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Objective: The purpose of this study was to determine if the prevalence of neonatal and maternal infectious morbidity in patients with preterm premature rupture of membranes (PROM) who received ampicillin prophylaxis for presemptive group B streptococcal colonization is increased compared to those who received no prophylaxis., Methods: The charts of all patients with preterm PROM who delivered between January 1988 and December 1993 were retrospectively reviewed. The routine use of ampicillin prophylaxis was initiated in January 1991. Patients with singleton gestations were included in the analysis only if chorioamnionitis was excluded on admission. Variables used in the final analysis included gestational age at the time of preterm PROM, gestational age at delivery, duration of rupture of membranes, birth weight, method of delivery, use of steroids, tocolytics, or antibiotics for group B streptococcus prophylaxis, neonatal sepsis, neonatal mortality, and postpartum endomyometritis. Data were analyzed using Student's t-test, chi-square test, Fisher's exact test, and stepwise logistic regression analysis to evaluate the effect of chemoprophylaxis for group B streptococcus on the incidence of neonatal sepsis and maternal postpartum endomyometritis. A two-tailed P < 0.05 was used to denote statistical significance., Results: The charts of 206 patients were reviewed; 146 patients received ampicillin for group B streptococcal prophylaxis and 60 patients did not. There was a significantly higher incidence of postpartum endomyometritis among the patients who received ampicillin (62% vs. 22%; P < 0.01). The association between postpartum endomyometritis and chemoprophylaxis remained significant even after controlling for other confounding variables. There was no significant difference in the incidence of neonatal sepsis (5% vs. 7%; P = 0.7) or death (5% vs. 3%; P = 0.9) between both groups., Conclusions: Group B streptococcal prophylaxis with a short course of intravenous ampicillin increases the risk of postpartum endomyometritis in patients with premature PROM.

Background: Thrombolytic agents have been used successfully to treat patients with massive pulmonary embolism and cardiorespiratory insufficiency, but experience with these drugs in pregnancy is limited., Case: A 20-year-old woman at 21 weeks' gestation was admitted with a massive pulmonary embolism. She was initially given intravenous heparin therapy but because of worsening clinical condition, urokinase was used. After two 12-hour periods of therapy, the urokinase was discontinued and the heparin restarted. She remained on subcutaneous heparin therapy for the remainder of her pregnancy, which was otherwise uncomplicated. She delivered a healthy male infant at term without complications and was discharged on warfarin therapy., Conclusion: Thrombolytic therapy can be life-saving and should be considered in the treatment of hemodynamically significant pulmonary embolism in pregnancy.

Objective: Our purpose was to compare different echocardiographic methods to quantitate maternal ventricular function., Study Design: Eleven critically ill obstetric patients requiring invasive monitoring and M-mode and two-dimensional Doppler echocardiographic studies were retrospectively studied. Ventricular volumes and ejection fraction derived from multiple methods were computed and compared with analysis of variance and Newman-Keuls tests., Results: Two M-mode studies could not be analyzed. M-mode and two-dimensional estimates of stroke volume were similar to the previously validated Doppler stroke volume values of these 11 patients. End-diastolic volume estimates were similar. There was no difference in ejection fraction for the five different two-dimensional Doppler methods used (66%, 66%, 67%, 63%, and 63%)., Conclusion: Left ventricular function is reliably calculated in pregnant women by a number of different echocardiographic techniques. The ability to combine echocardiographic techniques is helpful when any single method does not provide all of the information required.

