Middle cerebral artery Doppler for the prediction of fetal anaemia in cases without hydrops: a practical approach.

The aim of this study was to assess the value of the middle cerebral artery (MCA) Doppler time-averaged mean velocity (TAMV) for the prediction of fetal anaemia in at-risk cases without ultrasound evidence of hydrops. The study included 35 pregnant women with non-hydropic fetuses and with known red cell antibodies, referred either because of a rapid increase in antibody levels or because of a previous history of a severely anaemic fetus or neonate. After full ultrasound examination of the fetus, MCA Doppler TAMV was measured and, if severe anaemia was suspected, fetal blood sampling by cordocentesis was performed with blood ready for intrauterine transfusion if necessary. Of the 35 fetuses, 28 were anaemic and 7 had a haemoglobin (Hb) value within the normal range. There was a strong negative correlation between the MCA Doppler TAMV and the Hb values (correlation coefficient r=-0.65, p<0.0001). The mean MCA Doppler TAMV (z score) for fetuses with normal Hb was 1.55+/-1.68, while that for the anaemic fetuses was 4.06+/-1.38, (p<0.001). The sensitivity of the increased MCA Doppler TAMV to predict fetal anaemia in these cases was 96.4% and the specificity was 71.4%. These data confirm that MCA Doppler TAMV is significantly correlated to fetal Hb. This non-invasive investigation can be reliable in predicting anaemia in cases in which the need to sample fetal blood is not certain, therefore delaying invasive testing until treatment is likely to be required.

Noninvasive diagnosis of anemia in hydrops fetalis with the use of middle cerebral artery Doppler velocity.

OBJECTIVE: The purpose of this study was to assess the value of the middle cerebral artery time-averaged mean velocity for the detection of anemia as the cause of fetal hydrops. STUDY DESIGN: We examined 17 pregnant women with fetuses with hydrops (with ascites as the main component of hydrops) and who were considered at risk for anemia because there was no obvious explanation for the hydrops on the initial scan. Assessment included the measurement of the middle cerebral artery time-averaged mean velocity by color flow Doppler scan, followed by fetal blood sampling for investigations that included fetal hemoglobin. We investigated the correlation between increased middle cerebral artery time-averaged mean velocity (>2 SDs for gestational age) and fetal anemia (<2 SDs for gestational age). RESULTS: Eleven fetuses had anemia; 3 of the fetuses had red cell antibodies, and 6 of the fetuses had normal hemoglobin. There was a strong negative correlation between the middle cerebral artery time-averaged mean velocity and the hemoglobin values (r = -.9; P <.0001). The mean (z score) of middle cerebral artery time-averaged mean velocity for fetuses with normal hemoglobin was 1.1 +/- 0.81 and for the fetuses with anemia was 4.71 +/- 2.16 (P <.001). The sensitivity for the increased middle cerebral artery time-averaged mean velocity to predict fetal anemia was 91%, and the specificity was 100%. CONCLUSION: The middle cerebral artery time-averaged mean velocity is significantly increased in cases of hydrops caused by anemia, including cases other than red-cell alloimmunization. These findings can be useful for counseling and treatment and allow the investigation of the cause of hydrops without awaiting blood for intrauterine transfusion in patients who are very unlikely to be anemic and often avoids 2 procedures in those patients who require transfusion. Larger studies are required to further confirm these findings.

Analysis of outcome in hydrops fetalis in relation to gestational age at diagnosis, cause and treatment.

