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Biomedical subjects

L Impey

Publications and source records attributed to L Impey.

18 recordsLinked to original sources
PubMed2005

Why is there a modifying effect of gestational age on risk factors for cerebral palsy?

OBJECTIVE: To investigate risk factors for cerebral palsy in relation to gestational age. DESIGN: Three case-control studies within a geographically defined cohort. SETTING: The former Oxfordshire Health Authority. PARTICIPANTS: A total of 235 singleton children with cerebral palsy not of postnatal origin, born between 1984 and 1993, identified from the Oxford Register of Early Childhood Impairment; 646 controls matched for gestation in three bands: or=37 weeks. RESULTS: Markers of intrapartum hypoxia and infection were associated with an increased risk of cerebral palsy in term and preterm infants. The odds ratio (OR) for hypoxia was 12.2 (95% confidence interval 1.2 to 119) at or=37 weeks. Corresponding ORs for neonatal sepsis were 3.1 (1.8 to 5.4) and 10.6 (2.1 to 51.9). In contrast, pre-eclampsia carried an increased risk of cerebral palsy at >or=37 weeks (OR 5.1 (2.2 to 12.0)) but a decreased risk at <or=32 weeks (OR 0.4 (0.2 to 1.0)). However, all infants <or=32 weeks with maternal pre-eclampsia were delivered electively, and their risk of cerebral palsy was no lower than that of other electively delivered <or=32 week infants (OR 0.9 (0.3 to 2.7)). Nearly 60% of <or=32 week controls were delivered after spontaneous preterm labour, itself an abnormal event. CONCLUSION: Inflammatory processes, including pre-eclampsia, are important in the aetiology of cerebral palsy. The apparent reduced risk of cerebral palsy associated with pre-eclampsia in very preterm infants is driven by the characteristics of the gestation matched control group. Use of the term "protective" in this context should be abandoned.

Biomarkers↗
PubMed2001

Fever in labour and neonatal encephalopathy: a prospective cohort study.

OBJECTIVE: To determine whether the reported association of maternal fever with neonatal encephalopathy is independent of other associated intrapartum risk factors. DESIGN: Prospective cohort study. SETTING: Dublin teaching hospital delivery ward. POPULATION: 4,915 low risk women in labour at 36-41 weeks of gestation. METHODS: Using logistic regression with odds ratios and 95% confidence intervals, the incidence of neonatal encephalopathy and other neonatal outcomes of women who had an intrapartum fever >37.5 degrees C was compared with those who did not. RESULTS: The cohort comprised 33% of all deliveries during the study period. Neonatal encephalopathy was diagnosed in 3.25/1,000 births. The incidence of intrapartum fever was 6.8%. Maternal fever was strongly associated with neonatal encephalopathy (crude OR 10.8, 95% CI 4.0-29.3). Univariate analysis showed maternal fever was associated with epidural analgesia, nulliparity, induction, longer labour, oxytocin administration, greater fetal birthweight and gestational age and instrumental vaginal delivery, but not with prolonged (>24hours) prelabour rupture of the membranes. The association of fever with neonatal encephalopathy persisted having adjusting for these covariates (adjusted OR 4.72, 95% CI 1.28-17.4). CONCLUSIONS: The relationship between maternal intrapartum fever and neonatal encephalopathy is independent of other known intrapartum risk factors. This provides further evidence for the role of inflammatory processes in the aetiology of neonatal neurological morbidity.

Brain Diseases↗
PubMed2001

The relation between pre-eclampsia at term and neonatal encephalopathy.

