Intrapartum management of nonvertex second-born twins: a critical analysis.

OBJECTIVE: Our purpose was to assess the impact of the mode of delivery--vaginal delivery versus cesarean section--on the perinatal outcomes of the second-born breech twins. STUDY DESIGN: This study was a retrospective analysis of second-born breech twins with a gestational age of > or =24 weeks at the onset of labor. The patients are divided into three groups: cesarean section without labor (group I), cesarean section after labor (group II), and vaginal breech delivery (group III). RESULTS: There were 141 patients: 40 in group I, 66 in group II, and 35 in group III. There was no birth injury or neonatal death. Group II had one fetus with grade II intraventricular hemorrhage. There was no significant difference among the groups with regard to gestational age, birth weight, hyaline membrane disease, Apgar scores at 1 and 5 minutes, and cord blood gas indices, except venous pH in infants with birth weights <1500 g. CONCLUSIONS: Vaginal delivery of breech second-born twins, with gestational ages of at least 24 weeks, especially those with birth weights of > or =1500 g, appears to be a safe alternative to cesarean section.

A new device for measuring intrauterine temperature.

OBJECTIVE: We evaluated a new device that uses the intrauterine pressure catheter to measure the maternal temperature in patients who are in labor. STUDY DESIGN: The study was conducted at two medical centers, Christiana Hospital in Newark, Delaware, and Saint Louis University/St Mary's Health Center in St Louis, Missouri, from September 1, 1997, to May 2, 1998. An intrauterine pressure catheter with a thermistor sensor in the tip was placed into the uterus after spontaneous rupture of membranes. The intrauterine, oral, and tympanic temperatures were simultaneously obtained immediately after insertion of the intrauterine pressure catheter and then hourly until delivery or the initiation of amnioinfusion. RESULTS: The study comprised 97 patients and 404 temperature readings with a temperature range of 34.7 degrees C to 40.7 degrees C. The normal mean +/- SD for the oral, tympanic, and intrauterine temperatures was 36.7 degrees C +/- 0.5 degrees C, 36.8 degrees C +/- 0.5 degrees C, and 37.3 degrees C +/- 0.4 degrees C, respectively. There was a linear relationship among the oral, tympanic, and intrauterine temperatures. All three methods showed a significant increase in mean body temperature after epidural anesthesia. CONCLUSION: The new device, the intrauterine pressure-temperature catheter, provides a convenient and accurate means of continuously measuring uterine temperature in patients who are in labor and require intrauterine monitoring.

Does preeclampsia influence fetal lung maturity?

OBJECTIVE: This retrospective study compared the fetal lung maturity biochemical profile of patients having preeclampsia with that of patients having preterm labor. STUDY DESIGN: Amniotic fluid was obtained by transabdominal amniocentesis in 90 patients, 59 patients with preterm labor (PTL) and 31 patients with preeclampsia (PRE). Pregnancies with fetal growth restriction were excluded. Fetal lung maturity was assessed by lecithin/sphingomyelin ratio (L/S) and by a fluorescence polarimetry assay (FLM). Mean values of L/S ratios and FLM were compared between the PTL and the PRE groups, each within two gestational age subgroups (27-32.9 weeks gestation and 33-36 weeks gestation). Student t-test, Chi-square test Fisher's exact test were used for statistical analysis. A p value < 0.05 was considered significant. RESULTS: During the gestational age interval of 33-36 weeks, the mean L/S ratios were significantly lower in pregnancies complicated by PRE than in those complicated by PTL (1.99 +/- 0.26 and 2.4 +/- 0.57, respectively; p = 0.01). Similarly, during this gestational age interval, the FLM values were also lower in PRE than in PTL, although the difference did not reach statistical significance. CONCLUSION: During the gestational age between 33 and 36 weeks of gestation, the biochemical profile of preeclamptic patients without IUGR has a significant lower L/S ratio compared to that of preterm patients.

Neonatal pulmonary hypoplasia and perinatal mortality in patients with midtrimester rupture of amniotic membranes--a critical analysis.

