Low molecular weight heparin therapy during pregnancy is associated with elevated circulatory levels of placental growth factor.

INTRODUCTION: Low molecular weight heparin (LMWH) has been shown to be effective in decreasing the recurrence of placenta-mediated complications of pregnant women. The aim of this study was to determine the effect of LMWH on circulating levels of soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PLGF) in pregnant women who required anticoagulation therapy. METHODS: A longitudinal prospective cohort study was performed including pregnant women in whom anticoagulation therapy by LMWH during pregnancy was clinically indicated (n = 33). Healthy pregnant women, matched for gestational age, who did not require thromboprophylaxis served as controls (n = 29). Maternal plasma samples were obtained throughout gestation every 4 weeks and stored at -70 °C. Maternal plasma concentrations of sFlt-1, sEng and PLGF were determined by ELISA and compared between the two groups. RESULTS: Patients treated with LMWH had significantly increased circulatory levels of PLGF during the third trimester compared with controls (28-34 weeks: 719.2 pg/ml vs 558.6 pg/ml at, p < 0.01; 35-40 weeks: 975.6 pg/ml vs 511.2 pg/ml, p < 0.01, respectively). In contrast, circulatory levels of sFlt-1 and sEng were similar between the LMWH treatment group and controls throughout gestation. Consistent with these findings, the ratio of sFlt-1/PLGF was lower in patients treated with LMWH compared to controls (28-34 weeks: 1.9 vs 7.2, p < 0.05; 35-40 weeks: 5 vs 12.9, p < 0.05, respectively). DISCUSSION: Anticoagulation treatment of pregnant women with LMWH is associated with a pro-angiogenic state. These findings may explain the effectiveness of LMWH in the prevention of placenta-mediated complications of pregnancy.

Antiphospholipid antibodies in neonates with stroke--a unique entity or variant of antiphospholipid syndrome?

OBJECTIVE: YB current affiliation: Department of Pediatrics, Hadassah-Hebrew University Medical Center, Mount Scopus, Israel YB and MJS contributed equally to the study and should be regarded as joint first authors on this manuscript. Antiphospholipid syndrome (APS) may present with thrombosis and persistently elevated titers of antiphospholipid antibodies (aPL) in the neonatal period. Our aim was to investigate the course and impact of elevated titers of aPL in a cohort of infants presenting with either perinatal arterial ischemic stroke (PAS) or cerebral sinus vein thrombosis (CSVT) during the perinatal period. STUDY DESIGN: Sixty-two infants with clinically and radiologically confirmed PAS or CSVT presenting in the neonatal period underwent thrombophilia workup that included Factor V Leiden (FVL), PII20210A mutation, MTHFR 677T polymorphism, protein C, protein S, aPL namely either circulating lupus anticoagulant (CLA), anticardiolipin antibodies (aCL) or anti-ß2-glycoprotein-1 (ß2GP1). Mothers also underwent thrombophilia workup. RESULTS: Twelve infants with persistently elevated aPL were prospectively followed. Infants with positive aPL showed no concordance with presence of maternal aPL. All children were followed for a median of 3.5 years (range: nine months to 19 years) with repeated aPL testing every three to six months. Anticoagulant therapy initiation and therapy duration varied at the physician's discretion. In 10/12 cases aPL decreased to normal range within 2.5 years; one female with complex thrombophilia risk factors required indefinite prolonged anticoagulation. None of the infants showed recurrent thrombosis or any other APS manifestations, despite lack of prolonged anticoagulation. CONCLUSIONS: The presence of aPL may be important in the pathogenesis of cerebral thrombosis in neonates. Nevertheless, the nature of thrombophilia interactions in this period and their therapeutic impact warrants further investigation.

Impaired platelet function in neonates born to mothers with diabetes or hypertension during pregnancy.

OBJECTIVE: In a recent pilot study, platelet function of 4 neonates born to mothers with pregnancy-induced hypertension (PIH) was found to display lower platelet adhesion compared to healthy neonates. The present study aimed at confirming and validating these findings. STUDY DESIGN: Platelet adhesion was measured using a Cone Platelet Analyzer (CPA). The platelet function in the cord blood of 35 term infants born to mothers with PIH or gestational diabetes (GD) was compared with the platelet function of 196 infants born to healthy mothers. All neonates were monitored for perinatal complications until hospital discharge. RESULTS: Neonates born to mothers with PIH and with GD displayed poorer platelet function, with decreased platelet surface coverage as tested by CPA (control group 8.53+/-3.81%; PIH: 5.9+/-3.91%, p=0.003; GD: 6.64+/-3.64%, p=0.005). No association was found between CPA values and post-natal complications. CONCLUSIONS: Maternal PIH or GD is associated with impaired platelet function in neonates. The clinical impact of these findings is yet to be studied.

