Posterior fossa abnormalities in high-risk term infants: comparison of ultrasound and MRI.

OBJECTIVES: We aimed to assess the characteristics of posterior fossa (PF) abnormalities in a cohort of high-risk term neonates, as well as the diagnostic performance of cranial ultrasound (CUS) with additional mastoid fontanelle (MF) views for the detection of these abnormalities, with magnetic resonance imaging (MRI) being the reference standard. METHODS: In this retrospective study, 113 term neonates with CUS and subsequent MRI were included. Sensitivity, specificity, and predictive values of routine CUS and CUS with MF views were calculated. RESULTS: Posterior fossa abnormalities were diagnosed on CUS in 46 of 113 infants. MRI confirmed these findings in 43 and showed additional abnormalities in 32 infants. The sensitivity and specificity of anterior fontanelle views for major PF abnormalities as seen on MRI were 16% and 99%. Adding MF views increased the sensitivity of US to 82%. The sensitivity and specificity of MF views for the detection of any (major or minor) PF abnormality were 57% and 95%. Especially acute hypoxic-ischemic injury and small subdural and punctate cerebellar haemorrhage remained undetected by CUS. CONCLUSIONS: PF abnormalities are frequent in high-risk term infants. MF-CUS enables early diagnosis of major PF abnormalities. We therefore advocate to perform MF-CUS in high-risk term neonates. KEY POINTS: • Posterior fossa abnormalities are a frequent finding in high-risk term infants. • Adding mastoid fontanelle views improves ultrasound detection of clinically relevant abnormalities. • Hypoxic-ischemic injury and small posterior fossa haemorrhages are better detected with MRI. • Cranial ultrasound examination should include mastoid fontanelle views in high-risk term neonates.

Reproductive outcomes of women and men born very preterm and/or with a very low birth weight in 1983: a longitudinal cohort study in the Netherlands.

UNLABELLED: The aims of this study were to analyze reproductive outcomes of women and men born very preterm (gestational age <32 weeks) or with a very low birth weight (<1500 g) in 1983 in the Netherlands and to compare their reproductive outcomes with the total population at a similar age of 28 years. Young adults who were born after a pregnancy complicated by very preterm (VP) delivery or with a very low birth weight (VLBW) in the Netherlands in 1983 (Project on Preterm and Small for Gestational Age Infants (POPS) cohort) were invited to complete an online questionnaire at the age of 28. In total, 293 POPS-28 participants (31.6%) completed the questionnaire including 185 female and 108 male participants. Female and male participants who were born VP or with a VLBW had significant reduced reproductive rates compared to the total Dutch population at 28 years of age (female 23.2 vs 31.9% and male 7.4 vs 22.2%). Pregnancies of the female participants were in 14% complicated by preterm delivery in at least one pregnancy. CONCLUSION: This study indicates that women and men born VP or with a VLBW have reduced reproductive rates at the age of 28 compared to the total Dutch population at a similar age.

Early-onset thrombocytopenia in near-term and term infants with perinatal asphyxia.

BACKGROUND: Neonates after perinatal asphyxia are at increased risk of thrombocytopenia. The correlation between perinatal asphyxia and the risk and severity of early-onset thrombocytopenia is not well known. OBJECTIVE: To estimate the incidence, severity and risk factors for early-onset thrombocytopenia in neonates after perinatal asphyxia. METHODS: We included all newborns (gestational age ≥ 36 weeks) admitted to our neonatal nursery due to perinatal asphyxia in this retrospective study. We collected platelet counts that were obtained within the first 48 h of life to estimate the incidence and severity of early-onset thrombocytopenia. RESULTS: A total number of 171 neonates with perinatal asphyxia were included in the study. The incidence of early-onset thrombocytopenia (platelet count < 150 × 109/l) was 51% (87/171). Several factors were associated with increased risk of early-onset thrombocytopenia, including prolonged prothrombin time (PT) [odds ratio (OR) 1·18, 95% confidence interval (CI) 1·08­1·30, P < 0·01], prolonged activated partial thromboplastin time (APTT) (OR 1·07, 95% CI 1·03­1·11, P < 0·01), low Apgar score at 10 min (OR 1·25, 95% CI 1·08­1·45, P < 0·01) and high serum lactate (OR 1·12, 95% CI 1·06­1·19, P < 0·01). After multiple logistic regression analysis, we found an independent association between early-onset thrombocytopenia and prolonged PT (OR 1·15, 95% CI 1·00­1·33, P = 0·045) and higher lactate level (OR 1·15, 95% CI 1·03­1·28, P = 0·01). CONCLUSIONS: Early-onset thrombocytopenia occurs frequently in neonates after perinatal asphyxia and is independently associated with PT and lactate level.

