Management of immune haemolytic disease in the fetus.

Although Rh alloimmunization has been successfully reduced in frequency and severity since the implementation of Rh immune globulin, cases still occur. The management of affected pregnancies requires the efforts of a team which includes obstetrics/fetal medicine, the blood transfusion service, haematological support, nursing assistance and neonatology. The aim of antenatal management is to predict whether or not the fetus is severely affected, to correct the fetal anaemia and to deliver the baby at the optimal time. The management has improved markedly with the introduction of high-resolution real-time ultrasound, fetal blood sampling, intravascular fetal blood transfusion and/or intraperitoneal transfusion and meticulous fetal surveillance. With appropriate and timely management in severely alloimmunized patient, the survival rate of affected fetuses in some centres is now about 90%. There is still a need for research into new methods of treatment such as high dose intravenous immunoglobulin, which might non-invasively diminish fetal red cell destruction. Due to the reduced frequency of severe disease, regionalized treatment centres are essential in order to maximize the experience and efficiency of the management teams.

Fetal macrocytosis in association with chromosomal abnormalities.

Mean red cell volume (MCV) was determined in 264 fetuses between 15-41 weeks. After exclusion of anemic, hypoxic, and chromosomally abnormal fetuses, the MCV in 208 umbilical venous samples was shown to decrease with gestation (r = 0.64; P less than .001), and a normal range was constructed by linear regression analysis. An elevated MCV was found in both fetuses with triploidy, in four of five with monosomy X, and in four of ten with trisomies 18 or 21. The MCV was similarly raised in four of five fetuses with gross anomalies in whom cytogenetic cultures had failed. Significant correlations were found in chromosomally abnormal fetuses between the elevation in MCV and both the nucleated red cell (r = 0.69; P less than .01) and reticulocyte counts (r = 0.57; P less than .05). There was a similar correlation with nucleated red cells in 16 severely anemic fetuses with Rh disease, 12 of whom had a raised MCV. Elevation in MCV was unrelated to hypoxia. Macrocytosis had a sensitivity of 71% and a specificity of 95% in the second trimester for predicting an abnormal karyotype in nonanemic fetuses (kappa index 0.60). Fetal MCV may provide clinically useful information while one awaits culture results. We suggest that karyotyping be considered in fetuses undergoing blood sampling for other indications in whom the MCV is raised.

Fetal blood sampling from the intrahepatic vein: analysis of safety and clinical experience with 214 procedures.

Transabdominal fetal blood sampling under ultrasonic guidance was performed at the intrahepatic vein on 214 occasions in 177 fetuses. In 72 cases, an intravascular transfusion was also attempted at the same site. In 91.1% of the samplings, more than 1 mL of pure fetal blood was obtained, and in 89.9% of transfusions, fetal hematocrit or platelet concentration was raised to a satisfactory level. Fetal bradycardia and intraperitoneal bleeding occurred in 2.3% of the cases. Among fetuses at low risk, there was only one intrauterine death, which occurred 3 weeks after the procedure, and one spontaneous abortion in a patient with twin pregnancy. In fetuses with Rh/Kell alloimmunization or perinatal alloimmune thrombocytopenia, the survival rate was 86%. Four liver enzymes were assayed in the blood of 13 fetuses that underwent transfusions at the intrahepatic vein and 13 controls in whom the site of sampling was the umbilical vein at the placental cord insertion. No differences were found between the groups at the subsequent transfusion 2-5 weeks later. The intrahepatic vein is an alternate site of sampling/transfusion when access is difficult or failure occurs at the placental cord insertion. This approach minimizes the risks of fetal blood loss, fetomaternal hemorrhage, arterial vasospasm, and cord tamponade.

Amniotic pressure in disorders of amniotic fluid volume.

