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Biomedical subjects

M De Swiet

Publications and source records attributed to M De Swiet.

At least 19 recordsLinked to original sources
PubMed2001

Association of maternal endothelial dysfunction with preeclampsia.

CONTEXT: Preeclampsia is believed to result from release of placental factors that damage maternal vascular endothelium. However, because most studies have been conducted during pregnancy, it has not been possible to separate maternal from placental mechanisms underlying endothelial dysfunction in preeclampsia. OBJECTIVE: To determine whether endothelial function is impaired in nonpregnant women with previous preeclampsia and whether endothelial dysfunction is mediated by oxidative stress. DESIGN AND SETTING: Case-control study conducted at 3 hospital maternity units in London, England, between July 1997 and June 2000. PARTICIPANTS: A total of 113 women with previous preeclampsia (n = 35 with recurrent episodes; n = 78 with a single episode) and 48 women with previous uncomplicated pregnancies, all of whom were at least 3 months (median, 3 years) postpartum. MAIN OUTCOME MEASURES: Brachial artery flow-mediated (endothelium-dependent) and glyceryl trinitrate-induced (endothelium-independent) dilatation were compared between previously preeclamptic women and controls. To investigate oxidative stress, these measurements were repeated after administration of ascorbic acid, 1 g intravenously, in 15 cases and 15 controls. RESULTS: Mean (SD) flow-mediated dilatation was lower in women with previous preeclampsia compared with controls (recurrent group, 0.9% [4.1%]; single-episode group, 2.7% [3.5%]; and control group, 4.7% [4.3%]; P<.001). In contrast, glyceryl trinitrate-induced dilatation was similar in the 3 groups (recurrent, 19.5% [5.9%]; single-episode, 21.0% [8.0%]; and control, 21.0% [8.3%]; P =.65). Impaired flow-mediated dilatation in previously preeclamptic women was not accounted for by recognized vascular risk factors. Ascorbic acid administration increased flow-mediated dilatation in previously preeclamptic women (baseline, 2.6% [3.3%]; after administration, 5.6% [3.0%]; P =.001) but not in controls (baseline, 6.2% [3.3%]; after administration, 6.7% [5.0%]; P =.72). CONCLUSIONS: Our results indicate that endothelial function is impaired in women with previous preeclampsia and is not explained by established maternal risk factors but is reversed by antioxidant ascorbic acid administration.

Adult↗
PubMed2000

Impaired vasoconstriction in pregnancy-induced hypertension assessed using doppler fluximetry.

OBJECTIVE: To determine whether there is a difference in peripheral vascular reactivity between normal women and those with pregnancy-induced hypertension. METHODS: Capillary blood flow (flux) was recorded in the skin over the ankle in 26 pregnant women with pregnancy-induced hypertension at term. Twelve of these women had proteinuria, and 14 were nonproteinuric. Leg lowering was used to activate the venoarteriolar reflex, and the resultant change in flux, expressed as a percentage change from the baseline, was used as an index of vascular reactivity. The results were compared with those of a control group comprising 23 matched normotensive women. The study was repeated on all of the women after delivery. RESULTS: Women with hypertension showed a median (range) increase in flux of +24.4% (-15.5% to +151.1%), significantly different from controls: -39.3% (-80.9% to -4.3%, P <.001). This difference persisted regardless of the presence or absence of proteinuria. Responses in women with pregnancy-induced hypertension were significantly different after delivery (median -60.7%; range -158.5% to -19.5%, P <.001) when compared with predelivery responses. Similar changes as a result of delivery were seen in women with proteinuric (medians +25.9% and -57. 9%, P <.002) and nonproteinuric (medians +7.8% and -62.8%, P <.001) hypertension but not in controls. Postdelivery responses in women with hypertension were no different from those of controls. CONCLUSION: Women with pregnancy-induced hypertension have abnormal cutaneous vascular reactivity that returns to normal after delivery.

Adult↗
PubMed2000

Birth weight and 24-hour ambulatory blood pressure in nonproteinuric hypertensive pregnancy.

