Difference In Hemoglobin Concentration Research Articles

Study of Black-White Differences in Anemia Prevalence in the United States: The Reasons for Geographic and Racial Differences in Stroke Study.

Introduction: Anemia by the WHO criteria is more common in American blacks than whites. There are few data examining differential associations of demographic, socio-economic, and co-morbid conditions with anemia by race.Methods: The Reasons for Geographic and Racial Differences in Stroke (REGARDS) study is a national longitudinal cohort currently enrolling 30,000 blacks and whites aged ≥ 45 years to assess stroke risk. Half the cohort will be black and half will live in the southeast. A phone interview for health history was followed by an in-home visit for phlebotomy and physical exam. After enrolling 8400 subjects, a complete blood count was added to the baseline exam. As of March 30th 2006 this was available in 12,060 participants. Anemia was defined by the WHO criteria and categorized into 3 non-exclusive groups: (1) low glomerular filtration rate (GFR) (<60ml/min/1.73m2), (2) inflammation (C-reactive protein ≥ 10mg/L or leukocyte count ≥ 15×109/L, and (3) microcytosis (mean red cell volume < 80fL).Results: The prevalence of anemia was 13.3% (1600 of 12,060); 21.5% for blacks (1047 of 4860) and 7.7% for whites (553 of 7195). The age- and sex-adjusted OR of anemia for blacks vs. whites was 3.71 (95% CI 3.30, 4.18). After additional adjustment for socio-economic variables (high school education, annual income), and co-morbid conditions (vascular disease, diabetes, hypertension, ever smoker, body mass index), blacks had a 2.79-fold (95% CI 2.44, 3.19) greater prevalence of anemia. Correlates of anemia differed by race; compared to whites, blacks with anemia were younger (66.2 vs. 69.9 years old, p <0.01), more likely to be female (70% vs. 58%, p <0.01), and less likely to live in the southeast (52% vs. 66%, p <0.01) with lower socio-economic indicators for blacks vs. whites (74% vs. 89% for high school education; 37% vs. 21% for annual income < $25,000; both p <0.01). Blacks with anemia, despite a higher prevalence of diabetes (42% vs. 32%, p <0.01) and hypertension (78% vs. 65%, p <0.01) than whites, had a lower prevalence of vascular disease (27% vs. 39%, p <0.01). Anemia type differed by race; fewer blacks than whites had anemia with a low GFR (45% vs. 67%, p <0.01)., while more blacks than whites had anemia with inflammation (18% vs. 14%, p = 0.04) or microcytosis (22% vs. 10%, p <0.01). Addition of anemia type (low GFR, inflammation, and microcytosis) to the multivariable model did not alter the association of black race with anemia (HR 2.71, 95% CI 2.35, 3.13).Conclusions: Anemia is more common in blacks than whites and correlates of anemia differ greatly by race. While risk factors for low GFR were more common in blacks (diabetes, hypertension), anemia with low GFR was more prevalent in whites. Adjustment for demographics, socio-economic variables, co-morbid conditions, and anemia type did not eliminate the association of black race with anemia. Whether this represents intrinsic differences in hemoglobin concentration between blacks and whites or undetermined or unmeasured co-morbid conditions requires further study.

Effect of Perinatal Antiretroviral Drug Exposure on Hematologic Values in HIV‐Uninfected Children: An Analysis of the Women and Infants Transmission Study

With the increasing use of antiretroviral (ARV) drugs to prevent mother-to-child transmission of human immunodeficiency virus (HIV), large numbers of infants are exposed, with possible consequent toxicity. Hematologic values in 1820 uninfected HIV- and ARV-exposed children were compared with those in 351 ARV-unexposed children from the Women and Infants Transmission Study. Hemoglobin concentrations and platelet, neutrophil, lymphocyte, and CD4+ and CD8+ cell counts were analyzed at birth and ages 2, 6, 12, 18, and 24 months. Multivariate analysis was conducted age 0-2 and 6-24 months, with adjustment for multiple cofactors. Hemoglobin concentrations and neutrophil, lymphocyte, and CD4+ cell counts were significantly lower at age 0-2 months in infants exposed to ARV drugs than in those who were not. At 6-24 months, differences in hemoglobin concentrations and neutrophil counts were no longer significant, whereas differences in platelet, lymphocyte, and CD4+ cell counts persisted and CD8+ cell counts became significantly lower. In comparison with ARV monotherapy, combination therapy was associated with larger decreases in neutrophil, lymphocyte, and CD8+ cell counts at age 0-2 months but with only differences in CD8+ cell counts at age 6-24 months. Clinically significant abnormalities were rare and did not differ by exposure to ARV drugs. Infants exposed to ARV drugs have small but significant differences in several hematologic parameters for the first 24 months of life. These results indicate the need for long-term follow-up of uninfected infants with ARV exposure.

