Severe pre-eclampsia remote from term: what to expect of expectant management.

OBJECTIVE: To describe the duration of expectant management and the indications for termination of expectant management of pregnancies complicated by severe pre-eclampsia remote from term. STUDY DESIGN: We identified pregnancies complicated by severe pre-eclampsia diagnosed between 24 weeks and 31 weeks 6 days at our institution in 1991-98. Pertinent clinical data were obtained from review of maternal and neonatal charts. Comparison of patients was based on the duration of time from admission to delivery: < 48 h (group 1), 48 h to 7 days (group 2), and > or = 7 days (group 3). RESULTS: A total of 142 women met all study criteria. Seventy-nine (55.6%) women were delivered within 48 h, 42 (29.6%) between 48 h and 7 days, and 21 (14.8%) at > or = 7 days from diagnosis. Of group 1 patients (< 48 h), 59 (74.7%) were delivered for maternal indications while 20 (25.3%) were delivered for fetal indications. Of group 2 patients (48 h to 7 days), 35 (83.3%) were delivered for maternal indications while seven (16.7%) were delivered for fetal indications. Of group 3 patients (> or = 7 days), 16 (76.2%) were delivered for maternal indications while five (23.8%) were delivered for fetal indications. There were no significant differences in the indications for delivery based on the duration from admission to delivery. CONCLUSIONS: Despite an aggressive approach towards expectant management of preterm pregnancies complicated by severe pre-eclampsia, most patients were delivered within 48 h for maternal indications.

The effect of intrapartum magnesium sulfate therapy on fetal cardiac troponin I levels at delivery.

OBJECTIVE: To determine whether intrapartum magnesium sulfate (MgSO4) therapy for seizure prophylaxis in pre-eclampsia-eclampsia is associated with biochemical evidence of subacute fetal myocardial damage at delivery. STUDY DESIGN: Troponin I, a cardiac-specific protein used to detect myocardial injury, was measured from the umbilical vein at delivery in term pregnancies complicated by pre-eclampsia and uncomplicated control pregnancies. Women with pre-eclampsia received intravenous MgSO4 as a 6-g load followed by 2 g/hour until delivery. Clinical characteristics and fetal troponin levels were compared between groups. RESULTS: There was no difference in troponin I concentrations between term patients with intrapartum MgSO4 therapy and controls who did not receive MgSO4 (median 0.86 ng/ml, range 0.72-1.10 vs. 0.89 ng/ml, range 0.68-1.50; p = 1.0). There was also no statistically significant difference in the number of patients with a troponin I level of > or = 1.0 ng/ml between groups (30.8% (4/13) vs. 15.4% (4/26); p = 0.4). CONCLUSIONS: Our findings suggest that, in term fetuses that are not growth impaired, exposure to intrapartum MgSO4 is not associated with subacute myocardial injury.

Labor induction for the preterm severe pre-eclamptic patient: is it worth the effort?

OBJECTIVE: The purpose of this study was to examine the success rate of labor induction in patients with severe pre-eclampsia delivered at < or = 34 weeks' gestation; to identify factors associated with its success; and to evaluate neonatal outcomes based on induction success or failure. METHODS: We identified pregnancies complicated by severe pre-eclampsia delivered at < or = 34 weeks' at our institution from 1991 to 1998. Women who underwent labor induction and had successful vaginal delivery were compared to those who underwent labor induction, but required Cesarean delivery. Multiple logistic regression analyses were performed to assess factors associated with successful induction and neonatal outcome. RESULTS: Over the 7-year study period, there were 215 patients meeting the criteria. Sixty-four (29.8%) did not undergo a labor attempt; 69 of 151 (46%) women who underwent labor induction achieved vaginal delivery. Labor induction was successful in 0%, 6.6%, 35.3% and 68.5% of cases at 24-26, 27-28, 29-31 and 32-34 weeks' gestation, respectively. By logistic regression the only factor positively associated with successful induction was gestational age at delivery (p = 0.001), while induction for non-reassuring fetal testing was inversely associated (p = 0.02). Induction attempt, failed induction and delivery mode were not associated with increased neonatal morbidity. CONCLUSIONS: In women with severe pre-eclampsia remote from term, attempted labor induction did not appear to increase neonatal morbidity, but was rarely successful at < 28 weeks.