Amniotic pressure was measured in 49 pregnancies with abnormal quantities of amniotic fluid. Among 17 with polyhydramnios, the pressure was always above the normal mean for gestation and exceeded the upper limit of normal in nine. In polyhydramnios, amniotic pressure correlated positively with the depth of the deepest pool (r = 0.65, P = .04) and negatively with fetal PO2 (r = -0.57, P = .03) and pH (r = -0.56, P = .04). Amniotic pressure was raised in all those with a deepest pool of greater than 15 cm, and was normal in all with a deepest pool less than 15 cm. Amniotic pressure fell significantly with drainage of amniotic fluid in those with raised pressure (mean 12.7 mmHg, 95% confidence interval 7.0-18.3; P = .002) but not in those with normal pressure (mean 0.3, 95% confidence interval -3.2 to +3.9; P = .82). Restoration of normal amniotic pressure in one pregnancy was accompanied by marked improvement in fetal acid-base status. Among 24 pregnancies with severe oligohydramnios, amniotic pressure was always below the normal mean, falling below the lower limit of normal in eight; whereas in another eight pregnancies with mild/moderate oligohydramnios, amniotic pressure was scattered evenly within the normal range. Amnioinfusion of 55-500 mL of normal saline in cases of severe oligohydramnios led to a significant rise in pressure (4.7 mmHg, 95% confidence interval 3.5-5.9; P less than .0001). We conclude that amniotic pressure is high in polyhydramnios and low in oligohydramnios. Pressure monitoring may be beneficial during amnioinfusion and therapeutic amniocentesis.

Endocrine pancreatic function in growth-retarded fetuses.

Maternal-fetal glucose gradient and fetal plasma glucose, insulin, and glucagon were measured in 63 fetuses: 34 controls and 29 with growth retardation (nine with and 20 without end-diastolic frequencies in the umbilical artery). Maternal-fetal glucose gradient and fetal glucagon levels were higher in the growth-retarded group than in controls (P less than .001), whereas fetal insulin and glucose concentrations were lower (P less than .001). Although maternal-fetal glucose gradient, fetal glucose, and insulin concentrations were similar among the growth-retarded fetuses, fetuses without end-diastolic frequencies in the umbilical artery had higher fetal glucagon levels (P = .01) than those with end-diastolic frequencies. In growth-retarded fetuses, the increase in fetal glucagon might reflect a compensatory response to hypoglycemia and appears to be a better index of fetal compromise than is glucose or insulin.

Production of urinary 11-keto-thromboxane B2 in normal and hypertensive pregnancies.

Urinary levels of 11-keto-thromboxane B2 (11-keto-TXB2), were elevated at all gestational ages (12-41 weeks) compared with non-pregnant levels. 11-keto-TXB2 levels exceeded those of TXB2 throughout pregnancy, which suggested that 11-keto-TXB2 may be the major urinary metabolite of TXA2 in normotensive pregnancy, as in the non-pregnant state. This was reversed in women with mild pregnancy-induced hypertension (P.I.H.), such that urinary levels of TXB2 were higher (p less than 0.01) than those of 11-keto-TXB2. Since the 11-thromboxane dehydrogenase enzyme is found in the placenta, the low levels of 11-keto-TXB2 may be the result of placental damage decreasing the activity of the enzyme. The relationship between these findings and the aetiology of P.I.H. is not clear, but changes in urinary 11-keto-TXB2 may be of use in identifying those women at risk of developing P.I.H.

Fetal blood sampling from the intrahepatic vein for rapid karyotyping in the second and third trimesters.

One hundred and twelve fetuses with structural anomalies (n = 84), intrauterine growth retardation (n = 21) or amniotic fluid volume disorders (n = 7) detected by ultrasound underwent blood sampling from the intrahepatic vein for rapid karyotyping. The procedure was successful in 95.5%. 12.5% of the fetuses had an abnormal karyotype. Fetal bradycardia was observed in two fetuses (1.8%) and intraperitoneal bleeding in three (2.7%). There were three procedure-related losses but these were not due to the intrahepatic vein sampling itself. Fetal blood sampling is the method of choice for rapid karyotyping in the second and third trimesters, and the intrahepatic vein is an alternate site when access is difficult or failure to sample occurs at the placental cord insertion. Additional advantages of fetal blood sampling at the intrahepatic vein include absence of cord complications, reduced risk of fetal blood loss and fetomaternal haemorrhage, and the lack of need to confirm the fetal origin of the sample.

Vibroacoustic stimulation is not associated with sudden fetal catecholamine release.

The safety of vibroacoustic stimulation (VAS), which produces marked changes in fetal heart rate, movements and behavioural state, remains unclear. In order to determine whether VAS is associated with catecholamine release, we measured plasma noradrenaline and adrenaline in 13 appropriately grown normoxaemic fetuses between 28 and 40 weeks gestation immediately before and 60 and 75 s after VAS. Over this time interval, VAS is known to increase fetal heart rate. There was no significant change in either noradrenaline (median change = +0.06 ng/ml, P = 0.26) or adrenaline levels (median change = +0.03 ng/ml, P = 0.4). This study suggests that sympathoadrenal activation is not part of the fetal response to VAS. These findings do not support the recent suggestion that VAS may be deleterious to the fetus by provoking sudden release of catecholamines.

