fetal heart rate alterations.
All of these abnormalities can be responsible for neurological signs after birth, including neonatal seizures and sequelae, mainly brain motor failure.
Do you have to start a childbirth after the term?
The High Health Authority issued recommendations in 2008 regarding artificial outbreak of work from 37 SA, similar to Canadian and U.S. recommendations.