Determination of 3′-azido-2′,3′-dideoxyuridine in maternal plasma, amniotic fluid, fetal and placental tissues by high-performance liquid chromatography

3′-Azido-2′,3′-dideoxyuridine (AZDU, Azddu, CS-87) is a nucleoside analog of 3′-azido-3′-deoxythymidine (zidovudine, AZT) that has been shown to inhibit human immunodeficiency virus (HIV-1). AZDU is a potential candidate for treatment of pregnant mothers to prevent prenatal transmission of HIV/AIDS to their unborn children. A rapid and efficient high-performance liquid chromatography (HPLC) method for the determination of AZDU concentrations in rat maternal plasma, amniotic fluid, placental and fetal tissue samples has been developed and validated. Tissue samples were homogenized in distilled water, protein precipitated and extracted using a C-18 solid-phase extraction (SPE) method prior to analysis. Plasma and amniotic fluid samples were protein precipitated with 2 M perchloric acid prior to analysis. Baseline resolution was achieved using a 4.5% acetonitrile in 40 mM sodium acetate (pH 7) buffer mobile phase for amniotic fluid, placenta and fetus samples and with a 5.5% acetonitrile in buffer solution for plasma at flow-rates of 2.0 ml/min. The HPLC system consists of a Hypersil ODS column (150×4.6 mm) with a Nova-Pak C-18 guard column with detection at 263 nm. The method yields retention times of 6.2 and 12.2 min for AZDU and AZT in plasma and 8.3 and 17.6 min for AZDU and AZT in amniotic fluid, fetal and placental tissues. Limits of detection ranged from 0.01 to 0.075 μg/ml. Recoveries ranged from 81 to 96% for AZDU and from 82 to 96% for AZT in the different matrices. Intra-day (n=6) and inter-day (n=9) precision (% RSD) and accuracy (% Error) ranged from 1.48 to 6.25% and from 0.50 to 10.07%, respectively.     

Determination of lamivudine in plasma, amniotic fluid, and rat tissues by liquid chromatography

An HPLC method for the quantification of lamivudine (3TC) in rat plasma, amniotic fluid, placental and fetal tissues has been developed, validated and applied to the study of the placental transport of this drug in the pregnant rat. Placental and fetal tissues were processed using liquid-liquid extraction enhanced by salting out the sample using a saturated solution of ammonium sulfate. Plasma and amniotic fluid samples were processed by protein precipitation using 2 M perchloric acid. Reverse phase chromatography was performed using a phenyl column (5 microm, 150 mm x 2 mm i.d.) under a flow rate of 0.2 ml/min. The mobile phase consisted of 5% methanol in 20 mM dibasic phosphate buffer (pH 6). The method was validated over the range from 0.1 to 50 microg/ml for plasma and amniotic fluid and 0.2-50 microg/ml for the placental and fetal tissues.     

Liquid chromatography–tandem mass spectrometry analysis of cocaine and its metabolites from blood, amniotic fluid, placental and fetal tissues: study of the metabolism and distribution of cocaine in pregnant rats