Intra-amniotic pressures following vaginal gemeprost prior to first and second trimester termination of pregnancy.

Intra-amniotic pressures were measured following 1 mg gemeprost for cervical preparation before first trimester vacuum aspiration (n = 10) and following 2 mg gemeprost before second trimester dilatation and evacuation (n = 15). Twenty-five women, matched for gestational age and parity, who did not receive gemeprost served as controls. Compared to control values (2-8 mmHg), basal intra-amniotic pressure (IAP) was significantly increased after 1 mg and 2 mg of gemeprost (median 20.0, range 4-45 mmHg, median 20.0, range 8-60 mmHg, respectively). Uterine contractions were recorded in 8 of 10 subjects after 1 mg (median delta IAP 28.0, 95% CI 10.0-42.6 mmHg) and 14 of 15 subjects after 2 mg (median delta IAP 52.5, 95% CI 26.7-60.3 mmHg). Gemeprost produces an increase in uterine contractility which may be additional to cervical softening properties and which may be responsible for the adverse effects of pain and bleeding experienced by some women prior to termination.

Fetal loss in threatened abortion after embryonic/fetal heart activity.

OBJECTIVES: To study the incidence of fetal loss in threatened abortion after detection of embryonic/fetal heart activity. METHODS: A prospective study was performed on pregnant women with clinically diagnosed threatened abortion between 6 and 14 weeks of gestation. All had a good menstrual history and the calculated gestational age using crown-rump length in the first trimester ultrasound was in agreement. Embryonic/fetal heart rate measurements were obtained by a 5 MHz vaginal probe using M-mode and real-time B mode imaging. All cases were followed up with respect to pregnancy outcomes. The data were analyzed using the SPSS computer program. RESULTS: Eighty-seven pregnant women were included in the study. There were three pregnancies (3.4%) which resulted in fetal loss before 20 weeks of gestation. In viable pregnancies, the mean embryonic/fetal heart rate increased with advancing gestational age. The individual values of embryonic/fetal heart rate for fetal losses were within the reference range. CONCLUSIONS: The incidence of fetal loss in threatened abortion after detection of embryonic/fetal heart activity was 3.4%. There was no evident pattern of bradycardia or tachycardia that signaled the incipient of viability.

Cut-off criteria for second-trimester nuchal skinfold thickness for prenatal detection of Down syndrome in a Thai population.

OBJECTIVE: To evaluate the use of progressive cut-offs for nuchal skinfold thickness with advancing gestational age and the commonly applied cut-off method (> 6 mm) for prenatal detection of Down syndrome in a Thai population. METHOD: A prospective study was performed by experienced perinatologists on 2150 women undergoing second-trimester amniocentesis for the indications of advanced maternal age and past history of chromosomal abnormality. Reference ranges were established for nuchal skinfold thickness from the 16th to the 24th week, using either gestational-specific centiles or the parametric method. Assaying different cut-off criteria for both centile and the parametric methods were calculated and then compared with the commonly applied cut-off level (> or = 6 mm.). RESULTS: There were 2114 chromosomally normal pregnancies, 19 fetuses with Down syndrome (1:113), and 17 other chromosome abnormalities. In fetuses with normal karyotype the nuchal skinfold thickness increased with advancing gestational age [NF (mm) = -0.502 + 0.212 GA (week), r = 0.36, P < 0.001]. The sensitivities of an abnormal nuchal skinfold thickness using different cut-off criteria for detecting Down syndrome were low (5.3-26.3%) with the false positive rates ranging from 2.5 to 16.5%. CONCLUSIONS: In this study, measurement of second-trimester nuchal skinfold thickness was a poor and unreliable screening test for fetal Down syndrome in a Thai population.

Evaluation of fetal femur length to detect Down syndrome in a Thai population.