Objective: Our objective was to study the direct effects of meconium on isolated umbilical artery and vein in vitro., Study Design: Intact umbilical artery and vein rings were suspended in 5 ml organ baths containing kreb's solution (pH 7.2, 37 degrees C; bubbled with 2.5% oxygen and 8.07% carbon dioxide, balance nitrogen) for isometric tension recording. Meconium alone (final bath concentration 1%), centrifuged and filtered meconium, and meconium with the lipid fraction removed (separated into < 30,000 kd and > 30,000 kd) were added to the baths. Some vessels were also incubated in 1% meconium for 30 minutes, after which the meconium was washed out. Concentration-response curves to U46619 were obtained. The negative log of the concentration that evokes 50% of the maximal contraction was determined., Results: Umbilical artery and vein had no sustained response to meconium. Tension that developed by rings exposed to meconium was significantly less than control at all concentrations of U46619. There was some loss of the efficacy of meconium after centrifugation-filtration and washing out. Meconium without the lipid fraction had less inhibitory effect than did native meconium., Conclusions: Meconium does not cause sustained contraction of umbilical artery and vein in vitro. It does, however, inhibit the contractile effect of U46619 in both umbilical artery and vein smooth muscle. The inhibitory activity of meconium appears to be concentrated in the lipid fraction.

Objective: The addition of ultrasonography and ultrasonographically directed fetal blood sampling was attempted in an effort to study the fetal effects of red blood cell alloimmunization in a rabbit model., Study Design: Nineteen New Zealand does were alloimmunized to incompatible red blood cells. Sensitized does were bred twice, once with a homozygous buck of incompatible blood type and once with a homozygous buck of compatible blood type. Ultrasonographic examinations were performed on days 20 and 27 of gestation (term 28 to 31 days). Fetal blood sampling was undertaken on day 27 of gestation, and hematologic data were compared between compatible and incompatible litters., Results: A total of 41 pregnancies occurred in 19 does. Fetal hemoglobin was higher in the compatible litters (9.7 gm/dl vs 5.8 gm/dl, p < 0.001), whereas no difference could be detected between the respective reticulocyte counts (31.9 vs 36.0/100 red blood cells, p = 0.2). Hydrops fetalis was noted in none of 18 compatible litters versus 12 of 19 incompatible litters (p < 0.01)., Conclusion: A disease analogous to human hemolytic disease of the newborn can be induced in the rabbit fetus.

Objective: Our purpose was to study the effects of some drugs frequently used in pregnant women on isolated human umbilical artery and vein segments., Study Design: Umbilical artery and vein rings from normal term pregnancies were mounted in Krebs-bicarbonate solution in organ baths for isometric tension recording. Rings were contracted with potassium chloride (60 mmol/L) or U46619 (10(-8) mol/L) and then exposed to cumulative concentrations of nimodipine, nifedipine, nicardipine, phenytoin, magnesium sulfate, and hydralazine. Concentration-response curves were constructed by means of the difference in the percent relaxation between test and control vessels. Data analysis was by repeated measures analysis of variance, Newman-Keuls test, and the unpaired Student t test as appropriate. A value of p < 0.05 was considered statistically significant., Results: All the agents studied were effective umbilical vasodilators, except for hydralazine, which had minimal effect. The dihydropyridine calcium antagonists were more potent vasodilators than were the other agents studied. Nifedipine was the most potent calcium blocker and was the only dihydropyridine that relaxed the umbilical vein to a greater extent than the umbilical artery., Conclusion: The most commonly used drugs in preeclampsia have variable effects on the umbilical vessels.

Objective: We compared the blood velocity and vascular resistance in the central retinal and ophthalmic arteries in healthy nonpregnant, pregnant, and postmenopausal women (before and after estrogen replacement therapy)., Study Design: Color flow Doppler ultrasonography was used to determine systolic, diastolic, and mean velocity, as well as the resistance index in the central retinal and ophthalmic arteries in 10 nonpregnant women, 10 third-trimester pregnant women, and 10 hypoestrogenic postmenopausal women. The postmenopausal patients were again studied 2 months after starting daily oral therapy with 2 mg of micronized 17 beta-estradiol., Results: Pregnant women had a significantly (p < 0.05) higher diastolic blood velocity (4.2 +/- 0.8 cm/sec) and a lower resistance index (0.56 +/- 0.05) in the central retinal artery, when compared with nonpregnant women (diastolic velocity 2.8 +/- 0.8 cm/sec, resistance index 0.68 +/- 0.1), and hypoestrogenic postmenopausal women (diastolic velocity 2.6 +/- 0.9 cm/sec, resistance index 0.73 +/- 0.08). Significant differences were not seen in the ophthalmic artery. In the postmenopausal patients estradiol therapy was associated with an increase in diastolic velocity (2.6 +/- 0.9 cm/sec vs 4.1 +/- 1.6 cm/sec) and a decrease in the resistance index (0.73 +/- 0.08 vs 0.66 +/- 0.1) in the central retinal artery but not in the ophthalmic artery., Conclusions: The blood velocity and vascular resistance in the cerebral microcirculation appear to change according to the phases of a woman's reproductive life. This may be related, in part, to estrogen levels, because estradiol vasodilates small-diameter cerebral vessels in hypoestrogenic postmenopausal women.

