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Philip J Steer

Publications and source records attributed to Philip J Steer.

12 recordsLinked to original sources
PubMed2005

Hemoglobin concentration in pregnancy and perinatal mortality: a London-based cohort study.

OBJECTIVE: Failure of fetal growth during pregnancy, and preterm birth, are the major causes of stillbirth and early neonatal death. The objective of the study was to determine the association between maternal hemoglobin concentration during pregnancy and perinatal mortality. STUDY DESIGN: The design was prospective, using data on 222,614 first singleton pregnancies in the St Mary's Maternity Information System database in the Northwest Thames region of London. RESULTS: The association of perinatal mortality with maternal hemoglobin at first antenatal check was not statistically significant (P>.10), but a statistically significant (P<.001) U-shaped pattern was found with lowest recorded maternal hemoglobin concentration. Both early neonatal mortality and stillbirth rates were statistically significantly (P<.005) associated with lowest maternal hemoglobin concentration. The relationship of lowest hemoglobin with early neonatal mortality was largely mediated by the effect of preterm birth, and that between lowest hemoglobin and stillbirth by fetal growth restriction. The lowest perinatal mortality was associated with a lowest recorded maternal hemoglobin concentration of between 9-11 g/dL. CONCLUSION: There is an optimal range of lowest hemoglobin concentration in pregnancy, and on either side of this perinatal mortality is increased. The effect of lowest hemoglobin is largely mediated through associations with preterm birth and fetal growth restriction.

Birth Weight↗
PubMed2004

Maternal blood pressure in pregnancy, birth weight, and perinatal mortality in first births: prospective study.

OBJECTIVE: To investigate the relation of diastolic blood pressure in pregnancy with birth weight and perinatal mortality. DESIGN: Prospective study. SETTING: 15 maternity units in one London health region, 1988-2000. PARTICIPANTS: 210 814 first singleton births of babies weighing more than 200 g among mothers with no hypertension before 20 weeks' gestation and without proteinuria, delivering between 24 and 43 weeks' gestation. MAIN OUTCOME MEASURES: Birth weight and perinatal mortality. RESULTS: The mean (SD) birth weight of babies born to mothers with no hypertension before 20 weeks' gestation or proteinuria was 3282 g (545 g) and there were 1335 perinatal deaths, compared with 94 perinatal deaths among women with proteinuria or a history of hypertension. Diastolic blood pressure at booking for antenatal checks was progressively higher from weeks 34 to 40 of gestation. The birth weight of babies being delivered after 34 weeks was highest for highest recorded maternal diastolic blood pressures of between 70 and 80 mm Hg and lower for blood pressures outside this range. Both low and high diastolic blood pressures were associated with statistically significantly higher perinatal mortality. Using a linear quadratic model, 94 of 825 (11.4%) perinatal deaths could be attributed to mothers having blood pressure differing from the optimal blood pressure (82.7 mm Hg) predicted by the fitted model. Most of these excess deaths occurred with blood pressures below the optimal value. CONCLUSIONS: Both low and high diastolic blood pressures in women during pregnancy are associated with small babies and high perinatal mortality.

Adolescent↗
PubMed2004

Garlic supplementation increases peripheral blood flow: a role for interleukin-6?

There is considerable epidemiological and clinical evidence that regular garlic supplementation reduces cardiovascular risk. In this study, we have investigated the hypothesis that dietary garlic supplementation increases tissue blood flow and this is mediated by the vasodilatory actions of interleukin-6 (IL-6). Venous occlusion plethysmography was used to measure resting calf blood flow before and after oral administration of 600 mg of garlic tablets once daily for 7 days in 13 young healthy female volunteers (treatment group) and 13 female controls matched for age and body mass index (BMI). Blood samples were obtained at the time of plethysmography to measure plasma levels of IL-6, nitrate, nitrite and c-GMP. In the treatment group, calf blood flow increased significantly from 3.01 (2.56 to 3.3) ml min(-1) 100 mL(-1) of tissue before garlic to 3.46 (3.0 to 4.03) ml min(-1) 100 mL(-1) of tissue after 7 days of garlic (P = 0.001). Plasma IL-6 concentrations increased significantly from 54.6 (32.3 to 151.6) mcg/mL before to 151 (135.75 to 422.3) mcg/mL after 7 days of garlic (P = 0.02). However, there was no significant change in the plasma levels of nitrate, nitrite and c-GMP after the garlic (P = 0.4, 0.9 and 0.65 respectively). In the control group, resting calf blood flow and plasma levels of IL-6, nitrite, nitrate and c-GMP remained unchanged after 7 days (P = 0.62, 0.92, 0.28 and 0.35 respectively). Calf blood flow showed a non-linear correlation with plasma IL-6 levels after garlic supplementation (r = 0.86, p = <0.001) but not before. There was no significant relationship between blood flow and plasma nitrate, nitrite and c-GMP in either groups and between blood flow and IL-6 in the control group. These data suggest that garlic supplementation increases resting tissue blood flow and this may be mediated by IL-6.