Outcome and management in neonatal thrombocytopenia due to maternal idiopathic thrombocytopenic purpura.

BACKGROUND AND OBJECTIVES: Pregnant women with Idiopathic thrombocytopenic purpura (ITP) can deliver neonates with severe thrombocytopenia. Clear evidence declaring the pathophysiological cause of this neonatal thrombocytopenia is lacking, as antiplatelet antibodies are not always detectable in maternal serum. Severe neonatal thrombocytopenia below 50 × 10(9) /l is reported in 8-13% of the neonates from mothers with ITP and intracranial haemorrhage (ICH) in 0-2·9%. Evidence about the optimal postnatal treatment is scarce. Our objective was to evaluate the outcome and management in neonates with passive ITP. MATERIALS AND METHODS: All neonates from mothers with ITP born between 1980 and 2011 were included. Platelet counts during the first 10 days, presence of ICH and postnatal treatment were recorded. Maternal characteristics were analysed as possible risk factors for severe neonatal thrombocytopenia. RESULTS: Sixty-seven neonates were included. Severe thrombocytopenia (<50 × 10(9) /l) occurred in 20/67 (29·9%) neonates. In three neonates, platelet count rose spontaneously, 18 neonates were treated (one with persistent moderate thrombocytopenia) with the following: platelet transfusions (3), prednisone (2), intravenous immunoglobulin (IVIG) (1), platelet transfusions and IVIG (11), platelet transfusion and prednisone (1). Recurrence of low platelet counts after transfusions was commonly seen. Risk factors for severe neonatal thrombocytopenia were a previous sibling with severe thrombocytopenia and low maternal platelet nadir during pregnancy. CONCLUSION: In this cohort, severe neonatal thrombocytopenia occurs more frequently than previously reported. To maintain a platelet count above 50 × 10(9) /l, often multiple transfusions and IVIG are required. Multiple transfusions may be avoided by starting IVIG, when platelet count falls below 50 × 10(9) /l after the first platelet transfusion.

Iron status in infants with alloimmune haemolytic disease in the first three months of life.

BACKGROUND AND OBJECTIVES: Ferritin levels are often highly elevated at birth in neonates with alloimmune haemolytic disease of the fetus and newborn (HDFN). Data on ferritin levels in these infants in the first 3 months of life are lacking. Objective of this study was to examine the course of iron status and incidence of iron deficiency and overload in neonates with alloimmune HDFN up to 3 months of age. Secondary objective was to analyse bilirubin levels, liver enzymes and red-blood-cell indices in the same time period and the association with intrauterine transfusion (IUT). MATERIALS AND METHODS: Observational study of neonates with alloimmune HDFN admitted to our centre between November 2010 and March 2012. Data on iron status, bilirubin levels, liver enzymes and red-blood-cell indices up to 3 months of age were routinely collected and compared between neonates treated with and without IUT. RESULTS: Thirty-five infants with alloimmune HDFN were included. Iron overload occurred in 70% of neonates at birth and in 50% and 18% at the age of 1 and 3 months, respectively. No cases of iron deficiency at birth and only one case of iron deficiency at 3 months of age were found. No infants received iron therapy. Infants who received IUT had a significantly lower haemoglobin level and reticulocyte count and higher ferritin level at birth. CONCLUSION: The vast majority of neonates with alloimmune HDFN have iron overload at birth. Incidence of iron overload gradually decreases within the first 3 months without iron supplementation.