Risk factors of disseminated intravascular coagulation in septic systemic inflammatory response syndrome in nursing home residents

Aims: Disseminated intravascular coagulation syndrome (DIC) is a serious complication in elderly patients with systemic inflammatory response syndrome (SIRS). We investigated whether the clinically relevant parameters of atherosclerosis, nutrition and cellular immunity are determining factors for DIC in septic SIRS patients or not. Patients and methods: Forty-four subjects aged 65 years or over were enrolled, all of whom had bacterial sepsis and a high concentration of C-reactive protein (≥ 15.0 mg/dL). Subjects were given gabexate mesilate (GM) following diagnosis of DIC. They were divided into the following groups: N-DIC, subjects with SIRS but not DIC (n = 22); DIC-A, subjects with SIRS and DIC who survived through treatment with GM (n = 6); and DIC-D, subjects who had SIRS and DIC and died despite treatment with GM (n = 16). Results: Subjects with a low hemoglobin or serum albumin concentration, and atrial fibrillation at admission had a significantly high incidence of DIC, which was not high in subjects with myocardial ischemia, past history of overt cerebral infarctions or periventricular lucency. There was no difference in hemoglobin concentration between DIC-A and DIC-D. Differences in increases in CD11b- and CD14-positive mononuclear cells between DIC and N-DIC subjects were not significant. Post-mortem examinations showed that the ratio of the width of the thoracic aorta to that of the abdominal aorta was significantly higher for DIC-D than DIC-A. Conclusion: Nutritional disorders and irregularity in aortic blood flow are significant risks of DIC. Treatment with GM alone is not sufficient to achieve survival in patients with DIC and SIRS.

Ceruloplasmin Is Essential for the Mobilization of Tissue Iron Stores.

In extracellular fluid, iron is in the ferric (oxidized form) but the intracellular form is ferrous iron (reduced). The outflow of iron from cells is dependent on oxidase activity that converts ferrous to ferric iron. Iron-absorbing enterocytes possess a unique iron oxidase, hephaestin. It is presumed that the circulating hephaestin paralog ceruloplasmin fulfils this role in hepatocytes and macrophages. The DiSnA mouse lacks ceruloplasmin. We hypothesized that iron homeostasis in this mouse would be unusually dependent on dietary iron because the mouse would not be able to mobilize iron from tissue stores in hepatocytes and macrophages. We fed 4-week-old DiSnA and wildtype (WT) mice a high iron (1%) diet for 4 weeks to load tissue stores. We then switched them to an iron-deficient diet and analyzed them weekly to measure iron and hemoglobin concentrations. Even on the high iron diet, DiSnA mice had lower serum iron concentrations than WT control (32.9±17.9 vs. 53.5±17.6 μM, p=0.05) but after two weeks on the iron deficient diet, the DiSnA mice had almost undetectable serum iron (4.2±1.8 μM) whereas the WT controls had only declined slightly (43.2±9.6 μM, p<0.001). Iron saturation followed a similar trend. Neither WT nor DiSnA mice were anemic at baseline (Hgb = 13.9±0.3 and 13.9±1.1 g/dL, respectively; p=0.994) but by the end of two weeks, the DiSnA mice had developed anemia whereas the WT mice had not (Hgb = 10.4±0.5 vs. 12.6±0.5 g/dL; p<0.001). The difference in hemoglobin concentrations persisted to the 6-week timepoint (Hgb = 8.4±0.5 vs. 12.6±1.4; p<0.001). After 6-weeks on a low iron diet, iron was still present in livers and spleens of both groups. Ceruloplasmin is essential for the mobilization of iron stores to protect against iron deficiency anemia in response to periods of dietary iron deficiency.