The ability to simultaneously quantitate cocaine and its 12 metabolites from pregnant rat blood, amniotic fluid, placental and fetal tissue homogenates aids in elucidating the metabolism and distribution of cocaine. An efficient extraction method was developed to simultaneously recover these 13 components using underivatized silica solid-phase extraction (SPE) cartridges. The overall recoveries for cocaine and its metabolites were studied from pregnant rat blood (47–100%), amniotic fluid (61–100%), placental homogenate (31–83%), and fetal homogenate (39–87%). Extraction of the samples using silica is not classical SPE, but rather allows for the concentration of the sample into a small volume prior to injection and the removal of the proteins due to their strong interaction with the active silica surface. A positive ion mode electrospray ionization liquid chromatography–tandem mass spectrometry (LC–MS–MS) method was used and validated to simultaneously quantitate cocaine and 12 metabolites from these four biological matrices. A gradient elution method with a Zorbax XDB C₈ reversed-phase column was used to separate the components. Multiple reaction monitoring (MRM) of a product ion arising from the corresponding precursor ion was used in order to enhance the selectivity and sensitivity of the method. Low background noise was observed from the complex biological matrices due to efficient SPE and the selectivity of the MRM mode. Linear calibration curves were generated from 0.01 to 2.50 ppm. The method also showed high intra-day (n=3) and inter-day (n=9) precision (% RSD) and accuracy (% error) for all components. The limits of detection (LODs) for the method ranged from 0.15 to 10 ppb. The LODs of cocaine and its major metabolites were less than 1 ppb from all four biological matrices. This method was applied to the study of the metabolism and distribution of cocaine in pregnant rats following intravenous infusion to a steady state plasma drug concentration. The following results were observed in the pregnant rat study: (1) the observations correlated strongly with the previous literature data on cocaine metabolism and distribution, (2) cocaine and norcocaine accumulated in the placenta, (3) arylhydroxylation of cocaine was a major metabolic pathway, (4) para-arylhydroxylation of cocaine was favored over meta-arylhydroxylation in rats and (5) accumulation of cocaine and its major metabolites was observed in the amniotic fluid.     

Determination of acyclovir in maternal plasma,amniotic fluid,fetal and placental tissues by high-performance liquid chromatography

Acyclovir [9-[(2-hydroxyethoxy)-methyl]-guanosine, Zovirax, ACV] is a synthetic purine nucleoside analog active against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella zoster virus. Acyclovir has frequently been used in HSV-2 seropositive mothers to prevent prenatal transmission of herpes virus to their unborn children. A fast and reproducible HPLC method for the determination of the highly polar acyclvoir in maternal rat plasma, amniotic fluid, placental tissue, and fetal tissue has been developed and validated. Plasma and amniotic fluid samples were prepared by protein precipitation using 2 M perchloric acid and syringe filtering. Tissue samples were homogenized in distilled water, centrifuged, and extracted using a C(18) solid-phase extraction method prior to analysis. Baseline resolution was achieved for acyclovir and the internal standard gancyclovir, an anti-viral of similar structure to acyclovir, using an Agilent Eclipse XDB C(8) column (150 x 2.1 mm, 5 microm). The mobile phase used for the plasma and amniotic fluid was 10 mM acetate/citrate buffer-3.7 mM aqueous octanesulfonic acid (87.5:12.5, v/v) at a flow-rate of 0.2 ml/min. The mobile phase used for the tissue samples was 30 mM acetate/citrate buffer with 5 mM octanesulfonic acid-acetonitrile (99:1, v/v). Both aqueous mobile phase portions were pH adjusted to 3.08. All separations were done using an Agilent 1100 Series HPLC system with UV detection of 254 nm. The assay was validated for each matrix over a range of 0.25-100 microg/ml over 3 days using five replicates of three spiked concentrations. The relative standard deviation and percent error for each validation data set was <15% for middle and high quality control (QC) points and <20% for all low QC points. All calibration curves showed good linearity with an R(2)>0.99. The extraction efficiency for recovery of acyclovir from all matrices was >80%.     

Maternal DDAVP-induced hyponatremia preserves fetal urine flow during acute fetal hemorrhage