Adrenomedullin levels in normal and preeclamptic pregnancy at term.

OBJECTIVE: To describe maternal plasma levels of adrenomedullin (AM), a hypotensive and natriuretic peptide, in normal and preeclamptic women at term. STUDY DESIGN: Maternal plasma AM levels were determined in 13 preeclamptic and 15 normotensive primigravidas by radioimmunoassay. Plasma samples were obtained with the patients in the lateral recumbent position before the administration of any medications. RESULTS: Women with preeclampsia had significantly elevated AM levels when compared with normotensive controls (42.3 +/- 10.5 pg/mL versus 16.9 +/- 3.1 pg/mL, P < .011). CONCLUSION: In this pilot study, AM levels were significantly increased at term in preeclamptic women.

Maternal thrombocytopenia. Predicting neonatal thrombocytopenia with cordocentesis.

OBJECTIVE: To evaluate the efficacy of cordocentesis for predicting fetal thrombocytopenia in the presence of maternal thrombocytopenia. STUDY DESIGN: We studied platelet counts obtained by cordocentesis from 42 consecutive immune thrombocytopenia purpura patients. Platelet counts were obtained on 36 neonates, and the statistical analysis included only these infants. Presence of maternal antiplatelet antibodies, interval from fetal sampling to delivery, neonatal platelet counts and outcome were evaluated. Thrombocytopenia was defined as a platelet count < or = 150,000/microL, with < or = 50,000 microL considered severe. RESULTS: No procedure-related complications occurred. A moderate correlation existed between fetal and neonatal platelet counts (r = .48, P = .003), unrelated to the interval between sampling and delivery. Eight of 36 fetuses had thrombocytopenia, and 4 were confirmed at delivery. Two neonates had thrombocytopenia at birth but not at cordocentesis. Two neonatal thrombocytopenia cases were severe. Neither was categorized as severe antenatally. The sensitivity, specificity, and positive and negative value for predicting severe neonatal thrombocytopenia were 0%, 100%, 0%, and 94%, respectively. Grade 1 intraventricular hemorrhages occurred in two neonates delivered at 35 weeks' with normal platelet counts. CONCLUSION: Cordocentesis was not reliable in predicting severe neonatal thrombocytopenia; however, the high negative predictive value was reassuring. The clinical utility of the technique and the population in which it should be used remain to be defined.

Serum ionized magnesium levels in normal and preeclamptic gestation.

OBJECTIVE: To compare serum levels of ionized and total magnesium with those of ionized calcium, total calcium, sodium, and potassium over the course of pregnancy in normal women and in women who develop preeclampsia. METHODS: We collected venous serum samples from 31 pregnant women during their first, second, and third trimesters. Gestational ages ranged from 6 to 37 weeks. Samples were analyzed for ionized and total magnesium, ionized and total calcium, sodium, and potassium using a biomedical chemistry analyzer. Data were analyzed with repeated-measures analysis of variance and two-way repeated-measured analysis of variance. RESULTS: In 22 normal pregnant women, both serum ionized and total magnesium levels decreased significantly with increasing gestational age. No changes in sodium, potassium, or ionized or total calcium were observed. Nine of the 31 subjects developed preeclampsia by term; serum total magnesium levels decreased significantly by the second trimester in these women compared with those of normal pregnant women. CONCLUSION: Our results provide evidence of decreases in ionized and total magnesium levels with increasing gestational age during normal pregnancy, as well as evidence of a magnesium disturbance in women who later develop preeclampsia. Future studies of magnesium balance in women at risk for developing complications of pregnancy are indicated.

