Glial contributions to visceral pain: implications for disease etiology and the female predominance of persistent pain

In the central nervous system, bidirectional signaling between glial cells and neurons ('neuroimmune communication') facilitates the development of persistent pain. Spinal glia can contribute to heightened pain states by a prolonged release of neurokine signals that sensitize adjacent centrally projecting neurons. Although many persistent pain conditions are disproportionately common in females, whether specific neuroimmune mechanisms lead to this increased susceptibility remains unclear. This review summarizes the major known contributions of glia and neuroimmune interactions in pain, which has been determined principally in male rodents and in the context of somatic pain conditions. It is then postulated that studying neuroimmune interactions involved in pain attributed to visceral diseases common to females may offer a more suitable avenue for investigating unique mechanisms involved in female pain. Further, we discuss the potential for primed spinal glia and subsequent neurogenic inflammation as a contributing factor in the development of peripheral inflammation, therefore, representing a predisposing factor for females in developing a high percentage of such persistent pain conditions.

Effectiveness and safety of a structured swimming program in previously sedentary women during pregnancy

OBJECTIVE

To determine whether undertaking a swimming program in sedentary women during pregnancy would improve maternal fitness without adverse fetal consequences.

METHODS

Prospective observational investigation of healthy sedentary pregnant women participating in a monitored swimming program.

RESULTS

Twenty-three women attended swimming sessions from 16 to 28 weeks of gestation resulting in increasing distances swum and improved aerobic fitness as measured by physical work capacity (PWC170) (p = 0.003). Resting maternal heart rate decreased (p = 0.041) and resting systolic (p = 0.092) and diastolic (p = 0.971) blood pressures remained unchanged over gestation. The mean fetal heart rates decreased with advancing gestational age (p = 0.001), consistent with normal physiology. Non-stress tests and umbilical artery systolic/diastolic ratios were similar before and after swimming sessions, providing evidence that fetal well-being was unchanged.

CONCLUSIONS

A structured swimming program in sedentary pregnant women increases maternal fitness without any alteration in maternal and fetal well-being.

Muscle mass deficits are associated with bone mineral density in men with idiopathic vertebral fracture

INTRODUCTION AND HYPOTHESIS

The causes of idiopathic vertebral fractures (IVF) in men are poorly understood. We hypothesised that in IVF, areal bone mineral density (aBMD) deficits would be associated with reduced muscle mass.

METHODS

In this case-control study, 48 men (61.5 +/- 12.1 years old) presenting with symptomatic IVF were compared with 48 healthy controls matched for age (+/-5 years) and stature (+/-5 cm). The aBMD and soft-tissue body composition were determined by dual energy X-ray absorptiometry (DXA). Muscle mass was defined as the ratio of appendicular lean mass to the square of height (ALMI). Sex hormones, IGF-I and its binding protein IGFBP-3 were measured by immunoassay.

RESULTS

ALMI was significantly lower in IVF patients (8.27 +/- 0.90 vs 8.65 +/- 0.88 kg/m(2), t = 2.193, df = 47, P = 0.033 by paired sample t-test). Hierarchical regression analysis revealed that for IVF patients, ALMI explained the greatest proportion of variance in BMD at the lumbar spine, femoral neck and total hip (R (2) (change) = 16.4-22.7%, P = 0.012-0.002) and only IGFBP-3 explained variance in ALMI (R (2) (change) = 19.9%, P = 0.006).

CONCLUSIONS

In men with IVF, ALMI was reduced and associated with IGFBP-3. ALMI was identified as a novel factor that explained a greater proportion of variance in BMD than either fat mass or serum biochemistry.

Impact of domestic violence and drug abuse in pregnancy on maternal attachment and infant temperament in teenage mothers in the setting of best clinical practice

We examined whether the prenatal detection of family violence and initiation of a comprehensive prenatal individualised care program could ameliorate the impact of family violence on maternal attachment to her infant at 6-months of age. An assessment of domestic violence was established for each subject at the 1(st) antenatal visit and women were classified as being exposed to domestic violence in pregnancy (EDV) or as being not exposed to domestic violence. Outcomes were determined 6 months postpartum. Of 173 consecutive women who met the eligibility criteria, consent was obtained from 150 (87% response). Women who had been subjected to domestic violence showed reduced overall attachment scores to their infants. Following multivariate analysis, drug use in pregnancy and domestic violence showed a significant independent effect on maternal attachment. Drug abuse and domestic violence were also associated with an increase in the easy-difficult scale of infant temperament. Thus, despite excellence in prenatal care, drug abuse and domestic violence were associated with poorer maternal attachment and assessment of infant temperament, suggesting that additional interventions are still required.

A bio-assay for effectors of osteoclast differentiation in serum from patients with bone disease

Osteoclast differentiation and activity, and hence bone loss, depend on two opposing cytokines. Receptor activator of NF-(kappa)B ligand (RANKL) produced by osteoblasts and T-cells stimulates, while osteoprotegerin inhibits. Both of these cytokines are found in serum. Our aim was to develop a functional assay for any factors present in human serum that can affect osteoclast differentiation and to assess whether any such factors vary in diseases in which bone loss occurs.

METHODS

Using a culture model of osteoclast differentiation in the presence of macrophage colony stimulating factor and soluble RANKL, we have measured the effects of different human sera on osteoclast differentiation. The production of a marker enzyme for the osteoclast, tartrate-resistant acid phosphatase (TRAP), was used to follow osteoclast differentiation.

RESULTS

In general, human serum stimulates osteoclast differentiation as indicated by TRAP activity, but in patients with low bone density this stimulation was attenuated. Sera from 40 female subjects with low bone mineral density showed significantly lower TRAP cell differentiation activity than sera from the healthy female controls.

CONCLUSION

We describe a functional bio-assay for factors in human serum which can affect osteoclast differentiation. This assay may have application in monitoring the effects of therapy in bone disease.

The progression of disease stage in twin-twin transfusion syndrome

OBJECTIVE

To estimate the frequency of progression or regression of disease stage in pregnancies complicated by twin-twin transfusion syndrome (TTTS) managed with non-placental laser techniques.

METHODS

A cohort of TTTS pregnancies within the sole perinatal center for the state of Western Australia was examined. All cases of prenatally identified TTTS from 1992 to 2002 were staged at diagnosis (retrospectively prior to 2000, prospectively since). Amnioreduction and septostomy were the principal therapies used. Features associated with progression, regression or stability were identified.

RESULTS

During the study period, 71 cases of TTTS were managed. Amnioreduction was performed in 73.2%, with no difference in the median number of procedures by stage (p = 0.178). In 21.1% of cases, TTTS resolved completely with persistent normalization of amniotic fluid volumes after amnioreduction (median number of procedures: 2). Disease resolution was associated with pregnancy prolongation, greater gestational age at delivery (36 weeks vs. 28.4 weeks, p < 0.001) and increased perinatal survival (100% vs. 42.6%, p < 0.001) compared with stage progression. Logistic regression analysis predicted that the probability of both infants surviving was 80% if the pregnancy remained at Stage I or II throughout, compared with a probability of 50% if it reached Stage III or more at 26 weeks, and only 25% if the disease reached Stage III or more at 16 weeks' gestation.

CONCLUSION

Pregnancy outcome for TTTS managed with amnioreduction techniques is correlated with stage at diagnosis and the subsequent disease evolution. However, the progression of stage in TTTS is unpredictable and the likelihood of spontaneous fetal demise was not different between stages.