Malaria in camps for internally-displaced persons in Uganda: evaluation of an insecticide-treated bednet distribution programme

Malaria is a key health problem among displaced populations in malaria-endemic areas. Mass distribution of insecticide-treated bednets (ITN) to prevent malaria is often carried out in complex emergencies, but there are few data on the outcome or operational effectiveness of such programmes. In June 2001, Médecins Sans Frontières completed a mass distribution of ITNs (Permanet ®) to internally displaced persons in Bundibugyo, southwest Uganda, distributing one to four nets per household, and aiming to provide coverage for all residents. In July 2002, we did a cross-sectional survey using three-stage cluster sampling to evaluate the programme. A total of 1245 individuals from 835 households were interviewed. An ITN was present in 75.6% (95% CI 72.7–78.5) of the households, but only 56.5% (95% CI 52.3–60.4) of individuals were sleeping under an ITN, and nets were often damaged. The prevalence of malarial parasitaemia was 11.2% (95% CI 9.4–13.0), and was significantly lower in ITN users compared to non-users (9.2% vs. 13.8%, relative risk [RR] 0.63, 95% CI 0.46–0.87); ITNs with severe damage remained effective (RR for severely damaged net 0.58, 95% CI 0.35–0.98). There was no significant difference in haemoglobin concentration between ITN users and non-users.

Relation between the response to iron supplementation and sickle cell hemoglobin phenotype in preschool children in western Kenya

Iron supplementation has been associated with greater susceptibility to malaria and lower hematologic responses in pregnant Gambian women with sickle cell trait (HbAS) than in similar women with the normal (HbAA) phenotype. It is not known whether a similar interaction exists in children. Our aim was to determine the influence of the HbAS phenotype on hematologic responses and malaria after iron supplementation in anemic (hemoglobin: 70-109 g/L) children aged 2-35 mo. We conducted a double-blind, randomized, placebo-controlled trial (HbAS, n = 115; HbAA, n = 408) of intermittent preventive treatment with sulfadoxine pyrimethamine (IPT-SP) at 4 and 8 wk and daily supervised iron for 12 wk. The mean difference in hemoglobin concentrations at 12 wk between children assigned iron and placebo iron, after adjustment for the effect of IPT-SP, was 9.1 g/L (95% CI: 6.4, 11.8) and 8.2 g/L (4.0, 12.4) in HbAA and HbAS children, respectively (P for interaction = 0.68). Although malaria parasitemia and clinical malaria occurred more often in HbAS children in the iron group than in those in the placebo iron group, this difference was not significant; incidence rate ratios were 1.23 (95% CI: 0.64, 2.34) and 1.41 (0.39, 5.00), respectively. The corresponding incidence rate ratios in HbAA children in the same groups were 1.07 (95% CI: 0.77, 1.48) and 0.59 (0.35, 1.01), respectively. The corresponding interactions between the effects of iron and hemoglobin phenotype were not significant. There was no evidence for a clinically relevant modification by the hemoglobin S phenotype of the effects of iron supplementation in the treatment of mild anemia. The benefits of iron supplementation are likely to outweigh possible risks associated with malaria in children with the HbAA or HbAS phenotype.

Iron metabolism and requirements in early childhood: do we know enough?: a commentary by the ESPGHAN Committee on Nutrition.

*University of Lancashire, Lancashire, United Kingdom; †University of Milano, Milano, Italy; ‡University of Lund, Malmo, Sweden; §Hopital des Enfants Malades, Paris, France; Hopital Necker Enfants-Malades, Paris, France, ¶Umea University, Umea, Sweden; #University of Munich, Munich, Germany; **Free University of Amsterdam, Amsterdam, The Netherlands; ††Royal Veterinary and Agricultural University, Frederiksberg, Denmark; ‡‡CHUV University Hospital, Lausanne, Switzerland; §§University of Liege, Liege, Belgium; Medical University of Warsaw, Warsaw, Poland; and ¶¶University of Glasgow, Glasgow, United Kingdom

Plasma Erythropoietin in Essential Thrombocythaemia: at Diagnosis and in Response to Myelosuppressive Treatment

Sixty-five patients with essential thrombocythaemia (ET) on different treatment regimens were studied with regard to EDTA-plasma erythropoietin (EPO) concentrations. In accordance with other studies we found that close to 50% of the untreated ET patients had subnormal (<3.7 IUL) plasma EPO. The mean plasma EPO concentration for untreated ET patients was significantly lower compared to patients treated with hydroxyurea (HU), radiophospho-rous, a-interferon or combinations of myelosuppressive agents. This was also true after correction for differences in haemoglobin concentrations had been introduced. An increase in plasma EPO was recorded in all 20 ET patients in whom plasma EPO was registered before and after initiation of myelosuppressive therapy.At the time of diagnosis plasma EPO concentration was available in 31 of the ET patients. In 13 of them the plasma EPO was subnormal whereas the EPO concentrations were ≥3.7 IUL in the remaining 18 subjects. It was demonstrated that the time to initiation of myelosuppressive treatment was significantly shorter for the former group of patients; they also had more vascular events (11 out of 13) than the group of patients with plasma EPO concentrations ≥3.7 IUL (9 out of 18). It therefore appears that a subnormal plasma EPO in newly diagnosed ET might be a risk factor for the development of vascular complications.