Effect of magnesium sulfate on excitatory amino acid receptors in the rat brain. I. N-methyl-D-aspartate receptor channel complex.

OBJECTIVE: Our purpose was to determine the effect of peripherally administered magnesium sulfate on the N-methyl-D-aspartate receptor channel complex in the rat central nervous system. STUDY DESIGN: Six rats were injected intraperitoneally with 270 mg/kg magnesium sulfate, followed by 27 mg/kg every 20 minutes for 4 hours. Controls (n = 6) received saline solution. Six rats received intraperitoneal injections of magnesium sulfate (270 mg/kg) every 4 hours for 24 hours and 6 received saline solution. Six rats received intraperitoneal magnesium sulfate (270 mg/kg) every 12 hours for 2 weeks and 6 received saline solution. Rats were subsequently perfused and killed and their brains dissected and frozen. Cryostate sections were taken, labeled in vitro by one of three ligands for autoradiography assay, and mounted on tritium-sensitive film for 4 weeks. The ligands were tritiated glutamate agonist, N-methyl-D-aspartate binding site; tritiated glycine agonist, glycine binding site; and tritiated MK-801 noncompetitive antagonist, channel site. Optical density measurements of binding of 11 brain regions on each section were performed with an image analyzing system. RESULTS: N-methyl-D-aspartate receptor binding in the hippocampus was higher than in all other brain regions in all three experiments. Systemic administration of magnesium sulfate for 24 hours resulted in reduced tritiated glutamate binding, whereas long-term administration (2 weeks) resulted in significantly decreased tritiated glycine binding in all brain regions sampled. Binding of tritiated MK-801 was significantly increased in both short- and intermediate-term administration of magnesium sulfate. CONCLUSIONS: These data suggest that short-term magnesium sulfate administration results in increased inhibition of the ion channel. This effect is also continued with prolonged treatment, along with decreased sensitivity of the N-methyl-D-aspartate receptor channel complex to its agonists glutamate and glycine. This proposed time-dependent, twofold effect may provide insight into the mechanisms of magnesium sulfate's central anticonvulsant effect.

Effect of magnesium sulfate on excitatory amino acid receptors in the rat brain. II. Kainate and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors.

OBJECTIVE: Our purpose was to determine the effect of peripherally administered magnesium sulfate on kainate and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors in the rat brain. STUDY DESIGN: Six rats were injected intraperitoneally with 270 mg/kg magnesium sulfate, followed by 27 mg/kg every 20 minutes for 4 hours. Controls (n = 6) received saline solution. Six rats received intraperitoneal injections of magnesium sulfate (270 mg/kg) every 4 hours for 24 hours and six received saline solution. Then 6 rats received intraperitoneal magnesium sulfate (270 mg/kg) every 12 hours for 2 weeks and six received saline solution. Rats were subsequently perfused and killed; their brains were dissected and frozen. Cryostat sections were labeled in vitro for autoradiography assay. The ligands used were tritiated kainate agonist, kainate binding site; tritiated alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid agonist, and tritiated 6-cyano-7-nitroquinoxaline-2,3-dione antagonist, both at the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid binding site. RESULTS: Magnesium sulfate caused decreased binding of the agonist to the kainate receptor recognition site after both short-term and intermediate-term systemic administration, whereas long-term treatment resulted in increased binding. No significant consistent effect on the binding to the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor agonist site was recorded after magnesium administration. The receptor antagonist showed an increased binding after short-term treatment. Long-term administration also resulted in increased binding of the antagonist, an effect that was limited to the hippocampus. CONCLUSIONS: These data suggest down-regulation of the kainate receptor population during short- and intermediate-term magnesium sulfate treatment. However, long-term inhibition by magnesium resulted in up-regulation of the receptor population. The results may also reflect an increased inhibitory effect of magnesium sulfate on the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor.

Effects of tumor necrosis factor-alpha on human trophoblast cell adhesion and motility.