OBJECTIVE: To examine fetal outcome in hydrops fetalis in relation to gestational age at diagnosis and following investigation and treatment. METHODS: All cases of hydrops fetalis presenting to the Fetal Medicine Unit during the last seven years, between 1993 and 1999, were identified from the Fetal Medicine Database. During this time 87 of 13,980 patients who attended the Fetal Medicine Unit had hydrops fetalis. The cases were examined for gestational age at presentation according to etiology and fetal survival following investigation and treatment. The fetal survival rates for non-immune cases of hydrops before and after 24 weeks were compared. RESULTS: The cause of hydrops was determined antenatally in 71 of the 87 (82%) cases. Of the 51 cases presenting before 24 weeks' gestation, 23 (45%) were due to chromosomal abnormality. After 24 weeks, fetal tachyarrhythmias and hydrothorax were the most common causes and accounted for 14 (38%) of the 36 cases. Thirty-four cases (39%) of hydrops received intrauterine treatment. The survival rates excluding chromosomal abnormalities in the non-immune cases before and after 24 weeks' gestation were 31% and 48%, respectively, and were not significantly different. CONCLUSIONS: The survival rate in cases of hydrops fetalis may be improved with appropriate prenatal investigation and therapy. The etiology of hydrops is different before and after 24 weeks, and even when cases of chromosomal abnormality are excluded the survival rate is similar before and after 24 weeks.

Fetal protein loss in gastroschisis as an explanation of associated morbidity.

OBJECTIVE: Our purpose was to examine whether protein deficiency in utero develops in fetuses with gastroschisis. STUDY DESIGN: Twelve infants with prenatally diagnosed gastroschisis were compared with 29 control infants without gastroschisis and 2 infants with exomphalos who were delivered between 35 and 42 weeks of gestation. The groups were compared for birth weight, cord serum total protein and amniotic fluid total protein, and alpha-fetoprotein concentrations. The amniotic fluid samples were collected when the amniotic membranes were ruptured either during cesarean delivery or at artificial rupture of the membranes, and umbilical cord blood was obtained after delivery. RESULTS: In the 10 cases of gastroschisis in which cord serum total protein was measured, the median concentration was 51 g/L (range, 43-61 g/L) and was significantly lower than the median level of 62 g/L (range, 47-78 g/L) in the control group (P <.001). In the 8 cases of gastroschisis in which amniotic fluid total protein and alpha-fetoprotein concentrations were measured, the respective median levels were 5.1 g/L (range, 4.3-18.4 g/L) and 5.0 g/L (range, 2.4-13.2 g/L), which were significantly higher than the median levels of 2.0 g/L (range, 0.5-5.4 g/L) and 0.8 g/L (range, 0.5-1.7 g/L) in the control group (P <.0001). The ratio of amniotic fluid to cord serum total protein was significantly higher than that in the cases of exomphalos and in the control group (P <.001). The median birth weight in the neonates with gastroschisis was 2400 g (range, 1192-3155 g) and was significantly lower than the median value of 3535 g (range, 2520-4680 g) in the control group (P <.0001). CONCLUSIONS: Fetuses with gastroschisis have protein loss that could partly explain associated morbidity. However, whether this is a major contributor to poor fetal outcome remains to be shown.

Vesicocentesis at 10-14 weeks of gestation for treatment of fetal megacystis.

This report of four cases shows that fetal vesicocentesis at 10-14 weeks of gestation is a useful treatment option in some cases with megacystis. Although megacystis at this gestation has been reported, there are few studies examining the role of early vesicocentesis. The natural history of the condition and outcome following treatment is reviewed with reference to the literature.

Outcome of fetal talipes following in utero sonographic diagnosis.

