The use of percutaneous umbilical blood sampling in immune thrombocytopenic purpura

Thrombocytopenia in pregnancy: is this immune thrombocytopenia or…?

Thrombocytopenia is a common finding in pregnancy. Establishing the diagnosis of immune thrombocytopenia (ITP) in a pregnant patient is similar to doing so in a nonpregnant patient, except that the evaluation must specifically rule out other disorders of pregnancy associated with low platelet counts that present different risks to the mother and fetus and may require alternate distinct therapy. Many of the same treatment modalities are used to manage the pregnant patient with ITP, but others have not been determined to be safe for the fetus, are limited to a particular gestational period, or side effects may be more problematic during pregnancy. The therapeutic objective differs from that in chronic ITP in the adult because many pregnant patients recover or improve spontaneously after delivery and therefore maintenance of a safe platelet count, rather than prolonged remission, is the goal. Thrombocytopenia may the limit choices of anesthesia, but does not guide mode of delivery, and the fetus is rarely severely affected at birth. Patients should be advised that a history of ITP or ITP in a previous pregnancy is not a contraindication to future pregnancies and that, with proper management and monitoring, positive outcomes can be expected in the majority of patients.

Diagnosis and management of maternal thrombocytopenia in pregnancy

Thrombocytopenia is a common finding in pregnancy, occurring in approximately 7-10% of pregnancies. It may be a diagnostic and management problem, and has many causes, some of which are specific to pregnancy. Although most cases of thrombocytopenia in pregnancy are mild, and have no adverse outcome for either mother or baby, occasionally a low platelet count may be part of a more complex disorder with significant morbidity and may be life-threatening. Overall, about 75% of cases are due to gestational thrombocytopenia, 15-20% secondary to hypertensive disorders; 3-4% due to an immune process, and the remaining 1-2% made up of rare constitutional thrombocytopenias, infections and malignancies. In this review, a diagnostic approach to investigating thrombocytopenia in pregnancy is presented, together with antenatal, anaesthetic and peri-natal management issues for mother and baby, followed by a detailed discussion on the specific causes of thrombocytopenia and the management options in each case.

DIAGNOSIS AND MANAGEMENT OF THROMBOCYTOPENIA IN PREGNANCY

Platelets are an essential component of the first step in the process of haemostasis, plugging defects in the endothelium and providing a surface for secondary haemostasis to occur, via the coagulation pathway. Platelet aggregation and activation cause granule release of von Willebrand factor, ADP and serotonin, which, in turn, results in recruitment of more platelets to form the platelet plug. This serves to stop the bleeding, and also to activate the coagulation pathway on the surface of the activated platelets, leading to a firm fibrin clot.

Immune thrombocytopenia in pregnancy

Management of immune thrombocytopenia in pregnancy can be a complex and challenging task and may be complicated by fetal-neonatal thrombocytopenia. Although fetal intracranial hemorrhage is a rare complication of immune thrombocytopenia in pregnancy, invasive studies designed to determine the fetal platelet count before delivery are associated with greater risk than that of fetal intracranial hemorrhage and are discouraged. Moreover, the risk of neonatal bleeding complications does not correlate with the mode of delivery, and cesarean section should be reserved only for obstetric indications.

International consensus report on the investigation and management of primary immune thrombocytopenia

Previously published guidelines for the diagnosis and management of primary immune thrombocytopenia (ITP) require updating largely due to the introduction of new classes of therapeutic agents, and a greater understanding of the disease pathophysiology. However, treatment-related decisions still remain principally dependent on clinical expertise or patient preference rather than high-quality clinical trial evidence. This consensus document aims to report on new data and provide consensus-based recommendations relating to diagnosis and treatment of ITP in adults, in children, and during pregnancy. The inclusion of summary tables within this document, supported by information tables in the online appendices, is intended to aid in clinical decision making.

Nationwide study of idiopathic thrombocytopenic purpura in pregnant women and the clinical influence on neonates

Idiopathic thrombocytopenic purpura (ITP) occurs more commonly in young women during the reproductive years. To obtain information for management of ITP in pregnancy, we performed a nationwide retrospective survey. Findings from a total of 284 pregnant women with ITP and their 286 newborn infants were available for analysis. The bleeding tendency at delivery was managed chiefly with corticosteroid, intravenous high-dose gamma-globulin, and platelet transfusion. Maternal complications occurred in 77 cases (27.1%) and were frequently seen in cases with poor control of ITP. Neonatal abnormalities, which were not influenced by the clinical state of the mother, occurred at a frequency of 17.8%. Thrombocytopenia in neonates occurred in 48 cases (22.4%), and bleeding tendency was found in 16 cases (6.3%) without severe bleeding. Prediction of thrombocytopenia in neonates was difficult. However, infants from splenectomized mothers with well-controlled ITP showed thrombocytopenia more frequently than those from nonsplenectomized mothers. Mothers treated with steroids at doses greater than 15 mg/day showed a high frequency of maternal complications and fetal abnormal body weight. These observations will be useful in the management of pregnant women with ITP and their infants.