PROBLEM: Adhesive interaction between trophoblast cells and uterine endometrial basement membrane is one of the critical processes in embryo implantation. This interaction is directly or indirectly regulated by hormones, growth factors, and cytokines. Since tumor necrosis factor-alpha (TNF-alpha) is synthesized by both decidual and trophoblast cells, we hypothesized that TNF-alpha may play a regulatory role in trophoblast cell invasion. To test this hypothesis, we have used in vitro models to determine the effect of TNF-alpha on human trophoblast cell adhesion and motility, two major steps in trophoblast invasion. METHODS: The effect of TNF-alpha on the motility of extended-lifespan first trimester trophoblasts (HTR) and JEG-3 choriocarcinoma cells was tested using the phagokinetic track motility assay. An in vitro adhesion assay was used to determine the effect of TNF-alpha on the adhesion of HTR and JEG-3 cells to laminin, a major basement membrane component. In addition, the effect of TNF-alpha on the surface expression of the laminin receptor beta 1 integrin subunit was examined using flow cytometry. RESULTS: HTR or JEG-3 cells strongly adherent to laminin which was not significantly altered by TNF-alpha treatment. We also measured the effect of TNF-alpha on the surface expression of beta 1 integrin on HTR and JEG-3 cells; no difference was observed between control and treatment groups. Interestingly, the motility of both HTR and choriocarcinoma JEG-3 cells was significantly inhibited by TNF-alpha. CONCLUSIONS: The role of TNF-alpha in human embryo implantation is currently unknown. Our data demonstrate that TNF-alpha does alter trophoblast cell adhesion to laminin, but significantly inhibits trophoblast cell motility in vitro, suggesting that TNF-alpha may play a regulatory role in trophoblast cell invasion.

Brain ionized magnesium and calcium levels during magnesium supplementation and deficiency in female Long-Evans rats.

OBJECTIVE: To examine the effect of changes in the state of magnesium balance on ionized magnesium and ionized calcium in serum and brain tissue of female rats. METHODS: Forty-two mature rats were used in the study. To induce hypermagnesemia, 12 rats received 270 mg/kg of magnesium sulfate intraperitoneally, followed every 20 minutes for 2 hours with 27 mg/kg magnesium sulfate. Ten control rats received an equal volume of saline. To induce hypomagnesemia, ten rats were placed on a magnesium-deficient diet for 4 (n = 5) or 8 (n = 5) days. Ten control rats were placed on basal diets of equal duration. Following treatment, rats were euthanized and serum and brain tissue were analyzed for ionized magnesium and calcium content. RESULTS: Hypermagnesemia produced a significant increase in serum ionized magnesium (P < .05) and calcium (P < .05). In addition, brain levels of ionized magnesium were significantly increased (P < .05), whereas calcium levels significantly decreased (P < .05) particularly in the hippocampus, parietal cortex, and cerebellum. Hypomagnesemia induced by 4 days on a magnesium-deficient diet led to decreased serum ionized magnesium (P < .01) and total magnesium (P < .05) but did not affect brain magnesium levels. Brain levels remained unaltered even after 8 days of hypomagnesemia. Serum and brain ionized calcium were not affected during peripheral magnesium deficiency. CONCLUSION: During peripheral magnesium deficiency, brain levels of ionized magnesium and ionized calcium are tightly regulated and appear unaffected. However, central levels of these electrolytes are altered under hypermagnesemic conditions. Thus, magnesium administration may change biologically active portions of magnesium and calcium in the brain.

Fetal ionized magnesium levels parallel maternal levels during magnesium sulfate therapy for preeclampsia.