OBJECTIVE: The aim of this study was to examine the relationship between maternal ambulatory blood pressure monitor measurements during pregnancy and birth weight in a population of women considered to have hypertension according to conventional antenatal clinic measurement. STUDY DESIGN: A prospective observational study was carried out within the obstetric departments of Leicester Royal Infirmary and Queen Charlotte's Hospital. A total of 237 women were found to have hypertension (blood pressure >/=140/90 mm Hg) without significant proteinuria during examination in the antenatal assessment area. Sequential-day unit blood pressure recordings and a 24-hour automated ambulatory blood pressure recording were performed, and the results were compared with the principal outcome measure of birth weight. RESULTS: A significant inverse association (gradient, -13.5; 95% confidence interval -23.4 to -3.6) was found between daytime ambulatory diastolic blood pressure measurement and birth weight. An increase of 5 mm Hg in daytime mean diastolic blood pressure was associated with a fall in birth weight of 68.5 g. This association remained after adjustment for potential confounders that included maternal age, maternal weight, smoking status, ethnicity, and gestational age at delivery. No such association was found between obstetric day unit assessment of blood pressure and birth weight. CONCLUSION: There is a significant association between blood pressure and birth weight in nonproteinuric hypertensive pregnancies. The best predictor of this association is the daytime mean ambulatory diastolic blood pressure measurement. This is further evidence that maternal blood pressure may be an important confounding and potentially genetic variable in the association between birth weight and subsequent adult hypertension.

Adult↗
PubMed2000

A comparison of hemodynamic data derived by pulmonary artery flotation catheter and the esophageal Doppler monitor in preeclampsia.

OBJECTIVE: This study was undertaken to compare hemodynamic data derived with the esophageal Doppler monitor against those obtained with a pulmonary artery flotation catheter in women with complicated preeclampsia. STUDY DESIGN: Seventeen women with severe preeclampsia who had a pulmonary artery flotation catheter placed for clinical indications also had an esophageal Doppler monitor inserted. Hemodynamic data were recorded on 2 occasions separated by several hours with both the pulmonary artery flotation catheter and the esophageal Doppler monitor simultaneously. RESULTS: The esophageal Doppler monitor underestimated cardiac output by 36% +/- 14% (mean +/- SD). The esophageal Doppler monitor accurately estimated cardiac output in 3 women >40 years old, whereas in the remaining women (all <35 years old) the esophageal Doppler monitor underestimated cardiac output by 38% +/- 11%. The esophageal Doppler monitor accurately reflected changes in cardiac output with time when compared with the pulmonary artery flotation catheter. CONCLUSION: In women with preeclampsia the esophageal Doppler monitor consistently underestimated cardiac output by approximately 40%. It is not known whether the apparent increase in accuracy among the women >40 years old arose by chance or reflected a real improvement in performance. The esophageal Doppler monitor accurately reflected the direction and magnitude of the changes in cardiac output with time.

Adult↗
PubMed1996

Hypertension in pregnancy: which method of blood pressure measurement is most predictive of outcome?

OBJECTIVE: To determine the clinical effectiveness of blood pressure (BP) measurement using conventional sphygmomanometry in the antenatal clinic and obstetric day unit compared with automated BP monitoring at home. METHODS: The study population consisted of 109 nulliparous white women with BPs of at least 140 or 90 mmHg at the antenatal clinic after 20 weeks' gestation, who underwent obstetric day unit and 24-hour automated BP monitoring on the same day. Automated measurement was obtained every half hour for 24 hours using a commercially available device that had been previously validated in pregnancy. RESULTS: At the traditional BP cutoff point (140/90 mmHg), the relative risk for subsequent development of adverse obstetric outcome was greatest for automated BP measurement: The relationships between outcome and automated diastolic BP were all statistically significant: proteinuria (P = .034), preterm delivery (P < .001), birth weight below the tenth percentile (P = .001), admission to the special care neonatal unit (P = .001), and cesarean delivery (P = .007). CONCLUSION: Automated BP measurement appears to improve the identification of patients who are at high risk of poor obstetric outcome. Automated BP measurement is worthy of further evaluation as an antenatal screening and diagnostic test.

Adolescent↗
PubMed1995

Discordant blood flow velocity waveforms in left and right brachial arteries in growth-retarded fetuses.

