While most maternal deaths occur during labor and delivery, most perinatal deaths are due to labor and events occurring during delivery. Causes of maternal death at this stage include: prolonged delivery with the sequelae of water and electrolyte imbalance, obstructed labor with sequelae of water and electrolyte imbalance and uterine rupture, eclampsia, bleeding and thromboembolism, and complications of anesthesia for cesarean section; all of these can also lead to perinatal death.
Perinatal death during labor may also result from vacuum delivery complications, including subgaleal hemorrhage, subdural hematoma, cerebral infaction, skull fracture, and neonatal jaundice. All birth injuries that occur during shoulder dystocia and breech delivery can result in perinatal death. Almost all of these can be avoided with good workforce management, including proper case selection and partograph use. During delivery, including ultrasound imaging, assessment of cervical length during induction, knowledge of head position and descent during delivery, case selection for vaginal delivery (VBAC) after cesarean section, detection of uterine rupture, prevention of obstructed delivery, bleeding and fetal heart monitoring, determination of intrapartum cause is useful.
Induction Application Range
The success of labor induction is directly related to the preferability of the cervix indicated by the Bishop score. Ultrasound accurately measures cervical length and dilation to help determine the score to avoid prolonged labor. Evaluation of cervical length is described in the second trimester. Second, TVS measurement to the perineum distance of the fetal head and TAS measurement of fetal head position provide the most accurate estimate of successful induction of labor.
Baby’s Head-Butt Position
Studies have shown that sonographic measurement of head position and descent is more accurate than digital examination. More recently, it has been suggested that the angle formed by a line connecting the lowest point of the fetal head to the lower edge of the pubic symphysis provides an objective, accurate, and reproducible way to assess descent using a translabial sonography approach. At an angle of progression of about 120 degrees or more, either spontaneous vaginal delivery or an easy and successful vacuum extraction is likely. Also, the gold standard technique for evaluating fetal head position during delivery is transabdominal suprapubic transverse ultrasound. Therefore, the lack of progress leads to intervention, as demonstrated by the partographic representation of this sonographic finding.
The main concern with VBAC is uterine scar rupture. Fetal size and scar thickness are among the factors that predict uterine rupture. Fetal size and weight estimation helps in selecting cases. Studies have found that antepartum uterine scar thickness is inversely proportional to the risk of intrapartum uterine rupture, and intrapartum assessment of uterine scar can predict uterine rupture with a high degree of accuracy. There is evidence that ultrasound imaging can aid in determining uterine scar thickness and case selection for VBAC.
Detection of Uterus Rupture
Labor pains and uterine rupture during delivery are often diagnosed clinically; Therefore, valuable time should not be wasted on ultrasound imaging if the clinical diagnosis is clear. However, in cases where the clinical features are not clear, such as during prenatal silent rupture, or sometimes especially during labor with an epidural, ultrasound imaging may show contamination in the uterine wall.
Head Position for Vacuum
The success of the vacuum distribution depends on the location of the cover, among other conditions. Incorrect placement can deflect the fetal head and cause the procedure to fail. The head should be placed at or near the flexion point on the vertex. It has been shown that ultrasound-assisted examination detects this flexion point better than digital examination alone.
This condition, if not detected, will lead to umbilical cord prolapse when fetal membranes rupture. It can be difficult to feel a presented cord. Color Doppler sonography can clearly identify this cord to guide appropriate intervention to prevent fetal or neonatal death.
Fake Labor Pains
Fetal macrosomia, misrepresentation, and abnormal lying are the causes of obstructed labor. Apart from macrosomia, all other conditions also predispose to cord prolapse. Ultrasound, fetal biometry and EFW and presentation / lie evaluation are useful in detecting all of these for appropriate intervention to prevent obstruction or cord prolapse.
Fetal Heart Rate Detection
Sometimes the fetal heart rate may not be heard with the Pinard fetal stethoscope. As ultrasound is becoming more available than a sonicaid (sound Doppler) or cardiotocography (CTG) machine, especially in low-income countries, ultrasound is used to check the fetal condition and if the fetus is alive and in distress, rapid delivery by cesarean section or vacuum will prevent perinatal death.
After the birth of the first twin, there is an increased perinatal mortality compared to the first twin with the second twin due to cord accidents, premature separation of the placenta and other factors. Therefore, there is a need to speed up the birth of the second twin as early as possible. After the birth of the first twin, if the second twin is not cephalic, ultrasound-guided external cephalic version (if membranes are intact) or internal podalic version (if membranes are intact or only ruptured) can be performed to ensure vaginal delivery.
Uterine inversion, which causes bleeding and shock, pregnancy products that cause bleeding and infection, puerperal sepsis, postpartum eclampsia and thromboembolism are the main causes of maternal death after birth. The usefulness of ultrasound imaging in detecting thromboembolism and the imaging technique have been discussed before. In some cases of uterine inversion for which clinical diagnosis is not clear, ultrasound has been used to reveal the diagnosis to ensure appropriate management. If conception products are retained, ultrasound can distinguish between retained products and endometritis. Even small pregnancy products that occur in the first trimester abortion are correctly detected by TVS with Doppler application.
Postpartum Detection of Uterine Rupture
Sometimes, suspicion of uterine rupture does not appear until after delivery, especially if it occurs during the second stage of labor. There is evidence that ultrasound can detect a cesarean wound tear after birth and even postpartum scarring. Others have suggested that the combined anterior uterine wall and bladder thickness (<3 mm) associated with ballooning of the lower segment indicate a defect in the myometrium.
Detection of Postpartum Wide Ligament Hematoma
Wide ligament hematoma can occur when the uterine ruptures or cervical tear with upper extension, causing shock that may be disproportionate in the postpartum period. Ultrasound imaging can help detect a hematoma.
In addition to helping diagnose postpartum endometritis, ultrasound accurately detects pelvic abscess that can appear as a hypoechoic or complex focal collection.
Writer: Ozlem Guvenc Agaoglu