OBJECTIVES: To examine the association between fetal talipes and other defects, and outcome in relation to postnatal surgery. METHODS: All cases of talipes presenting to the fetal medicine unit between 1993 and 1998 and cases of isolated talipes presenting to the ultrasound department between 1991 and 1998 were examined. The infants were followed-up to determine the number of cases that had structural or positional talipes and the number of cases requiring surgery. RESULTS: There were 76 cases, 59 of which attended the fetal medicine unit and 17 the ultrasound department. Postnatal follow-up details were available in 31 of the 40 live births. There were three neonates with unilateral talipes at birth who were thought to have bilateral talipes on prenatal ultrasound and one neonate had bilateral talipes at birth who had been thought to have unilateral talipes prenatally. In two (6.4%) neonates in whom talipes was not confirmed at birth the abnormality was diagnosed prenatally. Of the 29 neonates with confirmed talipes at birth, the defect was structural in 26 (90%) cases and positional in three. Surgery was necessary in 21 (72%) of the 29 cases and 18 (86%) of those undergoing surgery required only one operation. When live births with associated anomalies were excluded, there were 24 cases with confirmed isolated talipes and 18 (75%) required surgery. CONCLUSIONS: This study provides long-term outcome data which can be used to complement current prenatal counseling and shows that in cases of fetal talipes diagnosed prenatally, 90% have a structural rather than a positional deformity. For isolated talipes three quarters of children will require surgery and in the majority of cases only one operation on the foot is necessary. Parents should be made aware of the small possibility of a false-positive diagnosis and discrepancy between the ultrasound and postnatal diagnoses of laterality.

Correlation of prenatal ultrasound diagnosis and pathologic findings in fetal brain abnormalities.

OBJECTIVE: To determine the degree of agreement between prenatal ultrasound diagnosis of brain abnormalities and subsequent pathologic findings. METHODS: Between August 1993 and August 1999 there were 62 cases where a fetus with a prenatal ultrasound diagnosis of a brain abnormality other than neural tube defects underwent autopsy at the Regional Department of Pediatric Pathology. The cerebral diagnosis at ultrasound was compared with the findings at autopsy in all cases. RESULTS: In 47 of 61 (77%) cases the same defects were seen on ultrasound and at autopsy. The most common disparity was with the Dandy-Walker malformation or variant, where only six of the 14 (43%) cases prenatally diagnosed with this condition showed the same abnormality at autopsy. When fetuses with the Dandy-Walker malformation or variant were excluded, the scan findings correlated with autopsy in 41 of 47 (87%). In the main group with discordant findings, five of the seven cases where termination of pregnancy was undertaken had other fetal anomalies on ultrasound examination which were confirmed at autopsy. In the sixth case there was autolysis of brain tissue which affected detailed autopsy. CONCLUSIONS: A very high level of agreement between prenatal ultrasound and autopsy findings was found for all abnormalities of the fetal brain, except for the Dandy-Walker malformation or variant. Potential discrepancy in findings between ultrasound and autopsy should be explained to patients who are considering termination of pregnancy for the Dandy-Walker type of abnormality.

The effect of fetal hydrops on the rate of fall of hemoglobin after fetal intravascular transfusion for red cell alloimmunization.

OBJECTIVE: We aimed to assess whether there is a difference between hydropic and nonhydropic fetuses in the rate of fall of hemoglobin (Hb) following intravascular transfusions. METHODS: Eighty-three intravascular transfusions in 34 fetuses were analyzed. The pretransfusion and posttransfusion Hb values, the gestational age, the volume of blood transfused, the number of days between transfusions and the rate of fall of Hb per day following a transfusion were assessed. Hb levels were expressed as multiples of standard deviation from the normal mean for gestational age. RESULTS: Eleven fetuses were hydropic at presentation and 23 were not. Twenty-three transfusions were undertaken in the 11 fetuses while they were hydropic and 60 transfusions were performed in nonhydropic fetuses. Comparisons of transfusion variables between the two groups were performed both for the first transfusion only and also for the total number of transfusions. The rate of Hb fall per day following a transfusion was similar in the two groups on both comparisons. The posttransfusion Hb level tended to be lower and the intervals between transfusions were a little shorter in the hydropic group, but these differences were not statistically significant. CONCLUSION: The posttransfusion Hb tended to be lower in the hydropic fetuses, but the fall in Hb was not faster in these cases. Therefore, with a similar rate of daily Hb decline in both groups, the hydropic fetuses are expected to become anemic again sooner than the nonhydropic fetuses only because of the lower posttransfusion Hb. The timing of the next transfusion should therefore be based on the posttransfusion Hb and the normal predicted drop per day irrespective of the presence or absence of hydrops.