Management of idiopathic thrombocytopenic purpura in pregnancy

Idiopathic thrombocytopenic purpura (ITP) is a relatively common autoimmune disorder among women of child-bearing age. It has a frequency of approximately one to two per 1,000 live births, accounting for about 3% of all cases of maternal thrombocytopenia at delivery. ITP in pregnancy necessitates the management of two patients, the mother and her baby; hence, the close collaboration of a multidisciplinary group composed of a hematologist, obstetrician, and pediatrician is essential. Our understanding of thrombocytopenia in pregnancy has evolved considerably over the last decade, yet the optimal diagnostic and treatment strategies for ITP in pregnancy continues to create controversy. In reviewing the recent literature, there is resurgence in the trend towards treating these patients in a more conservative fashion. This review will summarize the current approach to the diagnosis of ITP in pregnancy, as well as explore the pertinent and controversial issues of investigation and management.

Perinatal management of women with immune thrombocytopenic purpura: survey of United States perinatologists

OBJECTIVE

The aim of the study was to determine how perinatologists in the United States manage the care of women with immune thrombocytopenic purpura with respect to mode of delivery.

STUDY DESIGN

US members of the Society of Perinatal Obstetricians were surveyed with a 4-question questionnaire. Two mailings were sent. Questions 1 and 2 asked for a response regarding the perinatal management of delivery for women with chronic immune thrombocytopenic purpura and new-onset disease. The options were cordocentesis or fetal scalp blood sampling and cesarean delivery if the platelet count was <50,000 cells/microL, cesarean delivery if the maternal platelet count was <50,000 cells/microL, cesarean delivery of all women with immune thrombocytopenic purpura, and trial of labor without determining fetal platelet count. The third question asked for an opinion on whether cesarean delivery was protective against intracranial hemorrhage in cases of immune thrombocytopenic purpura. The fourth question asked whether the practitioner was in academic or private practice or both.

RESULTS

Among the 1596 perinatologists surveyed, there were 940 informative responses (58.9%). Most would allow a trial of labor for women with chronic (59.0%) or new-onset (66.6%) immune thrombocytopenic purpura. In cases of chronic immune thrombocytopenic purpura, 31.0% of those responding would perform an invasive procedure to determine fetal platelet count, followed by cesarean delivery if this count was <50, 000 cells/microL. In cases of new-onset immune thrombocytopenic purpura, 25.4% would do so. Of the respondents, 11.8% reportedly considered cesarean delivery protective against intracranial hemorrhage, whereas 56.6% did not and 31.6% were unsure.

CONCLUSIONS

The management of women with immune thrombocytopenic purpura remains controversial in the United States. Approximately two thirds of perinatologists would allow a trial of labor without a procedure to determine fetal platelet count. Most physicians surveyed did not consider cesarean delivery to be protective against intracranial hemorrhage.

Relationships between severe neonatal thrombocytopenia and maternal characteristics in pregnancies associated with autoimmune thrombocytopenia

In pregnant women with antecedents of autoimmune thrombocytopenia (AITP), no predictive factor for severe fetal thrombocytopenia has been identified. We evaluated the relationships between the course of the maternal disease before and during pregnancy and the risk of severe fetal thrombocytopenia, in 64 pregnant women with known chronic AITP antecedents, over a 12-year period. 28 pregnant women had undergone splenectomy before pregnancy and 17 experienced severe thrombocytopenia (< 50 x 10(9)/l) during pregnancy (monthly determination). Eight infants presented with severe thrombocytopenia at birth (12.5%), and four in the following days (6.25%). No severe haemorrhage was observed. Severe thrombocytopenia at birth was present in 57% (CI 95% 18-90%) of the infants born to mothers with severe pregnancy-associated thrombocytopenia and splenectomy antecedents, and in 0% (CI 95% 0-15%) of the infants born to mothers who presented none of these antecedents (P=0.001). In thrombocytopenic mothers the infant platelet counts at birth were positively correlated to the nadir maternal platelet count during the index pregnancy (r=0.42, P=0.0075). These results suggest that severe autoimmune disease is a risk factor for severe fetal thrombocytopenia, and that pregnant women with no antecedent of splenectomy nor severe thrombocytopenia during pregnancy have a very low risk of severe fetal thrombocytopenia.