Intrathecal fentanyl-induced pruritus during labour: the effect of prophylactic ondansetron

Fentanyl is commonly used for spinal analgesia during labour but it is associated with a high incidence of pruritus. This randomised, double-blind, placebo-controlled study was performed to evaluate the effect of prophylactic ondansetron on the incidence and severity of pruritus among parturients receiving intrathecal fentanyl as part of combined spinal-epidural analgesia. Seventy-three women were randomised to receive either saline placebo (group P, n = 25), ondansetron 4 mg (group O4, n = 23) or ondansetron 8 mg (group O8, n = 25) intravenously before intrathecal fentanyl 25 micrograms and bupivacaine 2 mg. The incidence and severity of pruritus were measured using a verbal rating and a visual analogue scale, and by the requirement for rescue anti-pruritic medication (naloxone). The overall incidence of pruritus was 95% (group P 100%, group O4 95%, group O8 90%). There were no significant differences between groups for severity of pruritus or requirement for treatment (naloxone given to 45%, 28% and 35% of groups P, O4 and O8 respectively). Secondary outcomes such as the incidence of headache, pain and nausea were not significantly different between groups. We conclude that prophylactic ondansetron 4 or 8 mg intravenously was ineffective in reducing the incidence or severity of intrathecal fentanyl-induced pruritus during labour.

Oral corticosteroid prescribing in women over 50, use of fracture prevention therapy, and bone densitometry service

OBJECTIVE

To identify the most common diseases and age of corticosteroid use in women over 50, dosage in last year, duration of oral corticosteroid use, prescription for fracture prevention (drug used), and referrals for bone densitometry.

METHODS

General practice records from 41 practices in Shropshire identified 62,230 women aged >50 from a population of 80,082. Data on fractures, duration of corticosteroid use, dose in the study year (1 April 1997-31 March 1998), use of fracture prevention therapy and bone densitometry were sampled from one out of three records.

RESULTS

3.2% were prescribed corticosteroids; 633 patients investigated in detail aged 70.1 (SD 10.5) years, had been prescribed 1526 (SD 1727) mg prednisolone (median 1040 mg) for 3.31 (SD 3.20) years (median 2.0 years). Patients with asthma/lung disease, most common in the younger group, had the lowest annual corticosteroid use; patients with rheumatoid arthritis (RA), polymyalgia rheumatica/temporal arteritis (PMR/TA), who were more likely to be elderly, had the highest annual use. Between the age of 70 and 79 years patients with RA had significantly more hip fractures than the other groups, and corticosteroid prescribing was most common. Bisphosphonates or hormone replacement therapy were prescribed for 48% aged 50-59 years but only 32% at 70-79 years (p<0.01); patients with asthma and RA being less likely recipients (p<0.01). Referrals for bone densitometry had occurred in 20.2%,with 60.2% having osteoporosis. Referrals were more common in those taking corticosteroids for longer periods (p<0.01).

CONCLUSIONS

The elderly had the most prescriptions for corticosteroid treatment but the fewest for effective fracture prevention therapy. Patients with RA, PMR/TA had the greatest corticosteroid dosage, for the longest time. Patients with RA sustained more hip fractures than other groups but were least likely to have effective fracture prevention therapy prescribed.

Effect of postural supports on neuromotor function in very preterm infants to term equivalent age

OBJECTIVE

To determine the effect of a postural support nappy and/or a postural support roll on neuromotor function in very preterm infants when nursed prone to term equivalent age.

METHODS

A randomized observer blind controlled trial of 123 very preterm infants was conducted in the neonatal intensive care unit of the sole tertiary referral centre in Western Australia. Infants were stratified by gestational age (< 29 weeks or 29-30 weeks), then randomized into one of three intervention groups: postural support nappy, postural support nappy and postural support roll, or disposable nappy and postural support roll. Interventions started when infants were stable and ceased when routine side-lying commenced. Measurements of shoulder and hip posture were performed pre-intervention, 5 weeks post-intervention and term postmenstrual age.

RESULTS

Infants nursed with a postural support roll and a postural support nappy demonstrated improved hip posture to term equivalent age compared with infants nursed with either a postural support roll only, or a postural support nappy only. Infants nursed with a postural support roll either with or without a postural support nappy demonstrated improved shoulder posture to term equivalent age.

CONCLUSIONS

Combined use of a postural support roll and a postural support nappy while very preterm infants are nursed prone improves hip posture up to term postmenstrual age. Use of a postural support roll improves shoulder posture up to term equivalent age.

The effect of anaesthetic technique on postoperative nausea and vomiting after day-case gynaecological laparoscopy

Gynaecological surgery is of high emetogenic potential and both total intravenous anaesthesia (TIVA) and prophylactic antiemetic therapy may reduce the incidence of postoperative nausea and vomiting (PONV). We studied 144 patients scheduled for day-case gynaecological laparoscopy in a randomized trial comparing balanced inhalational anaesthesia and prophylactic dolasetron (group I+D) with propofol TIVA and dolasetron (group T+D) or TIVA alone (group T). The primary outcome of "complete response" (no vomiting, no treatment for PONV) was not significantly different among groups (34%, 51%, 32%; groups I+D vs T+D vs T, P=0.12). During the first hour after surgery, group I+D had nausea of greater severity (P<0.03). During hospital admission, group T had more vomiting (P<0.03). From discharge until 24 hours postoperatively, 55% of group I+D experience nausea and 38% vomited. The incidence and severity of nausea were significantly lower in the TIVA groups (P<0.04 and <0.05 respectively). There were no significant differences between groups T+D and T, although comparing all groups the complete response rate was highest and the post-discharge incidence and severity of nausea lowest in group T+D. In conclusion, propofol TIVA, with or without dolasetron, reduced postoperative nausea, but not perioperative vomiting or antiemetic requirement, when compared with inhalational anaesthesia plus dolasetron.

Low body size and elevated sex-hormone binding globulin distinguish men with idiopathic vertebral fracture

Factors predisposing to vertebral fracture in men are less well defined compared with women. Most studies of osteoporosis in men have included patients with low bone mineral density (BMD), with or without vertebral fracture, or have included other fractures. To clarify these associations we investigated sex hormone levels, bone markers, and (indirectly) lean body mass (LBM) in 81 men with idiopathic vertebral fracture. Serum testosterone, estradiol, sex-hormone binding globulin (SHBG), 24-hr urinary creatinine (24-hr UCr), urinary free deoxypyridinoline (UfDPD) and serum type I procollagen carboxy-terminal propeptide, type I procollagen amino-terminal propeptide, type I collagen carboxy-terminal telopeptide, and osteocalcin were measured. SHBG was higher and 24-hr UCr lower in osteoporotic subjects. UfDPD was higher when corrected for 24-hr UCr. Serum bone turnover markers were not significantly increased, nor were serum sex hormones (and free hormone indices) significantly decreased in patients. SHBG levels were inversely related with lumbar spine and femoral neck BMD in both patients and control subjects. Free estradiol index was only correlated with BMD in men with osteoporosis. Body size is lower in men with established osteoporosis. The normal free hormone indices suggest that SHBG does not affect free hormone levels whereas the relationship between SHBG (but not sex hormones) and 24-hr UCr points to a relationship between SHBG and LBM. The association of high levels of SHBG with low levels of LBM may indicate an action via the known inverse relationship of SHBG with IGF-I, though any action through IGF-I probably occurred at an earlier age than that at which the patients presented. Estrogen has no relationship with BMD in normal men but may play a role in men with osteoporosis.