Maternal administration of DDAVP induces maternal and fetal plasma hyponatremia, accentuates fetal urine flow, and increases amniotic fluid volume. Fetal hemorrhage represents an acute stress that results in fetal AVP secretion and reduced urine flow rate. In view of the potential therapeutic use of DDAVP for pregnancies with reduced amniotic fluid volume, we sought to examine the impact of maternal hypotonicity during acute fetal hemorrhage. Chronically catheterized pregnant ewes (130 +/- 2 days) were allocated to control or to DDAVP-induced hyponatremia groups. In the latter group, tap water (2,000 ml) was administered intragastrically to the ewe followed by DDAVP (20 microg bolus, 4 microg/h) and a maintenance intravenous infusion of 5% dextrose water for 4 h to achieve maternal hyponatremia of 10-12 meq/l. Thereafter, ovine fetuses from both groups were continuously hemorrhaged to 30% of estimated blood volume over a 60-min period. DDAVP caused similar degree of reductions in plasma sodium and osmolality in pregnant ewes and their fetuses. In response to hemorrhage, DDAVP fetuses showed greater reduction in hematocrit than control fetuses (14 vs. 10%). Both groups of fetuses demonstrated similar increases in plasma AVP concentration. However, the AVP-hemorrhage threshold was greater in DDAVP fetuses (22.5%) than in control (17.5%). Hemorrhage had no significant impact on plasma osmolality, electrolyte levels, or cardiovascular responses in either group of fetuses. Despite similar increases in plasma AVP, DDAVP fetuses preserved fetal urine flow rates, with values threefold those of control fetuses. These results suggest that under conditions of acute fetal stress of hemorrhage, maternal DDAVP may preserve fetal urine flow and amniotic fluid volume.     

Determination of pindolol enantiomers in amniotic fluid and breast milk by high-performance liquid chromatography: applications to pharmacokinetics in pregnant and lactating women

A method for the determination of pindolol enantiomers in amniotic fluid and breast milk was developed, validated, and applied to the investigation of six pregnant women treated with rac-pindolol (10 mg/12 h). Biological samples were extracted with tert-methyl-butyl ether, and the pindolol enantiomers were resolved on a Chiralpak AD column. Amniotic fluid/plasma and milk/plasma concentrations ratios ranged from 0.4 to 4.5 and from 0.6 to 3.7, respectively, for (+)-R-pindolol and from 0.5 to 3.5 and from 1.1 to 2.8, respectively, for (-)-S-pindolol. Preliminary data suggest that amniotic fluid and breast milk are routes of fetal exposure to pindolol enantiomers.     

Amniotic fluid and hemodynamic model in monochorionic twin pregnancies and twin-twin transfusion syndrome

We developed a mathematical model of monochorionic twin pregnancies and twin-twin transfusion syndrome (TTTS), combining both fetal fluid dynamics and fetoplacental growth and circulation alterations and assuming that transplacental fluid flow from mother to fetus accounts for normal fetal and amniotic fluid volumes. Ten coupled differential equations, describing fetal total body and amniotic fluid volumes, their osmolalities, and fetal blood colloid osmotic pressure, for both donor and recipient twins, were solved numerically. Amniotic flows are controlled by fetal plasma osmolality and hydrostatic and colloid osmotic pressures. We included varying placental anastomoses and placental sharing of the circulations. Consistent with clinical experience, model predictions are: fetofetal transfusion from unidirectional arteriovenous anastomoses cause oligo-polyhydramnios, a normal size recipient but hypovolemic donor; compensating oppositely directed deep and superficial anastomoses moderate discordant development; and anhydramnios results from mild and severe TTTS, where milder forms may even present earlier in gestation than severe TTTS. Unequal placental circulatory sharing may exacerbate discordant development. In conclusion, our model simulates a wide variety of realistic manifestations of amniotic fluid volume and fetal growth in TTTS related to placental angioarchitecture. The model may allow an assessment of the efficacy of current therapeutic interventions for TTTS.     

Reduced fetal, placental, and amniotic fluid PTHrP in the growth-restricted spontaneously hypertensive rat

Evidence implicates pivotal roles for parathyroid hormone-related protein (PTHrP) in stimulating cell growth and differentiation, placental calcium transport, and placental vasodilatation. As spontaneously hypertensive rat (SHR) fetuses are growth restricted compared with those of its normotensive control, the Wistar Kyoto (WKY) rat, we examined intrauterine PTHrP and total and ionic calcium concentrations in these rats. Fetal plasma PTHrP concentrations, but not total calcium concentrations, were lower in the SHR compared with WKY (P < 0.05). SHR placental concentrations of PTHrP were lower than in WKY (P < 0.03) and failed to show the increase observed in WKY near term (P < 0.05). PTHrP concentrations in amniotic fluid from SHR were not raised near term and were lower compared with WKY (P < 0.0005). The increased ionic calcium concentrations in amniotic fluid in the WKY near term (P < 0.05) were not detected in the SHR. Thus SHR fetal plasma, placental, and amniotic fluid PTHrP concentrations were reduced and associated with fetal growth restriction. We suggest that PTHrP may play a role in the etiology of both growth restriction during pregnancy and hypertension later in life.     