OBJECTIVE: Little is known about ion regulation in fetuses. Our aim was to determine the effects of magnesium sulfate therapy on ionized (bioactive) magnesium in the cord blood of pregnancies complicated by preeclampsia. STUDY DESIGN: Seventy-four pregnant women were studied (37 preeclamptic and 37 controls matched for maternal age, gravidity, and gestational age). The preeclamptic women received intravenous magnesium sulfate 6 gm load followed by 2 gm/hour for > or = 4 hours; controls were not preeclamptic and received no magnesium. Maternal venous and fetal cord blood samples were obtained from study and control patients and were analyzed for sodium, potassium, total magnesium, ionized magnesium, total calcium, and ionized calcium. Comparisons between the groups were made and analyzed by the Mann-Whitney U test. RESULTS: There were no significant differences between the treatment and control group cord samples with respect to sodium or potassium. However, total magnesium and ionized magnesium were significantly elevated (p < 0.001) in cord samples of the treated group. At the same time ionized calcium and total calcium were reduced. Interestingly, ionized calcium levels were lower in preeclamptic women before magnesium sulfate therapy was begun, whereas total calcium levels were not different. Importantly, there was no difference between maternal and fetal ionized magnesium levels in either treatment or control groups. CONCLUSIONS: In preeclamptic women undergoing magnesium sulfate therapy, ionized magnesium levels in cord blood parallel maternal levels. Before magnesium therapy ionized calcium levels were lower in preeclamptic women than in matched controls. In the presence of elevated magnesium levels ionized calcium appears to be tightly regulated.

The effect of capitated and fee-for-service remuneration on physician decision making in gynecology.

OBJECTIVE: To evaluate the variations in physician behavior leading to performance of gynecologic surgical procedures related to fee-for-service and capitation reimbursement systems. METHODS: This study compared the physician practice utilization of surgical services for fee-for-service and capitated contract reimbursement systems within a gynecology clinic. Attending gynecologists were reimbursed on a fee-for-service basis for all surgical services performed during a 6-month interval; subsequently, the same physicians were reimbursed on a capitated basis for 6 months and received a fixed payment for the clinical and surgical services provided. RESULTS: Three thousand seven hundred eighty consecutive outpatient gynecology visits were evaluated at the university gynecology clinic during 1994. We found a 15% overall decrease in the number of surgical procedures that were performed during the capitated reimbursement period compared with the fee-for-service time interval. The procedure most responsible for the reduction of surgical services was elective sterilization by laparoscopy, which underwent a statistically significant decrease (P < .01). CONCLUSION: The remuneration system in our review seemed to affect physician decision making for only the most elective procedures, whereas physicians maintained similar practice patterns for more severe conditions. Fee-for-service seems to encourage, whereas capitation seems to discourage, gynecologist from performing elective procedures.

Brain natriuretic peptide and cyclic guanosine-3',5' monophosphate in pre-eclampsia.

The objective of this study is to determine the possibility that pre-eclampsia, a disease characterized by altered vascular tone, may result in altered levels of fetal BNP and cGMP, and to determine whether pre-eclampsia alters the maternal-fetal relationship of BNP and cGMP. Paired maternal and umbilical venous plasma levels of BNP and cGMP were determined in 13 pre-eclamptic and 9 normotensive primigravidas in the third trimester. Statistical analysis was performed using multivariate analysis of variance, linear regression, and canonical correlation. Overall, levels of cGMP were lower in pre-eclampsia (P < 0.03). Pre-eclampsia was also associated with an altered maternal-fetal relationship for BNP and cGMP (P < 0.008, P < 0.02, respectively). With pre-eclampsia, the maternal:fetal ratio was reduced for BNP and was increased for cGMP. Because of its role as a second messenger for many vasoactive hormones, we hypothesize that fetal cGMP levels may better reflect overall vascular tone than do individual hormones. Altered BNP and cGMP maternal-fetal homeostasis raises the possibility of maternal-fetal coordination of vascular control.

Changes in health care delivery: a threat to academic obstetrics.