Fetal cardiac calcifications: report of four prenatally diagnosed cases and review of the literature.

Fetal cardiac calcifications are defined as diffuse hyperechogenicities in the different layers of the heart. This is an uncommon fetal ultrasound finding associated with significant myocardial dysfunction. We report four cases with massive fetal myocardial calcifications detected on prenatal ultrasound at 18-22 weeks' gestation and associated, in all cases, with significant cardiac dysfunction. Detailed fetal echocardiographic evaluation, chromosome analysis, and an extensive search for intrauterine infection as a cause of these abnormalities, were carried out on all cases. A thorough autopsy was performed on all deceased fetuses and postnatal investigation of the sole survivor was performed. Two of our patients chose to interrupt their pregnancies, one fetus suffered intrauterine demise, and one child was born alive. In all of our cases the karyotypes were normal, and no specific infectious etiology or maternal autoantibody was noted. Histopathology findings in the non-survivors included myo- and epicardial calcification maximal at the base of the heart. The living child has findings suggestive of an intrauterine infection, although no infectious entity was identified. Long-term follow-up showed sensorineural hearing loss and severe developmental delay.

Effects of maternal hyperoxia with and without normocapnia in uteroplacental and fetal Doppler studies.

OBJECTIVE: One hundred percent oxygen is given in pregnancy to improve fetal oxygenation, yet has been shown in both animal and human studies ex utero to increase cerebral vascular resistance. Adjusting end-tidal pCO2 (ET-pCO2) levels to normocapnic levels during hyperoxygenation offsets this effect in non-pregnant individuals. We aimed to evaluate the effect of maternal hyperoxygenation with and without maintaining normocapnia on the fetal and uteroplacental circulations in healthy near-term human pregnancies. METHODS: Eight healthy pregnant women, serving as their own controls, sequentially breathed room air, breathed 100% oxygen, and underwent normocapnic hyperoxygenation (NH) in a three-phase experiment involving a tight-fitting facemask. Each phase lasted 10-15 min. After steady state had been reached, peak velocities and pulsatility index (PI) values were obtained from the uterine, umbilical and fetal middle cerebral arteries (MCA) by color/pulsed Doppler. In addition, maternal ventilation and ET-pCO2 were monitored. RESULTS: One hundred percent oxygen induced maternal hyperventilation and hypocapnea. Uterine artery PI and peak systolic velocities were stable during 100% oxygen. In contrast, during NH uterine artery PI values decreased by 21% (P=0.04). Umbilical artery PI and peak velocities were stable during 100% oxygen; PI increased by 16% during NH (P=0.056), with no change in peak velocities. Peak MCA velocities decreased by 8% during 100% oxygen, and by 9.6% during NH, while MCA-PI decreased by 13% during 100% oxygen and by 21% during NH (P=0.06). CONCLUSIONS: Maternal and fetal circulations exhibit divergent responses to 100% oxygen and NH. While no change is observed in the uteroplacental circulation on 100% oxygen, decreased resistance and increased flow velocity are evident during NH. Increased umbilical artery PI during NH with no change in absolute velocities may suggest a reduction in fetoplacental blood flow. Maintaining normocapnia during hyperoxygenation does not appear to beneficially influence the circulation of the near-term human fetus as it does in non-pregnant individuals.

Prognostic value of placental ultrasound in pregnancies complicated by absent end-diastolic flow velocity in the umbilical arteries.

Our objective was to evaluate the utility of gray-scale placental ultrasound for the detection of pathological lesions in the placentas of preterm pregnancies with abnormal fetoplacental blood flow (defined by absent or reversed end-diastolic flow velocities [ARED] in the umbilical arteries) before 32 weeks of gestation. Sixty consecutive structurally and chromosomally normal singleton pregnancies were evaluated. Pre-defined criteria were used to describe placental appearances using gray-scale real-time ultrasound. Proximal uterine artery Doppler waveforms were recorded using pulsed and color Doppler ultrasound. Each patient had a thrombophilia profile. Following delivery, a single perinatal pathologist reviewed each placenta at a gross and microscopic level blinded to the placental ultrasound findings. Placental shape or texture was abnormal on gray-scale ultrasound in 43/59 (73%) and echogenic cystic lesions (ECL) were found in 16 (27%). Uterine artery Doppler was abnormal in 47/60 (78%) cases. Thirty-eight pregnancies were subsequently delivered by planned Caesarean section in the fetal and/or maternal interest (birthweights 540-2300 g, mean gestational age 30.6 weeks) and 21 pregnancies resulted in the vaginal delivery of a stillborn fetus where fetal weight and/or gestational age did not justify Caesarean section (birthweights 85-600 g, mean gestational age 24.9 weeks). ECL had a low positive predictive value for both villous infarcts (63%) and for focal/massive perivillous fibrin deposition (40%). Nevertheless, the combination of abnormal uterine artery Doppler and abnormal gray-scale findings (abnormal placental morphology or ECL) was strongly predictive of stillbirth (17/21; sensitivity 81%, PPV 52%, p = 0.006 Fisher's exact test). Pregnancies with ARED in the umbilical arteries have a high perinatal mortality associated with pathology of the placental villi. Ultrasound examination of the placenta and its maternal blood supply may contribute to the perinatal management of these pregnancies.

