Obstructed labor: focus on the different types of obstructed labor

Le terme “dystocie”Comes from ancient Greek“dys”, Meaning difficulty, and“tokos”, Meaning childbirth. A so-called obstructed birth is therefore a difficult childbirth, as opposed to a eutocic childbirth, which takes place normally, without hindrance. We thus group together under the term obstructed birth all deliveries where difficulties arise, in particular concerning uterine contractions, dilation of the cervix, the descent and engagement of the baby in the pelvis, the baby’s position during childbirth (in breech in particular), etc. There are two main types of dystocia:

  • -dynamic dystocia, linked to a dysfunction of the uterine “motor” or dilation of the cervix;
  • -and mechanical dystocia, when obstructed, of fetal origin (size and / or presentation of the baby…) or not (tumor, placenta praevia, cyst…).

Note that obstructed labor is sometimes classified according to whether it is of maternal origin (dilation of the cervix, uterine contractions, placenta previa, pelvis too narrow, etc.) or of fetal origin.

Obstructed labor: when obstructed labor is dynamic

According to the estimates of obstetrician-gynecologists, dynamic obstructed labor represents more than 50% of the causes of obstructed labor. It can be related to insufficient uterine labor, when uterine contractions are not effective enough to allow the baby to be expelled. Conversely, too violent contractions can also cause obstructed labor. “Abnormal” contractions, too weak or too intense, can also prevent proper dilation of the cervix, and therefore complicate childbirth. The cervix itself may have peculiarities that prevent it from dilating properly and sufficiently.

Obstructed labor: when the obstructed labor is mechanical

There are three main types of mechanical dystocia here, when there is a mechanical obstacle complicating vaginal delivery:

  • -We are talking about bone dystocia when the mother-to-be’s pelvis presents an anomaly of size, shape or inclination, which complicates the passage of the baby through the different straits of the basin;
  • -We are talking about mechanical dystociaof fetal origin when it is the fetus that complicates childbirth due to its position (in particular in a completed or incomplete breech), its size and its significant weight (we speak of fetal macrosomia, when the weight of the child is greater than 4 kg) or due to malformation (hydrocephalus, spina bifida, etc.);
  • we are finally talking about soft tissue mechanical dystocia when the obstructed labor is due to a placenta previa at least partially covering the cervix, ovarian cysts, uterine problems (fibroids, malformations, scars, etc.) etc.

A special case of mechanical obstructed labor of fetal origin is shoulder dystocia, when the baby’s head has been expelled but the shoulders are struggling to engage in the pelvis afterwards. We talk more broadly about dystocie d’engagement when the fetus struggles to engage properly in the pelvis, despite good cervical dilation.

Obstructed labor: is cesarean section always necessary?

Depending on the type and degree of obstructed labor during childbirth, cesarean section may be indicated.

Note that advances in ultrasound today make it possible to avoid certain obstructed deliveries, by opting for a scheduled cesarean section, when there is a placenta previa covering the cervix, for example, or when the baby is really too big for the width of the mother-to-be’s pelvis. However, vaginal birth can prove to be a success despite the difficulties mentioned above. 

In the face of dynamic dystocia, the artificial rupture of the membranes and the injection of oxytocin can make it possible to make the contractions more efficient and the cervix more dilated.

The use of instruments such as forceps or suction cups may be necessary in certain mechanical dystocia. 

But if these measures are not enough to deliver the baby, and / or signs of fetal distress appear, an emergency cesarean section is undertaken.

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