Diffuse reflectance spectroscopy of human adenomatous colon polyps in vivo

Diffuse reflectance spectra were collected from adenomatous colon polyps (cancer precursors) and normal colonic mucosa of patients undergoing colonoscopy. We analyzed the data by using an analytical light diffusion model, which was tested and validated on a physical tissue model composed of polystyrene beads and hemoglobin. Four parameters were obtained: hemoglobin concentration, hemoglobin oxygen saturation, effective scatterer density, and effective scatterer size. Normal and adenomatous tissue sites exhibited differences in hemoglobin concentration and, on average, in effective scatterer size, which were in general agreement with other studies that employ standard methods. These results suggest that diffuse reflectance can be used to obtain tissue information about tissue structure and composition in vivo.

Iron nutritional status in preterm infants fed formulas fortified with iron

AIMSTo prospectively evaluate the iron nutritional status of preterm infants fed either a term (0.5 mg/dl iron) or preterm (0.9 mg/dl) formulas fortified with iron after hospital discharge.METHODSHealthy low birthweight...

Iron supplemented formula milk related to reduction in psychomotor decline in infants from inner city areas: randomised study.

Objective: To compare the effect of unmodified cows‘ milk and iron supplemented formula milk on psychomotor development in infants from inner city areas when used as the main milk source.Design:...

Measurement of pH in Whole Blood by Near-Infrared Spectroscopy

Whole blood pH has been determined in vitro by using near-infrared spectroscopy over the wavelength range of 1500 to 1785 nm with multivariate calibration modeling of the spectral data obtained from two different sample sets. In the first sample set, the pH of whole blood was varied without controlling cell size and oxygen saturation (O2 Sat) variation. The result was that the red blood cell (RBC) size and O2 Sat correlated with pH. Although the partial least-squares (PLS) multivariate calibration of these data produced a good pH prediction cross-validation standard error of prediction (CVSEP) = 0.046, R2 = 0.982, the spectral data were dominated by scattering changes due to changing RBC size that correlated with the pH changes. A second experiment was carried out where the RBC size and O2 Sat were varied orthogonally to the pH variation. A PLS calibration of the spectral data obtained from these samples produced a pH prediction with an R2 of 0.954 and a cross-validated standard error of prediction of 0.064 pH units. The robustness of the PLS calibration models was tested by predicting the data obtained from the other sets. The predicted pH values obtained from both data sets yielded R2 values greater than 0.9 once the data were corrected for differences in hemoglobin concentration. For example, with the use of the calibration produced from the second sample set, the pH values from the first sample set were predicted with an R2 of 0.92 after the predictions were corrected for bias and slope. It is shown that spectral information specific to pH-induced chemical changes in the hemoglobin molecule is contained within the PLS loading vectors developed for both the first and second data sets. It is this pH specific information that allows the spectra dominated by pH-correlated scattering changes to provide robust pH predictive ability in the uncorrelated data, and visa versa.

CELL POPULATIONS IN THE BONE MARROW OF GUINEA PIG FETUSES WITH INTRAUTERINE GROWTH RETARDATION

Bone marrow smears and blood samples were examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) had been induced by uterine artery ligation and compared with those of control (well-grown) fetuses from uterine horns with intact circulation. Differential bone marrow cell counts were obtained from a count of 300 cells per smear and blood samples were assayed for hemoglobin concentration and 2,3-diphosphoglycerate (DPG). Results of blood assays showed no difference in hemoglobin concentration. DPG levels were reduced in the IUGR guinea pigs (P < .05), which could be a consequence of decreased glucose availability or represent an adaptation to reduced oxygen availability. Comparisons of bone marrow counts revealed an increase in total erythrocyte precursors (P < .05) and a decrease in total granulocytic precursors (P < .05) in IUGR fetuses. Within the erythroid lineage there was a significant increase in late (orthochromatic) erythroblasts (P < .005) in the IUGR animals compared with control animals. The granulocytic lineage of the IUGR fetuses showed a significant decrease in mature neutrophils (P < .05) and eosinophilic precursors (P < .05) compared with controls. These data suggest that the hypoxic stress of uterine artery ligation leads to an increase in medullary erythropoiesis. In concert with a previous study that showed a reduction in hepatic erythropoiesis, these data suggest a precocious shift of the anatomic site of erythropoiesis from the liver to the bone marrow under conditions of hypoxia.