Transplacental pharmacokinetics and fetal distribution of 2', 3'-didehydro-3'-deoxythymidine (d4T) and its metabolites in late-term rhesus macaques

BACKGROUND: The overall goal of human immunodeficiency virus (HIV) therapy during pregnancy is to maintain maternal health and reduce the probability of vertical transmission during gestation and delivery, while keeping toxicity risks low. Azidothymidine (AZT) is currently recommended for pregnant women infected with HIV; however, many pregnant women are unable to tolerate AZT because of toxicity. In the present study, the placental transfer and fetal accumulation of the anti-HIV compound 2',3'-didehydro-3'-deoxythymidine (d4T) and its active (triphosphorylated) and inactive (thymine and beta-aminoisobutyric acid) metabolites were examined at steady state in late-term rhesus macaques. METHODS: On the day of the hysterotomy, the mother was administered an intravenous loading dose of d4T, followed by a 3-hr steady-state intravenous infusion that also included [(3)H]d4T as a tracer. After 3 hr of infusion, the fetus was delivered by cesarean section under halothane/N(2)O anesthesia. Plasma, amniotic fluid, and tissues were analyzed for d4T and its inactive metabolites by HPLC; tissue samples were analyzed for d4T and active (phosphorylated) metabolites by strong anion-exchange HPLC. RESULTS: Maternal steady-state plasma concentrations of d4T were 1-2 microg/ml, with a fetal-to-maternal plasma ratio of 0.85 +/- 0.09. The fetal tissue distribution of radioactivity was highest in the kidney and lowest in the brain. D4T, thymine, and beta-aminoisobutyric acid were detected in all fetal tissues examined. CONCLUSIONS: Our data indicate that d4T readily crosses the placenta and is present in the fetus as parent compound or its inactive metabolites after maternal infusion. Although fetal plasma concentrations of d4T were similar to clinical d4T concentrations, no phosphorylated metabolites were detected. Teratology 62:93-99, 2000. Published 2000 Wiley-Liss, Inc.     

Gestational profiles of rat placental lactogen-II (rPL-II) and growth hormone (GH) in maternal and fetal serum, amniotic fluid, and placental tissue.

Rat placental lactogen-II (rPL-II) and growth hormone (rGH) in maternal and fetal serum, amniotic fluid, and placental tissue were measured by a homologous radioimmunoassay during the last half of pregnancy. rPL-II appeared first in maternal circulation and the placental tissue on day 11 of pregnancy. The maternal serum rPL-II concentration increased progressively and reached the peak value (684 +/- 76 ng/ml) on day 19, and declined thereafter up to term. rPL-II content in the tissue had a similar pattern to the maternal serum profile of rPL-II, while its concentration in the tissue increased dramatically on day 12 and remained high until day 19. Fetal serum rPL-II was detected on days 17 and 18, though its concentration was much lower (ranged between 3-10 ng/ml) than that of maternal serum. rPL-II in amniotic fluid was also detectable only on days 12-14 of pregnancy, and the peak value on day 13 was 22% of the maternal serum rPL-II concentration. The rGH concentration increased gradually as pregnancy advanced with a decline on the day before parturition. Although rGH in fetal serum increased on day 20 with a decline on the following day, it was slightly detectable in amniotic fluid on the last two days of pregnancy. The molecular profile of rPL-II in amniotic fluid and maternal serum of day 13 pregnant rats were examined by Western blotting. Anti-rPL-II serum detected two proteins with molecular weights (mol wt) of 19.5K and 20.5K in amniotic fluid and one protein with a mol wt of 20.5K in maternal serum under nonreducing conditions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of erythromycin in rat plasma with capillary electrophoresis-electrochemiluminescence detection of tris(2,2'-bipyridyl) ruthenium(II)