OBJECTIVE: Our purpose was to examine the effect of anticipated health care policy changes on delivery trends at leading academic obstetric institutions. STUDY DESIGN: The 51 centers in the United States with the most Society of Perinatal Obstetricians presentations in the past 2 years were surveyed regarding annual deliveries from 1990 to 1993 and reasons for any changes. Analysis of variance and chi 2 analysis were used as appropriate. RESULTS: Complete data were available from 43 hospitals representing 39 institutions. Their 1990 to 1993 delivery rates declined faster than United States delivery rates (12.3% vs 2.0%, p < 0.0001). The largest hospitals (> 6000 deliveries) had a decline of 18.2% compared with declines of 9.0% for medium and 0.9% for small hospitals (< 2500 deliveries). Regionally the greatest impact was seen in the West and the South, with 22% and 12% declines, respectively (p < 0.05). Reasons cited for the decline included competition from private or community physicians or hospitals (59%) and managed care (15%). CONCLUSION: As the national health care debate focuses on cost containment and coverage, we believe the potential effects of national policy on research and education should be considered. Continued selective reduction in deliveries at academic institutions can be expected to adversely affect research and education.

Differential regulation of seizure activity in the hippocampus of male and female rats.

OBJECTIVE: The aim of the current study was to directly examine and compare the susceptibility to N-methyl-D-aspartate-induced seizures in male versus female rats. We also sought to compare the anticonvulsant effects of magnesium sulfate in these two groups. STUDY DESIGN: Eighteen female and 10 male rats were stereotaxically implanted with a chronic bipolar recording electrode in the hippocampus and an injection cannula in the lateral cerebral ventricle. After 1 week rats randomly received an intravenous injection of 90 mg/kg magnesium sulfate or saline solution control. Fifteen minutes after the infusion rats were given the convulsant N-methyl-D-aspartate at a dose of 5 micrograms/microliters by direct intraventricular injection. Electrical seizure activity was thereafter assessed for 20 minutes. All data were analyzed by the Mann-Whitney U test and Student t test. RESULTS: In saline solution-treated rats receiving the convulsant N-methyl-D-aspartate, females had significantly lower total duration (p < 0.01) and total number of seizures (p < 0.05) compared with the male rats. The initial seizure was not affected by gender. In the female animals magnesium sulfate significantly reduced first seizure duration (p < 0.01) compared with saline solution controls. In males magnesium sulfate reduced both total duration (p < 0.05) and total seizure number (p < 0.05) compared with saline solution-treated animals. CONCLUSION: N-methyl-D-aspartate-induced seizure activity is more severe in males versus female rats. Magnesium sulfate's effect on N-methyl-D-aspartate-induced seizures is also dependent on gender. We speculate that seizure regulation may be hormonally influenced.

Premature parturition is characterized by in utero activation of the fetal immune system.

OBJECTIVE: At birth the fetus emerges from a sterile environment into a nonsterile one. This process is associated with activation of the fetal immune system which protects the fetus against infection in the newborn period. We conducted this study to determine whether activation of the monocyte-neutrophil system occurs in fetuses before premature birth. STUDY DESIGN: Forty patients in premature labor with intact membranes underwent cordocentesis for research purposes. Fetal blood was analyzed with the use of flow cytometry to measure the cell surface markers CD11c, CD13, CD15, and CD67, which are associated with monocyte and neutrophil activation, and CD14 and CD63, which were used as controls. RESULTS: Twenty-eight percent (11/40) of the infants were delivered prematurely within 72 hours of entering the study while the remainder were delivered at term. Our data clearly indicate that premature infants delivered within 72 hours had a higher percentage of CD11c, CD13, CD15, and CD67 than those delivered at term. In contrast, there were no significant differences in the percentages of CD14 and CD63. CONCLUSION: Activation of the monocyte-neutrophil system exists in fetuses destined for premature delivery. These findings indicate that premature parturition is associated with in utero immune system activation.

"Physiologic" intracellular acidosis in pregnancy.

