Transplacental IgG Subclass Concentrations in Pregnancies at Risk of Haemolytic Disease of the Newborn

The relationship of haemolytic disease of the newborn (HDN) to the transplacental passage of the four IgG subclasses was assessed at varous gestational ages by comparing the maternal and fetal IgG subclass concentrations in 34 pregnancies at risk of HDN with those in 30 pregnancies not at risk. Higher maternal and fetal IgG1 levels were attained in pregnancies at risk of HDN than in pregnancies not at risk. In contrast, a slight decrease in maternal IgG2 and IgG4 levels occurred in pregnancies at risk of HDN, as compared with a slight rise in maternal IgG2 and IgG4 levels in pregnancies not at risk of HDN. Changes in fetal IgG2 and 4 concentrations in either type of pregnancy were very similar, showing only slight increases between the 19th and 34th week of gestation. A slight decrease in maternal IgG3 occurred in both types of pregnancy. In contrast, higher and fairly steady levels of fetal IgG3 were observed in fetuses not at risk of HDN throughout gestation, when compared with those in 'at risk' pregnancies. However, the statistical reliability of these results is not clear since only small numbers of samples were tested and because wide variations in IgG concentrations were observed. The IgG subclass concentrations in 50 paired maternal and cord blood samples were also measured and revealed that IgG1 levels were substantially higher in cord rather than maternal blood; cord and maternal IgG2, 3 and 4 levels, on the other hand, were fairly similar.     

Pre- and post-transplant assessment of liver function in paediatric liver transplantation

The pre-operative risk of paediatric liver transplantation candidates (n=41) was assessed in a prospective study by means of clinical symptoms, conventional static and liver blood flow dependent dynamic liver function tests. Nine patients died during the 365-day waiting period. The data were subjected as covariates to a survival analysis in the Cox proportional hazards model. There was a significant relationsship between the results of mono-ethylglycinexylidide (MEGX) formation and ICG test and the 365-day survival rate. In the stepwise analysis, none of the remaining parameters improved the predictive ability when added to the dynamic liver function test results. The assessment of post-transplantation liver function was studied in 27 patients during the first 28 postoperative-day period. In addition, liver function was studied in a cross-sectional study 1–7 years after successful liver transplantation in children with complete or partial rehabilitation. In the early postoperative period severe organ damage was indicated by both static and dynamic liver function tests. In the later course after transplantation no deterioration of liver function measured with MEGX formation was to be observed. These findings demonstrate the usefulness of dynamic liver function tests in the pre- and post-transplant assessment of liver function.     

Normal amniotic pressure throughout gestation.

OBJECTIVE: To characterize amniotic pressure (AP) in pregnancies with normal amniotic fluid volume. DESIGN: Observational study, mainly cross-sectional. SETTING: Fetal medicine unit within a tertiary referral hospital. SUBJECTS: Patients undergoing transamniotic invasive procedures in whom amniotic fluid volume was subjectively assessed as normal on ultrasound. Those beyond 16 weeks with a deepest vertical pool on ultrasound less than 3.0 or greater than 8.0 cm were excluded. Overall 194 pregnancies were studied on 232 occasions between 7 and 38 weeks gestation. INTERVENTIONS: Manometry readings referenced to the top of the maternal abdomen were obtained via a fluid-filled line from the needle hub and either connected to a pressure transducer (n = 190) or held vertically against a ruler (n = 42). MAIN OUTCOME MEASURES: AP in mm Hg, AP corrected for gestational age (z scores), semi-quantitative ultrasonic indices of amniotic fluid volume, clinical variables. RESULTS: AP in singleton pregnancies increased with advancing gestation (P less than 0.001), and the sigmoid-shaped regression curve plateaued in the mid-trimester. AP z scores were not influenced by volume-related phenomena such as twin gestation, the deepest vertical pool, or amniotic fluid index, nor by maternal age, parity, gravidity, fetal sex, or subsequent spontaneous preterm delivery. CONCLUSIONS: These findings suggest that AP is not principally determined by intrauterine volume. We speculate that AP, which reflects change in uterine tension as a function of radius, may instead be determined by gestation-specific anatomical and hormonal influences on gravid uterine musculature. A reference range for AP has been constructed for use in amnioinfusion and amnioreduction procedures.     

Alpha thalassaemia hydrops fetalis in the UK: the importance of screening pregnant women of Chinese, other South East Asian and Mediterranean extraction for alpha thalassaemia trait.

OBJECTIVE: Alpha zero (alpha 0 or alpha-1) thalassaemia is an important genetic risk for women originating from Hong Kong, Singapore, Vietnam, Thailand, the Philippines or South China. Cypriots are also at risk. Carriers of alpha zero thalassaemia trait can be detected by routine haemoglobinopathy screening. When a couple are both carriers, in each pregnancy there is a 25% risk that the fetus will have alpha thalassaemia hydrops fetalis; this is fatal for the fetus and carries serious obstetric and psychological risks for the mother. Most informed couples at risk request prenatal diagnosis and selective abortion. This study investigates the effectiveness of screening, counselling and prenatal diagnosis for alpha thalassaemia hydrops fetalis in the UK. DESIGN: Retrospective analysis of the notes. SUBJECTS: 18 couples attending University College Hospital London for prenatal diagnosis of alpha thalassaemia hydrops fetalis since 1982. RESULTS: The study shows underdiagnosis of both alpha zero thalassaemia trait and alpha thalassaemia hydrops fetalis leading to avoidable stillbirths and complications in pregnancy. CONCLUSION: We recommend early screening for alpha zero thalassaemia trait for all women of Southeast Asian or eastern Mediterranean origin and the offer of prenatal diagnosis when indicated. The diagnosis of alpha thalassaemia hydrops fetalis should be considered in women of the relevant ethnic origin who have a stillbirth, neonatal death, abnormal ultrasound findings at fetal anomaly scanning (especially a large placenta), or who develop pre-eclampsia.     

Calcium homeostasis in second trimester fetuses.

The concentrations of ionised calcium ions (Ca++), total calcium, parathyroid hormone, pH, total protein, albumin, sodium, and potassium were measured in paired fetal and maternal blood from pregnancies at 15 to 24 weeks' gestation. Pure fetal blood samples were obtained fetoscopically. The concentrations of fetal ionised calcium ions (n = 26); mean (SD) 1.33 (0.12) mmol/l (5.32 (0.48) mg/100 ml) and those of parathyroid hormone (n = 9); 68 (19) pmol/l (58 (16) micrograms/100 ml) were significantly higher than those of the mothers: 1.18 (0.09) mmol/l (4.7 (0.4) mg/100 ml), and 40 pmol/l (less than 34 micrograms/100 ml), respectively. There was no difference between measured fetal and maternal total calcium, pH, and electrolytes. The fetal total protein and albumin concentrations increased with gestation but were always lower than the equivalent maternal values. The calculated total calcium was 0.23-0.45 mmol/l (0.9-1.8 mg/100 ml) higher in the fetal than in maternal blood from the same pregnancy. There were no fetal arteriovenous differences in ionised calcium ions despite higher venous pH.