OBJECTIVES: To determine whether pre-eclampsia, hypothesised to be an inflammatory condition, is associated with fever in term labour, and confirm and examine the reported association of pre-eclampsia at term with neonatal encephalopathy. DESIGN: Prospective cohort study. SETTING: A Dublin teaching hospital. PARTICIPANTS: 6163 women in labour with singleton pregnancies at term at low risk for intrapartum hypoxia, recruited to a randomised trial examining the effect of admission cardiotocography on neonatal outcome. RESULTS: Pre-eclampsia was associated with maternal fever > 37.5 degrees in labour (odds ratio (OR) 3.39, 95% confidence interval (CI) 2.1 to 5.4); this was independent of obstetric intervention (adjusted OR 2.07, 95% CI 1.24 to 3.47). Pre-eclampsia was associated with neonatal encephalopathy (OR 25.5, 95% CI 8.4 to 74.7); this too was independent of obstetric intervention (adjusted OR 18.5, 95% CI 5.9 to 58.1). Cord arterial pH values were significantly lower in pre-eclamptics (7.20 v 7.24), although severe cord acidaemia was not significantly more common (OR 2.91, 95% CI 0.7 to 9.9). The association of pre-eclampsia with encephalopathy was independent of maternal fever (adjusted OR 16.5, 95% CI 5.1 to 54) and cord acidaemia (adjusted OR 13.5, 95% CI 3.2 to 56.7). CONCLUSIONS: The association of pre-eclampsia with maternal fever at term supports the hypothesis that pre-eclampsia is an inflammatory condition. The association of pre-eclampsia with neonatal encephalopathy is independent of obstetric intervention and cannot be explained by either acidaemia or maternal fever. A systemic inflammatory response in the fetus, perhaps secondary to oxidative stress, could explain the link between maternal pre-eclampsia and neonatal encephalopathy, and this may occur through cerebral vasoconstriction.

Blood Gas Analysis↗
PubMed2000

Epidural analgesia need not increase operative delivery rates.

OBJECTIVE: We sought to examine the relationship between epidural analgesia and cesarean and instrumental vaginal delivery rates. STUDY DESIGN: This is a retrospective analysis of the first 1000 nulliparous pregnancies in women with a cephalic presentation in spontaneous labor at term in each of 3 different years, over which the epidural rate increased from 10% to 57%. RESULTS: Cesarean and instrumental vaginal delivery rates were similar in all 3 years. Demographic characteristics remained unchanged or altered in a manner that has previously been associated with an increase in intervention. Electronic fetal monitoring and first-stage oxytocin use remained unchanged, but oxytocin use in the second stage increased considerably. CONCLUSIONS: Increased use of epidural analgesia had no effect on cesarean delivery rates. Although randomized trials have suggested that it increases instrumental vaginal delivery rates, this might be overcome by active management of labor or judicious use of oxytocin in the second stage.

Adult↗
PubMed2000

Graphic analysis of actively managed labor: prospective computation of labor progress in 500 consecutive nulliparous women in spontaneous labor at term.

OBJECTIVE: Active management has been shown to shorten the length of labor and reduce the incidence of prolonged labor. We examined the influence of this protocol on the rate of cervical dilatation by calculating a mean partogram to explain how this acceleration is achieved. STUDY DESIGN: We retrospectively analyzed partograms of cervical dilation in 500 consecutive nulliparous women in spontaneous labor at term with a singleton fetus in a cephalic presentation; cesarean deliveries were not excluded. Mean cervical dilations at admission and mean time intervals to reach 2, 3, 4, 6, 8, and 10 cm of dilatation and delivery were calculated, with 95% confidence intervals, both for the whole cohort and specifically in women with cervical dilatations <3 cm at admission. These data were used to construct mean partograms. RESULTS: The mean duration of labor was 6.1 hours. The mean cervical dilatation at admission was 1. 7 cm; all but 2.8% were delivered within 12 hours. The cesarean rate was 5.4%. The mean partogram, with narrow 95% confidence intervals, shows a rapid active phase after a much shorter latent phase than reported in other analyses of labor. CONCLUSION: Active management reduces the duration of first labor mainly by shortening the latent phase in association with amniotomy at very early cervical dilatations and does not delay the diagnosis of labor until the active phase has begun.

Adolescent↗
PubMed1999

Maternal attitudes to amniotomy and labor duration: a survey in early pregnancy.