Statistical measures of foetal growth using linear mixed models applied to the foetal origins hypothesis

Statistical models of the relationship between the distribution of each of five foetal dimensions and gestational age are developed based on serial ultrasound biometric data from a prospective longitudinal study in Perth, Western Australia. Both the response variable and the gestational age timescale are transformed to establish an approximately linear relationship within subjects. This relationship is modelled using a linear mixed effects model that accounts for between-subject heterogeneity by incorporating subject specific random effects for both intercept and gradient. These models are used to motivate three measures of foetal growth: the conditional centile or z-score of a current measurement given an earlier value for the same measurement; the best linear unbiased predictor (BLUP) of the subject specific random effect gradient (which is shown to be invariant to transformations of location and scale), and the standardized residual at a given gestational age, which characterizes departures from the modelled growth trajectory. We illustrate how these three measures of growth might be applied to subsequent health outcomes in later life by relating growth in foetal abdominal circumference to blood pressure in children from the same cohort at six years of age. Foetuses whose summary measures indicate poor growth in abdominal circumference have higher blood pressure in early childhood, supporting the 'foetal origins' hypothesis that many chronic diseases of adulthood have their origins before birth.

Repeated ultrasound guided fetal injections of corticosteroid alter nervous system maturation in the ovine fetus

INTRODUCTION

Recent studies in sheep have shown that repeated maternal injections of betamethasone are associated with adverse effects within the nervous system. Repeated fetal injections of betamethasone achieve serial improvements in preterm lung function in sheep and are a possible alternative to repeated maternal therapy. We have evaluated the effect of repeated fetal administration of betamethasone on nervous system maturation in an ovine model.

METHODS

Date-mated ewes (n = 48) were randomized to receive ultrasound-guided fetal injections of betamethasone or saline between days 104 to 124 of gestation and were delivered by cesarean section on day 125 or 145 (term = 150). Optic and sciatic nerves were prepared for light and electronmicroscopy. Eye diameters were measured and transverse sections of retinae were evaluated. Data were analyzed using a mixed model analysis of variance.

RESULTS

Repeated fetal administration of corticosteroid did not significantly affect optic nerve myelination but resulted in significant delays in sciatic axonal growth (p < 0.02) and retinal maturation (p < 0.04). The process of performing repeated fetal injections also significantly affected some retinal parameters.

CONCLUSION

Repeated fetal administration of betamethasone alters some aspects of nervous system maturation in sheep. It is premature to plan trials of repeated fetal corticosteroid therapy in humans.

Repeated prenatal corticosteroid administration delays astrocyte and capillary tight junction maturation in fetal sheep

Glucocorticoids are powerful regulators of cell differentiation and maturation. Their synthetic counterparts, the corticosteroids, are used widely in obstetric practice to enhance fetal lung maturation in cases of threatened preterm birth. Here we examined the effects of repeated corticosteroid administration on astrocyte and capillary tight junction development in the fetal sheep brain, selecting the corpus callosum for analysis. Pregnant ewes were given saline or betamethasone (0.5 mg/kg) at 104, 111, 118 and 124 days gestation. Lambs were delivered at term, terminally anaesthetized and transcardially perfused. Transverse semi-thin sections of the corpus callosum were cut and immuno-stained with antibody against glial fibrillary acidic protein (GFAP). Ultra-thin sections were examined in the electron microscope. The percentage area of GFAP staining was reduced in the corticosteroid-treated group compared to control (5.2 vs. 8.7%, P<0.05). The expression of GFAP in peri-capillary and parenchymal astrocytes was also reduced compared to control (peri-capillary: 3.0 vs. 9.5 microm2; parenchymal: 14.6 vs. 29.4 microm2, P<0.05). Furthermore, capillary tight junction maturation was delayed compared to control. Immature 'type II' junctions were more common in the corticosteroid-treated group (63 vs. 22%, P<0.05), whereas more mature 'type III' junctions were less common (27 vs. 65%, P<0.05). Our data suggest that repeated corticosteroids delay both astrocyte and capillary tight junction maturation. The implications for clinical practice are as yet unknown.

Repeated prenatal corticosteroid administration delays myelination of the corpus callosum in fetal sheep

Glucocorticoids regulate oligodendrocyte maturation and the myelin biosynthetic pathways. Synthetic glucocorticoids, the corticosteroids have been successfully used in clinical practice as a single course to enhance lung maturation and reduce mortality and morbidity in preterm infants with no long-term neurologic or cognitive side effects. However, a trend has arisen to use repeated courses despite an absence of safety data from clinical trials. We examined the effects of clinically appropriate, maternally administrated, repeated courses of corticosteroids on myelination of the corpus callosum using sheep as a large animal model. The corpus callosum is a major white matter tract that undergoes protracted myelination, underpins higher order cognitive processing and developmental damage to which is associated with, for example, cerebral palsy, mental retardation and attention deficit hyperactivity disorder. Pregnant ewes were given saline or betamethasone (0.5 mg/kg) at 104,111,118 and 124 days gestation, stages equivalent to the third trimester in humans. Lambs were delivered at 145 days (term), perfused and the corpus callosum examined light and electron microscopically. Total axon numbers were unaffected (P>0.05). However, myelination was significantly delayed. Myelinated axons were 5.7% in the experimental group and 9.2% in controls (P<0.05); conversely, unmyelinated axons were 88.3 and 83.7% (P<0.05). Myelinated axon diameter and myelin sheath thickness were also reduced (0.68 vs. 0.94 and 0.11 vs. 0.14 microm, P<0.05). Our data suggest that repeated prenatal corticosteroid administration delays myelination of the corpus callosum and that further safety data are needed to evaluate clinical practice.

The effect of intravenous ketorolac on opioid requirement and pain after cesarean delivery

Nonsteroidal antiinflammatory drugs, including ketorolac, are widely used for postoperative analgesia. This randomized, double-blinded trial compared IV ketorolac or saline combined with meperidine patient-controlled epidural analgesia (PCEA) after cesarean delivery. Fifty healthy parturients scheduled for elective cesarean delivery under combined spinal-epidural anesthesia received PCEA plus either IV ketorolac (Group K) or saline (Group C) for 24 h. The ketorolac dose was modified, after six patients had been studied, based on new product information recommending a maximum of 120 mg ketorolac over 24 h. Group K (n = 24) and Group C (n = 20) were demographically similar. During the first 24 h, Group K used significantly less meperidine (P < 0.05). Postoperative pain at rest and with movement, and patient satisfaction, did not differ significantly between groups, except that worst pain at 12 h was less in Group K (P < 0.005). The two groups were similar with respect to patient recovery and side effects. IV ketorolac, as an adjunct to PCEA after cesarean delivery, produced a meperidine dose-sparing effect of approximately 30%, but did not significantly improve pain relief, reduce opioid-related side effects, or change patient outcome.

A prospective cohort study of the impact of domestic violence on young teenage pregnancy outcomes

INTRODUCTION

The incidence of domestic violence among pregnant Australian teenagers is higher than rates reported for the general community. However, there are limited data that address the impact of this abuse upon pregnancy outcome. We have examined the significant antenatal associations of domestic violence in young teenage pregnancy, and the impact of this abuse upon pregnancy outcome.

DESIGN, SETTING, PARTICIPANTS

A multicenter prospective cohort study was performed between January 1, 1997 and June 30, 1999. Patients were interviewed and completed questionnaires in the antenatal period to establish whether they were victims of domestic violence. Labor and delivery details were independently collated after discharge for mother and infant. Data were analyzed using an analysis of variance, with a P-value of 0.05 considered significant.

RESULTS

Of 537 patients enrolled in the study, 157 (29.2%) were victims of domestic violence; 380 (70.8%) were not and acted as pregnant teenage controls. Key findings were that teenage victims of domestic violence (VDV) were more likely to smoke, drink alcohol, or use illegal drugs than controls (P < 0.0001). VDV had a higher incidence of infectious morbidity and Pap smear abnormalities (P < 0.007) and psychosocial pathology (P < 0.0001) than controls. A higher incidence of puerperal and neonatal morbidity was observed in VDV and their newborns compared to controls (P < 0.007). The estimated cost of hospital care for teenage VDV was double that of the Australian average.