Routine maternal platelet count: an assessment of a technologically driven screening practice

Because automated blood cell counters are now widely used in many clinical settings, an assessment of hemoglobin concentration or hematocrit is invariably accompanied by a platelet count. Thus many asymptomatic pregnant women are being screened for thrombocytopenia. The objective of a good screening program is to reduce morbidity and mortality and thereby improve the quality of life; criteria for the evaluation of proposed or ongoing screening programs are well established. However, the screening of pregnant women for thrombocytopenia seems to have been both technologically mandated and passively accepted. Therefore we systematically evaluated the current de facto screening of asymptomatic pregnant patients for thrombocytopenia in the context of well-explained, desirable characteristics for a successful screening program. We conclude that screening for thrombocytopenia in pregnancy fails to meet established criteria, may actually be harmful (by placing unaffected fetuses of thrombocytopenic women, and the women themselves, at risk from invasive procedures), and should therefore be discontinued.

Immune thrombocytopenic purpura in pregnancy

Of all pregnant women 1.2% have platelet counts below 100 x 10(9)/l. Only a small proportion of these have immune thrombocytopenic purpura (ITP). ITP is caused by antibodies directed against one's own platelets and may affect the mother as well as the fetus. No cases with documented intrauterine fetal bleeding have been reported. The most critical time for the fetus is usually a few days after birth. Hitherto the patient's history has been the best predictor of maternal and neonatal complications. Diagnostic cordocentesis entails a considerable risk and is to be discouraged in most situations. Intrauterine transfusions are effective only for a very limited period. There is no evidence that caesarean section protects the thrombocytopenic infant from intracranial haemorrhage. We therefore recommend restricting caesarean section to obstetric indications and to situations with proven fetal thrombocytopenia and enhanced obstetric risk. The safe cut-off level has yet to be ascertained. It is mandatory to control the newborn's platelet count during the first three days of life.

Immune thrombocytopenia in pregnancy: autoimmune and alloimmune

Auto- and alloimmune thrombocytopenias in pregnancy may seriously impact on both mother and fetus. Autoimmune thrombocytopenia (ITP) affects both mothers and fetuses but is considered to be quite benign for both groups. The 'facts' are that: 1) ITP occurs commonly in pregnancy; 2) there has been no reported maternal mortality in more than 20 years; 3) management, except at delivery, is similar to management in the non-pregnant state; 4) splenectomy is virtually never required during pregnancy; 5) significant neonatal thrombocytopenia occurs in approximately 10% of cases and intra-cranial hemorrhage (ICH) 1%; 6) the course of the first sibling predicts that of the next sibling; and 7) the fetal platelet count can be successfully determined (if desired) by either fetal blood sampling (FBS) or by fetal scalp sampling. Many other important considerations remain undetermined: 1) non-invasive prediction of severe fetal thrombocytopenia; 2) the appropriate mode of delivery for a thrombocytopenic fetus; 3) the role of anti-platelet antibody testing; and 4) the effects on the fetal platelet count of maternal therapy. Alloimmune thrombocytopenia (AIT) is easier to outline because it is a far more serious fetal disorder: 1) neonatal platelet counts < 20,000/microliter are common in AIT; 2) there is a 10-30% ICH rate in first affected newborns, some of which occur antenatally; 3) there is no universal prenatal screening although this would be scientifically feasible; 4) testing is complex and requires an experienced laboratory that can test at least five platelet antigens and has sufficient typed controls to confirm the specificity of any anti-platelet antibodies detected; 5) the second affected sibling in a family is usually more severely affected than the first; 6) treatment of the thrombocytopenic neonate can be accomplished with intravenous (i.v.) gammaglobulin and/or platelet transfusions; and 7) treatment of the fetal platelet count can be accomplished in most instances by infusing the mother with i.v. gammaglobulin with or without steroids; platelet transfusions to the fetus is another option.

Maternal characteristics and risk of severe neonatal thrombocytopenia and intracranial hemorrhage in pregnancies complicated by autoimmune thrombocytopenia

OBJECTIVE

The antenatal and intrapartum management of women with autoimmune thrombocytopenia is controversial. The current approach emphasizes an effort to identify maternal characteristics predictive of severe neonatal thrombocytopenia or to measure fetal platelet counts and perform cesarean section in patients considered to be at risk for neonatal intracranial hemorrhage. In the current study we review our experience with maternal autoimmune thrombocytopenia and neonatal outcome.