Fetal karyotyping by chorionic villus sampling after the first trimester.

OBJECTIVE: To evaluate chorionic villus sampling (CVS) as a technique for karyotyping after the first trimester by examining the incidence of result failure, confined placental mosaicism, and false positive or negative results at different gestational ages. METHODS: During a nine year period between 1989 and 1997, all results of CVS between 8 and 37 weeks of gestation provided by the Regional Cytogenetics Centre were analysed retrospectively by examining indications for CVS, weights of tissue received, gestational age at sampling and karyotype results. RESULTS: There were 2424 chorionic villus samples analysed by the direct method and/or cell culture. In 1548 cases CVS was performed before 14 weeks (Group 1), in 685 between 15 and 20 weeks (Group 2), in 160 between 21 and 28 weeks (Group 3) and in 31 cases after 29 weeks (Group 4). Although there was a trend for an increasing rate of failed direct preparation results from Groups 1 to 4 which were 3.8%, 4.7%, 5.6% and 6.6%, respectively; these results were not significantly different. There were 19 cases of confined placental mosaicism and the incidence was significantly greater in Group 3 compared with Group 1 (P < 0.05), and in Groups 3 and 4 combined compared with Group 1. There were six false positive and one false negative result following direct analysis with no significant differences between gestationar ages. CONCLUSIONS: CVS is a useful test after the first trimester, especially when a fast result is clinically required. However, after 20 weeks, when cordocentesis is available, the higher rate of cytogenetic discordancy between the placenta and the fetus means that cordocentesis may be preferable.

Amnioreduction: how much to drain?

OBJECTIVES: To assess the relationship between the volume of amniotic fluid removed and the change in amniotic fluid index (AFI) and calculate an equation describing this association. MATERIALS AND METHODS: A retrospective analysis of 19 amnioreduction procedures performed in our unit. Multiple regression analysis was used to assess the effect of gestational age and pre-procedure AFI on the change in AFI (DeltaAFI) after adjusting for the volume removed. RESULTS: As expected, a significant linear relationship was found between the change in AFI and the volume removed (r = 0.82, n = 19, p < 0.0001). DeltaAFI was not dependent on the gestational age or the pre-procedure AFI. The equation describing the association between the volume removed and DeltaAFI was: volume = (DeltaAFI - 2. 26)/0.008, which is close to 1 cm DeltaAFI for every 100 ml removed. DISCUSSION: Using the described equation, it is possible to predict the required volume to be removed in order to achieve a particular DeltaAFI, which may reduce the need to interrupt the procedure to measure the AFI. However, the limitation of AFI as a semiquantitative assessment of the liquor volume, together with its inter- and intra-observer variations mean this equation should be used only as a guide.

Chlamydia trachomatis infection in prelabour amniorrhexis.

The prevalence of Chlamydia trachomatis in the lower genital tract and amniotic fluid of women with preterm prelabour amniorrhexis was assessed by DNA amplification for C. trachomatis performed in cervical swabs and amniotic fluid obtained by amniocentesis. C. trachomatis was present in the cervix of 20 (23%) of the cases and in six (30%) of those the organism was also present in the amniotic fluid. There was no association with other pathogens in the lower genital tract or amniotic fluid. The presence of C. trachomatis was not associated with a significant decrease in the amniorrhexis to delivery interval or with an increase in perinatal mortality or morbidity.

Spontaneous spinal extradural hematoma during pregnancy.