Objective: Our purpose was to determine the effect of oxidized lipids on the contractile activity of isolated human umbilical arteries., Study Design: Umbilical artery rings were prepared for isometric tension recording and exposed to cumulative concentrations of oxidized and nonoxidized lipid and control solutions. Rings were also incubated with the lipid or control solutions and then contracted with cumulative concentrations of U46619. A final set of rings in Ca(++)-free depolarized solution was incubated with the agents above, and then the Ca++ concentration was increased cumulatively., Results: The lipids had no direct contractile effect. Both lipids inhibited the response to U46619 and Ca++, with the oxidized lipids having the most significant effect., Conclusion: Oxidized lipids lack a direct contractile effect on isolated human umbilical arteries and inhibit the contractile response to thromboxane and calcium.

Pulmonary hypoplasia is a major problem in infants with congenital diaphragmatic hernia. Intrauterine reparative procedures are associated with a high complication rate. The development of less complex operations to reduce the degree of fetal lung hypoplasia may improve neonatal survival. Our objective was to investigate the effectiveness of an iatrogenic gastroschisis in reducing fetal pulmonary hypoplasia in a sheep model with an artificially created diaphragmatic hernia. A left-sided diaphragmatic hernia (Bochdalek type) was created at 75 days' gestation in an ovine fetal model during the pseudoglandular phase of lung development. At 110 days' gestational age, a left-sided gastroschisis was created by excising part of the lower abdominal wall and buttressing the opening with a rubber ring. The fetus remained in utero until 135 days' gestation, at which time it was sacrificed for autopsy. Histopathologic and morphometric studies were performed on the lungs. Ten animals had creation of a diaphragmatic hernia. Four underwent the second surgery to create a gastroschisis. One animal completed the entire protocol, 3 fetuses aborted after the second surgery. Autopsy confirmed effective decompression of the herniated abdominal contents from the chest into the amniotic cavity in all 4 cases. The lungs of the animal that completed the protocol were appropriately developed, while those fetuses that died soon after gastroschisis creation had severe pulmonary hypoplasia, mainly involving the left lung. Artificially induced diaphragmatic hernia, in the ovine fetus, causes severe pulmonary hypoplasia.(ABSTRACT TRUNCATED AT 250 WORDS)

Endothelin-1 (ET-1), known to be present in high concentrations in serum from pre-eclamptic compared with normotensive pregnant women, may contribute to the increased vascular reactivity seen in pre-eclampsia. Experiments were designed to compare the contractile activity of ET-1 in isolated omental arteries from menopausal women (n = 6), normotensive pregnant women (n = 7), and pre-eclamptic patients (n = 7). Intact rings (3-mm width) were suspended for isometric tension recording in organ chambers filled with modified Krebs/bicarbonate buffer aerated with 95% air and 5% CO2, 37 degrees C, pH 7.35-7.4, under tension of 1 g. No significant differences were found in either the sensitivity to (concentration producing 50% of contraction) or efficacy of (maximal increase in tension, normalized to reference contraction to KCl) ET-1 in the vessels of all three groups of patients studied. These data argue against ET-1 as a primary factor in pre-eclampsia. The modulatory role of ET-1 on the effects of other contractile factors of human blood, as a possible cause of pre-eclamptic changes, remains to be elucidated.

