thromboxane-b2 and Birth-Weight

To determine whether antenatal treatment (for > or = 14 days) with 100 mg aspirin daily, given to mothers with small for gestational age fetuses and abnormal umbilical Doppler, will increase birthweight.. Randomised, double-blind placebo controlled trial.. A tertiary referral centre.. Ninety-nine women, of whom 65 were treated for > or = 14 days (32 with aspirin and 33 with placebo) and comprised the study group. The entry criteria were: singleton pregnancy with ultrasound evidence of a small for gestational age fetus (abdominal circumference < 10%); previous anatomy scan < 20 weeks and no evidence of fetal abnormality; gestation between 24 and 36 weeks; umbilical artery Doppler resistance index > 95% for gestation; no previous aspirin treatment in pregnancy; and no contra-indication to aspirin treatment.. The mean duration of treatment was 30 days for aspirin treated, and 29 for placebo. No difference was found in birthweight or other measures of fetal growth or newborn morbidity between those treated with aspirin or placebo. Compliance, assessed by thromboxane B2 analysis, showed almost complete suppression of thromboxane B2 in aspirin treated women.. Low-dose aspirin did not increase birthweight in pregnancies where the fetus has abnormal umbilical Doppler and is thought to be small for gestational age.

Topics: Adult; Aspirin; Birth Weight; Double-Blind Method; Female; Fetal Growth Retardation; Humans; Platelet Aggregation Inhibitors; Pregnancy; Thromboxane B2; Ultrasonography, Doppler; Umbilical Cord

Our purpose was to determine whether in a low-dose aspirin trial a longitudinal decrease in maternal serum thromboxane B2 is associated with improvement in pregnancy outcomes.. A total of 606 healthy nulliparous women with singleton gestations were randomized at 24 weeks to either 60 mg of aspirin or a placebo. Maternal serum thromboxane B2 was measured at randomization, at 29 to 31 weeks, at 34 to 36 weeks, and at delivery. After delivery, and without knowledge of patient outcome or group assignment, patients were categorized as having had either a longitudinal twofold or greater (> or = 50%) or less than twofold reduction (< 50%) in thromboxane B2 from baseline levels at randomization.. Of 606 entrants, 92% had sufficient thromboxane B2 determinations to allow categorization. Whether patients were assigned to aspirin or placebo, birth weight was significantly greater in women who had a twofold or greater reduction in maternal serum thromboxane B2 levels. When the aspirin and placebo groups were combined, women with a twofold or greater reduction in thromboxane B2 levels had less preeclampsia, 1.9% (6/314) versus 5.7% (14/244) (p = 0.016), less preterm delivery (5.7% vs 10.7%, p = 0.032), fewer small-for-gestational-age newborns, 9 of 314 (2.95) versus 17 of 244 (7%) (p = 0.023), and a higher mean birth weight, 3314 gm versus 3121 gm (p = 0.0001).. Women with a twofold or greater longitudinal reduction in maternal serum thromboxane B2 had less preeclampsia and prematurity, fewer small-for-gestational-age newborns, and higher birth weights than women with less than a twofold reduction.

Topics: Aspirin; Birth Weight; Double-Blind Method; Embryonic and Fetal Development; Female; Humans; Obstetric Labor, Premature; Pre-Eclampsia; Pregnancy; Pregnancy Outcome; Thromboxane B2

Our objective was to determine the effect of chorioamnionitis on plasma prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) during the first week in preterm infants. Plasma PGE2 and TxB2 were measured at 1, 3, and 7 days of age in preterm infants (birth weights 501 to 1500 g), with ( N = 26) and without ( N = 22) chorioamnionitis. Infants with maternal chorioamnionitis had significantly lower mean gestational age ( P = 0.0001) and birth weight ( P = 0.03) and a marginally higher rate of bronchopulmonary dysplasia (37% versus 12.5, P = 0.05), a result that may be related to the lower mean gestational age. Plasma PGE2 and TxB2 varied widely, more so on the first day but did not significantly differ between the two groups. TxB2 was lower among infants who died or developed morbidities. Circulating PGE2 and TxB2 concentrations in preterm infants in the first week vary considerably, are relatively unaltered by chorioamnionitis, and are lower in association with mortality and clinical morbidities. Further research on their role in the causation of adverse neonatal outcomes is necessary.