BACKGROUND: Spontaneous spinal hematomas are rare in pregnancy, and only two cases have previously been described. This report reviews other similar cases and discusses the aetiology and management of this condition in relation to pregnancy. CASE: A 26-year-old primigravida presented at 35 weeks of gestation with a history of sudden onset of back pain and weakness with loss of sensation of her legs. On examination there was tenderness over the seventh thoracic vertebra with loss of sensation below the level of the T7 dermatome and reduced power in both lower limbs. Magnetic resonance imaging demonstrated an anterior extradural lesion in the mid-thoracic region of the spinal cord. An elective cesarean section was performed followed by a costotransversectomy and removal of an extradural hematoma. The patient's neurological function subsequently improved. CONCLUSION: Acute spontaneous spinal extradural hematoma occurring during pregnancy can be associated with successful outcome following prompt diagnosis and surgical treatment.

Fetal hemoglobin changes in the twin oligohydramnios-polyhydramnios sequence.

Fetal hemoglobin concentration was measured in each twin from five monochorionic pregnancies complicated by twin-to-twin transfusion, diagnosed by growth discordance and coexistent oligohydramnios-polyhydramnios. In three cases the hemoglobin concentration of the smaller twin with oligohydramnios was lower than the normal mean for gestation, and the hemoglobin difference was more than 5 g/dl in two of these cases. In the other two cases, the hemoglobin concentration of the four fetuses with coexistent oligohydramnios-polyhydramnios was within the normal range. This suggests that twin-to-twin transfusion may occur without hemoglobin changes, or that alternatively coexistent oligohydramnios-polyhydramnios occurs in the absence of twin-to-twin transfusion.

Evolution of sonographic findings in a fetus with agenesis of the urethra, vagina, and rectum.

In a 12-week gestation fetus, routine ultrasound examination suggested dilated loops of bowel. Repeat scans at 13 and 15 weeks showed normal growth but persistence of bowel dilatation. At 20 weeks there was megacystis, hyperechogenic bowel, ascites, and oligohydramnios. The diagnosis of cloacal abnormality was suspected and the parents chose to have pregnancy termination. Post-mortem examination demonstrated female pseudohermaphroditism with agenesis of the urethra, vagina, and rectum.

Preterm prelabour amniorrhexis: relation to histological chorioamnionitis.

Infection-mediated inflammation may be responsible for premature delivery in cases of preterm prelabour amniorrhexis. Histological examination of the cord and placenta was performed in 54 such pregnancies, in addition to amniocentesis and cordocentesis at presentation. Histological chorioamnionitis was more likely in those with positive amniotic fluid and/or fetal blood cultures, and in those cases with histological evidence of inflammation, the interval to delivery was short regardless of the culture results. Inflammation rather than infection per se may be the best indicator of preterm delivery in preterm prelabour amniorrhexis.

Amniotic fluid gram stain and leukocyte count in the prediction of intrauterine infection in preterm prelabour amniorrhexis.

The purpose of the study was to examine the sensitivity and specificity of the amniotic fluid Gram stain and leukocyte count in the prediction of positive fetal blood and amniotic fluid cultures in 80 patients with preterm prelabour amniorrhexis. Amniocentesis and cordocentesis were performed and amniotic fluid and fetal blood were cultured for aerobic and anaerobic bacteria. Amniotic fluid was also cultured for Ureaplasma urealyticum and Mycoplasma hominis. The sensitivity of the Gram stain in the prediction of positive fetal blood and amniotic fluid cultures was 50 and 40% and the respective false positive rates were 12 and 4%. In the detection of aerobic or anaerobic infection of the amniotic fluid, the sensitivity and false positive rate of the Gram stain were 80 and 3% respectively. This compared favourably with the respective values of 66 and 35% for amniotic fluid leukocyte count > 30/mm3. Positive amniotic fluid Gram stain provides useful prediction of intra-uterine infection with aerobic or anaerobic organisms.

Lower genital tract swabs in the prediction of intrauterine infection in preterm prelabour rupture of the membranes.