CONCLUSION

We need to identify all teenage mothers exposed to domestic violence and provide them with expert intervention services. Early intervention programs are likely to be cost effective.

Postoperative intraspinal opioid analgesia after caesarean section; a randomised comparison of subarachnoid morphine and epidural pethidine

A randomised, blinded clinical trial was performed to evaluate intraspinal opioid analgesic techniques after caesarean section. Healthy term parturients having elective caesarean section under combined spinal-epidural anaesthesia were allocated to one of three groups. Postoperative analgesia, including non-steroidal anti-inflammatory drugs, was provided using either pethidine patient-controlled epidural analgesia (group PCEA) or subarachnoid morphine 200 microg, the latter supplemented as required with patient-controlled intravenous pethidine (group SMPCIA) or oral paracetamol and codeine (group SMO). Maternal analgesia, side effects, recovery and satisfaction were assessed for 48 h. Of 144 parturients enrolled, 137 completed the study (PCEA n = 44, SMPCIA n = 45, SMO n = 48). The groups were demographically similar. All participants experienced good pain relief, including median visual analogue pain scores (0-100) with movement <40 between 0-24 h. However, pain scores were significantly lower at 8 and 12 h in those receiving subarachnoid morphine (P< 0.05). Women in groups receiving subarachnoid morphine experienced more severe pruritus (P<0.001), nausea (P< 0.001) and drowsiness (P< 0.05). Postoperative recovery of bowel function and ambulation occurred earlier in those using PCEA, although this did not appear to be of clinical significance. Patient satisfaction was similar, although women in group SMO were least likely to choose this approach again (P<0.05). We concluded that all three techniques provided effective analgesia for a prolonged period postoperatively. Better pain relief, but more opioid-related side effects, resulted from subarachnoid morphine 200 microg, and re-evaluation of reduced doses of subarachnoid morphine may be warranted.

Adjustment for current weight and the relationship between birth weight and blood pressure in childhood

OBJECTIVE

To determine the role of current weight in mediating the relationship between birth weight and blood pressure within the context of the 'fetal origins' hypothesis.

DESIGN

Prospective cohort study of 2507 pregnant women and their singleton offspring, delivered live at term, in Perth, Western Australia between 1989 and 1992. The study commenced at 16 weeks gestation with serial weight and blood pressure measurements recorded through early childhood.

RESULTS

Inverse associations were found between birth weight and systolic blood pressure at ages 1, 3 and 6. The effect of birth weight on systolic blood pressure at age 6 reached statistical significance and was increased fourfold in magnitude to -2.3 mmHg [95% confidence interval = (-3.3 to -1.3), P < 0.01] after adjustment for current weight. The interaction term for birth weight and current weight was not statistically significant. Including intermediate weights did not produce a statistically significantly better model but did increase the magnitude of the estimated regression coefficient of birth weight on blood pressure, and only the birth weight and current weight terms were significant

CONCLUSIONS

Adjustment for current weight serves to highlight the relationship between birth weight and blood pressure in childhood. Nevertheless, birth weight, rather than birth weight adjusted for current weight, is still the relevant predictor of later blood pressure within the context of the 'fetal origins' hypothesis.

Fetal sciatic nerve growth is delayed following repeated maternal injections of corticosteroid in sheep

AIMS

A single course of prenatal corticosteroid reduces the mortality and morbidity of preterm birth. Repeated courses of prenatal corticosteroids are widely prescribed despite a lack of safety data. Repeated corticosteroids delay myelination in the ovine central nervous system at the time of preterm delivery but with catch-up at term. We aimed to evaluate their effect in the peripheral nervous system.

METHODS

Thirty date-mated ewes were administered either saline, a single injection of betamethasone, or four injections of betamethasone between 104 and 124 days' gestation, with delivery on day 125 or 145 (term = 150 days). Sciatic nerves were dissected and fixed in modified Karnovsky's fixative and prepared for light and electron microscopy to determine the proportion of myelinated axons and mean axon diameter.

RESULTS

Repeated, but not single, corticosteroid administration resulted in significant decreases in the total cross-sectional and fascicle-containing areas of the sciatic nerve, and in the mean diameter of myelinated and unmyelinated axons. Deficits persisted at term. The proportion of myelinated axons was unaffected.

CONCLUSION

Repeated prenatal corticosteroids have the capacity to affect the growth of peripheral nerve axons in sheep. Documentation of their effects in human pregnancy await randomized trials.

Vertebral fractures and bone mineral density in idiopathic, secondary and corticosteroid associated osteoporosis in men

OBJECTIVE

To investigate bone mineral density (BMD) in men with symptomatic osteoporosis and compare BMD in patients with idiopathic, secondary and corticosteroid associated osteoporosis.

METHODS

Age, number of vertebral fractures at presentation and BMD were investigated in men presenting to a bone metabolism clinic with idiopathic (n=105; group 1), secondary (n=67; group 2) and corticosteroid osteoporosis (n=48; group 3). BMD was measured in 176 healthy men (controls). Osteoporosis was diagnosed if there was >/=20% vertebral deformity.

RESULTS

Age at peak BMD in controls was 20-29 years at spine (LS-BMD) and femoral neck (FN-BMD). LS-BMD did not change with age but FN-BMD decreased in controls and groups 1 and 2. Mean (SD) age was similar in groups 1 (62.8 (11.5) years, 2 (60.2 (11.0)) years and 3 (62.7 (10.4) years with 45%, 51% and 40% of patients respectively presenting before 60 years. Back pain, present for up to 12 months, was the commonest cause of referral. Vertebral fractures at presentation averaged mean (SD) 2.51 (1.9) in group 1, 2.76 (2.2) in group 2 and 2.48 (1.8) in group 3. LS-BMD Z scores and T scores were more negative in group 1 patients with </=3 vertebral fractures compared with FN-BMD suggesting a greater trabecular bone deficit. LS-BMD Z score in group 1 is -1.71, lower than in population studies. LS T score associated with fracture was about -2.4 in all groups. T8, T12 and L1 were the most frequent levels for fracture.

CONCLUSIONS

Men with symptomatic osteoporosis present in middle age, have low BMD with similar T scores irrespective of aetiology and sustain >/= 1 fracture.

Obstetric and perinatal outcomes from the australian and new zealand twin-twin transfusion syndrome registry

OBJECTIVE

Our purpose was to investigate the antepartum characteristics and perinatal outcomes of twin-twin transfusion syndrome cases from a multicenter national registry.

STUDY DESIGN

Perinatal centers in Australia and New Zealand voluntarily notified a central evaluation registry with information on identified pregnancies with twin-twin transfusion syndrome during 1995 through 1998.

RESULTS

One hundred twelve cases of twin-twin transfusion syndrome were registered. The median gestation at diagnosis was 21.5 weeks (range, 14.4-34.6 weeks). Oligohydramnios-polyhydramnios sequence was the most common presentation, with 84% of cases involving "stuck" twinning. Therapeutic amnioreduction was used in 92 cases (82.1%), with the median number of procedures per case being 2 (range, 1-23). The median gestation at delivery was 29 weeks (range, 18-38 weeks). The overall perinatal survival rate was 62.5%. Abnormal findings on cranial ultrasonography were present in 27.3% of live neonates, and periventricular leukomalacia was reported in 10.8%. Increased gestational age at delivery, the presence of umbilical artery diastolic flow, and a prolonged interval from final amnioreduction to delivery were positively associated with the delivery of live fetuses without complications.

