Abstract
A prospective study of the fetal heart rate pattern during labor before and after paracervical blockade (PCB) was performed. The material comprised 469 women in labor, or 28% of 1 673 women delivered during a 6-month period. The majority of the anesthesias (87%) were administered by specially trained midwives. Bupivacain (Marcain) was the anestethic used. The injections were made at four different points at a cervical diameter of 3 - 9 cm. The concentration of the anesthetic was 0.25 or 1.25% generally in 10 ml of normal saline. A second PCB was administered in 54 patients at least one hour after the preceding one. Fetal heart rate (FHR) was recorded via a scalp electrode and the pattern studied 15 min before and 30 min after the injection of the anesthetic. Bradycardia was defined as a persistent deceleration exceeding 3 min and occurring within 30 min of the PCB. Variability and acceleration pattern persisted independently of the PCB. Following PCB, decelerations of all types increased, while the basal rhythm decreased by on average 1.5 beats/min. Following PCB fetal bradycardia occurred in 1.9%. The bradycardia persisted on average for 6.5 min with a lowest average FHR of 73 beats/min. Retrospectively, 6 out of 9 infants exhibited recognized risk factors for bradycardia. All infants with bradycardia scored 9-10/5 min, according to the Apgar rating scale and all had a normal development with regard to growth, motor and speech development at the age of 2 years. There were no significant differences in vaginal operative deliveries between the PCB and the non-PCB group. However, the incidence of acute cesarean section was significantly and appreciably lower in the PCB than in the vaginally delivered non-PCB group. Judging by the Apgar rating scale the general condition of the infants at birth was significantly better in the PCB than in the vaginally delivered non-PCB group. In conclousion: Apart from a 2% incidence of fetal bradycardia following PCB, no untoward effects have been observed. The incidence of acute cesarean section was lower and the general condition of the infants better in the PCB than in the non-PCB group. Adequate teching of the technique, contra-indications to PCB and the side effects of the anesthetic agent are needed. Thereafter, it would seem appropriate not only that doctors but also specially trained midwives should be able to use paracervical blockade in order to alleviate pain during the first stage of labor.
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