OBJECTIVE: We sought to critically assess the risk factors for neonatal pulmonary hypoplasia and perinatal death in patients with preterm rupture of the amniotic membranes from 15 to 28 weeks' gestation. STUDY DESIGN: This was a prospective cohort study. The study patients had preterm rupture of the amniotic membranes at 15 to 28 weeks' gestation and were without fetal anomalies, multiple gestation, and oligohydramnios before rupture of the membranes. The amniotic fluid volume index was determined at admission and weekly afterward until delivery. RESULTS: The incidence of pulmonary hypoplasia was 12.9% (21/163). The overall perinatal mortality rate was 54% (88/163). Logistic regression analysis revealed the following: (1) Gestational age at rupture of the membranes, the latency period, and either the initial or the average amniotic fluid index have significant influence on the development of pulmonary hypoplasia; (2) gestational age at rupture of the membranes and latency period are significant factors in predicting perinatal death. CONCLUSIONS: In this large population of patients with rupture of membranes at 15 to 28 weeks' gestation, gestational age at rupture of the membranes, latency period, and amniotic fluid index were important independent predictors of neonatal pulmonary hypoplasia. In addition, gestational age at rupture of the membranes and latency period were important independent determinants of perinatal death. Expectant management of patients with preterm rupture of the amniotic membranes during this gestational age interval was associated with improved perinatal survival, even though it may increase the risk of pulmonary hypoplasia.

Impact of oligohydramnios on maternal and perinatal outcomes of spontaneous premature rupture of the membranes at 18-28 weeks.

OBJECTIVE: We compare the maternal and perinatal outcomes between 69 patients with oligohydramnios and 49 patients with adequate fluid at the time of initial evaluation for PROM. METHODS: One hundred and eighteen patients with spontaneous premature rupture of the membranes (PROM) at 18-28 weeks are included in the study. Inclusion criteria are singleton gestation, normal fetal anatomical survey and normal amniotic fluid prior to PROM, and absence of labor or abruption at the time of PROM. Oligohydramnios is defined as an amniotic fluid index (AFI) <5 cm of measurable pockets of amniotic fluid which are free of umbilical cord. Expectant management was carried during the 3-year period. The overall perinatal survival is 66%. Pulmonary hypoplasia is present in 18%, and skeletal deformities in 3% of all neonates. RESULTS: There is no significant difference between the two groups in the mean gestational ages at PROM (172+/-17 d vs. 171+/-14 d), latency periods (9+/-14 d vs. 8+/-13 d), incidences of chorioamnionitis (48 vs. 39%), endometritis (19 vs. 14%), neonatal sepsis (11 vs. 13%), or skeletal deformities (6 vs. 0%). Patients with oligohydraminos have significantly higher incidences of fetal heart rate decelerations (59 vs. 38%) and C-section (38 vs. 16%) (P < 0.05) than patients with adequate amniotic fluid. CONCLUSIONS: After adjusting for confounding variables, neonates with oligohydramnios are twice as likely to develop pulmonary hypoplasia (20 vs. 10%) and more likely to experience neonatal death (30 vs. 20%) when compared to those with adequate fluid, even though the difference is not statistically significant.

Role of fetal echocardiography in the management of isolated fetal heart block with ventricular rate <55 bpm.

Persistent bradycardia is an uncommon cardiac problem in fetuses but carries a high mortality in those with a ventricular rate <55 bpm. Fetal heart block is one of the most common causes of persistent fetal bradycardia (PFB). An optimal method for assessing and monitoring cardiovascular compensation in the setting of PFB due to heart block has not been fully established. We report the application of two-dimensional and Doppler echocardiography in close monitoring of cardiac function and hemodynamics in a third-trimester fetus with a ventricular rate <55 bpm due to heart block, which assisted in successful management of the pregnancy to term. Hemodynamic and cardiac adaptive changes in compromised fetuses, particularly due to heart block, are discussed.

Effects of serum from preeclamptic women on prostacyclin production by human endothelial cells.

There is growing evidence that proteinuric hypertension of pregnancy (preeclampsia) is associated with endothelial dysfunction. The aim of this study was to evaluate the effects of serum from preeclamptic patients on basal and agonist-stimulated prostacyclin production by human umbilical vein endothelial cells (HUVEC) in culture and to compare these to the effects of serum from normal pregnant and nonpregnant women. During a 24 h incubation of HUVEC with 20% of preeclampsia serum, baseline prostacyclin output was significantly (P < 0.01) increased over the control groups. However, this response was attenuated by extending the exposure to 72 h. Histamine, thrombin and the calcium ionophore, A23187, all acutely increased prostacyclin production, but the increase relative to baseline levels was greatest in HUVEC preincubated for 24 h in normal serum transiently promotes prostacyclin production in HUVEC derived from normal pregnancies, preeclampsia serum transiently promotes prostacyclin production in HUVEC derived from normal pregnancies, and 2) the relative increase in response to agonists is reduced by preeclampsia serum, compared to normal pregnancy sera.