Acute hemorrhage in monochorionic twins with ruptured velamentous vessels: anemic twin resuscitated by its co-twin through placental vascular anastomoses?

Monochorionic (MC) twin pregnancies are at increased risk of several complications including acute or chronic twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). Both TTTS and TAPS result from inter-twin fetofetal transfusion through the placental vascular anastomoses. In addition, MC twin pregnancies are at increased risk of having a velamentous cord insertion, which has been linked with poor perinatal outcome due to risk of rupture of the velamentous vessels. In sporadic cases, these vascular connections may have a positive effect instead of a deleterious effect. We present a case of acute fetal distress in a MC twin pregnancy caused by acute hemorrhage following rupture of velamentous vessels. An emergency cesarean section delivery was performed at 29+2 weeks' gestation. One infant was severely anemic at birth and required immediate treatment with volume expansion and blood transfusion. Acute fetal blood loss through the ruptured vessels led to an acute fetofetal transfusion from the co-twin through the placental vascular anastomoses. Delayed intervention could have resulted in severe hypovolemic shock and acute anemia in both fetuses. Instead, in the current case, placental vascular anastomoses had a transient protective role and allowed transfusion of blood from one co-twin into the circulation of the anemic twin.

Hypoalbuminemia in donors with twin anemia-polycythemia sequence: a matched case-control study.

OBJECTIVE: To determine the differences in albumin levels between donors and recipients with twin anemia-polycythemia sequence (TAPS). METHODS: We included all consecutive monochorionic twins with TAPS with double survivors. Each twin pair was matched for gestational age at birth with 2 control monochorionic twin pairs unaffected by TAPS or twin-twin transfusion syndrome. We measured levels of albumin, total protein, and hemoglobin on the first day of life in donors and recipients (TAPS group) and the control group. RESULTS: A total of 25 TAPS twin pairs and 50 control twin pairs were included in the study. The median gestational age at birth was 32 weeks in both groups. In the TAPS group, median levels (IQR) of albumin in donor twins were significantly lower than in recipient twins, i.e. 28.0 g/l (24.0-32.0) versus 32.0 g/l (30.0-34.5) (p = 0.008). Median levels (IQR) of total protein in donor twins were also lower than in recipients, i.e. 44.0 g/l (36.5-49.0) versus 49.0 g/l (46.5-51.0), respectively (p = 0.004). The median (IQR) intertwin albumin difference was significantly higher in the TAPS group than in the control group, i.e. 4.0 g/l (2.5-10.5) versus 2.0 g/l (1.0-4.0) (p = 0.003). The rate of hypoalbuminemia (<20 g/l) and hypoproteinemia (<40 g/l) in donor twins with TAPS was 20% (5/25) and 32% (8/25). CONCLUSIONS: In addition to lower hemoglobin levels, donor twins with TAPS also have significantly lower albumin and total protein levels compared to recipient twins.

Hypoalbuminemia in donors with twin-twin transfusion syndrome.

OBJECTIVE: To estimate the differences in albumin levels between donors and recipients with twin-twin transfusion syndrome (TTTS). METHODS: We performed a matched case-control study including twin pairs with TTTS treated conservatively (conservative group) or with fetoscopic laser surgery (laser group) and analyzed the albumin levels at birth in donor and recipient twins. RESULTS: We included 18 twin pairs in the conservative group and 36 control twin pairs (laser group), matched for gestational age at birth. Median albumin levels in donor twins in the conservative group were significantly lower than in recipient twins, 25.0 versus 33.0 g/l, respectively (p = 0.001). In the laser group, albumin levels in donors and recipients were similar, 32.0 versus 32.0 g/l, respectively (p = 0.633). Hypoalbuminemia (albumin level <20 g/l) occurred in 22% (4/18) of donor twins in the conservative group. CONCLUSIONS: Hypoalbuminemia occurs frequently in donor twins with TTTS treated conservatively. In TTTS treated with laser, donor twins have similar and normal albumin levels compared to recipients, confirming a successfully performed fetoscopic laser procedure.