CONCLUSION

The majority of antenatally identified cases of twin-twin transfusion syndrome are managed with serial amnioreduction. Despite contemporary obstetric and neonatal management strategies, perinatal mortality and morbidity rates are high.

Retinal maturation is delayed by repeated, but not single, maternal injections of betamethasone in sheep

PURPOSE

The safety and efficacy of prescribing a single maternal course of corticosteroid during pregnancy has been documented in human trials. However, the current trend is to prescribe repeated courses of corticosteroid. We investigated an aspect of the safety of this practice in an animal model.

METHODS

Date-mated ewes received saline, single or four corticosteroid injections between days 104 and 124 of gestation (term = 150). Lambs were delivered on day 125 or 145 by caesarian section after spinal anaesthesia. Eye diameters were measured and semi-thin toluidine-blue-stained transverse sections of retinae were analysed using an Optimus Image Analysis program.

RESULTS

At 125 days, retinal measures in the ventral periphery and area centralis were significantly thinner than control (p = 0.0001). At 145 days, total eye size was significantly reduced compared with control (p = 0.03), and retinal measures in the ventral periphery (p = 0.0001), but not the area centralis (p = 0.19), remained significantly different from control.

CONCLUSION

Repeated maternal administration of corticosteroid may affect retinal maturation in the fetus.

Maternal cigarette smoking during pregnancy, low birth weight and subsequent blood pressure in early childhood

Given the widely acknowledged inverse relationship between birth weight and blood pressure, a raised blood pressure in the offspring of smoking mothers as compared to those whose mothers did not smoke, would be anticipated by virtue of the reduction in birth weight associated with smoking during pregnancy. The objective of the present study was to test the hypothesis that maternal cigarette smoking during pregnancy has an effect on blood pressure in childhood independent of its effect on birth weight. Data was obtained from a prospective cohort study of 1708 pregnant women and their singleton offspring, delivered live at term, in Perth, Western Australia, commenced at 16 weeks gestation with serial blood pressure measurements through early childhood. Statistically significant associations were found between maternal smoking during pregnancy and systolic blood pressure at age six, between birth weight and systolic blood pressure at ages three and six, and between maternal smoking during pregnancy and birth weight. The relationship between birth weight and blood pressure in early childhood differed significantly on the basis of maternal cigarette smoking or not during pregnancy. This differential relationship persisted after adjustment for the child's current weight and socio-economic status. We concluded that intra-uterine exposure to maternal cigarette smoking increased children's blood pressure at age one through to age six. This was not wholly attributable to an effect on birth weight or confounding of the association between birth weight and subsequent blood pressure by the child's current weight or socio-economic factors. Furthermore, maternal smoking during pregnancy does not account for the acknowledged elevation in blood pressure associated with low birth weight. The present study is an exploration of a possible causal pathway underlying the birth weight/blood pressure association rather than simply a confirmation of such an association which has been detailed in many other papers.

Reference ranges for blood pressure in preschool Australians, obtained by oscillometry

OBJECTIVE

To derive reference centiles for blood pressure in children aged 1-6 years which seek to address shortcomings in available reference ranges.

METHODS

Prospective cohort study of 2876 children in Perth, Western Australia, commenced in 1989 with serial blood pressure measurements through early childhood obtained by oscillometry under standardized conditions.

RESULTS

Gender-specific reference centile charts for systolic and diastolic blood pressure, (i) across ages 1-6 years and (ii) across the range of corrected Body Mass Index values at ages 1, 3 and 6 years, were generated by fitting linear models with both fixed and random effects.

CONCLUSIONS

Reference values for blood pressure for young children are of clinical use and may be of long-term predictive value.

Patient-controlled epidural analgesia in labor: the addition of clonidine to bupivacaine-fentanyl

BACKGROUND AND OBJECTIVES

Epidural clonidine has not been evaluated as a component of patient-controlled epidural analgesia (PCEA) solutions during labor. A randomized, double-blind trial was conducted to investigate the efficacy and side effects of PCEA using bupivacaine and fentanyl, with or without clonidine.

METHODS

Seventy-five healthy parturients in active labor were assigned to a PCEA solution of 0.0625% bupivacaine and fentanyl 2 microg/mL (4 mL demand bolus, 15 min lockout), with or without clonidine 4.5 microg/mL. The primary outcome measure was parturient rating of analgesia; others assessments included pain scores, drug utilization, supplementation and side effects.

RESULTS

Thirty-one parturients received clonidine (group BFC) and 38 received control solution (group BF). Eight (6 group BF, 2 group BFC, P = .28) failed to achieve satisfactory epidural analgesia. There was a trend for parturient ratings of pain relief to be higher in group BFC, with significantly more reporting excellent first-stage analgesia (81% v. 57%, P<.05). Pain scores were similar. Clonidine (median dose, 28 microg/h) reduced total bupivacaine and fentanyl use (P<.01), and reduced supplementation (P<.01). Maternal blood pressure (BP) and recordings of systolic BP below 100 mm Hg did not differ. Group BFC had higher sedation scores (P<.01), but no one appeared oversedated. Shivering was reduced in group BFC (P<.01).

CONCLUSIONS

The addition of clonidine to epidural bupivacaine and fentanyl for PCEA in labor improved analgesia, reduced the supplementation rate, and reduced shivering. Increased sedation and lower BP were not clinically important.

Effect of corticosteroids on brain growth in fetal sheep

OBJECTIVE

To compare the effects of single and repeated courses of corticosteroids on brain growth in fetal sheep.

METHODS

Pregnant sheep were given intramuscular betamethasone (0.5 mg/kg) at 104 days' gestation followed at 111, 118, and 124 days by equivalent volumes of sterile normal saline (n = 12) or betamethasone (n = 12). Controls received equivalent volumes of sterile normal saline at all four intervals (n = 12). Lambs were delivered at 125 (preterm) or 145 (term) days. After perfusion, we measured weights (grams) for whole brain, cerebrum, cerebellum, and brain stem, volumes (milliliters) for whole brain and cerebrum, and maximum cerebral anterior-posterior length, width, and depth (centimeters).

RESULTS

In the single-injection group at preterm, there were no significant differences (P = .070) in whole-brain weight between the corticosteroid-treated animals (38.0 +/- 1.81 g) and controls (42.5 +/- 1.65 g). Cerebral length and depth were significantly reduced in the corticosteroid group (P < .05); other measures were not significantly different. At term, whole-brain weight was significantly lower (47.5 +/- 1.70 g; P = .022) compared with controls (53.4 +/- 1.73 g). All other measures were significantly reduced (P < .05) except cerebral and brain-stem weights and cerebral length. In the group that received repeated injections at preterm, whole-brain weight was significantly reduced (35.5 +/- 1.65 g; P = .005) compared with controls (42.5 +/- 1.65 g). All other measures were significantly reduced (P < .05) except cerebellar and brain-stem weights. At term, whole-brain weight was also significantly reduced (42.4 +/- 1.52 g; P = .001) compared with controls (53.4 +/- 1.73 g) as were all other measures (P < .05).

CONCLUSION

Administration of single and repeated courses of corticosteroids to pregnant sheep retarded fetal brain growth.

Effect of nappy liners on temperature stability in very preterm infants

OBJECTIVE

To determine whether absorbent liners used in posturally supportive cloth nappies influence temperature stability in infants < 31 weeks gestation.

METHODOLOGY

Randomized cross-over trial conducted at King Edward Memorial Hospital for Women, Perth, Western Australia. Twenty-three infants nursed in incubators on Infant Servo Control were randomly assigned to wear cloth postural support nappies alternately with or without absorbent liners for 24-h periods over 4 days. Measurements of skin and incubator temperatures were recorded hourly. Times of all nappy changes and infant handling procedures were also recorded.