OBJECTIVE: To assess the value of femur length shortening for prenatal detection of Down syndrome in a Thai population. METHOD: A prospective study was performed by experienced perinatologists on 3137 women undergoing second-trimester amniocentesis, between 16 and 24 weeks of gestation, for the indications of advanced maternal age and past history of chromosomal abnormality. Biparietal diameter and femur length measurements were obtained before the procedures. Regression equations relating biparietal diameter to femur length were used to calculate observed femur length/expected femur length ratio in the chromosomally normal and Down syndrome fetuses. Sensitivity, specificity, false-positive rate and likelihood ratio of a positive test result at various observed femur length/expected femur length ratios for detection of Down syndrome were calculated. A receiver-operator characteristic curve was used to determine threshold screening ratio. RESULTS: There were 3084 chromosomally normal pregnancies, 26 fetuses with Down syndrome (1:118), and 27 other chromosomal abnormalities. The relationship between femur length and biparietal diameter (BPD) was: expected femur length=-7.631+0.814 BPD, R(2)=0.78, P<0.001). Femur length in Down syndrome fetuses was significantly shorter than in normal fetuses (P<0.001). A ratio of 0.91 for observed femur length/expected femur length yielded a sensitivity of 42.3%, specificity of 86.2%, false positive rate of 13.8% and likelihood ratio of a positive test result of 3.07 (95% CI 1.94-4.84) for detection of Down syndrome. CONCLUSIONS: In this study, femur length shortening in the second trimester appears to be a useful screening parameter for fetal Down syndrome in a Thai population.

A comparative study of membrane stripping and nonstripping for induction of labor in uncomplicated term pregnancy.

A prospective, randomized controlled trial was undertaken at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn Hospital to determine whether stripping of the fetal membranes is a safe and effective method for induction of labor in uncomplicated term pregnancy. Ninety-six women were included in this study; 16 were excluded; 41 were randomized to a study group and 39 to a control group. Both groups had pelvic examination performed under sterile technique and a Bishop score was assessed. In the study group, membrane stripping was performed. Gentle pelvic examination for Bishop scoring was continued weekly in both groups. Thirty five of 41 women (85.4%) in the study group delivered within 7 days as compared to 22 of 39 women (56.4%) in the control group, a statistically significant difference (P = 0.004). A statistically significant difference was also observed with respect to the mean number of days to delivery (5.3 +/- 4.9 versus 9.5 +/- 5.9 days, respectively; P = 0.002). No statistically significant differences were observed in both maternal and fetal complications. In conclusion, membrane stripping is a safe and effective method for induction of labor in uncomplicated term pregnancy.

Vaginal vault granulations after total abdominal hysterectomy using polyglactin for vault closure.

The purpose of this study was to determine the incidence of vaginal vault granulation after total abdominal hysterectomy using polyglactin (Vicryl) for vault closure. Fifty women who underwent total abdominal hysterectomy for benign and elective conditions were included into the study. Standard surgical technique of total abdominal hysterectomy was employed except for closure of the vaginal vault performed by interrupted figure-of-eight sutures using No. 1 polyglactin. All patients were prospectively followed-up at approximately 6 weeks postoperatively and vaginal vault granulation was diagnosed as present or absent. It was found that 5 patients had vaginal vault granulation without any symptoms, giving the incidence of 10 per cent. One patient who developed vault granulation had postoperative morbidity from cuff cellulitis. The remaining 49 patients had no immediate postoperative complications.

Intrauterine-pressure studies in Thai nulliparous labour: the use of catheter-tip pressure transducer.

Uterine activity was studied in 35 nulliparous Thai women who were in the active phase of spontaneous labour, and who were delivered vaginally without supplementary oxytocin or assisted delivery. A catheter-tip pressure transducer coupled with a uterine activity integrator was used to measure and quantitate uterine activity. Progression of normal labour was defined as labour progressing along the Friedman's curve in the active phase. In nulliparous Thai women, the minimum level of uterine activity likely to be associated with labour progress was 322 kPas/15 min at 3 cm cervical dilatation. The mean and median levels in the active phase of normal labour were 1,075.6 and 952.0 kPas/15 min, respectively. There was a weak correlation (R = 0.3) between an increasing cervical dilatation and uterine activity.

Accuracy of ultrasonographic criteria for the prenatal diagnosis of placental amnionicity and chorionicity in twin gestations.

A total of 31 twin pregnancies were studied antenatally with ultrasound, followed up clinically, and the placentas examined to determine if, solely on the basis of prenatal sonography, an accurate assessment of amnionicity and chorionicity could be made. Sonographic features noted included number of placental sites, fetal gender, qualitative and quantitative evaluation of the dividing membrane. Documentation of two placental sites or different fetal gender confirms the presence of a dichorionic-diamniotic pregnancy. When only one placental site or similar fetal gender is demonstrated, examination of the membrane is helpful for distinguishing between dichorionic and monochorionic diamniotic gestations. A thick membrane separating the fetuses was seen in all dichorionic diamniotic pregnancies. A thin membrane was visible in 94.4 per cent of monochorionic-diamniotic pregnancies. The predictive value of a thick membrane with regard to a dichorionic-diamniotic pregnancy was 92.3 per cent and the predictive value of a thin membrane with regard to a monochorionic-diamniotic pregnancy was 100 per cent. The thickness of the membrane was measured in 13 cases. With a thickness of 2 mm used as a cutoff point, the accuracy in predicting monochorionic or dichorionic twinning was 100 per cent for both. Lack of visualization of a separating membrane suggests a monochorionic-monoamniotic pregnancy.

