Alan D. Cameron

Neonatal respiratory morbidity at term and the risk of childhood asthma

Objective: To determine whether neonatal respiratory morbidity at term is associated with an increased risk of later asthma and whether this may explain previously described associations between caesarean delivery and asthma. Design: Retrospective cohort study using Scottish Morbidity Record (SMR) data of maternity (SMR02), neonatal (SMR11), and acute hospital (SMR01) discharges. Setting: Scotland. Participants: All singleton births at term between 1992–1995 in 23 Scottish maternity hospitals. Main outcome measures: Hospital admission with a diagnosis of asthma in the principal position between 1992 and 2000. Results: Children who had a diagnosis of transient tachypnoea of the newborn or respiratory distress syndrome were at increased risk of being admitted to hospital with a diagnosis of asthma (hazard ratio (HR) 1.7, 95% confidence interval (95% CI) 1.4 to 2.2, p<0.001). This association was observed both among children delivered vaginally (HR 1.5, 95% CI 1.1 to 2.0, pu200a=u200a0.007) and among those delivered by caesarean section (HR 2.2, 95% CI 1.6 to 3.0, p<0.001). In the absence of neonatal respiratory morbidity, delivery by caesarean section was weakly associated with the risk of asthma in childhood (HR 1.1, 95% CI 1.0 to 1.2, pu200a=u200a0.004). The strengths of the associations were similar whether the caesarean delivery was planned or emergency and were not significantly altered by adjustment for maternal, obstetric, and other neonatal characteristics. Conclusions: Neonatal respiratory morbidity at term is associated with an increased risk of asthma in childhood which may explain previously described associations between caesarean delivery and later asthma.

Prospective study of external cephalic version in Glasgow: patient selection, outcome and factors associated with outcome

Data were collected prospectively on all 67 women who underwent an attempt at external cephalic version (ECV) over 1 year in the four Glasgow maternity hospitals. Ultrasonography was used in all women. However, tocolytics were used in only two (6%) nulliparous women despite published evidence of their efficacy. Only 25 (37%) women undergoing ECV had a free presenting part which is known to be associated with success. Seventeen (25%) women were less than 37 weeks pregnant despite spontaneous version being common at this stage. ECV was successful in only 26 (39%) women and only 18 (27%) had a vaginal cephalic delivery. These results compare unfavourably with published results of around two-thirds for both end-points. Although publication bias is likely, patient selection, under-usage of tocolytics and lack of experience may also be factors. Consideration should be given to a reduced number of operators who can maximise their throughput and expertise.

Middle cerebral artery Doppler: the value of a non-invasive test of fetal anaemia in the management of alloimmunised pregnancies

We set out to determine the usefulness of fetal middle cerebral artery peak systolic velocity (MCA-PSV) in predicting fetal anaemia in Rhesus alloimmunised pregnancies before first and subsequent in-utero transfusions. This was a retrospective analysis of fetal MCA-PSV values and haematocrits (Hct) performed in 30 alloimmunised fetuses before their first intrauterine blood transfusion, and before 35 repeat transfusions. A MCA-PSV of greater than 1.5u2009MoM for gestation would have identified seven of eight severely anaemic fetuses (Hct < 22%) and 3/7 moderately anaemic fetuses (Hct 22–26%). Five fetuses with haematocrits > 26% would have been identified falsely, of which one had a Hctu2009> 35%. Following one intrauterine transfusion the use of this test cut-off was less predictive, detecting 3/4 fetuses with severe anaemia but none of the four fetuses with moderate anaemia. A higher cut-off (1.69u2009MoM) was as sensitive but more specific in the prediction of severe anaemia. A lower threshold of 1.32u2009MoM would have identified of 2/4 fetuses with moderate anaemia, but only when utilising a cut-off value of 0.98u2009MoM could all the severe and moderately anaemic fetuses have been identified.

Risk of perinatal death associated with labor after previous cesarean delivery in uncomplicated term pregnancies

Although a trial of labor after a past cesarean delivery is known to carry an increased risk of uterine rupture, there is no reliable information on whether it also increases the risk of perinatal death in otherwise uncomplicated term pregnancies. This question was addressed in a retrospective, population-based cohort study comprising 313,238 singleton births at 37 to 43 weeks gestation where the fetus was in a cephalic presentation. At 12.9 per 10,000 women, the rate of perinatal death was highest for women having a trial of labor. The odds ratio (OR), compared with women having a planned repeat cesarean delivery, was 11.6. The risk of death from a trial of labor was similar when compared with that for nulliparous women in labor, but it was more than twice that of other multiparous women in labor (OR, 2.2). More than 90% of all delivery-related perinatal deaths among women with a previous cesarean delivery were attributable to the increased risk associated with a trial of labor. Adjusting for maternal age, smoking status, height, gestational age at birth, and birth weight strengthened the association between a trial of labor and perinatal death compared with elective repeat cesarean delivery. Similar results were obtained when only births at or after 40 weeks gestation were analyzed. Compared with other multiparas, those having a trial of labor were more than 8-fold likelier to have a perinatal death due to a mechanical cause and nearly 3-fold likelier to have a perinatal death due to intrapartum anoxia. Although the absolute risk of perinatal death in women with a past cesarean delivery who undergo a trial of labor is low, the risk in the present study was higher than that of planned repeat cesarean delivery.

Variations in the investigation and management of group B streptococcus in Scotland

This article describes the practice of Scottish obstetricians in terms of their investigation and treatment of group B streptococcus (GBS). This was a postal questionnaire survey of all 125 consultant obstetricians in Scotland. We recorded indications for testing for GBS, categories of women to whom treatment is given empirically and following confirmed infection, type of antibiotic used, and timing and route of administration. No respondents screened all pregnant women but 97% screened some or all of those at highest risk. Three-quarters administered antibiotics empirically to women with intrapartum pyrexia. However, other high-risk groups were unlikely to receive treatment without confirmation of colonisation. Only one-third of respondents gave antibiotics to all women with confirmed GBS, and up to one-half withheld them from some colonised women in high-risk groups. Contrary to US guidelines, only 29% tested for GBS using low vaginal swabs and only 13% administered intrapartum antibiotics intravenously. There are wide variations in investigating and treating GBS throughout Scotland. It is likely that similar variations exist throughout the United Kingdom. UK guidelines are required to reduce variations and ensure appropriate and effective management.This article describes the practice of Scottish obstetricians in terms of their investigation and treatment of group B streptococcus (GBS). This was a postal questionnaire survey of all 125 consultant obstetricians in Scotland. We recorded indications for testing for GBS, categories of women to whom treatment is given empirically and following confirmed infection, type of antibiotic used, and timing and route of administration. No respondents screened all pregnant women but 97% screened some or all of those at highest risk. Three-quarters administered antibiotics empirically to women with intrapartum pyrexia. However, other high-risk groups were unlikely to receive treatment without confirmation of colonisation. Only one-third of respondents gave antibiotics to all women with confirmed GBS, and up to one-half withheld them from some colonised women in high-risk groups. Contrary to US guidelines, only 29% tested for GBS using low vaginal swabs and only 13% administered intrapartum antibiotics intravenously. There are wide variations in investigating and treating GBS throughout Scotland. It is likely that similar variations exist throughout the United Kingdom. UK guidelines are required to reduce variations and ensure appropriate and effective management.