Adult↗
PubMed2004

Tinzaparin sodium for thrombosis treatment and prevention during pregnancy.

OBJECTIVE: This study was undertaken to assess the pharmacodynamic profile, safety, and efficacy of tinzaparin during pregnancy. STUDY DESIGN: Fifty-four pregnant women, 12 for treatment of thrombosis and 42 for thromboprophylaxis, received tinzaparin by once daily injection. Four-hour postdose anti-Xa results were analyzed by use of repeated measures statistical methods. RESULTS: One woman (3.4%) on the 175 anti-Xa U/kg dose and three women (20%) on the 50 anti-Xa U/kg dose required a dose increase during the initial dose titration phase to achieve target anti-Xa activity. No thrombotic events occurred. CONCLUSION: The 175 anti-Xa U/kg dose is appropriate for treatment and for high-risk thromboprophylaxis throughout pregnancy. In pregnant women at moderate risk of thrombosis, a higher tinzaparin dose is required than in the nonpregnant state and 75 anti-Xa U/kg appears to be appropriate. The majority of women do not need a dose increase with advancing gestation.

Female↗
PubMed2004

Are reported preterm birth rates reliable? An analysis of interhospital differences in the calculation of the weeks of gestation at delivery and preterm birth rate.

We investigated the possibility of preterm birth misclassification as a determinant of variation in its reported rates. Using a database of 497,105 deliveries from 17 hospitals, the best estimate of gestational age made at delivery and entered into the database at that time was recalculated from the menstrual dates and mid-trimester ultrasound scan. The recalculated completed weeks of gestation at delivery was compared with that made at birth. Calculation of estimated gestational age varied between hospitals due to inconsistencies in 'rounding' and 'truncating' the weeks of gestation at delivery. This resulted in preterm birth misclassification rates of up to 10.1%.

Birth Rate↗
PubMed2004

Maternal temperature monitoring during labor: concordance and variability among monitoring sites.

OBJECTIVE: Elevated maternal temperature in labor is associated with adverse immediate and long-term neonatal outcomes. Conventional methods of temperature measurement may not reflect the intrauterine temperature, which constitutes the fetal environment. The purpose of this study was to ascertain the most reliable noninvasive method of temperature monitoring in labor that would best reflect changes in intrauterine temperature. METHODS: Women in labor receiving epidural analgesia had temperature readings taken every 10 seconds from the uterine cavity, ear canal, and skin surface of the leg and abdomen and hourly from the mouth. RESULTS: Eighteen patients were studied for a mean of 228 minutes (range 56-464 minutes). The best indicator of intrauterine temperature was oral temperature, with a mean intraclass correlation coefficient of 0.6 (95% confidence interval 0.42, 0.77). On average, oral temperature underestimated intrauterine temperature by 0.8 degrees C (95% confidence interval 0.7 degrees C, 1 degrees C). Allowing for this, oral temperature greater than 37.2 degrees C detected an intrauterine temperature greater than 38 degrees C with a sensitivity of 81% and a specificity of 96%. The intraclass correlation coefficients of all other sites with intrauterine temperature were poor (0.1 or less). As expected, the temperature at all sites increased as labor progressed. CONCLUSION: Oral temperature, measured carefully, has an acceptable correlation with intrauterine temperature and is recommended for routine detection of maternal pyrexia in labor. Continuous skin and external auditory canal temperature measurements did not correlate well. LEVEL OF EVIDENCE: II-3

Adult↗
PubMed2004

Low molecular weight heparin (tinzaparin) therapy for moderate risk thromboprophylaxis during pregnancy. A pharmacokinetic study.