A fast and sensitive approach for determination of erythromycin in rat plasma was described. The method used capillary electrophoresis coupled with end-column electrochemiluminescence (ECL) detection of Ru(bpy)(3)(2+). The separation column used had an inner diameter of 75 microm. The running buffer was 15 mmol/L sodium phosphate (pH=7.5). The solution in the detection cell was 50 mmol/L sodium phosphate (pH=8.0) and 5 mmol/L Ru(bpy)(3)(2+). ECL intensity varied linearly with erythromycin concentration from 1.0 ng/mL to 10 microg/mL. The detection limit (S/N=3) was 0.35 ng/mL. The relative standard deviations, of ECL intensity and migration time for eight consecutive injections of 1.0 microg/mL erythromycin (n=8), were 1.3% and 1.8%, respectively. The method was successfully applied to erythromycin determination in rat plasma. The recovery ranged from 92.5 to 97.5%.     

Rapid and selective liquid chromatographic/tandem mass spectrometric method for the determination of fosfomycin in human plasma

A rapid and selective liquid chromatographic/tandem mass spectrometric method for determination of fosfomycin was developed and validated. Following protein-precipitation, the analyte and internal standard (fudosteine) were separated from human plasma using an isocratic mobile phase on an Ultimate XB-CN column. An API 4000 tandem mass spectrometer equipped with Turbo IonSpray ionization source was used as detector and was operated in the negative ion mode. Multiple reaction monitoring using the precursor to product ion combinations of m/z 137-->79 and m/z 178-->91 was performed to quantify fosfomycin and fudosteine, respectively. The method was linear in the concentration range of 0.10-12.0 microg/mL using 50 microL of plasma. The lower limit of quantification was 0.10 microg/mL. The intra- and inter-day relative standard deviation over the entire concentration range was less than 10.6%. Accuracy determined at three concentrations (0.25, 1.00 and 8.00 microg/mL for fosfomycin) ranged from -1.0% to -4.2% in terms of relative error. Each plasma sample was chromatographed within 5.0 min. The method was successfully used in a bioequivalence study of fosfomycin in human plasma after an oral administration of capsules containing 1.0 g fosfomycin (approximately 1.3g calcium fosfomycin).     

Hormonal and physical changes associated with bovine conceptus development.

Conceptus (placental membranes, fetal fluids and fetus) development was characterized between Days 27 and 111 of gestation. Progestagens, oestrone, oestradiol, oestrone sulphate and prostaglandins (PG) F were measured in maternal plasma and allantoic and amniotic fluids. Protein concentrations are described for fetal fluids. The early increase in placental membrane weight from 1.12 g (27 days) to 58.45 g (50 days) was associated with oestrogen production presumably of conceptus origin. Oestrogens increased significantly in allantoic and amniotic fluids throughout the period studied with oestrone being the primary free oestrogen, rising from 2 pg/ml (Day 33) to 144 ng/ml by 111 days in allantoic fluid. Changes in plasma oestrogens of the maternal circulation were not detected until after Day 70 at which time oestrone concentration was greater than that of oestradiol. Fetal fluid concentrations of progestagens, oestrone sulphate and PGF were not related to maternal plasma levels and a sequestration of these hormones by the allantois is postulated.     