RESULTS

There was no change in any temperature measurement over time, between days, or between day/night periods. Infants nursed with the liner demonstrated a higher skin temperature (0.04°C), and a lower incubator temperature (1.05°C). A drop in skin temperature of 0.02°C and an increase in incubator temperature of 0.28°C occurred following handling of infants. There was no effect due to sex, gestational age, or actual age of the infants.

CONCLUSION

Use of an absorbent liner within a cloth postural support nappy promotes better temperature regulation in infants < 31 weeks gestation, by reducing incubator temperature and increasing skin temperature.

Maternal, but not fetal, administration of corticosteroids restricts fetal growth

OBJECTIVE

Previous studies have shown that repeated doses of corticosteroids given to pregnant sheep improve postnatal lung function, but restrict fetal growth. Repeated administration of corticosteroids directly to the fetus also enhances postnatal lung function. The purpose of the present study was to investigate and characterize the relative effects on growth of repeated maternal and fetal treatments by study of body, organ, and placental weights.

METHODS

Date-bred pregnant sheep were given intramuscular betamethasone or saline to either the mother or fetus on three occasions at weekly intervals commencing at 104 days gestation, followed by cesarean section at 125 days. Twenty-two animals which had received three doses of betamethasone were compared with 21 which had received a single dose at 104 days and with 12 saline-treated controls.

RESULTS

Repeated maternal doses of betamethasone resulted in reductions in birthweight and weights of the placenta and major organs. Direct fetal injection did not affect birthweight, placental weight, placental/ birthweight ratio, or weights of the major organs with the exception of the liver.

CONCLUSIONS

Administration of repeated doses of betamethasone directly to the sheep fetus does not produce the growth-restricting effects induced by maternal administration and does not affect the placental/birthweight ratio.

Hospital admissions in the first year of life in very preterm infants

OBJECTIVE

To analyse hospital readmissions to 1 year in infants < 33 weeks' gestation.

STUDY DESIGN

Cohort of very preterm infants born in Western Australia.

METHODS

Parental social class, history of asthma, race, gestational age, birthweight, sex, severity of respiratory disease and oxygen requirement at 28 days chronic lung disease (CLD), 36 weeks and term, maternal smoking, cohabitation with siblings, breast-feeding duration and hospital readmissions were recorded prospectively.

RESULTS

Data were available for 538 of 560 (96%) infants discharged. Eight died in the first year. Two hundred and twenty-five infants (42%) had 443 readmissions, of which 370 were medical and 73 surgical. Risk factors for medical readmission were Aboriginal race, male sex and CLD. Breast-feeding was protective. Risk factors for surgical admission were male sex, lower gestation, severe hyaline membrane disease, severe CLD and birthweight < 10th centile.

CONCLUSIONS

Readmission is common after very preterm birth. Risk factors for medical and surgical admission differ with CLD being the only perinatal factor associated with both medical and surgical admission.

Repeated antenatal corticosteroids: size at birth and subsequent development

OBJECTIVE

The objective was to study the effects of repeated antenatal corticosteroids on birth size, growth, and development in preterm infants.

STUDY DESIGN

This observational study followed up for 3 years a prospective geographic cohort in the state of Western Australia of 477 singleton infants born at <33 weeks' gestation.

RESULTS

Birth weight ratio decreased with increasing number of corticosteroid courses (P =.001), and multivariate analyses confirmed a reduction in birth weight of as much as 9% (P =.014) and a reduction in head circumference of as much as 4% (P =.0024). There were no additional benefits in mortality or respiratory outcomes, and there was a trend toward more severe chronic lung disease. At age 3 years growth and severe disability outcomes did not appear to be related to increasing number of corticosteroid courses.

CONCLUSIONS

In this cohort study repeated corticosteroid courses were associated with adverse effects on size at birth without apparent benefits. These changes have the potential to affect later development.

Placental implantation at 18 weeks and migration throughout pregnancy

BACKGROUND

We wanted to find the most frequent site of placental implantation at 18 weeks' gestation and placental migration during gestation.

METHODS

Placental location was identified in 2,526 singleton pregnancies at 18 weeks' gestation and characterized into nine groups. Placental migration in 1,336 of these pregnancies was assessed by serial ultrasonography.

RESULTS

At 18 weeks' gestation, posterior, high placental implantation was more common (45.1%) than anterior, high implantation (42.1%). Relocation of posterior, high placentas farther fundally (16.9%) was three times more likely than farther fundal migration of anterior, high placentas (4%).

CONCLUSIONS

Posterior fundal placental implantation is more common at 18 weeks' gestation than anterior implantation. Posteriorly implanted placentas are more likely than anterior placentas to migrate farther fundally during gestation. The greater relocation of posterior placentas farther fundally suggests a greater growth of posterior versus anterior uterine wall smooth muscle.

Fetal growth retardation, particularly within lymphoid organs, following repeated maternal injections of betamethasone in sheep

OBJECTIVE

To examine the effect of single or repeated injections of maternally administered corticosteroids on fetal growth in sheep.

METHODS

Forty-six date-mated singleton gestation ewes were allocated at random to one of 3 groups: a single, or repeated injections of betamethasone, or a control group which received saline. On days 125 (preterm) or 145 (term) caesarean section delivery was performed. After lambs were killed, measures of size and weight were recorded. Data were analysed using Fishers Exact test and the Student's t-test.

RESULTS

Significant betamethasone dose dependent reductions in body and organ weights and biometry were found at preterm and term gestational ages (p < 0.05). There was little catch up growth in those in whom delivery was delayed until term. Thymus, spleen and liver were particularly targeted.

CONCLUSION

Repeated injections of betamethasone to the pregnant ewe cause significant reductions in fetal growth with little evidence of catch up by term. The effect of repeated maternal injections of corticosteroids in human pregnancy will await the results of randomized controlled trails.

Microlaparoscopy for suspected pelvic pathology--a comparison of 2mm versus 10mm laparoscope

This study presents an independently-assessed comparison of the laparoscopic view obtained using a 2mm versus 10mm laparoscope in women with suspected pelvic pathology. Fifteen female volunteers booked for laparoscopy with clinical evidence of pelvic abnormality according to clinical findings and/or pelvic ultrasound were recruited for this study. Sequential observations were carried out by independent observers for clinically significant differences. Although discrepancies were noted in 3 patients the view obtained with the 2mm microendoscope was considered to be comparable to that obtained with the 10mm telescope. The cases with discordant findings included mild or minimal endometriosis and distal tubal disease. The results of this study suggest that microendoscopy is likely to be entirely adequate for many routine laparoscopic procedures and sterilization.