BACKGROUND: Although maternal choice increasingly influences intrapartum care, little is known about maternal attitudes about many outcomes and interventions, particularly the length of labor. Early amniotomy decreases the length of labor and particularly the frequency of prolonged (> 12 hr) labor but is often avoided by health professionals. The objective of this survey was to assess the attitudes of women in a major Dublin teaching hospital about the length of labor, amniotomy, and epidural analgesia. METHODS: An anonymous, structured, self-completed questionnaire was given to 438 women at their booking visit to the hospital antenatal clinic in February 1998. Participants could ring "agree," "disagree," "don't know," or "don't care" to seven different statements. RESULTS: The questionnaire was returned by 398 (92%) women; demographic details were similar to those for the overall hospital population. Of these, 73.5 percent of women wanted a quick labor; 82 percent wanted it to last less than 12 hours. Nearly one-half specifically wanted epidural analgesia. Only 13 percent wished to avoid amniotomy; significantly more multiparas disagreed with "avoiding amniotomy." CONCLUSIONS: Many women want a quick and painless labor, and do not object to the interventions that help achieve this.

Adolescent↗
PubMed1998

First delivery after cesarean delivery for strictly defined cephalopelvic disproportion.

OBJECTIVE: To examine the outcome of trial second labor after a first cesarean performed because of cephalopelvic disproportion, defined according to strict diagnostic criteria. METHODS: Obstetric details of nulliparous women delivering at 37 or more weeks' gestation by cesarean for cephalopelvic disproportion, between 1975 and 1990, were recorded prospectively. The diagnostic criteria for cephalopelvic disproportion were cervical dilation arrested after 5 cm, unresponsive to oxytocin augmentation, after active dilatation of 2 cm or more in 2 hours. Fetal malpresentations and malpositions were excluded. The outcome of next delivery in our hospital by each woman enrolled was then examined. RESULTS: Eighty-four of 42,793 women met the criteria for disproportion, and 40 with cephalic presentations delivered their next baby in our hospital. All 40 underwent a trial of labor and 27 (68%) delivered vaginally, comprising seven (47%) women with larger second and 20 (80%) with smaller second babies. Of 15 women previously delivered by cesarean at full dilatation, 11 (73%) delivered vaginally with no serious maternal or neonatal morbidity. CONCLUSION: The strictly defined diagnosis of nulliparous cephalopelvic disproportion should not constitute an automatic "recurrent" indication for elective cesarean delivery, because 68% of patients in our series had successful vaginal deliveries in their next pregnancies. This rate is similar to those reported after all nulliparous cesareans for dystocia.

Cesarean Section↗
PubMedDate not supplied

Outcome of external cephalic version after 36 weeks' gestation without tocolysis.

OBJECTIVE: Despite its efficacy, external cephalic version (ECV) at term is not universally employed. Published series of Caucasian women are small and concerns regarding safety and spontaneous version remain. We review the outcomes of 26 months of a breech clinic in a Dublin teaching hospital. METHODS: All women with known breech presentation at 36+ weeks were referred unless another indication for cesarean section existed. Unstable lie, fetal compromise, antepartum hemorrhage, and patient refusal were the only contraindications to ECV. One operator attempted all versions, without tocolysis. RESULTS: Three hundred seventy women were referred and in 356 (95%), version was attempted at a mean gestation of 37 + 3 weeks; 195 (55%) were nulliparous and 161 (45%) were multiparous. The success rate was 43%, including 33% of nulliparous and 54% of multiparous women. There were three perinatal deaths (0.8%), all unrelated to the version. Minor complications were rare, although two women were delivered by cesarean section shortly after unsuccessful version. Ninety-three percent of successful versions were cephalic at delivery, as were 4% of unsuccessful versions; 12% of infants with a cephalic presentation after successful version were delivered by cesarean section. CONCLUSIONS: From this large series, ECV is extremely safe. Spontaneous version after unsuccessful ECV and reversion after successful ECV are unusual.

Adolescent↗
PubMedDate not supplied

Recurrent acquired sideroblastic anemia in a twin pregnancy.

A woman whose sideroblastic anemia had relapsed with progestogen and combined oral contraceptive therapy suffered further relapses in a (twin) pregnancy. Previous reports exist of relapses both from progestogens and in pregnancy, and we postulate a shared etiology. Affected women considering pregnancy or sex hormone usage should be advised accordingly.

Adult↗