Prevention of neonatal infections by vaginal chlorhexidine disinfection during labour.

Comparison of two different methods of vaginal disinfection was made with regard to prevention of neonatal infections. In method I, an antepartum vaginal douche with a chlorhexidine solution was used; method II involved the use of chlorhexidine gluconate obstetrical gel during vaginal exploration. We studied 2853 normal deliveries from a total number of 3236 deliveries: 1467 deliveries were allocated randomly to receive a vaginal douche whereas 1386 underwent vaginal exploration using chlorhexidine gel. A total of 203 neonates were transferred to the neonatal unit (120 males and 83 females): 101 belonged to the group where the mothers were subjected to method I, whereas in 102 method II had been used. Within 48 h postpartum 30 neonates from the method I group and 34 neonates from the method II group received systemic antibiotics. There was a tendency towards a higher proportion of full-term neonates with verified septicaemia in the method II group (6 versus 2), whereas the numbers of probable infections were 8 versus 12. The corresponding total numbers in preterm infants were 3 and 2, respectively. These differences were not statistically significant. We conclude that the use of chlorhexidine douche compared with vaginal exploration with chlorhexidine gel provides no additional advantages.

Retinal hemorrhages and traction forces in vacuum extraction.

The relationship between the traction forces used in 53 clinically indicated vacuum extractions and the incidence and degree of retinal hemorrhages observed in the neonates within 24 hours after birth was examined. A Vacuum Extractor Recorder (Type SF 30, Knick), was used to measure the traction force necessary for delivery of the fetal head. No relationship could be demonstrated between the force time integral and the appearance and grading of retinal bleedings.

A method for objective measurement of fetal head compression during the second stage of labor.

The article describes a novel method for the objective measurement of compression forces to which the fetal head is exposed during labor. This involves the placement of a transducer, housed in a silicone rubber and brass casing (18 mm diameter, 6.5 mm thick), over the parietal bone area. The compression forces monitored with the transducer in this position provide an estimate of the intracranial pressure. The technique thus not only provides a means of assessing fetal head compression, but also the efficacy of the expulsion efforts of the mother. Pressure recordings taken during the second stage of 24 deliveries revealed a marked variation in the magnitude of the compression forces between the births.

Measurements of fetal head compression pressure during bearing down and their relationship to the condition of the newborn.

Fetal head compression pressure (FHCP) and its clinical importance has been investigated in a group of 46 spontaneous births. Measurement of FHCP was facilitated using a compression transducer positioned between the fetal head and the wall of the birth canal. This method not only constitutes a means of quantitating the forces acting directly on the fetal head, but also provides information about the intracranial pressure generated during delivery. The latter extrapolation is based on the principle of applanation. The technique provides an objective and reliable estimate of intracranial strain and therefore a means of comparing the forces generated under different delivery modes. The condition of the same neonates at birth was assessed using umbilical artery pH, Apgar score, neurobehavioral testing and fundoscopic examination. The mean amplitude of FHCP in the different deliveries ranged from 38 to 390 mmHg (5-52 kPa) with an overall mean of 157.9 mmHg (21.1 kPa). The study indicated that the appearance of retinal hemorrhages in the newborn cannot be explained by exposure of the fetal head to abnormally high compression during birth. Other explanations must be sought for infants with a neurobehavioral deficit, reduced Apgar score, or umbilical artery acidosis at birth. It is concluded that a relatively short period of high FHCP has no obvious consequences for fetal well-being, at least within the limits described in the present report.

Birth progression and traction forces developed under vacuum extraction after slow or rapid application of suction.

A vacuum extraction recorder was used to provide an objective measure of the traction forces developed on the fetal head during 120 vacuum extractions. In half of the deliveries the vacuum was gradually and stepwise increased to -0.8 kg/cm2 before traction. In the others, a rapid application of vacuum to the same level was chosen. No significant difference could be recorded in the traction forces developed by the different methods. In fact, once an adequate level of vacuum had been achieved, high degrees of traction could be applied to the suction cup, regardless of the rate at which the vacuum was developed. Furthermore, the number and nature of neonatal complications were not influenced by the method chosen.

Neonatal retinal hemorrhages and neurobehavior related to tractive force in vacuum extraction.

Fifty clinically indicated vacuum extractions were studied to evaluate a possible relationship between neurobehavioral abnormality, retinal hemorrhages and the tractive force used for delivery. A Vacuum Extractor Recorder (Type SF 30, Knick), was used to measure the forces necessary for delivery of the head. Infants delivered by the use of extensive tractive force showed no greater incidence of neuropathology than those delivered with less tractive force. The retinal hemorrhages were equally distributed among the infants, irrespective of the tractive force applied or the neurobehavioral assessment. The implication is that retinal hemorrhages cannot be used to evaluate the extent of cerebral influence after birth and that the main cause of neurobehavioral abnormality is the condition leading to the use of the vacuum extractor (VE).

Lack of correlation between umbilical artery pH, retinal hemorrhages and Apgar score in the newborn.

Measurement of pH was carried out in blood from the umbilical artery in 100 uncomplicated deliveries immediately after birth. The data were correlated with the results of fundoscopic examination carried out on the same infants within the subsequent 24 h. No relationship could be demonstrated between the grade of retinal hemorrhages and the cord blood pH measurements. Similarly, none of the neonatal birth parameters, including Apgar scores, could be related to individual differences in umbilical blood pH or the incidence or grade of retinal bleedings. The duration of bearing down was significantly and positively correlated (p less than 0.001) to the degree of acidosis in the umbilical blood. It is concluded that the presence of retinal hemorrhages provides little or no information about neonatal wellbeing or the impact of spontaneous birth on the fetus.

Application of fiberoptics to the clinical measurement of intra-uterine pressure in labor.

In the present report we describe a new technique for monitoring intra-uterine pressures during labor. The method utilizes a fiberoptic pressure transducer which is both accurate and stable. The pressure sensor is located at the catheter tip thus eliminating hydrostatic errors during monitoring. At body temperature the catheter is soft and flexible and represents no harm to the fetus. The membrane is housed in a metal dome with large lateral apertures. This arrangement greatly reduces the possibility of blockage. A comparison was made between recordings from the fiberoptic pressure transducer and those from a fluid-filled catheter implanted simultaneously in non-selected subjects during labor. Close agreement was obtained in the majority of cases. Large discrepancies between the two techniques were assumed to reflect the fact that the precise measuring point is not identical in each system. To date, recordings have been made in 52 parturients with no problems with insertion of the device and without any indication of equipment malfunction.