Uteroplacental restriction in the rat impairs fetal growth in association with alterations in placental growth factors including PTHrP

During pregnancy, parathyroid hormone-related protein (PTHrP) is one of many growth factors that play important roles to promote fetal growth and development, including stimulation of placental calcium transport. Angiotensin II, acting through the AT(1a) receptor, is also known to promote placental growth. We examined the effects of bilateral uterine artery and vein ligation (restriction), which mimics placental insufficiency in humans, on growth, intrauterine PTHrP, placental AT(1a), and pup calcium. Growth restriction was surgically induced on day 18 of pregnancy in Wistar-Kyoto female rats by uterine vessel ligation. Uteroplacental insufficiency reduced fetal body weight by 15% and litter size (P < 0.001) compared with the control rats with no effect on placental weight or amniotic fluid volume. Uteroplacental insufficiency reduced placental PTHrP content by 46%, with increases in PTHrP (by 2.6-fold), parathyroid hormone (PTH)/PTHrP receptor (by 11.6-fold), and AT(1a) (by 1.7-fold) relative mRNA in placenta following restriction compared with results in control (P < 0.05). There were no alterations in uterine PTHrP and PTH/PTHrP receptor mRNA expression. Maternal and fetal plasma PTHrP and calcium concentrations were unchanged. Although fetal total body calcium was not altered, placental restriction altered perinatal calcium homeostasis, as evidenced by lower pup total body calcium after birth (P < 0.05). The increased uterine and amniotic fluid PTHrP (P < 0.05) may be an attempt to compensate for the induced impaired placental function. The present study demonstrates that uteroplacental insufficiency alters intrauterine PTHrP, placental AT(1a) expression, and perinatal calcium in association with a reduction in fetal growth. Uteroplacental insufficiency may provide an important model for exploring the early origins of adult diseases.     

Arginine nutrition and fetal brown adipose tissue development in diet-induced obese sheep

The global incidence of human obesity has more than doubled over the past three decades. An ovine model of obesity was developed to determine effects of maternal obesity and arginine supplementation on maternal, placental, and fetal parameters of growth, health, and well being. One-hundred-twenty days prior to embryo transfer, ewes were fed either ad libitum (n?=?10) to induce obesity or 100% National Research Council-recommended nutrient requirements (n?=?10) as controls. Embryos from superovulated ewes with normal body condition were transferred to the uterus of control-fed and obese ewes on day 5.5 post-estrus to generate genetically similar singleton pregnancies. Beginning on day 100 of gestation, obese ewes received intravenous administration of saline or L-arginine-HCl three times daily (81?mg arginine/kg?body?weight/day) to day 125, whereas control-fed ewes received saline. Fetal growth was assessed at necropsy on day 125. Maternal obesity increased (1) percentages of maternal and fetal carcass lipids and (2) concentrations of leptin, insulin, glucose, glutamate, leucine, lysine and threonine in maternal plasma while reducing (1) concentrations of progesterone, glycine and serine in maternal plasma and (2) amniotic and allantoic fluid volumes. Administration of L-arginine to obese ewes increased arginine and ornithine concentrations in maternal and fetal plasma, amniotic fluid volume, protein content in maternal carcass, and fetal brown adipose tissue (+60%), while reducing maternal lipid content and circulating leptin levels. Fetal or placental weight did not differ among treatments. Results indicate that arginine treatment beneficially reduces maternal adiposity and enhances fetal brown adipose tissue development in obese ewes.     

Concentrations of altrenogest in plasma of mares and foals and in allantoic and amniotic fluid at parturition

Treatment with the progestin altrenogest is widely used in pregnant mares. The fact that foals born from healthy mares treated with altrenogest until term suffered from neonatal problems raises the question of direct effects of altrenogest on vital functions in the neonate. We have therefore investigated altrenogest concentrations in maternal and neonatal blood plasma and in fetal fluids. Pregnant mares were treated with altrenogest orally once daily (0,088 mg/kg bodyweight, n = 7) or left untreated (n = 8) from 280 d of gestation until foaling. Altrenogest concentration was determined in plasma of the mares, their foals and in amniotic and allantoic fluid. The concentration of altrenogest in plasma from treated mares (2.6 ± 1.0 ng/mL) was significantly lower than in plasma from their foals immediately after birth (5.6 ± 1.9 ng/mL; p < 0.05), but was significantly higher than in their fetal fluids (amniotic fluid: 0.4 ± 0.1 ng/mL; p < 0.05; allantoic fluid: 3.0 ± 1.5 ng/mL). Altrenogest was undetectable in maternal and fetal plasma and fetal fluids of control pregnancies at all times. Altrenogest concentration in plasma of foals from treated mares was strongly correlated to the altrenogest concentration in plasma of their dams (r = 0.938, p < 0.001) and in amniotic (r = 0.886, p < 0.001) and allantoic fluid (r = 0.562, p < 0.05). A significant decrease in altrenogest concentration between the time periods 0-15 min, 30-120 min, and 180-360 min after parturition was seen in the plasma from foals born to altrenogest-treated mares. In conclusion, our data demonstrate that altrenogest reaches the equine fetus at high concentrations.     

