Management of birth under ultrasound guidance in patients with the transversely contracted pelvis

Relevance: Currently, different types of the contracted pelvis are mainly determined with the help of radiological diagnostic methods before pregnancy or in the antenatal period. Intranatally, biomechanism of childbirth characterizes the form of the pelvic contraction. In order to obtain objective manual data, a combined transabdominal and transperineal ultrasound assessment is proposed, as it an effective, safe and accurate method for monitoring the ratio of the fetal head and the birth canal.

Case report: The article presents a clinical case of a patient whose transperineal ultrasound scanning revealed that labor started with asynclitic insertion of the fetal head with a sagittal suture in the conjugate of the pelvic inlet. The occipital posterior presentation was diagnosed and the type of the transversely contracted pelvis was suspected. The progress of the fetal head in labor was evident due to an increase in the angle of progression from 106° to 125°, while the sagittal suture remained in the conjugate of the true pelvis. When the cervix was fully dilated and the angle of progression was 154°, the rotation of the head by 180° began in the plane of the pelvic outlet. The birth occurred with the anterior occipital cephalic presentation.

Conclusion: The patients with the transversely contracted pelvis may give birth spontaneously only if fetus takes the anterior occipital cephalic presentation. In case of initial posterior presentation, giving birth will occur naturally through the birth canal, only when the fetal head is rotated 180° and the fetus takes the anterior presentation. The high direct position of the fetal head is accompanied by signs of clinical inconsistency. The use of ultrasound criteria made it possible to establish a type of the contracted pelvis, which was confirmed by MRI, and it was also possible to provide evidence of the likelihood of the spontaneous birth.