Objective: Our purpose was to compare noninvasive two-dimensional and Doppler echocardiography and right heart catheterization with a pulmonary artery catheter in the estimation of stroke volume, cardiac output, cardiac index, left ventricular filling pressure, pulmonary artery systolic pressure, and right atrial pressure in a heterogeneous group of critically ill obstetric patients., Study Design: Eleven critically ill obstetric patients requiring invasive monitoring for clinical management were prospectively studied. Simultaneous Doppler and pulmonary artery catheter readings of stroke volume, cardiac output, cardiac index, left ventricular filling pressure, pulmonary artery systolic pressure, and right atrial pressure were acquired. Mean +/- SD or median and range, as appropriate, of each parameter were compared, and data for all parameters were subjected to regression analysis. A two-tailed p value < 0.05 was regarded as significant., Results: There was no significant difference between the two techniques in the estimation of cardiac index, intracardiac pressures, or pulmonary artery systolic pressure. There was a good correlation between the two methods for stroke volume (R2 = 0.98), cardiac output (R2 = 0.98), cardiac index (R2 = 0.96), left ventricular filling pressure (R2 = 0.79), pulmonary artery systolic pressure (R2 = 0.85), and right atrial pressure (R2 = 0.86)., Conclusion: Two-dimensional and Doppler echocardiography allow rapid, reliable, noninvasive assessment of hemodynamic parameters in critically ill obstetric patients and may give the clinician valuable information that may influence therapeutic and clinical management.

Objective: To compare the tocolytic effects of magnesium sulfate, ritodrine, terbutaline, and nifedipine on human myometrial strips., Methods: Myometrial strips were suspended in organ chambers for isotonic measurements and contracted with KCI. STrips from nonpregnant patients were used to obtain concentration-response curves. Myometrial strips from pregnant uteri were then exposed to the molar concentrations causing 50% relaxation in the nonpregnant tissues., Results: In strips from nonpregnant patients, nifedipine was found to be the most potent tocolytic. Using strips from nonlaboring patients, nifedipine caused relaxation similar to ritodrine, and both were more effective than magnesium sulfate or terbutaline. Combinations were more effective than single agents. These agents were found to be equally less effective in myometrial strips from laboring patients., Conclusions: Nifedipine, alone or in combination, relaxes myometrial strips more effectively than the other agents studied. Myometrial strips from laboring patients are more resistant to inhibition, with none of the agents being superior.

Objective: Our purpose was to determine the effects of orally administered nimodipine on selected maternal and fetal parameters in patients with preeclampsia., Study Design: Ten consecutive patients were given 30 mg of nimodipine orally every 4 hours from admission until 24 hours after delivery. Maternal and fetal cerebral blood velocity, umbilical artery blood velocity, fetal heart rate variability, maternal blood pressure and heart rate, and transplacental passage of the drug were studied. All 10 patients were delivered within 24 hours of the first dose of nimodipine., Results: There was an acute and significant reduction in the pulsatility index in the smaller diameter maternal cerebral arteries (ophthalmic and central retinal) and in the fetal middle cerebral artery. The umbilical artery systolic/diastolic ratio was also significantly reduced. Maternal blood pressure was controlled without the need for other antihypertensive medication, and although there was an increase in heart rate after administration of the drug, it was well tolerated. Nimodipine reached significant maternal and fetal levels within 2 hours., Conclusions: Nimodipine is rapidly absorbed after oral administration and has significant maternal and fetal cerebral vasodilator activity. It is an effective, easily administered antihypertensive agent when used in patients with preeclampsia.