Ultrasound diagnosis of severe thrombotic placental damage in the second trimester: an observational study.

OBJECTIVES: To screen women with uteroplacental insufficiency between 18 and 26 weeks' gestation for sonographic evidence of destructive placental lesions, to observe the effect of low molecular-weight heparin (LMWH) in these cases, and to compare the outcome with similar but untreated controls. METHODS: We screened 180 women at high risk for placental damage using 16-week maternal serum screening (alpha-fetoprotein and human chorionic gonadotropin), placental shape and texture, and uterine artery Doppler waveforms at the 18-20-week level II examination. Serial gray-scale examinations of placental texture were performed at 22, 24 and 26 weeks. LMWH was offered to women with ultrasound evidence of destructive placental lesions in the absence of intrauterine growth restriction and/or pre-eclampsia. RESULTS: We prospectively identified six women (3.3%) with abnormal maternal serum screening and uterine artery Doppler in whom abnormal placental texture (echogenic cystic lesions) suggestive of destructive lesions in the placental parenchyma was found either at the 18-20-week ultrasound examination (n = 4), or by 26 weeks of gestation (n = 2). All six received LMWH and had live births (gestational age at delivery, 33-37 weeks; birth weight, 1000-3200 g). A further 14 women were referred with similar multiparameter evidence of placental damage at or after 26 weeks, outside the screening study. All had significant fetal growth restriction and were therefore not offered heparin. In 9/14 cases there was a perinatal death. Ischemic and/or thrombotic placental pathology was confirmed in each case, but no maternal thrombophilia disorders were identified in the 20 women. CONCLUSIONS: Integrated biochemical and ultrasound testing of placental function at 16-20 weeks of gestation, followed by serial placental gray-scale ultrasound, may be an effective method of identifying a subset of pregnancies at high risk of adverse pregnancy outcome due to destructive lesions in the placental parenchyma. This strategy of identifying thrombo-occlusive placental lesions before the development of pregnancy complications may prove useful in the design of trials to study the effectiveness of LMWH in the prevention of clinical complications resulting from thrombo-occlusive placental disease.

Hematopoietic progenitor cells as targets for non-invasive prenatal diagnosis: detection of fetal CD34+ cells and assessment of post-delivery persistence in the maternal circulation.

Culture expansion of fetal cells from the maternal circulation will provide an increased number of cells for non-invasive prenatal diagnosis. Hematopoietic CD34+ cells are potential candidates for this application. More information is needed regarding the frequency of these cells and the phenomenon of post-delivery persistence in the maternal circulation. In this study we assessed the number of fetal CD34+ cells in the maternal circulation, the effect of culture expansion on the number of fetal cells and the persistence of fetal CD34+ cells from previous pregnancies. Fetal cells were identified by the presence of Y-chromosome sequences detected by FISH and nested PCR. Fetal CD34+ cells were detected in all samples from women carrying a male fetus. A low number of residual fetal cells from previous pregnancies was detected (1-3 XY cells in 20 ml blood) in less than 1/3 of the samples from both non-pregnant women and those pregnant with a female fetus. Culturing of CD34+ cells resulted in a significant increase in fetal cell numbers. However, the number of fetal cells persisting from previous pregnancies also increased after culture. It is proposed that information derived from CD34+ cells could potentially support data derived from other cell types for more accurate non-invasive prenatal diagnosis.

Fetal hemoglobin-expressing nucleated red blood cell frequencies in pregnancies with intrauterine growth restriction.