OBJECTIVE: To determine if the increase in cerebral blood flow ("brain-sparing" effect) with fetal hypoxemia is associated with discordant hemodynamics in the upper extremities. METHODS: We studied 12 fetuses with severe growth retardation, absent or reverse end-diastolic blood flow in the umbilical artery, and low pulsatility index (PI) in the middle cerebral artery, and 12 appropriately grown control fetuses with normal fetoplacental Doppler studies. The right and left brachial arteries were identified by high-resolution color Doppler ultrasonography, and the PI was measured in each brachial artery. RESULTS: All growth-retarded fetuses had lower impedance indices in the right than in the left brachial artery (mean delta PI 1.0, 95% confidence interval [CI] 0.7-1.3, P < .001). No differences in the brachial artery impedance indices were found in control fetuses matched for gestational age (mean delta PI 0.0, 95% CI -0.2 to 0.2). CONCLUSIONS: Left and right brachial artery blood flow velocity waveforms are discordant in fetuses with growth retardation and cerebral vasodilation. Because the right arm receives its blood supply from the same source as the brain (brachiocephalic artery) and given the proximity of the left subclavian artery to the ductus arteriosus, we speculate that this might be the result of increased blood flow into the brachiocephalic circulation and/or functional differences in the distribution of left and right ventricular output within the aortic arch in response to fetal hypoxemia.

Birth Weight↗
PubMed1988

Pregnancy and lupus: prognostic indicators and response to treatment.

A cohort study was undertaken of 18 consecutive pregnancies in 16 patients with systemic lupus erythematosus without significant renal impairment. Of these, eight each had at least two previously unexplained pregnancy failures, 10 had elevated anticardiolipin antibodies, nine had the lupus anticoagulant and five had antibodies to Ro. Twelve live births resulted but a Downs syndrome baby died in the perinatal period. Fetal morbidity was confined to four cases of fetal growth retardation, all in mothers positive for anticardiolipin antibodies, and fetal distress in another two. There were no cases of the neonatal lupus syndrome. There was one maternal death. An obstetric history of at least two previously unexplained pregnancy failures and the presence of maternal anticardiolipin or anti-Ro antibodies accurately predicted fetal loss in six of seven cases. No other serological risk factors for fetal loss were identified. We were unable to show that suppression of antibodies in those mothers with at least two previously unexplained pregnancy failures improved fetal outcome.

Adult↗
PubMed1986

The use of a birthroom: a randomized controlled trial comparing delivery with that in the labour ward.

A randomized controlled trial of two environments for delivery was conducted at Queen Charlotte's Maternity Hospital. A total of 253 parous women expecting to have a labour ward delivery were invited to participate in the trial but only 148 agreed. These women were randomly allocated to be delivered either with standard labour ward management (n = 72) or in the birthroom--a small bedroom decorated in a homely manner, without facilities for epidural analgesia or electronic fetal monitoring (n = 76). Eleven women in the birthroom group and 10 in the labour ward group withdrew from the trial before labour and four were transferred from the birthroom to the labour ward when in labour. A questionnaire sent in the postnatal period to the women who completed the trial was returned by 80%. In the birthroom group there was significantly (i) decreased admission-to-delivery interval (ii) less analgesia (iii) more freedom of movement (iv) less suturing (v) increased rooming-in. No difference was found in the assessment of difficulty of labour nor in the method of subsequent infant feeding.

Clinical Trials as Topic↗
PubMed1985

alpha-Fetoprotein elevation and proteinuric pre-eclampsia.

In a retrospective study of pregnancy complicated by unexplained elevation of maternal serum alpha-fetoprotein (AFP), 60 patients were compared with 120 control subjects. Proteinuric pre-eclampsia occurred in 13% of the study patients compared with 1% of the control subjects. Primiparity, previous mid-trimester abortion and recurrent abortions were also significantly more common in the study group. It is proposed that an abnormality of the placenta predisposes to complications and that this abnormality is expressed early in pregnancy when the AFP level is first measured. This group of women is at high risk of adverse pregnancy outcome and requires careful monitoring.

Abortion, Spontaneous↗
PubMed1983

Randomised controlled comparative study of methyldopa and oxprenolol in treatment of hypertension in pregnancy.

One hundred pregnant women with hypertension (defined as diastolic blood pressure at or above 95 mm Hg) were allocated at random to treatment with methyldopa or oxprenolol and were compared with nonhypertensive controls matched according to parity and gestation at delivery. The patients were also stratified into those entering the study early (before 32 weeks' gestation) and those entering late (after 32 weeks' gestation). Although there were no differences in diastolic blood pressure between the hypertensive groups before or during treatment, in the early entry group the systolic blood pressure at entry of those allocated to oxprenolol was significantly higher than that of those receiving methyldopa; this difference remained throughout the treatment period. Also in the early entry group further increments of drug treatment were required to control blood pressure of patients receiving oxprenolol than in those receiving methyldopa. The eventual fetal outcome for all patients treated with methyldopa was the same as that for those treated with oxprenolol; birth weight, placental weight, head circumference, and Apgar score were not significantly different and there were no stillbirths in either group.

Adult↗