Topics: Adolescent; Adult; Anti-Inflammatory Agents, Non-Steroidal; Birth Weight; Bronchopulmonary Dysplasia; Chorioamnionitis; Dinoprostone; Female; Gestational Age; Humans; Indomethacin; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Pregnancy; Pregnancy Outcome; Respiratory Distress Syndrome, Newborn; Thromboxane B2; Young Adult

Very early human pregnancy is a state of cardiovascular underfilling. The renin-angiotensin system (RAS) is directly concerned with sodium and water homeostasis. Angiotensinogen is known to be the rate-limiting component in the generation of angiotensin I, and hence angiotensin II, in pregnancy. The usual measurement of 'renin activity' does not differentiate between enzyme and substrate. We hypothesized that the RAS is activated from the start of pregnancy; plasma renin concentration (PRC) and angiotensinogen will show differential regulation and might stimulate the rise in prostacyclin.. A prospective study of 12 nulliparous normal women. PRC and angiotensinogen and excretion of prostacyclin and thromboxane metabolites were measured pre-pregnancy and four to six times after conception to 13 weeks.. By 6 weeks gestation, mean PRC was markedly raised and remained stable to 13 weeks. The initial angiotensinogen response varied, but rose consistently after 6-8 weeks. Regression analysis showed angiotensinogen in the first trimester to be strongly associated with corrected birthweight centile (P < 0.001). Excretion of eicosanoid metabolites was very variable, but rose significantly from 6 weeks; the ratio between prostacyclin and thromboxane excretion did not alter over this time. There was no correlation between the various hormones measured.. Angiotensinogen is known to be rate-limiting in pregnancy. Its association with birthweight may be through effects on early plasma volume expansion and may have implications for intrauterine growth restriction and pre-eclampsia.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Angiotensinogen; Birth Weight; Creatinine; Female; Humans; Longitudinal Studies; Pregnancy; Pregnancy Trimester, First; Prospective Studies; Renin; Renin-Angiotensin System; Thromboxane B2

To analyse whether pregnancies resulting in a small for gestational age neonate are preceded by a prostacyclin deficiency or an imbalance between thromboxane and prostacyclin.. At five fixed time points during pregnancy, 24-h urine samples were collected for the measurement of thromboxane and prostacyclin metabolites thromboxane-B(2) (TXB(2)) and 6-keto-prostaglandin F(1alpha) (6-keto-PGF(1alpha)). In order to study trend differences between pregnancies with appropriate (AGA; n=26) and small for gestational age neonates (SGA; n=17), trend analysis with simple contrasts were accomplished for TXB(2), 6-keto-PGF(1alpha) and the TXB(2)/6-keto-PGF(1alpha) ratio.. Trend analysis showed higher TXB(2) levels and higher TXB(2)/6-keto-PGF(1alpha) ratios in patients with SGA versus AGA newborns. No statistically significant difference in 6-keto-PGF(1alpha) excretion between patients with SGA and AGA newborns was detected.. The birth of an SGA neonate is not preceded by prostacyclin deficiency. With ongoing pregnancy an imbalance between thromboxane and prostacyclin becomes more obvious in pregnancies with SGA newborns.

Topics: 6-Ketoprostaglandin F1 alpha; Adult; Birth Weight; Female; Gestational Age; Humans; Infant, Newborn; Infant, Small for Gestational Age; Pre-Eclampsia; Pregnancy; Thromboxane B2