The neonatal bisacromial diameter: a prenatal sonographic evaluation.

This study was designed to determine which fetal ultrasonographic parameter best correlates with the neonatal bisacromial diameter (BAD). The latter is defined as the distance between the two acromions of the scapulae. The study population included fifty-four uncomplicated singleton pregnant patients whose infants with birth weights of more than 3000 grams were delivered within a week of ultrasound examinations. Six fetal biometric parameters: circumferences of the chest, abdomen, head, arm, and thigh, and estimated fetal weight were obtained by ultrasonography and were compared with the BAD. The best predictor of the neonatal bisacromial diameter was the fetal chest circumference (r = 0.67, p = 0.003) followed by the arm circumference, (r = 0.59, p = 0.03). The fetal chest circumference correlates well with the neonatal shoulder girth as reflected by the neonatal bisacromial diameter.

Feasibility of an obstetrician-based cord blood collection network for unrelated donor umbilical cord blood banking.

The purpose of this study was to evaluate the feasibility of an obstetrician-based cord blood collection system for the purpose of banking cord blood for unrelated donor hematopoietic stem cell transplantation. Over 200 delivering physicians and 40 area obstetrical units were educated and became involved in the collection of cord blood during the third stage of labor. These products compared favorable with those obtained after placental delivery. Issues involved in the development of quality assurance for unrelated donor banking are discussed. An obstetrician-based cord blood collection network is feasible and advantageous in that cord blood can be collected from a wider variety of communities, thus enhancing the ethnic diversity of a bank.

Fetal responses to maternal exercise: effect on fetal breathing and body movement.

This study was conducted to determine the impact of maternal exercise on fetal breathing and fetal body movement, which are commonly used for assessing fetal well-being. Twelve healthy patients with a range of gestational ages of 26 to 36 weeks, who actively exercised throughout pregnancy, participated in the study. The patients walked on a motorized treadmill using a modified Bruce protocol until the maternal heart rate reached 75% of the age-predicted maximal heart rate. Fetal activities (fetal breathing and fetal body movement) were continuously monitored with real-time ultrasonography for 20 minutes before and after the standardized exercise test. Our results demonstrate that there is a significant increase in maternal heart rate and blood pressure associated with exercise. In addition, there is a significant decrease in the total duration and frequency of fetal breathing and fetal body movements following acute maternal exercise.

Fetal nonmuscular soft tissue: a prenatal assessment.

In this study, the fetal nonmuscular soft tissue is evaluated prenatally in 52 uncomplicated singleton pregnancies at 36 weeks of gestation or later. The means and standard deviations of the NMST at the midarm region and the ratio of NMST to HL are 6.0 +/- 1.0 mm and 0.08 +/- 0.02, respectively. No correlation was seen between the NMST and birth weight.

Comparison of fetal lung maturation in preterm singleton and twin pregnancies.

Preterm labor or premature rupture of membranes is one of the major complications of twin pregnancies and contributes to the increased maternal and perinatal morbidity and mortality. Forty-seven twin pregnancies and a comparable group of singleton pregnancies constitute the study population. These patients' pregnancies were complicated only by preterm labor. The lecithin to sphingomyelin ratio is used as an index of fetal lung maturation. Analysis of the data reveals that fetal lung maturation is biochemically comparable between twin and singleton pregnancies and among twins for a given gestational age in this clinical setting.

Use of the fetal chest in estimating fetal weight.

OBJECTIVE: This study was designed to develop formulas using the chest circumference instead of the abdominal circumference for estimating fetal weight. STUDY DESIGN: Ultrasonographic measurements of the chest circumference, biparietal diameter, abdominal circumference, humeral length, and femoral length were obtained in 75 term fetuses of uncomplicated pregnancies within 24 hours of delivery. Three equations for fetal weight estimation that used the chest circumference, instead of the abdominal circumference, in combination with the biparietal diameter or the humeral length were developed by regression analysis. RESULTS: The average mean errors of fetal weight estimation for these equations vary from 7.1% to 7.6%. CONCLUSIONS: These equations may be used in predicting the birth weight when the fetal abdomen is altered by certain fetal abnormalities.

Isolated fetal ascites: prenatal diagnosis and management.