Objectives: We aimed to investigate the relation between orbital vessel flow velocity and oxygen delivery, oxygen consumption, cardiac index, and systemic vascular resistance index in critically ill pregnant patients., Study Design: Eighteen pregnant or early postpartum patients requiring invasive monitoring were prospectively studied with Doppler ultrasonography. The blood flow velocity and resistance index from the central retinal and ophthalmic arteries were plotted against the oxygen delivery index, oxygen consumption index, cardiac index, and systemic vascular resistance index. Linear and polynomial regression analysis and receiver-operator characteristic curves were used to examine the data., Results: The ophthalmic artery resistance index correlated with oxygen consumption, oxygen delivery index, and cardiac index. Only the cardiac index was independently related to the the ophthalmic artery resistance index. The ophthalmic artery diastolic velocity correlated with oxygen consumption index, oxygen delivery index, and cardiac index. The ophthalmic artery diastolic velocity correlated independently with mixed venous oxygen content and arteriovenous oxygen content difference. The central retinal artery Doppler index did not correlate with any of the invasively measured parameters. An ophthalmic artery diastolic velocity of > 7.12 cm/sec identified 75% of patients with an oxygen consumption index of < 140 ml/min per square meter and 91% of patients with an oxygen delivery index of < 600 ml/min per square meter., Conclusions: These data suggest that the ophthalmic artery flow velocity is correlated with systemic oxygen delivery and consumption. This relationship may have potential research applications in the noninvasive assessment of oxygen delivery index and oxygen consumption index in critically ill pregnant patients.

Objective: To determine the relation between magnesium sulfate therapy and fetal heart rate (FHR) variability., Methods: Twelve women diagnosed with preeclampsia who were to receive magnesium sulfate for seizure prophylaxis were recruited. Exclusion criteria included delivery anticipated within 2 hours, gestational age less than 28 weeks, abnormal fetal testing, fetal growth retardation, and use of illicit drugs or medications. Six grams of magnesium sulfate in 100 mL 0.9% saline was administered intravenously over 20 minutes, followed by a continuous infusion of 2 g/hour. A cardiotocogram analysis computer system was used to analyze various elements of the FHR pattern before, during, immediately after, and 60 minutes following magnesium sulfate loading. For each time interval, the basal heart rate, number of accelerations and decelerations, number of minutes of high and low variability, mean minute range variation, and the short-term (3.75-second interval) variability were measured., Results: There was a statistically significant decrease in short-term variability 60 minutes after initiation of therapy (6.7 +/- 2.0 versus 9.8 +/- 3.3 milliseconds; P = .003). Long- and medium-term variability did not change significantly after magnesium sulfate was administered., Conclusion: Although magnesium sulfate therapy was associated with an objectively measured, statistically significant decrease in short-term variability, the decrease was not clinically significant; furthermore, it was not associated with a decrease in long-term variability or in the number of accelerations measured.

Objective: Increased total body oxygen consumption requirements are usually met by increased oxygen delivery and increased oxygen extraction. In certain conditions (e.g., adult respiratory distress syndrome) the ability to increase oxygen extraction is lost, and any increase in oxygen consumption depends on increased oxygen delivery. The objective of this study was to investigate the oxygen delivery/oxygen consumption relationship in severe preeclampsia., Study Design: Thirty-two patients with severe preeclampsia (blood pressure > 160/110 mm Hg; 3 to 4+ proteinuria) were monitored with a pulmonary artery catheter. Baseline oxygen consumption and delivery in a group without volume expansion or pharmacologic vasodilatation were compared with those in a group who had received a magnesium sulfate infusion., Results: Oxygen consumption, oxygen delivery, arterial-venous-oxygen difference, and the oxygen extraction ratio were low when compared to that for normal 32 to 38 week pregnancy. The oxygen extraction ratio, defined as the ratio of oxygen consumption to oxygen delivery, was abnormally low for pregnancy, especially considering the low oxygen delivery levels in these patients. Oxygen consumption was dependent on oxygen delivery over the entire range of values seen., Conclusions: Severe preeclampsia is associated with an abnormality of tissue oxygen extraction, as evidenced by a low and unresponsive oxygen extraction ratio. Oxygen consumption increases proportionately with increases in oxygen delivery without reaching an oxygen delivery-independent state. Even at high oxygen delivery levels the oxygen consumption in preeclamptic patients is still abnormally low for pregnancy.