Prostacyclin has a vasodilating effect on pulmonary vessels, whereas thromboxane A2 results in vasoconstriction. This study was designed to test the hypothesis that recurrent central apneas in preterm infants are correlated with a reduced prostacyclin to thromboxane A2 ratio. Twelve preterm infants with clinical events of apneas were matched with 12 control infants. Urinary concentration of 2,3-dinor-6-keto-PGF1alpha and 2,3-dinor-TxB2 was determined, and the ratio correlated with the number of central apneas (>20s) measured in overnight polygraphy. The number of central apneas >20s/12h was 97.4 (SE 7.8) in the study group, and 47.3 (SE 6.6) in the control group (p = 0.001). There was a significant correlation between the number of central apneas and the 2,3-dinor-6-keto-PGF1alpha/2,3-dinor-TxB2-ratio in all infants combined (r = -0.72, p < 0.0001) as well as in the two subject groups. Central apneas in premature infants are correlated with an decreased prostacyclin to thromboxane A2 ratio. The underlying pathomechanism may be increased intrapulmonary shunts with reflexive central apneas due to reduced pulmonary oxygenation.

Topics: 6-Ketoprostaglandin F1 alpha; Apnea; Birth Weight; Epoprostenol; Gestational Age; Humans; Infant, Newborn; Infant, Premature; Polysomnography; Prostaglandins F; Thromboxane A2; Thromboxane B2

Low dose Aspirin in pregnancy reduces the incidence of intra uterine growth retardation (IUGR) and pregnancy induced hypertension (PIH) in women at risk for these complications. To investigate if this drug, even in a low dose, could expose the newborn to hemorrhagic complications, we studied ten neonates whose mothers had been taking 50 mg/day of Aspirin from the 12th week of pregnancy until delivery and compared them with eight newborns whose mothers didn't take the drug. No hemorrhagic complications (emathemesis, ecchymoses or petechiae, subconjunctival hemorrhage, cephaloematomas etc.) were observed in the fetuses exposed to Aspirin or in the control group. No hemorrhagic lesions were found by ultrasound brain scan on the fourth day of life. Newborns exposed to Aspirin showed a significantly lower thromboxane concentration on the first day of life (median 73 ng/ml versus 217 ng/ml); however on the fourth day the level of serum thromboxane in the cases exposed reached the values of the unexposed ones (median 146 ng/ml versus 143 ng/ml). In conclusion low dose Aspirin in pregnancy can be considered a safe drug without and adverse effect on the newborn.

Topics: Aspirin; Birth Weight; Cerebral Hemorrhage; Female; Fetal Blood; Fetal Growth Retardation; Gestational Age; Humans; Hypertension; Infant, Newborn; Maternal-Fetal Exchange; Pregnancy; Pregnancy Complications, Cardiovascular; Reference Values; Thromboxane B2

The increased TXA2 and decreased PGI2 seen in the toxemic pregnancies suggest the imbalance of arachidonic metabolism. Thromboxane (TX) B2 was thought to be a suitable parameter of TXA2 production in vivo. However, recently it has come to be recognized that a large amount of TXB2 is readily produced and decomposed to 11-dehydro TXB2 during blood sampling. In this study, a new RIA method was established, capable of measuring the urinary 11-dehydro TXB2 level. (1) The samples were measured with a 125I-labeled RIA kit for 11-dehydro TXB2 (Amersham, U.K.). In this assay system a highly specific antibody to 11-dehydro TXB2 was used. (2) The values for urinary 11-dehydro TXB2 measured by the RIA correlated closely with those measured by gas chromatography-mass spectrometry (r = 0.95). (3) The mean 11-dehydro TXB2 value in non pregnant was 2.62 +/- 1.71ng/mg Cr, The mean values in the first, second and third trimesters of pregnancy were 4.57 +/- 2.45ng/mg Cr, 5.75 +/- 2.81ng/mg Cr, 6.33 +/- 2.60ng/mg Cr, respectively. (4) The mean 11-dehydro TXB2 value in toxemic pregnancy was 4.13 +/- 1.86ng/mg Cr, which was significantly lower than that in normal pregnancies. (5) There was a significant negative correlation (p less than 0.0001) between the urinary 11-dehydro TXB2 concentration and the blood pressure.

Topics: Birth Weight; Female; Humans; Organ Size; Pre-Eclampsia; Pregnancy; Radioimmunoassay; Reagent Kits, Diagnostic; Thromboxane B2