STUDY DESIGN

Fifty-five pregnancies with autoimmune thrombocytopenia over a 10-year period in three major medical centers in San Diego, California, were evaluated. Maternal characteristics and neonatal outcomes were assessed and compared with those in other recent reports. Data were submitted to Fisher's exact (two-tailed), chi2, and Student t tests, with linear regression performed to analyze the association between variables.

RESULTS

Maternal characteristics including platelet count, presence of antiplatelet antibody, antecedent history of autoimmune thrombocytopenia, and corticosteroid therapy were not predictive of severe neonatal thrombocytopenia. Maternal history of splenectomy was significantly correlated with fetal platelet counts <50 x 10(9)/L (odds ratio 5.63; 95% confidence interval 2.2 to 14.3). There were four neonates with severe neonatal thrombocytopenia (8%), and one who was delivered by cesarean section had intracranial hemorrhage.

CONCLUSIONS

These findings, combined with others in the literature, confirm that severe neonatal thrombocytopenia is an infrequent complication of maternal autoimmune thrombocytopenia and is not reliably predicted by maternal characteristics. Intracranial hemorrhage is also a rare event and is not related to mode of delivery. Cesarean section should be reserved for obstetric indications only.

Antiplatelet antibody testing in thrombocytopenic pregnant women

OBJECTIVE

The purpose of the study was to attempt to distinguish pregnant women with gestational thrombocytopenia from those with idiopathic immune thrombocytopenia by eight different platelet antibody assays.

STUDY DESIGN

Sera from pregnant women with presumed gestational thrombocytopenia (n = 160) and idiopathic immune thrombocytopenia (n=90) were prospectively tested for indirect and platelet-associated immunoglobulins G and M and complement C3, as well as for serotonin release. After the results were analyzed, a subset of patients were subsequently analyzed for circulating antiplatelet antibody directed against platelet membrane glycoprotein GPIIb/IIIa.

RESULTS

Indirect immunoglobulin G was significantly greater in the 85 women with idiopathic immune thrombocytopenia than in the 129 women with gestational thrombocytopenia (p<0.001). Platelet-associated immunoglobulin G was elevated in the majority of women, both those with gestational thrombocytopenia and those with idiopathic immune thrombocytopenia. There were also no statistically significant difference in the values for platelet-associated C3 or indirect immunoglobulin M and C3. Levels of platelet-associated immunoglobulin M showed a tendency to be higher in women with gestational thrombocytopenia (p=0.04), as did the values in the serotonin release assay (p=0.06).

CONCLUSION

Our data demonstrate that patients with gestational thrombocytopenia had surprisingly high levels of platelet-associated immunoglobulin despite mild thrombocytopenia. Comparison of a relatively large number of patients with idiopathic immune thrombocytopenia and gestational thrombocytopenia indicates that women with idiopathic immune thrombocytopenia cannot be distinguished from those with gestational thrombocytopenia by means of one or more of the prototypic platelet antiglobulin tests currently in use. Our preliminary data with glycoprotein-specific assays indicate that they may be more useful.

Maternal thrombocytopenia in pregnancy: time for a reassessment

Antiplatelet autoantibodies in women with autoimmune thrombocytopenic purpura can cause fetal thrombocytopenia and serious bleeding problems. Obstetricians have used fetal scalp sampling, cordocentesis, and cesarean delivery in this disorder to avoid fetal complications such as intracranial hemorrhage. Accumulating evidence indicates that the fetal risk of intracranial hemorrhage is much lower than initially reported. Moreover, these invasive tests and treatments are costly, cause morbidity, and have little effect in preventing neonatal bleeding complications. Therefore we suggest these interventions should no longer be used in the management of maternal thrombocytopenia.

Fetal and neonatal thrombocytopenia

Thrombocytopenia is defined as platelet count less than 150,000 plat/mm3. Etiologic factors involved include immunological (NAIT and ITP), fetal infectious disease, chromosomal and nonchromosomal, and miscellaneous causes. While the understanding of fetal thrombocytopenia is driven by reason to do fetal blood sampling, discovery of neonatal thrombocytopenia is driven by blood counts performed because of the risk of infections. The most serious consequence of thrombocytopenia in the fetus/neonate is intracranial hemorrhage which can occur in utero as early as 18 weeks gestation. The key factor in perinatal prevention of intracranial hemorrhage is early diagnosis and treatment, possibly in utero. Cordocentesis under direct ultrasound guidance and platelet transfusions have played a major role in the management of fetal/neonatal thrombocytopenia. Ongoing studies and high resolution ultrasound will continue to explore and hopefully clarify fetal and neonatal thrombocytopenia and facilitate recognition of primary and secondary thrombocytopenias.