The ratio of amount of haemoglobin to total surface area of erythrocytes in birds in relation to body mass, age of nestlings, and season of the year.

The research examined differences in haemoglobin concentration (g%), number of erythrocytes (mm-3), length and width of red blood cells (micron), and haematocrit value (%) in adult birds of 21 species with body mass ranging from 8 to 170 g, in eight species of altricial birds during the course of their development and in two species throughout the seasons of the year. Erythrocyte total surface area was taken to be the product of the surface area of a single red blood cell and the erythrocyte count, and the ratio of haemoglobin to the total surface area of erythrocytes was then determined. Erythrocyte total surface area scaled with haemoglobin concentration in all three of the above situations, with the result that the ratio of haemoglobin to total surface area of erythrocytes was constant at a mean of 0.53 +/- 0.11 pg micron-2. Changes in the total surface area of erythrocytes occur as a consequence of simultaneous changes in the size and number of erythrocytes, with haematocrit values remaining relatively constant. The constant value of the ratio of haemoglobin to total surface area of erythrocytes may be optimal for haemoglobin saturation with oxygen in the lungs of birds.

Cell Populations in the Bone Marrow of Guinea Pig Fetuses with Intrauterine Growth Retardation

Bone marrow smears and blood samples were examined in guinea pig fetuses in which intrauterine growth retardation (IUGR) had been induced by uterine artery ligation and compared with those of control (well-grown) fetuses from uterine horns with intact circulation. Differential bone marrow cell counts were obtained from a count of 300 cells per smear and blood samples were assayed for hemoglobin concentration and 2,3-diphosphoglycerate (DPG). Results of blood assays showed no difference in hemoglobin concentration. DPG levels were reduced in the IUGR guinea pigs (P < .05), which could be a consequence of decreased glucose availability or represent an adaptation to reduced oxygen availability. Comparisons of bone marrow counts revealed an increase in total erythrocyte precursors (P < .05) and a decrease in total granulocytic precursors (P < .05) in IUGRfetuses. Within the erythroid lineage there was a significant increase in late (orthochromatic) erythroblasts (P < .005) in the IUGR animals compared with control animals. The granulocytic lineage of the IUGR fetuses showed a significant decrease in mature neutrophils (P < .05) and eosinophilic precursors (P < .05) compared with controls. These data suggest that the hypoxic stress of uterine artery ligation leads to an increase in medullary erythropoiesis. In concert with a previous study that showed a reduction in hepatic erythropoiesis, these data suggest a precocious shift of the anatomic site of erythropoiesis from the liver to the bone marrow under conditions of hypoxia.

Dietary exposure of mink to carp from Saginaw Bay, Michigan: 2. Hematology and liver pathology.

The effects of consumption of environmental contaminants contained in carp (Cyprinus carpio) from Saginaw Bay, Michigan on various hematological parameters and liver integrity of adult female mink (Mustela vision) were determined. Mink were fed diets that contained 0 (control), 10, 20, or 40% carp prior to and throughout the reproductive period (182 days). The diets contained 0.015, 0.72, 1.53, and 2.56 mg polychlorinated biphenyls (PCBs)/kg diet and 1.0, 19, 40, and 81 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEQs)/g diet, respectively. Mink fed the diets containing carp showed a general dose-dependent occurrence of clinical signs commonly associated with chlorinated hydrocarbon toxicity, including listlessness, nervousness when approached, anorexia, and melena. Erythrocyte counts were less in mink exposed to Saginaw Bay carp than in controls, while the number of white blood cells was greater than in controls. Significant differences (p < 0.05) in the concentrations of neutrophils, lymphocytes, monocytes, and eosinophils were also found between the control and carp-fed groups, but are considered to be of limited clinical or biological importance. Hematocrit values for the mink fed the 20 and 40% carp diets were significantly less than those of mink in the control and 10% carp groups. There were no significant differences in hemoglobin concentrations among the groups. Necropsies revealed enlarged yellowish livers in many of the carp-fed mink, especially those fed the 40% carp diet. Liver, spleen, and lung weights of carp-fed mink were significantly greater than those of control mink.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of bovine-hemoglobin-fortified cookies on iron status of schoolchildren: a nationwide program in Chile