Efficacy of intravaginal misoprostol in second-trimester pregnancy termination: a randomized controlled trial

A prospective randomized, double-blind, controlled clinical trial to compare the clinical efficacy and side effects of intravaginal misoprostol with the traditional prostaglandin, gemeprost, in second-trimester pregnancy interruption was conducted. A sample size of 100 women was calculated to demonstrate that misoprostol was as effective as gemeprost in achieving delivery within 24 hours (alpha = 0.1, 80% power). Women were recruited with fetal death in utero, severe fetal anomaly, or psychosocial pregnancy termination between 14 and 28 weeks gestation and randomized to receive either 1 mg gemeprost 3 hourly for 5 doses, or 200 mcg misoprostol 6 hourly for 4 doses, intravaginally. The therapeutic regimens were repeated if undelivered by 24 hours. Those undelivered after 48 hours received an extra-amniotic PGF2 alpha infusion. The median gestation at recruitment was identical: gemeprost 19 weeks (IQ 17-22 weeks) vs. misoprostol 19 weeks (IQ 17-21 weeks), P = 0.887. Delivery within 24 hours occurred in 75.1% of women receiving gemeprost and 74.9% receiving misoprostol (P = 1.0). The median time from prostaglandin commencement to delivery was similar: gemeprost 13.7 hours (IQ 9.0-23.5 hours) vs. misoprostol 16.9 hours (IQ 10.3-23.5 hours), P = 0.769. A significant reduction in the incidence of vomiting in women randomized to misoprostol occurred (34% vs. 13.2%, P = 0.017). There was no significant difference in the incidence of maternal fever > 37.5 degrees C, nausea, diarrhea, or placental retention. A 200-fold pharmaceutical cost advantage was observed with the use of misoprostol compared with gemeprost. Intravaginal misoprostol performs as effectively as gemeprost in achieving delivery in the second trimester without increase in adverse effects and displaying a significant cost advantage.

Use of corticosteroids by Australian obstetricians--a survey of clinical practice

All Fellows, Members and trainees of the Royal Australian College of Obstetricians and Gynaecologists resident in Australia (n= 1,281) received a questionnaire relating to their practice of prescribing antenatal corticosteroids. 833 (65%) responded. The key findings were that 97% of Australian obstetricians prescribe antenatal corticosteroids in the classical setting of uncomplicated early preterm labour and 85% prescribe repeated courses in those cases in which the risk of preterm birth persists or recurs; 50% of obstetricians prescribe this agent weekly in cases with persisting risk of preterm birth. Some of the prescribing practices were found to be related to the number of years since obtaining specialist qualification. In view of the widespread clinical use of repeated doses of corticosteroids revealed in this present survey, it is clear that further research is warranted to determine the possible benefits and hazards of repeated exposures of the developing fetus to this therapy.

Maternal experience during epidural or combined spinal-epidural anesthesia for cesarean section: a prospective, randomized trial

Epidural anesthesia (EA) and combined spinal-epidural anesthesia (CSEA) are popular anesthetic techniques for elective cesarean section. A randomized, blind study was conducted to compare maternal experiences during these regional anesthetics. EA was established using alkalinized 2% lidocaine with epinephrine and fentanyl, whereas spinal anesthesia was performed using 2.5 mL hyperbaric 0.5% bupivacaine and fentanyl via a single-space CSEA approach. Both patients and observers were blinded to the anesthetic technique allocation. One hundred twenty patients were enrolled; 6 were withdrawn (Group EA, n = 55; Group CSEA, n = 59). Of the two techniques, CSEA was associated with earlier onset times (P < 0.001), more intense motor block (P < 0.05), and greater ephedrine use (P < 0.01). Anxiety was significantly lower (P < 0.05) and satisfaction was higher (P < 0.05) before starting surgery with CSEA. Pain scores were lower pre- and intraoperatively with CSEA, a difference that became significant during block placement and at delivery (P < 0.05). There were no differences between groups in the incidence or severity of hypotension and nausea or analgesic supplementation rate; or for postoperative assessments of intraoperative pain, anxiety and satisfaction, and postpartum backache and headache. We conclude that maternal conditions and experience were good with both methods, although CSEA conferred several minor advantages.

IMPLICATIONS

Epidural and combined spinal-epidural anesthesia are often used for elective cesarean sections. Although the combined spinal-epidural anesthetic technique conferred minor advantages, both techniques were associated with low anesthetic failure rates, good operative conditions, and high maternal satisfaction levels.

Factors influencing the selection of analgesia in spontaneously labouring nulliparous women at term

We investigated the maternal characteristics, labour performance and delivery mode of 497 nulliparas entering labour spontaneously at term to identify the obstetric factors which influenced their choice of analgesia; 51.7% of these women used epidural analgesia. They were shorter (163 versus 165 cm, p = 0.002) and the mean gestation was 3 days greater than those not using epidural analgesia (40.2 versus 39.6 weeks, p = 0.0007). Median birth-weight in the epidural group was greater by 155 g (3,450 versus 3,295 gs, p = 0.0001). Analysis of the labour characteristics showed a lesser cervical dilatation on admission, significantly longer latent and active phases of labour and second stage length in the epidural cohort. The need for oxytocin augmentation was significantly greater in the epidural group, both prior to and after insertion. Oxytocin augmentation was strongly associated with an increased risk of operative intervention regardless of analgesia. Selection of intrapartum analgesia is not a random event and epidural analgesia appears to be an indicator of abnormal labour patterns. To further investigate the impact of analgesic methods on nulliparous labour we are currently conducting a prospective randomized controlled trial.

Prospective cohort study of factors influencing the relative weights of the placenta and the newborn infant

OBJECTIVES

To determine the demographic, environmental, and medical factors that influence the relative weights of the newborn infant and the placenta and compare this ratio with other factors known to predispose to adult ill health.

DESIGN

Prospective cohort study.

SETTING

The tertiary referral centre for perinatal care in Perth, Western Australia.

SUBJECTS

2507 pregnant women who delivered a single live infant at term.

MAIN OUTCOME MEASURES

Placental weight, birth weight, and the ratio of placental weight to birth weight.

RESULTS

By multiple regression analysis the placental weight to birthweight ratio was significantly and positively associated with gestational age, female sex, Asian parentage, increasing maternal body mass index, increased maternal weight at booking, lower socioeconomic status, maternal anaemia, and increasing number of cigarettes smoked daily. There were no consistent relations between the placental weight to birthweight ratio and measures of newborn size.

CONCLUSIONS

The ratio of placental weight to birth weight is not an accurate marker of fetal growth. In its role as a predictor of adult disease the ratio may be acting as a surrogate for other factors which are already known to influence health and may act before or after birth. Determining the role that relative growth rates of the fetus and placenta have in predisposing to adult disease requires prospective study to account for the many confounding variables which complicate this hypothesis.

Postoperative epidural infusion: a randomized, double-blind, dose-finding trial of clonidine in combination with bupivacaine and fentanyl

The aim of this randomized, double-blind trial of postoperative thoracic epidural analgesic infusions was to determine whether clonidine at 10 microg/h (group C10, n = 22), 15 microg/h (Group C15, n = 24), or 20 microg/h (Group C20, n = 24) improved postoperative analgesia in patients undergoing abdominal gynecologic surgery, without side effects or hemodynamic changes, when added to a 5-mL/h infusion of 0.125% bupivacaine and fentanyl 2 microg/mL (Group CO, n = 22). The 24-h study infusion was supplemented, as required, by patient-controlled epidural fentanyl. Groups were similar for age, weight, duration, and type of surgery. Clonidine produced a dose-dependent improvement in analgesia at rest. Only 20 microg/h significantly increased the percentage of patients who experienced no pain with coughing (relative risk 1.44, 95% confidence interval 1.24-1.94), reduced pain scores with coughing (P < 0.05), and significantly lowered supplementary fentanyl requirements (P < 0.05). Groups were similar for sedation, pruritus, nausea, time to ambulation, and satisfaction with analgesia. Clonidine produced a dose-dependent decrease in blood pressure and pulse rate and an increase in vasopressor requirement (P < 0.01). Epidural clonidine infused at 20 microg/h improves analgesia during coughing when combined with epidural bupivacaine-fentanyl in patients undergoing lower abdominal surgery but is associated with hemodynamic changes and increased vasopressor requirement.