Objective: To determine whether fetal anemia secondary to maternal red-cell alloimmunization is associated with thrombocytopenia., Methods: The records of 78 patients undergoing intrauterine transfusion for red-cell alloimmunization were reviewed. Pre-transfusion fetal platelet counts were compared between hydropic and nonhydropic fetuses. A regression analysis was performed between the fetal platelet counts and the fetal bilirubin levels, hematocrits, and reticulocyte counts taken at the initial transfusion. The hematocrits, reticulocyte counts, and bilirubin levels were adjusted for gestational age by calculating the number of standard deviations (SDs) from the mean for that age or the multiples of the mean (MOM). Student t test, Pearson coefficient, and contingency table randomization test were used to analyze the data. P < .05 was considered significant., Results: Thirty-seven fetuses were hydropic and 41 were nonhydropic. Hydropic fetuses had a significantly lower platelet count than nonhydropic fetuses (197.5 +/- 86.4 versus 252.6 +/- 73.7 x 10(3)/microL; P < .01). Platelet counts correlated negatively with the reticulocyte count MOM (r = -0.652; P < .01) and the hematocrit SDs below the mean (r = -0.659; P < .01), but did not correlate with the bilirubin MOM (r = -0.183; P = .2)., Conclusion: Hydropic and severely anemic fetuses are at increased risk for thrombocytopenia. We suggest that increased erythropoiesis diverts the hematopoietic stem cell away from thrombopoiesis.

The purpose of this study was to evaluate the effects of magnesium sulfate on maternal and fetal blood flow in pregnancy-induced hypertension. Twelve patients with pregnancy-induced hypertension were prospectively studied with transcranial pulsed Doppler and transabdominal color flow Doppler before and after infusion of a 6 gram intravenous loading dose of magnesium sulfate. The maternal vessels studied included the middle cerebral, common carotid, and internal carotid arteries. The fetal vessels studied included the middle cerebral, renal, and umbilical arteries. In addition the maternal circulation in the placental base plate was imaged. The results of this descriptive study suggest that a 6 gram loading dose of magnesium sulfate significantly vasodilates the vascular bed distal to the maternal middle cerebral artery, and increases blood velocity in this distribution. There was no significant change in pulsatility index or blood velocity in the central large vessels of the head and neck. There were no acute effects noted in the fetal or placental vessels evaluated.

This case report demonstrates retinal vasospasm during a period of visual disturbance in a patient with preeclampsia. Doppler assessment of the orbital vasculature was performed during and after the episode. Central retinal artery blood velocity increased, and resistance decreased, after resolution of symptoms. Visual disturbances in preeclampsia may be associated with retinal artery vasospasm and ischemia.

Color flow Doppler ultrasonography was used to demonstrate a significant and sustained reduction in the central retinal artery pulsatility index after administration of the calcium antagonist nimodipine to a patient with eclampsia. Nimodipine is an effective cerebral vasodilator and may be useful in the management of eclamptic patients with severe vasospasm.

The purpose of this study was to determine whether the need for late neonatal transfusion can be predicted in fetuses who received intrauterine transfusions. The records of 36 patients who underwent intrauterine transfusion were reviewed. Newborns who required late transfusions had a lower reticulocyte count at their last intrauterine transfusion, a longer duration between their lowest fetal reticulocyte count and delivery, and a higher umbilical cord blood hemoglobin and percent adult red cells on Kleihauer-Betke stain at delivery. The need for late transfusions appears to be related to the extent and duration of fetal bone marrow suppression.

Objectives: Our purpose was to determine the effect of a 6 gm intravenous bolus of magnesium sulfate on maternal retinal blood flow velocity waveforms in patients with preeclampsia., Study Design: Twenty-two patients were randomized to two groups and were studied with color flow Doppler before and immediately after infusion of either 6 gm of magnesium sulfate or placebo. The central retinal and posterior ciliary arteries were studied., Results: Magnesium sulfate significantly reduced the pulsatility index (p < 0.005) in both vessels (change in pulsatility index = 0.26 +/- 0.23 for central retinal and -0.22 +/- 0.15 for posterior ciliary) when compared with placebo (change in pulsatility index = 0.02 +/- 0.10 for central retinal and -0.03 +/- 0.09 for posterior ciliary)., Conclusions: These data suggest that magnesium sulfate dilates the vessels distal to the central retinal and posterior ciliary arteries. Changes in pulsatility index in the retinal arteries may be indicative of similar changes in other cerebral vessels.