The rise in obstetric intervention with maternal age: a continuous phenomenon

Population-based data from the Cardiff Births Survey has been used to examine the trends in obstetric intervention with increasing maternal age. As maternal age increases, spontaneous vaginal delivery rates fall, instrumental delivery rates, elective and emergency caesarean section, induction of labour and epidural rates rise. Induction of labour and epidural in labour are both associated with decreased spontaneous vaginal delivery rates and an increase in instrumental delivery rates and emergency caesarean section.

A second-stage partogram

OBJECTIVE

To describe a second-stage partogram based on a system of scoring the descent and position of the fetal head and to use this system for studying progress in the second stage of labor and predicting mode of delivery and obstetric outcome.

METHODS

A prospective observational study of 1413 women at term with a singleton, cephalic presentation. The position and station of the fetal head were observed and scored at diagnosis of the second stage of labor, 1 hour later, and then at 30 minute intervals until delivery was achieved. The score at diagnosis of the second stage of labor was assessed for its ability to predict eventual mode of delivery and duration of labor. A normogram was defined for nulliparas and multiparas and was used to define normal and abnormal progress in the second stage, associated factors in the first stage of labor, and mode of delivery.

RESULTS

Increasing total score at the start of the second stage of labor is associated with increasing chance of spontaneous vaginal delivery (odds ratio [OR] 1.68 for nulliparas, 1.59 for multiparas), decreasing chance of instrumental vaginal delivery (OR 0.67 for nulliparas, 0.64 for multiparas), and emergency cesarean delivery (OR 0.39 for nulliparas). Abnormal progress as defined by the normogram is associated with use of epidural anesthesia, induction of labor, augmentation, dystocia, and increased incidence of operative delivery. No significant difference is found between normal and abnormal second stages of labor in fetal outcome as determined by Apgar scores.

CONCLUSION

The second-stage partogram offers an objective basis for management of the second stage of labor.

Occipitoposterior position: associated factors and obstetric outcome in nulliparas

OBJECTIVE

To determine factors associated with term delivery in the occipitoposterior position and examine obstetric outcomes from that delivery position in nulliparas.

METHODS

We did a retrospective analysis of population-based data of 16,781 nulliparas who delivered at term (37-42 weeks) with singleton, cephalic presentations. Factors examined for possible association with occipitoposterior position were fetal weight, maternal age, completed weeks of gestation, epidural analgesia in labor, labor induction, and oxytocin augmentation. Obstetric outcome measures were mode of delivery and percentage of infants with Apgar scores less than 8 at 5 minutes.

RESULTS

The frequency of occipitoposterior position was 4. 6%. Fetal weight, epidural analgesia, and oxytocin augmentation were strongly associated with delivery in the occipitoposterior position (odds ratios 1.18, 2.21, 1.44, respectively, P <.001, logistic regression). There was a higher incidence of instrument and emergency cesarean deliveries in occipitoposterior compared with occipitoanterior labors (43.7% versus 24.4%, 41.7% versus 13.7%, respectively, P <.001, the chi(2) test). There was no significant difference in percentage of infants with low Apgar scores at 5 minutes between those who delivered occipitoposterior or occipitoanterior.

CONCLUSION

Epidural analgesia and oxytocin augmentation are associated with increased incidence of occipitoposterior position, which leads to increased operative obstetric intervention for delivery.

A post-synaptic depressant modulatory action of 5-hydroxytryptamine on excitatory amino acid responses in rat entorhinal cortex in vitro

The depressant action of 5-hydroxytryptamine (5-HT) in slices of entorhinal cortex of the rat has been examined. When single intracellular recordings of pyramidal cells in layers II/III of entorhinal cortex of the rat were made and drugs applied by iontophoresis, 5-HT evoked virtually no changes in passive membrane properties of the majority of cells studied. When short regular pulses of glutamate were applied to the neurones and 5-HT was ejected in addition, the depolarisations caused by glutamate were considerably reduced in amplitude. This attenuation persisted in medium containing cadmium chloride (200 microM) to block synaptic transmission. The magnitude of the response to 5-HT was dependent on the ejection current and this effect could not be mimicked by increasing ejections of Na+ or H+ ions. 5-Hydroxytryptamine had no apparent action on neuronal responses to iontophoretically ejected gamma-amino butyric acid (GABA). In later studies, the action of 5-HT was examined on epileptiform discharges, evoked in the presence of the GABA antagonist, bicuculline, in the same group of cells. Droplet application of 5-HT into the recording chamber, or perfusion of 10 microM 5-HT regularly attenuated the length of epileptiform bursts but, at this concentration, had no discernible effect on the resting membrane potential or membrane input resistance. The effect of 5-HT on the release of glutamate from slices of entorhinal cortex has also been examined using a fluorometric enzyme assay. Concentrations of 5-HT as large as 30 microM had no effect on the release of endogenous glutamate in these experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of the ontogeny of galanin in the rat central nervous system by immunohistochemistry and radioimmunoassay

The development of galanin-like immunoreactivity in the rat central nervous system has been investigated immunologically. Galanin-positive processes in the central nervous system were first recognized at day 1 post-natal, in the dorsal horn of the spinal cord. At day 2, the first galanin-immunoreactive neuronal somata were visualized in several regions of the diencephalon; at later stages of maturation positive cells were also detected in many brain stem areas. The number, density and staining intensity of galanin-positive structures in these and other regions increased steadily until day 28, by which age the adult disposition was attained. Increases in the concentrations of galanin-like immunoreactivity during maturation of the animals closely paralleled the immunohistochemical findings. No reduction in galanin-like immunoreactivity was noted in any area during later post-natal ages. The present study indicates that the ontogeny of galanin-like immunoreactivity in the rat central nervous system occurs entirely post-natally. The developmental profile is consistent with the role of galanin as a putative neurotransmitter/neuromodulator in the rat brain and spinal cord.

Afferent projections to the rostral anterior pretectal nucleus of the rat: a possible role in the processing of noxious stimuli

The afferent inputs to the rostral pole of the anterior pretectal nucleus have been examined by utilizing the retrograde axonal transport of a fluorescent dye, Fast Blue. After unilateral injection of the dye into the rostral anterior prectectal nucleus, large numbers of labelled neuronal somata were found in the somatosensory cortex, the ventrolateral geniculate nucleus, the zona incerta, the superior colliculus, the deep mesencephalic nuclei, the pedunculopontine tegmental nucleus and the medial vestibular nucleus. In addition, the contralateral parabigeminal nucleus provided a major input to the rostral part of the anterior pretectal nucleus. Smaller and sparser collections of stained cell bodies could be found in the ventromedial hypothalamus, the posterior pretectal nucleus, the nucleus of the posterior commissure, the peripeduncular nucleus, the periaqueductal central gray, the contralateral anterior pretectal nucleus, and the locus coeruleus. Many of the inputs originated in areas associated with nociceptive pathways. The regional distribution of neurons projecting to the rostral pole of the anterior pretectal nucleus differs substantially from that of the cells innervating the anterior pretectal nucleus proper, i.e. its more caudal parts. It is concluded from this that the rostral pole constitutes a separate nucleus, anatomically distinct from the rest of the anterior pretectal nucleus and other cell groups in the pretectal complex. The demonstration that many of the afferents to the rostral anterior pretectal nucleus arise in regions involved in nociception supports recent electrophysiological and behavioural evidence that this brain area plays a role in the processing of noxious stimuli, rather than as a component in the pretectal control of visual system reflexes.