To investigate acid-base homeostasis in pregnancy, we used phosphorus 31 nuclear magnetic resonance spectroscopy to measure intracellular pH in erythrocytes from nonpregnant (n = 33) and third-trimester pregnant women (n = 22). Intracellular pH was lower in pregnant compared with nonpregnant controls (7.23 +/- 0.015 vs 7.29 +/- 0.012, p = 0.003). We hypothesize that this "physiologic" intracellular acidosis of pregnancy potentiates oxygen-hemoglobin dissociation and oxygen delivery across the placenta.

In-utero percutaneous cystoscopy in the management of fetal lower obstructive uropathy.

In fetuses with lower obstructive uropathy, sonography cannot establish the cause of obstruction. We assessed whether percutaneous fetal cystoscopy could be useful in the evaluation and treatment of obstructive defects in utero. We inserted a fibreoptic endoscope through the lumen of the needle or trocar into the fetal bladder at the time of vesicocentesis or vesicoamniotic-shunt placement and looked at the the urethra, bladder neck, and ureteral orifices. Urethral vesicoamniotic shunting was considered in suitable cases; otherwise a percutaneous shunt was inserted. Fetal cystoscopy was possible in 11 of 13 patients referred. The bladder mucosa appeared haemorrhagic or oedematous in three. The ureteral orifices were seen in 9/11 fetuses, dilation was seen in five, but was only suspected in two by ultrasound. Ureteral webs were noted in two other fetuses. Two of seven fetuses underwent urethral vesicoamniotic shunting; urethral patency was achieved with urethral probing alone in one fetus. The remaining four fetuses were shunted with a standard technique. Fetal cystoscopy helps define the underlying conditions responsible for sonographic findings of lower obstructive uropathy, and allows the introduction of new treatments.

Comparison of intrauterine hematologic and biochemical values between twin pairs with and without stuck twin syndrome.

OBJECTIVE: Our purpose was to compare hematologic and biochemical values in cordocentesis specimens from twin pairs with and without stuck twin syndrome. STUDY DESIGN: Cordocentesis was performed on 38 twin pairs. Assignment to the stuck twin syndrome group (n = 8) was based on ultrasonographic findings of discordant size and amniotic fluid volume, concordant gender, and a single placenta. A receiver-operator characteristic curve was constructed with the use of intertwin hemoglobin differences. For the stuck twin syndrome group regression analysis of gestational age and intertwin hemoglobin difference was done. RESULTS: We found significant (p = 0.03) intertwin differences in hemoglobin between the stuck twin syndrome group (mean 5.35 gm/dl, range 0.5 to 15.4 gm/dl) and the comparison group (mean 0.10 gm/dl, range 0.0 to 2.4 gm/dl). A nearly significant relationship between gestational age and intertwin hemoglobin difference was noted in the stuck twin syndrome group. When the hemoglobin difference was > 2.4 gm/dl, all cases had stuck twin syndrome (sensitivity = 50%, specificity = 100%, positive predictive value = 100%, negative predictive value = 91%). In the stuck twin syndrome group there was a trend toward larger intertwin differences in albumin and total protein. Intertwin blood gas values between the groups did not differ, but the average PO2 was lower when the smaller twins of the two groups were compared. CONCLUSION: An intertwin difference in hemoglobin > 2.4 gm/dl is consistent with stuck twin syndrome. Large intertwin hemoglobin differences and imbalances in albumin and total protein may be seen in stuck twin syndrome.

Predictive value of fetal serum beta 2-microglobulin for neonatal renal function.

When fetal urinary-tract malformations (UTM) are discovered, management is based on the prediction of postnatal renal function, currently made by fetal urinary biochemistry and sonography. Serum beta 2-microglobulin has been used postnatally to estimate renal function and does not cross the placenta. We investigated the relation between fetal serum beta 2-microglobulin and renal function by comparing 64 unaffected fetuses and 15 fetuses with UTM. A beta 2-microglobulin above a 5.6 mg/L cut-off gave cross-validated sensitivity of 80.0%, specificity of 98.6%, a positive predictive value of 88.9%, and a negative predictive value of 97.1% for our cohort study.