Thrombocytopenia at birth in neonates with red cell alloimmune haemolytic disease.

OBJECTIVE: To evaluate the incidence and severity of and risk factors for thrombocytopenia at birth in neonates with red cell alloimmunization. STUDY DESIGN: All neonates with haemolytic disease of the foetus/newborn (HDFN) due to red cell alloimmunization admitted to our centre between January 2000 and September 2010 were included in this retrospective study. We measured platelet counts at birth and determined the incidence of thrombocytopenia (platelet count<150×10(9)/l) and severe thrombocytopenia (platelet count<50×10(9)/l). Risk factors for thrombocytopenia at birth were evaluated. RESULTS: Thrombocytopenia was present in 26% (94/362) of included neonates with HDFN at birth. Severe thrombocytopenia was found in 6% (20/362) of neonates. Three risk factors were found to be independently associated with thrombocytopenia at birth: treatment with intrauterine red cell transfusion (IUT) (OR 3·32, 95% CI 1·67-6·60, P=0·001), small for gestational age (SGA) below the 10th percentile (OR 3·32, 95% CI 1·25-8·80, P=0·016) and lower gestational age at birth (OR 1·22/week, 95% CI 1·02-1·44, P=0·025). CONCLUSIONS: Thrombocytopenia at birth occurs in 26% of neonates with HDFN due to red cell alloimmunization and is independently associated with IUT treatment, SGA and lower gestational age at birth.

Exchange transfusions and top-up transfusions in neonates with Kell haemolytic disease compared to Rh D haemolytic disease.

OBJECTIVE: To evaluate neonatal outcome in Kell haemolytic disease compared to Rh D haemolytic disease. STUDY DESIGN: Retrospective study of all (near)-term neonates with Kell (n=34) and Rh D haemolytic disease (n=157) admitted to our centre between January 2000 and December 2008. We recorded the need for exchange transfusion and top-up transfusions up to 3 months of age. RESULTS: Neonates in the Kell group required less days of phototherapy than neonates in the Rh D group [2.4 vs. 4.1 days, respectively (P<0.01)]. The percentage of neonates requiring an exchange transfusion was lower in the Kell group than in the Rh D group [6% (2/34) and 62% (98/157), respectively (P<0.01)]. The percentage of neonates in the Kell group and Rh D group requiring a top-up transfusion was 62% (21/34) and 72% (113/157), respectively (P=0.20). The median number of top-up transfusions per neonate in the Kell group and Rh D group was 1 [interquartile range (IQR) 0-2] and 2(IQR 0-2), respectively (P=0.07). CONCLUSION: Neonates with Kell haemolytic disease require less phototherapy and less exchange transfusions compared to neonates with Rh D haemolytic disease, but an equal number of top-up transfusions.

Parvovirus B19 infection in pregnancy: new insights and management.

In this article, we review the virology, pathology, epidemiology and clinical spectrum of intrauterine human parvovirus B19 (B19V) infection, including intrauterine fetal death, non-immune hydrops fetalis, thrombocytopenia and neurological manifestations such as pediatric stroke and perivascular calcifications. In addition, we discuss the new insights into the neurodevelopmental outcome of intrauterine B19V infection. Current diagnosis and management of B19V infection is summarized, including a diagnostic and follow-up flowchart for practical clinical use.

Top-up transfusions in neonates with Rh hemolytic disease in relation to exchange transfusions.