OBJECTIVE: To examine the genital tract flora in women with preterm prelabour rupture of the membranes and to determine the relationship of these microorganisms to those found in fetal blood and amniotic fluid. DESIGN: Prospective study of 97 patients with preterm prelabour rupture of the membranes. SETTING: Maternal-fetal medicine centre. METHODS: High vaginal and endocervical swabs were taken for routine culture of aerobic and anaerobic bacteria and Ureaplasma urealyticum and Mycoplasma hominis. Cordocentesis and amniocentesis were performed and fetal blood and amniotic fluid were cultured for aerobic and anaerobic bacteria. Amniotic fluid was also cultured for Mycoplasma spp. The sensitivities and specificities of genital tract colonisation in the prediction of fetal blood and amniotic fluid infection were calculated. RESULTS: Positive genital tract cultures for aerobic and anaerobic organisms predicted 40% of positive fetal blood and 53% of positive amniotic fluid cultures with false positive rates of 24% and 25%, respectively. The sensitivity and false positive rates for genital tract colonisation with Mycoplasma spp in the prediction of amniotic fluid infection with these organisms were 85% and 35%, respectively. CONCLUSIONS: In preterm prelabour rupture of the membranes lower genital tract cultures provide poor prediction of intrauterine infection.

Fetal haematological response to intra-uterine infection in preterm prelabour amniorrhexis.

The value of fetal haematological indices in the prediction of intra-uterine infection in 91 cases of preterm prelabour amniorrhexis was examined. Cordocentesis and amniocentesis were performed for the diagnosis of intra-uterine infection. The patients were subsequently divided into three groups, depending on the results of fetal blood and amniotic fluid cultures. In group 1 there were 53 patients with negative fetal blood and amniotic fluid cultures, group 2 consisted of 22 patients with negative fetal blood, but positive amniotic fluid cultures, and in group 3 there were 16 patients with positive fetal blood cultures. The mean leucocyte and neutrophil counts in all three groups were significantly higher than normal, and in group 3 the values were significantly higher than in group 1. The leucocyte and neutrophil counts were above the 95th centile of the normal range in 58% (22 cases) and 66% (25 cases), respectively, of the 38 cases with positive fetal blood and/or amniotic fluid cultures and in only 15% (8 cases) and 13% (7 cases), respectively, of the 53 patients with no infection. There were no significant differences between the groups, between the patients with amniorrhexis or for normal haemoglobin concentration, platelet count, or lymphocyte count. In the majority of the cases with positive fetal blood and/or amniotic fluid cultures, there is fetal leucocytosis. Since the results of the fetal leucocyte and neutrophil counts are available within a few minutes after cordocentesis, it would be reasonable to give antibiotics to all patients with a fetal leucocyte count above the 95th centile.

Maternal assessment in the prediction of intrauterine infection in preterm prelabor amniorrhexis.

The objective of this study was to evaluate maternal temperature, heart rate, leukocyte count and C-reactive protein in the prediction of fetal bacteraemia and positive amniotic fluid cultures in 75 pregnancies complicated by preterm prelabor amniorrhexis. Cordocentesis and amniocentesis were performed and fetal blood and amniotic fluid were cultured for aerobic and anaerobic bacteria. Amniotic fluid was also cultured for Ureaplasma urealyticum and Mycoplasma hominis. Patients were classified into 3 groups: negative fetal blood and amniotic fluid cultures (group 1, n = 45); negative fetal blood but positive amniotic fluid cultures (group 2, n = 18), and positive fetal blood cultures (group 3, n = 12). In the groups with intrauterine infection compared to the non-infected group, the median maternal temperature, leukocyte count and C-reactive protein were significantly higher. In groups 1, 2 and 3 the respective incidences of maternal pyrexia were 0, 7 and 16% and raised C-reactive protein 13, 28 and 33%. In pregnancies complicated by preterm prelabor amniorrhexis, maternal temperature, heart rate, leukocyte count and C-reactive protein do not provide sensitive prediction of intrauterine infection.