The perinatal outcomes of four patients with isolated fetal ascites were evaluated. The ascites disappeared prior to delivery in 50% of the cases and was resolved shortly after delivery in the remainder. Excellent neonatal outcomes were observed. Thus, isolated fetal ascites may represent a separate condition that significantly differs from the general category of nonimmune hydrops in both perinatal courses and prognoses. The prenatal diagnosis and management of this condition are discussed.

Does pregnancy alter the rate of progression of diabetic nephropathy?

The effect of gestation on the rate of decline in renal function was studied in 11 pregnancies complicated by diabetic nephropathy. For each pregnancy, serum creatinine levels were available within 4 years before pregnancy, during pregnancy, and within 4 years after delivery. Although all of these patients were hypertensive and had increased proteinuria during pregnancy, the mean serum creatinine just prior to conception (1.3 +/- 0.5 mg/dl) and the last follow-up value (1.2 +/- 0.3 mg/dl) were not significantly different. When the inverse of serum creatinine (1/Scr) was used to estimate creatinine clearance, the renal function was either improved or remained stable in the majority of the pregnancies (7 of 11). The observed decline in renal function through the end of follow-up appeared to be consistent with the expected natural course of diabetic nephropathy in the absence of pregnancy. Furthermore, the slope for inverse serum creatinine before and after pregnancy was not significantly different. In conclusion, pregnancy in patients with mild to moderate diabetic nephropathy does not seem to accelerate the rate of decline in renal function.

Sonographic assessment of growth of the fetal head in diabetic pregnancies compared with normal gestations.

A longitudinal ultrasound study was conducted in 45 insulin-dependent diabetic patients who maintained good glycemic control (mean plasma glucose less than 120 mg/dl) throughout most of their pregnancy in order to assess growth of the fetal head in the presence of euglycemia. Patients with and without vasculopathy were found to be comparable with regard to their glycemic control, medical and obstetric complications, as well as incremental growth and the velocity of growth of the fetal biparietal diameter (BPD). When compared with the control group, the velocity of growth of the BPD was not significantly different throughout pregnancy. However, the actual increment in BPD growth remained less than that of the control fetuses, especially during the second trimester when a significant statistical difference was found. Possible explanations may include delayed ovulation, reduced growth velocity in the first trimester, or constitutionally smaller embryos among the diabetic group. The pattern of BPD growth among diabetics was best described by a third degree polynomial regression equation. These results demonstrate that in well-controlled diabetics, although the increment in BPD was less than controls, the growth pattern of the fetal BPD was similar among the White classes B to FR, and the velocity of growth of the BPD was similar among diabetics and nondiabetics.

Hypersomatotropism in pregnant women, as measured by a human liver radioreceptor assay.

Radioreceptor assays (RRAs) provide useful information about the bioactivity of peptide hormones. We have developed a RRA for human GH using membranes prepared from human liver. The assay has 1% cross-reactivity with human PRL, 0.11% cross-reactivity with human chorionic somatomammotropin, and negligible cross-reactivity with bovine and rat GH. The assay has distinct advantages over the IM-9 lymphocyte RRA in having reduced nonspecific interference from serum proteins and providing a uniform source of receptors which can be stored for long periods at -70 C. The coefficient of variation of the assay is 13%. In studies of 55 sera from short children with normal or elevated serum GH concentrations the mean ratio of RRA GH to immunoradiometric assayed GH was 1.28. This assay provided important information about the total GH activity in pregnancy. There was a progressive rise in RRA GH during pregnancy, reaching 64.7 +/- 2.5 (+/- SE) micrograms/L at term. This level is 2-3 times higher than suggested by earlier estimates made with monoclonal antibody RIAs for pituitary GH. At term the contributions to total GH activity of serum are less than 3% from the pituitary, 12% from human chorionic somatomammotropin reacting with the GH receptor, and 85% from placental GH. Despite this great increase in receptor-reactive GH, somatomedin activity by bioassay is reduced, and IGF-I, determined by RIA after acid-gel filtration, is minimally elevated.

Ultrasonographic criteria for the prenatal diagnosis of placental chorionicity in twin gestations.

Thirty-two patients with uncomplicated twin pregnancies had ultrasonographic examinations for genetic amniocentesis, confirmation of twinning, or assessment of fetal growth. The dividing membranes between the fetuses were visualized, and the thickness of the membranes was measured. With a thickness of 2 mm used as a cutoff point, the accuracy in predicting monochorionic or dichorionic twinning was 82% and 95%, respectively. Prenatal assessment of these dividing membranes may be helpful in the management of twin gestations.