OBJECTIVE: To study the effect of a restrictive guideline for exchange transfusion (ET) on the number of top-up transfusions in neonates with Rh hemolytic disease. STUDY DESIGN: Retrospective study of all (near)-term neonates with Rh hemolytic disease admitted to our center between 2000 and 2008. In December 2005, policy changed from using liberal ET criteria to more restrictive ET criteria. We recorded the number of ETs and the number of top-up transfusions in the group of neonates before (group I, n = 156) and after (group II, n = 27) the guideline change. RESULTS: The percentage of neonates requiring an ET decreased from 66% (103/156) in group I to 26% (7/27) in group II (P < 0.01). The percentage of neonates receiving a top-up transfusion increased from 68% (105/154) in group I to 81% (22/27) in group II (P = 0.25). The median number of top-up transfusions increased from 1 (interquartile range 0-2) in group I to 2 (interquartile range 1-3) in group II (P = 0.01). CONCLUSION: In this study, restrictive ET criteria in neonates with Rh hemolytic disease lead to a reduction of the rate of ET but an increase in the number of top-up transfusions for neonatal anemia.

Hematological characteristics in neonates with twin anemia-polycythemia sequence (TAPS).

OBJECTIVE: To evaluate the neonatal hematological features of monochorionic twins with twin anemia-polycythemia sequence (TAPS) and to determine the additional diagnostic value of reticulocyte count measurement. METHODS: A cohort of consecutive monochorionic twins with TAPS (n = 19) was included in the study and each twin pair was compared with two monochorionic twin pairs (n = 38) unaffected by TAPS or twin-twin transfusion syndrome (TTTS), matched for gestational age at birth. We measured full blood counts on day 1 and determined the incidence of anemia, polycythemia, reticulocytosis and thrombocytopenia. RESULTS: Median inter-twin hemoglobin (Hb) difference in monochorionic twins with and without TAPS was 13.7 g/dL and 2.4 g/dL, respectively (p < 0.01). Median inter-twin reticulocyte count ratio in twins with and without TAPS was 3.1 and 1.0, respectively (p < 0.01). Thrombocytopenia (platelet count < 150 x 10(9)/L) occurred more often in the TAPS group than in the control group, 45% (17/38) versus 11% (11/38), respectively (p < 0.01). In the TAPS group, mean platelet count was significantly lower in recipients than in donors, 133 x 10(9)/L versus 218 x 10(9)/L, respectively (p < 0.01). CONCLUSIONS: TAPS twins have a large inter-twin Hb difference in combination with a large inter-twin reticulocyte count ratio. Recipients are more often thrombocytopenic than donors, probably due to polycythemia.

Monochorionic twins with ruptured vasa previa: double trouble!

Velamentous cord insertion and vasa previa occur more frequently in monochorionic twin pregnancies than in singleton pregnancies. Both have been linked with poor perinatal outcome due to the increased risk of rupture of the velamentous vessels. We present a case of acute fetal distress in 2 fetuses in a monochorionic twin pregnancy caused by ruptured vasa previa that was not detected antenatally. Both infants were severely anemic at birth. Acute blood loss in twin 1 through the ruptured vessels, led to an acute feto-fetal transfusion from the co-twin through the placental vascular anastomoses. In monochorionic twins, ruptured vasa previa and acute hemorrhage in one fetus can lead to acute feto-fetal transfusion and result in severe hypovolemic shock and acute anemia in both fetuses. Increased awareness for vasa previa and the characteristic placental angioarchitecture in monochorionic twinning is of paramount importance.

Twin anemia-polycythemia sequence: diagnostic criteria, classification, perinatal management and outcome.