The objective of this study was to examine whether there is a difference in the frequency of fetal erythroblasts in maternal blood in pregnancies with intrauterine growth restriction (IUGR) as compared with normal pregnancies. Nucleated red blood cells (NRBC) were isolated from nine pregnant women with ultrasonically diagnosed IUGR (estimated fetal weight less than the 10th percentile for gestational age) and 11 women with appropriately grown fetuses. The frequency of fetal hemoglobin-expressing NRBC (FHE-NRBC) in maternal blood was evaluated by triple density centrifugation and anti-CD71+ magnetic cell sorting, followed by indirect immunocytochemistry for the detection of gamma-chain fetal hemoglobin. The number of FHE-NRBC in 10 ml maternal blood in the IUGR group was higher than in the control group (454.5 vs 56.7, p<0.05). This difference was even more pronounced when FHE-NRBC frequency was calculated relative to the total CD71+ population of cells. There were 118.9 FHE-NRBC per 10(5) CD71+ cells in IUGR pregnancies as compared with 11.5 cells in the control group (p<0.01). There was no difference in the total mean number of CD71+ mononuclear cells between the two groups. The observed increase in the frequency of fetal cells in the maternal circulation found in IUGR pregnancies may be a result of an increase in total NRBC in the fetal circulation or rather of abnormalities in placental structure. This phenomenon may assist in identifying pregnancies at risk for this complication early in the course of the pregnancy, even before actual growth restriction presents itself ultrasonically.

Neonatal outcome in growth-restricted versus appropriately grown preterm infants.

The objective of this paper is to examine whether growth-restricted preterm infants have a different neonatal outcome than appropriately grown preterm infants. All consecutive, singleton preterm deliveries between 27-35 weeks' gestation were included over a 4-year period. Infants with congenital anomalies and infants of diabetic mothers were excluded. Infants were categorized as small-for-gestational-age (SGA) when birth weight was at or below the 10th percentile, and appropriate-for-gestational-age (AGA) when between the 11th and 90th percentiles. Outcome variables included: neonatal death, respiratory distress syndrome (RDS), sepsis, intraventricular hemorrhage (IVH), and necrotizing enterocolitis (NEC). Neonatal morbidity and mortality were examined by univariate and stepwise multivariate logistic regression analyses. Factors controlled for during the analysis included: maternal age; gestational age; mode of delivery; presence of preeclampsia, HELLP syndrome, prolonged premature rupture of membranes (PROM), placental abruption, placenta previa, prenatal steroid exposure, infant gender, and low Apgar score. Seventy-six infants were included in the SGA group and 209 in the AGA group. SGA infants had a higher mortality rate (p = 0.003). They also had more culture-proven sepsis episodes (p = 0.001). No differences were found with respect to the other outcomes. The results were similar when analyzed separately for the group of infants born at or below 32 weeks' gestation. Growth-restricted preterm infants were found to have both higher mortality and infection rates compared with AGA preterm infants. Growth restriction in the preterm neonate was not found to protect against other neonatal outcomes associated with prematurity. When considering elective preterm delivery for this high-risk group of pregnancies, the increased risks in the neonatal period should be taken into account.

Adjustment of magnesium sulfate infusion rate in patients with preterm labor.

OBJECTIVE: Our purpose was to investigate factors that might influence serum magnesium levels during intravenous magnesium sulfate tocolytic therapy. STUDY DESIGN: Thirty-three women receiving magnesium sulfate for preterm labor participated in this prospective, observational study. Gestational ages were 24 to 34 weeks. Four groups of women were identified according to the maintenance magnesium infusion rate required for arresting preterm labor after 5 g of therapy induction: 1.5, 2, 2.5, and 3 g/h. Serum magnesium samples were drawn after a predefined period of at least 18 hours of arrested preterm labor, at a minimum of every 6 hours. Variables examined included serum albumin; serum protein; serum ionized calcium; serum creatinine; creatinine clearance; 24-hour urine output; maternal height, weight, body surface area; and body mass index. RESULTS: By use of a multivariate stepwise regression model we identified four variables that independently and significantly contributed to the model: magnesium infusion rate (P < .001); total serum protein level (P < .001); serum creatinine level (P = .009); and maternal weight squared (P = .026). Seventy-two percent of the variance was accounted for by use of these parameters. A predictive linear model, developed to relate these factors, produced the following formula: Suggested magnesium infusion rate = 0.89 x Serum magnesium concentration (mg/dL) - 3.16 x Serum creatinine (mg/dL) - 0.66 x Serum total proteins (g/dL) + 0.0001 x (maternal weight)2 (kg) + 2.30. CONCLUSIONS: Serum creatinine, serum protein, and maternal weight can be used to adjust the dose of magnesium sulfate in patients with premature labor to achieve therapeutic serum levels of magnesium more rapidly and safely.