Transabdominal fetal reduction in quadruplet pregnancy during first trimester: a case report.

Multifetal pregnancy reduction was performed in a patient with quadruplet pregnancy at the 12th week of gestation. Reduction of the fetuses to two was carried out by injecting potassium chloride solution into the fetal chest under transabdominal ultrasound guidance. No complications were encountered and the woman was delivered of healthy twins at 37 weeks of gestation.

Significance of an absent or reversed end-diastolic flow velocity in Doppler umbilical artery waveforms.

Doppler velocity waveform analysis has been introduced as part of antenatal fetal biophysical assessment. Abnormal waveforms are associated with maternal and fetal complications. The most severe waveform patterns observed, absent end-diastolic velocity (AEDV) and reversed end-diastolic velocity (REDV), are of ominous significance in many cases but the incidence of these waveforms is low and the outcome is varied. The purpose of this study is to assess perinatal outcome in patients showing absent end-diastolic velocity (AEDV) and reversed end-diastolic velocity (REDV) in umbilical artery flow velocity waveforms. We reviewed our experience of patients showing AEDV and REDV in the umbilical artery flow velocity waveforms over nineteen months. Fifteen patients, all in high risk pregnancies, were identified during this period; 9 with AEDV and 6 with REDV. The results were not used in the clinical management. Twelve babies died (3 fetal deaths, 4 stillbirths and 5 neonatal deaths); giving the perinatal mortality is this group as 80 per cent. The interval between the abnormal waveform recording and fetal death or delivery was between 2 hours and 4 weeks. In three fetuses with abnormal diastolic flow, analysis of umbilical vein blood gases revealed severe acidosis and hypoxia. There was also significant perinatal morbidity as judged by low Apgar scores, days in neonatal intensive care, growth retardation and lethal anomalies. These findings suggest that once the diastolic component of umbilical artery flow velocity waveforms become absent or reversed, the fetus is in a state of hypoxia and acidosis and perinatal outcome is catastrophic.(ABSTRACT TRUNCATED AT 250 WORDS)

Short fetal acoustic stimulation test for rapid antepartum assessment of fetal well-being.

Short fetal acoustic stimulation test (FAST) was prospectively studied in 604 high risk pregnancies after 28 weeks of gestation. Fetal heart rates were recorded 3 minutes before and 5 minutes after fetal acoustic stimulation. The results of the tests performed within a week of delivery were compared with perinatal outcomes. Reactive response to short FAST occurred in 597 cases (98.8%) while nonreactive response was found in 7 cases (1.2%). Nine fetuses were considered poor outcomes. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of short FAST to predict poor fetal outcomes were 66.7, 99.8, 85.7, 99.5, and 99.3 per cent, respectively. Short FAST has high specificity, negative predictive value and accuracy for prediction of poor perinatal outcome. This rapid test should be used as a screening method for antepartum assessment of fetal well-being in a busy antenatal clinic.

Fetomaternal hemorrhage after midtrimester genetic amniocentesis at King Chulalongkorn Memorial Hospital.

Midtrimester genetic amniocentesis has become an accepted part of modern obstetric care. Although its accuracy is well established, the risk of fetomaternal hemorrhage remains controversial. This prospective study was conducted to determine how effective continuous ultrasound guided amniocentesis is in preventing fetomaternal hemorrhage. The authors investigated 30 patients undergoing midtrimester genetic amniocentesis at our institution. Amniocentesis was performed under continuous real-time ultrasound guidance using a 21-gauge, 3.5-inch long spinal needle. Maternal serum alpha-fetoprotein (AFP) levels were determined before, at 5 minutes and at 1 hour after amniocentesis. There were no significant changes in maternal serum AFP levels either at 5 minutes or at 1 hour after amniocentesis. Midtrimester genetic amniocentesis performed by a trained and experienced operator under continuous ultrasound guidance does not significantly increase the risk of fetomaternal hemorrhage after the procedure.