The Chilean School Lunch program, which serves one million children nationwide, was supplied with three 10-g cookies fortified with 6% bovine hemoglobin concentrate, designed to provide 1 mg bioavailable iron per day. A survey of 1000 children was performed after 3 y. Significant differences in hemoglobin concentrations were found in the children from the fortified vs the nonfortified province (P < 0.01). Low serum ferritin values were also significantly more prevalent in the nonfortified group. The effect was evident despite the very low prevalence of anemia in both the fortified and the unfortified school groups. Heme-iron-fortified cookies are a feasible and effective way to improve the iron status of school-age children. In regions of high prevalence of iron-deficiency anemia, the effect of a heme-fortified cookie program should be even more important.

Iron Nutrition Does Not Account for the Hemoglobin Differences between Blacks and Whites

Many researchers have reported lower hemoglobin concentrations in blacks than in whites, but the reason for this difference is unknown. Data for 2515 persons (in 3–12 y and 18–45 y age groups) from the Second National Health and Nutrition Examination Survey (NHANES II) were evaluated to investigate the roles of iron intake and biochemical iron status indicators in explaining black and white differences in hemoglobin concentration. Dietary iron intake was estimated from one 24-h food recall, and hemoglobin, serum ferritin, transferrin saturation and erythrocyte protoporphyrin were measured by standard laboratory methods. Hemoglobin levels were substantially lower in black children (120.3 g/L) than in white children (126.8 g/L). Hemoglobin concentrations were also lower in black women (128.4 g/L) than in white women (133.9 g/L), and in black men (144.8 g/L) than in white men (153.2 g/L). Blacks had lower hemoglobin concentration than whites at most levels of dietary iron intake, serum ferritin, transferrin saturation and erythrocyte protoporphyrin. Despite their lower hemoglobin levels, blacks had higher serum ferritin levels than whites. These results suggest that the difference in hemoglobin concentrations between blacks and whites in the United States is the result of factors other than iron intake and iron status. More specific investigations of both the genetic and environmental determinants of iron utilization in blacks are needed.

Relationship between determinants of oxygen delivery and respiratory abnormalities in preterm infants with anemia

To study the relationship between anemia and breathing abnormalities in preterm infants, we measured oxygen supply and demand in two groups of anemic infants less than or equal to 32 weeks of gestational age. Six-second apnea density was less than 1% in one group and greater than or equal to 5% in the other. There were no differences in hemoglobin concentration, available oxygen, oxygen consumption, or Doppler-determined cardiac output between the two groups of infants. Furthermore, in anemic preterm infants with apnea density greater than or equal to 5%, reductions in 6-second apnea density were similar after erythrocyte transfusion (mean +/- SEM: from 8.6% +/- 1.1% to 4.7% +/- 0.7%) or after an isovolemic infusion of 5% albumin (from 9.0% +/- 1.4% to 4.7% +/- 0.7%). These results show no relationship between measures of oxygen delivery and respiratory irregularities, and indicate that volume expansion may play a role in ameliorating the pneumocardiogram abnormalities.

Fetofetal transfusion syndrome: do the neonatal criteria apply in utero?

Thirteen fetuses (five twin, one triplet) were compromised by fetofetal transfusion syndrome in six pregnancies, five in the mid trimester, and one in the third trimester. This diagnosis, which was suspected because of ultrasound findings of discordant growth, discordant amniotic fluid volumes, concordant external genitalia, and monochorial placentation, was confirmed postnatally in each. Nine fetuses underwent blood sampling to aid diagnosis and assessment of fetal wellbeing. In contrast to fetofetal transfusion syndrome investigated postnatally, a difference in haemoglobin concentration of 50 g/l or more in utero was found in only one pregnancy, which was near term, although all had fetal erythroblastaemia and a difference in weight of 20% or more. In vivo confirmation of shared circulation was achieved in two pregnancies by transfusing adult Rh negative red cells into the smaller fetus and then detecting them by Kleihauer testing in blood aspirated from the larger. Invasive procedures also yielded information on fetal blood gas measurements (acidaemia in four and hypoxaemia in six) and amniotic pressure (raised in two). We suggest that comparison of haemoglobin concentrations is inaccurate in fetofetal transfusion syndrome in utero, the diagnosis of which may necessitate detection of a shared circulation using a marker such as adult red cells.