Monochorionic twins share a single placenta with intertwin vascular anastomoses, allowing the transfer of blood from one fetus to the other and vice versa. These anastomoses are the essential anatomical substrate for the development of several complications, including twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). TTTS and TAPS are both chronic forms of fetofetal transfusion. TTTS is characterized by the twin oligopolyhydramnios sequence, whereas TAPS is characterized by large intertwin hemoglobin differences in the absence of amniotic fluid discordances. TAPS may occur spontaneously in up to 5% of monochorionic twins and may also develop after incomplete laser treatment in TTTS cases. This review focuses on the pathogenesis, incidence, diagnostic criteria, management options and outcome in TAPS. In addition, we propose a classification system for antenatal and postnatal TAPS.

Quantification of feto-fetal transfusion rate through a single placental arterio-venous anastomosis in a monochorionic twin pregnancy.

Twin-to-twin transfusion syndrome (TTTS) is due to unbalanced inter-twin blood flow through placental vascular anastomoses. We present a TTTS-case treated with fetoscopic laser surgery that allowed us to calculate the net inter-twin blood flow. In the weeks following laser treatment, the ex-recipient developed severe fetal anemia and was treated with two intrauterine adult red cell transfusions (at 26 and 29 weeks' gestation, respectively). After birth, placental injection with color-latex identified a single residual arterio-venous anastomosis from the ex-recipient to the ex-donor. We measured the fetal and adult hemoglobin concentrations in the anemic fetus before and after both intrauterine transfusions, and in both twins at birth. On the basis of these measurements, we calculated the blood flow across the residual arterio-venous anastomosis and found it to be 5.8+/-1.5 mL/24h after the 1st transfusion and 11.4+/-2.9 mL/24h after the 2nd transfusion.

Single-needle laser treatment with drainage of hydrothorax in fetal bronchopulmonary sequestration with hydrops.

Bronchopulmonary sequestration (BPS) is sometimes associated with hydrothorax and hydrops in utero. In the absence of fetal hydrops, perinatal outcome is favorable and justifies expectant management. In the presence of fetal hydrops, perinatal outcome is reported to be extremely poor and intervention should be considered. Therapeutic options include open fetal surgery, minimally invasive coagulation of the blood supply and thoracoamniotic shunting. We present the first case of fetal hydrops and a large hydrothorax due to BPS treated successfully with one ultrasound-guided thin needle insertion, through which both laser coagulation of the feeding artery and drainage of the hydrothorax were performed. Following the procedure the hydrothorax and hydrops gradually disappeared and the BPS diminished in size. A healthy neonate was delivered uneventfully at term. We describe the case and discuss the different therapeutic options.

A comparative cohort study on transfusion practice and outcome in two Dutch tertiary neonatal centres.

The objective of this study was to investigate how a red blood cell transfusion volume of 15 or 20 mL kg(-1) body weight affects the total number of administered transfusions and neonatal complications in premature infants born before 32 gestational weeks. In this observational study, we analysed clinical data from two cohorts of 218 and 241 premature infants admitted to two neonatal centres which used the same transfusion guideline and product, but different transfusion volumes. Outcome parameters were the number of administered transfusions and the composite outcome of bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular haemorrhage and mortality. The proportion of transfused infants was significantly lower (59 vs. 77%) in the centre using a lower transfusion volume of 15 mL kg(-1). In infants born between a gestational age of 24 0/7 weeks and 27 6/7 weeks. a similar proportion received transfusions in both centres, with an equal number of transfusions per infant. In infants born between a gestational age of 28 0/7 weeks and 31 6/7 weeks, the proportion of transfused infants (49 vs. 74%) was significantly higher in the centre using a larger transfusion volume. In these infants, transfusion with 20 mL kg(-1) resulted, however, in a mean reduction of one transfusion episode per infant. The higher proportion of transfused infants was associated with a higher pre-transfusion haematocrit in less ill infants, suggesting the use of different triggers based on clinical grounds. Composite clinical complications were similar in both cohorts. Clinical neonatal outcome was similar disregard of a higher proportion of transfused patients and a higher total amount of RBC transfused in one of the centres. A larger transfusion volume of 20 mL kg(-1) prolonged the interval until next transfusion and can reduce donor exposure in infants born between a gestational age of 28 0/7 weeks and 31 6/7 weeks.