Maternal dehydration: impact on ovine amniotic fluid volume and composition

Maternal dehydration consistent with mild water deprivation or moderate exercise results in maternal and fetal plasma hyperosmolality and increased plasma arginine vasopressin (AVP). Previous studies have demonstrated a reduction in fetal urine and lung fluid production in response to maternal dehydration or exogenous fetal AVP. As fetal urine and perhaps lung liquid combine to produce amniotic fluid, maternal dehydration may affect the amniotic fluid volume and/or composition. In the present study, six chronically-prepared pregnant ewes with singleton fetuses (128 +/- 1 day) were water deprived for 54 h to determine the effect on amniotic fluid. Maternal plasma osmolality (306.5 +/- 0.9 to 315.6 +/- 1.9 mOsm/kg) and AVP (1.9 +/- 0.2 to 22.2 +/- 3.2 pg/ml) significantly increased during dehydration. Similarly, fetal plasma osmolality (300.0 +/- 0.9 to 312.7 +/- 1.7 mOsm/kg) and AVP (1.4 +/- 0.1 to 10.4 +/- 2.4 pg/ml) increased in parallel to maternal values. Amniotic fluid osmolality (276.8 +/- 5.7 to 311.6 +/- 6.5 mOsm/kg) and sodium (139.8 +/- 4.8 to 154.0 +/- 5.4 mEq/l) and potassium (9.1 +/- 1.3 to 13.9 +/- 2.4 mEq/l) concentrations increased while a significant (35%) reduction in amniotic fluid volume occurred (871 +/- 106 to 520 +/- 107 ml). These results indicate that maternal dehydration may have marked effects on maternal-fetal-amniotic fluid dynamics, possibly contributing to the development of oligohydramnios.     

Fetomaternal adrenomedullin levels in diabetic pregnancy.

We investigated whether maternal and fetoplacental adrenomedullin, a newly discovered hypotensive peptide involved in the insulin regulatory system, is modified in diabetic pregnancy. We studied its correlation with pregnancy complications associated with this disease. Thirty-six pregnant women with diabetes (13 with type I and 23 with gestational diabetes mellitus) and in 40 uncomplicated pregnancies were included. 10 out of 36 diabetic pregnancies were complicated by gestational hypertension. In each woman, adrenomedullin concentration in maternal and fetal plasma and in amniotic fluid was assessed by specific radioimmunoassay. We found that overall mean amniotic fluid adrenomedullin concentration was higher (p < 0.05) in diabetic (14.7 +/- 1.6 fmol/ml) than in uncomplicated pregnancies (10.8 +/- 0.9 fmol/ml), whereas no differences were present in maternal and fetal plasma adrenomedullin levels between diabetic and uncomplicated pregnant women. High levels of amniotic fluid adrenomedullin were found in both type I and gestational diabetes mellitus pregnancies (13.7 +/- 1.4 and 15.6 +/- 2.2 fmol/ml, respectively). Diabetic pregnancies complicated by gestational hypertension showed lower (p < 0.05) amniotic fluid adrenomedullin concentrations than normotensive diabetic patients. These findings suggest that placental adrenomedullin production is upregulated in diabetic pregnancy, and it may be important to prevent excessive vasoconstriction of placental vessels.