Antenatal patterns of uterine activity in low-risk women: a longitudinal study

There is a surprising lack of information on antenatal patterns of uterine activity in the normal obstetric population, with the majority of research having focussed on women at high-risk for preterm birth. We conducted a prospective longitudinal study to investigate patterns of uterine activity in women with singleton gestations at low-risk for preterm birth. Twenty pregnant women were recruited and their uterine activity was recorded using ambulatory tocodynamometry twice weekly throughout the latter half of pregnancy. The collected data were transmitted to a central receiving station for analysis. As gestation advanced there was a progressive increase in the median number of contractions detected per hour, peaking and stablizing at 37-40 weeks (median of 0 contractions/hour at 20-24 weeks rising to 5.4 contractions/hour at 37-40 weeks). In those women with uterine activity, contraction duration and amplitude of deflection significantly increased as gestation advanced. There was a progressive increase in the number of higher amplitude contractions throughout the third trimester. Increasing parity was not associated with increasing antenatal uterine contraction frequency. No association between normal daily physical activity and uterine contraction frequency was evident throughout gestation. In normal human pregnancy there is a steady, progressive increase in the frequency, duration and amplitude of antenatal uterine activity throughout the latter half of gestation. The uterine contractile profile alters from one of a low amplitude, low frequency pattern in the second trimester to a higher amplitude, higher frequency pattern at term.

A validation study of home uterine activity monitoring technology in Western Australia

Home uterine activity monitoring has been developed as an 'early warning' device to detect premature uterine activity, thereby encouraging earlier referral and tocolysis of women at risk of preterm delivery. This ambulatory monitoring system, utilizing a ring-guard tocodynamometer, was piloted in Western Australia to determine if it can reliably record and transmit antenatal uterine activity data in an Australian environment. Pregnant women were readily able to correctly apply and use the ambulatory monitoring device. The information collected was able to be transmitted using standard Australian telecommunications systems within our hospital environment. Validation studies with the ambulatory monitor and current external tocodynamometry hardware were performed. The ring-guard tocodynamometer detected more uterine activity at gestations less than 32 weeks compared with conventional external tocodynamometers. As term approached, however, the sensitivity of the ring-guard tocodynamometer decreased. A cross-sectional profile of antenatal uterine activity was developed for women at low risk of delivering preterm. A gradual increase in the number, duration and amplitude of uterine contractions as pregnancy advanced was observed.

Effects of low- and conventional-dose transcutaneous HRT over 2 years on bone metabolism in younger and older postmenopausal women

The minimum dosage of transcutaneous hormone replacement therapy (HRT) able to exert protective effects on postmenopausal bone mass, especially in older women, is uncertain. This study investigates the effects of transcutaneous HRT at two different doses of oestradiol [Estraderm 25 and 50 (E25, E50)] over 2 years in 44 postmenopausal women younger than 67 years and 27 of 67 years and older. Circulating biochemical markers of bone and connective tissue turnover, collagen type I (intact PINP, PICP) and type III (PIIINP) propeptides and type I telopeptide (ICTP), osteocalcin (OC) and alkaline phosphatase (AP) were measured. The responses of the biochemical markers in all the groups were very similar, and most of the observed changes occurred within the first year of treatment. E25 had an effect on the bone markers similar to that of E50, and there was little difference in response according to the patient's age. PINP fell markedly after 1 year in all groups to about half the pretreatment level, with a smaller drop in the second year. PICP responded more variably, and mean values were little changed. There was a slight fall at the higher dose in the younger women, and also in the older women (whose baseline level was higher) on the lower dose. The correlation between PINP and PICP was 0.52 at pretreatment and 0.84 after 2 years of treatment. PIIINP showed no changes. OC and AP both fell in all groups by the first year, but less markedly than PINP. Their response was slightly less pronounced in the older women. ICTP fell marginally in the younger women, and only after 2 years, regardless of dose. Postmenopausal serum oestradiol levels increased after HRT and were associated with decreased binding globulin (SHBG) levels in all groups. After E25 patch application individual serum oestradiol levels were variable and peaked between 13 and 36 h with a median value of 83.8 pmol L-1. Our data suggest that low-dose transcutaneous HRT restores circulating oestradiol levels in postmenopausal osteopenic women of all ages as effectively as conventional-dose HRT and is associated with decreased circulating markers of bone and connective tissue turnover.

Employment, exertion, and pregnancy outcome: assessment by kilocalories expended each day

OBJECTIVE

Our purpose was to evaluate the influence of employment and physical exertion on pregnancy outcome as quantified by kilocalories expended each day.

STUDY DESIGN

This prospective study assessed 2743 pregnant women who received prenatal care and were delivered at the major perinatal center in Western Australia between May 1989 and November 1991. All women completed an extensive questionnaire on their social, medical, psychosocial, and economic circumstances. The women were allocated to five groups on the basis of kilocalorie expenditure per day.

RESULTS

The characteristics of women in each energy expenditure group were different, with those in the least-expenditure group being younger and shorter, more likely to be living in worse socioeconomic conditions, smoke cigarettes, be nulliparous, and to be of an ethnic group other than white. After confounding effects were adjusted, women in the medium energy expenditure group were delivered of babies of higher birth weight than were women in other groups. However, the differences in birth weight between the energy expenditure categories were small, and mean birth weights within each group were within the normal range. Women in the medium energy expenditure group also had fewer incidences of prelabor rupture of membranes and women in the lower energy expenditure category had increased risks of antepartum admission to the hospital and preterm birth. A variety of other differences were observed in pregnancy outcomes for women in each of the categories of energy expenditure, but most of these differences were explained by the characteristics of the women in each expenditure level rather than the exercise pattern itself.

CONCLUSION

These results indicate that the effects of daily energy expenditure on pregnancy outcome are not great. Enthusiasm for counseling pregnant women of the benefits or hazards of extremes in daily activity should be tempered by the relative lack of an effect and the fact that most apparent differences are due to confounding variables rather than the exercise itself.

Recurrent wheezing in very preterm infants

AIMS

To document the prevalence of, and identify risk factors for, recurrent wheezing treated with bronchodilators in the first year of life.

METHODS

Parental history and neonatal data were collected prospectively in a regional cohort of very preterm infants (< 33 weeks). Data on maternal smoking, siblings at home, breast feeding, respiratory symptoms, and hospital re-admissions were documented at 12 months.

RESULTS

Outcome data were available for 525/560 (95%) of survivors. The incidence of recurrent wheeze was 76/525 (14.5%) in very preterm infants and 20/657 (3%) in a cohort of term newborns. Significant risk factors for recurrent wheeze in very preterm infants were parental history of asthma, maternal smoking, siblings at home, neonatal oxygen supplementation at 28 days, 36, and 40 weeks of gestation.

CONCLUSIONS

Wheezing respiratory illnesses are common in very preterm infants. The factors involved are similar to those in more mature infants, with the addition of immaturity and neonatal lung injury.

Patient-controlled epidural analgesia following caesarean delivery: a comparison of pethidine and fentanyl

Pethidine and fentanyl have both been used to provide patient-controlled epidural analgesia (PCEA) following caesarean delivery. Both have been compared with epidural morphine but these drugs have not been compared with each other. Patient-controlled epidural analgesia was used in a prospective, randomized, double-blind, cross-over trial to compare fentanyl and pethidine for postoperative epidural analgesia in women having elective caesarean deliveries. Two groups received either PCEA fentanyl or pethidine with a cross-over to the other drug after 24 hours. Results from 45 patients showed no difference in pain level outcomes, but pethidine scored better in all side-effects except for drowsiness at 48 hours. Patients were more satisfied with pethidine (P = 0.015) and overall 65% of patients preferred pethidine. We conclude that pethidine is a suitable drug for patient-controlled epidural analgesia and leads to greater patient satisfaction than does fentanyl.