Phosphodiesterase-4 inhibition attenuates pulmonary inflammation in neonatal lung injury.

Phosphodiesterase-4 (PDE4) inhibitors may offer novel therapeutic strategies in respiratory diseases, including asthma and chronic obstructive pulmonary disease. Therefore, selective PDE4 inhibitors may also provide a therapeutic option for very pre-term infants with bronchopulmonary dysplasia (BPD). The anti-inflammatory effect of two PDE4 inhibitors was investigated in a pre-term rat model of hyperoxia-induced lung injury. Pre-term rat pups were exposed to room air, hyperoxia, or hyperoxia and one of two PDE4 inhibitors: rolipram and piclamilast. The anti-inflammatory effects of prolonged PDE4 inhibitor therapy were investigated by studying survival, histopathology, fibrin deposition, alveolar vascular leakage and differential mRNA expression (real-time RT-PCR) of key genes involved in inflammation, alveolar enlargement, coagulation and fibrinolysis. PDE4 inhibitor therapy prolonged median survival by up to 7 days and reduced alveolar fibrin deposition, lung inflammation and vascular leakage by decreasing the influx of monocytes and macrophages and protein efflux in bronchoalveolar lavage fluid. Analysis of mRNA expression of key genes involved in experimental BPD revealed a significant PDE4 inhibitor-induced improvement of genes involved in inflammation, fibrin deposition and alveolarisation. In conclusion, phosphodiesterase-4 inhibition prolongs survival by inhibiting inflammation and reducing alveolar fibrin deposition in pre-term rat pups with neonatal hyperoxic lung injury, whereby piclamilast outperformed rolipram.

Thrombocytopenia in hydropic fetuses with parvovirus B19 infection: incidence, treatment and correlation with fetal B19 viral load.

OBJECTIVE: To examine (1) the incidence of fetal thrombocytopenia in hydropic fetuses with congenital B19 virus infection, (2) the effect of intrauterine platelet transfusions and (3) the correlation between fetal B19 viral load and severity of thrombocytopenia. DESIGN: Retrospective analysis of data from prospectively collected fetal blood samples. SETTING: Leiden University Medical Centre, the national centre for management of intrauterine fetal disease in the Netherlands. POPULATION: Thirty hydropic fetuses treated with intrauterine red blood cell and platelet transfusions for human B19 virus-induced severe fetal anaemia and thrombocytopenia over a 10-year period. METHODS: Fetal blood samples (n= 30) taken before and after intrauterine transfusion were investigated. No cases were excluded, and there was no loss to follow up. MAIN OUTCOME MEASURES: Parameters recorded were gestational age, experienced fetal movements, gravidity and parity, severity of fetal hydrops, severity of fetal anaemia and thrombocytopenia and megakaryocyte and reticulocyte counts. Survival and procedure-associated complications were documented. Quantitative B19 viral load measurements were performed on all fetal samples. RESULTS: Forty-six percent of all hydropic fetuses showed severe thrombocytopenia. No antenatal intracerebral haemorrhage or procedure-associated bleeding occurred. Overall, survival was 77%. Platelet counts increased following platelet transfusion and decreased significantly following red blood cell transfusion alone. No correlation was found between fetal viral loads and platelet counts. CONCLUSION: Thrombocytopenia was frequently encountered in fetal B19V infection, but fetal bleeding complications were not noted. Absence of a direct relationship between fetal B19 viral load and platelet counts suggests a temporal dissociation between these findings. Dilutional thrombocytopenia is frequently seen in the fetus following red blood cell transfusion alone. The clinical significance of this phenomenon is unclear. The risk of fluid overload by fetal platelet transfusion in a severely hydropic fetus should be weighed against the low incidence of fetal bleeding complications.