Low molecular weight heparin (LMWH) is used increasingly for prophylaxis and treatment of venous thromboembolism during pregnancy. However, the prophylactic dose for patients at moderate risk varies between centers, and the recommended LMWH dose for the non pregnant patient is frequently used in pregnant women. The aim of this study was to investigate the effects of pregnancy on the pharmacokinetics of anti-Xa levels during moderate risk thromboprophylaxis with the LMWH, tinzaparin. In 24 pregnant women, one of three doses of tinzaparin (50, 75 or 100 IU/kg) were given according to the treating physician's assessment of their risk profile. Four-hour peak anti-Xa levels were measured throughout pregnancy and 24-hour profiles were measured at 28 and 36 weeks gestation. Doses were adjusted when peak anti-Xa levels fell below 0.1 IU/ml and, in some cases, when levels at 10 and 18 hours post injection were undetectable (<0.05 IU/ml). Our results showed that women receiving tinzaparin (50 IU/kg) frequently had peak (4 hour) anti-Xa levels below 0.1IU/ml and that 46% of these patients required dose adjustment. Similarly anti-Xa levels were also found to be low over the 24-hour period. A starting dose of 75 IU/kg, once daily, gave greater anti-Xa cover over the 24-hour period and may avoid the need for dose adjustment. The results suggest that the pharmacokinetics of tinzaparin are affected by pregnancy. Larger studies are required to determine whether an increased tinzaparin dose (75 IU/kg) would be more effective in the prevention of thrombosis during pregnancy than 50 IU/kg.

Adult↗
PubMed2003

Microvascular permeability is related to circulating levels of tumour necrosis factor-alpha in pre-eclampsia.

INTRODUCTION: The mechanism for the increased microvascular permeability which, underline many of the complications of pre-eclampsia, remain unexplained. It has been suggested that a factor present in the maternal circulation in pregnancies complicated by the disease may be responsible for increased microvascular permeability. In this study, we have investigated the relationship between filtration capacity (K(f)), an index of microvascular permeability, and maternal levels of VEGF, leptin and TNF-alpha, all of which are known permeability factors whose plasma levels are increased in pre-eclampsia. METHODS: We used a small cumulative pressure step venous congestion plethysmography protocol to compare K(f), an index of microvascular permeability, during the third trimester of 20 women with pre-eclampsia, 18 normal pregnant women and 18 non-pregnant female matched controls. Blood samples were obtained to measure plasma levels of VEGF, leptin, TNF-alpha plasma protein concentrations and full blood count. RESULTS: Microvascular filtration capacity (K(f)) was significantly increased in pre-eclampsia compared to the other groups (P<<0.0001, ANOVA). K(f) was also increased in the normal pregnant group when compared to the non-pregnant controls (P=0.02). Plasma levels of VEGF, leptin and TNF-alpha were significantly greater in pre-eclampsia compared to normal pregnancy and non-pregnant controls (P<0.0001, ANOVA, for all three analyses). Total plasma protein and albumin concentrations were significantly lower in the normal pregnant and pre-eclamptic groups, compared to the non-pregnant controls (P<0.0001, ANOVA). K(f) was significantly related to TNF-alpha in pre-eclampsia (r=0.53, P=0.018), and with VEGF in the non-pregnant controls (r=0.6, P=0.02). No significant relationship was observed between K(f) and VEGF, leptin and TNF-alpha during normal pregnancy. There was a significant inverse correlation between plasma albumin concentration and filtration capacity in the normal pregnant (r=-0.94, P<0.0001) and non-pregnant (r=-0.87, P<0.0001) groups but not in the women with pre-eclampsia (r=-0.18, P=0.8). CONCLUSIONS: These data show that that microvascular filtration capacity is significantly increased in pre-eclampsia, and correlates with circulating levels of TNF-alpha but not leptin or VEGF.

Adult↗
PubMed2002

Cardiac disease in pregnancy.

Congenital heart disease in pregnancy is increasingly common because of the advances in surgery and medical therapy which have taken place over the last 30 years, which means that more affected women are surviving into the reproductive age. Antenatal counselling needs to be tailored to the specific lesion, with pulmonary hypertension and cyanotic disease presenting a risk of maternal mortality of up to 50%. The use of anticoagulants in women with artificial valves presents a particular challenge, heparin being safer for the baby and warfarin for the mother. Peripartum cardiomyopathy and Marfan's syndrome may be less dangerous than once thought. The risk of congenital heart disease in the fetus is increased, from twice to 20-fold, depending on the nature of the mother's lesion. Care throughout pregnancy and in the puerperium should be multidisciplinary and include cardiologists, obstetricians and midwives with experience of such cases, preferably in a tertiary centre.

Anticoagulants↗