The role of percutaneous umbilical blood sampling in the management of immune thrombocytopenic purpura

On consultation, percutaneous umbilical blood sampling (PUBS) was offered to women with immune thrombocytopenic purpura (ITP) to determine the mode and site of delivery prior to labour. Between January 1989 and December 1993, 41 pregnant women underwent PUBS. All women had a history of ITP, a platelet count less than 90 K, (+) antiplatelet antibody, and/or thrombocytopenia diagnosed early in pregnancy. PUBS was performed at term except in one patient with preterm labour, who underwent PUBS at 31 weeks' gestation. Patients with fetal platelet counts greater than 50 K returned to their referring physician for delivery. Records were complete in 39 pregnancies. Fetal blood was successfully obtained in 37 of 39 cases (95 per cent). Fetal platelet counts correlated with neonatal platelet counts in 36 of 37 cases (97 per cent). The interval between PUBS and delivery ranged from 0 to 31 days. Six of 37 fetuses (16 per cent) had significant fetal thrombocytopenia (< 50 K). These six patients underwent Caesarean section. Vaginal delivery was recommended in all others. There were two procedure-related complications. There were no cases of intraventricular haemorrhage in any of the neonates. In conclusion, there is a high incidence of fetal thrombocytopenia in women with ITP. PUBS reliably detects fetal thrombocytopenia and is therefore useful in the perinatal planning of the mode and site of delivery.

Prenatal evaluation and in utero platelet transfusion for thrombocytopenia absent radii syndrome

A fetus with absent radii in both forearms was discovered on routine ultrasound examination performed at 18 weeks of pregnancy. No other significant abnormalities were found, and no signs of haemorrhage were detected. Serial ultrasound examinations revealed no evidence of fetal internal bleeding. At 37 weeks of pregnancy, a CBC obtained by cordocentesis under ultrasound guidance confirmed the diagnosis of thrombocytopenia absent radii (TAR) syndrome. Apheresis platelets were transfused into the umbilical vein to correct the thrombocytopenia and was followed by an uncomplicated delivery. No bleeding was encountered during the remainder of the baby's neonatal course. We conclude that TAR syndrome can be readily identified prenatally on sonogram, and if severe thrombocytopenia is confirmed by cordocentesis, platelets should be transfused to diminish the risk of serious internal bleeding during and immediately after delivery.

Low fetal morbidity in pregnancy associated with acute and chronic idiopathic thrombocytopenic purpura

Forty-six mothers with immune thrombocytopenic purpura (ITP) gave birth to 72 babies. Sixty-two babies were delivered vaginally and 10 babies by cesarean section. There was no mortality among mothers or babies. Eighteen infants were born thrombocytopenic (PLT < 100 x 10(9)/l). Eleven infants had a platelet count of less than 50 x 10(9)/l. All the severely thrombocytopenic babies (except 1) were born to post splenectomy thrombocytopenic mothers, regardless of steroid treatment during pregnancy. Five babies had clinical manifestations of bleeding; 3 had mild purpura, 1 severe gastrointestinal bleeding, and 1 intracranial bleeding. The latter 2 babies were born prematurely to the same mother who was severely thrombocytopenic despite splenectomy in childhood. In view of very low morbidity in babies of ITP mothers, we suggest that they be delivered vaginally. Cesarean delivery should be performed in selected cases where the mother is severely thrombocytopenic despite splenectomy or where prematurity or obstetrical complications are encountered.

Complications of diagnostic ultrasound-guided percutaneous umbilical blood sampling: analysis of a series of 341 cases and review of the literature

OBJECTIVE

To study the complications of percutaneous umbilical blood sampling (PUBS) conducted for purely diagnostic purposes, in a retrospective study of 341 personal cases and an analysis of 4922 cases from literature.

SUBJECT

Analysis of the sampling procedure and complications seen in 341 punctures, including 12 failures.

INTERVENTIONS

Freehand echo-guided percutaneous umbilical blood sampling. PARAMETERS STUDIED: Conditions in which the blood samples were taken (gestational age, indications, placental location, technique--including number of punctures, duration); total number of fetal deaths and number of fetal deaths related to the procedure; other complications (bradycardia, hematoma of the umbilical cord, hemorrhage, premature births).

RESULTS

20 fetal deaths (FDs) were recorded in 341 cases (5.87%) (figures for the literature: 189/4922 = 3.84%); 3 FDs appeared to be directly related to the procedure (0.88) (figures for the literature: 48/4922 = 0.98%). There were 32 cases of bradycardia (9.38%); this complication was seen more frequently after repeated and prolonged punctures. Hematomas of the cord (1.47%) were seen when punctures were attempted in a free loop of the cord. There was a marked increase in the number of complications (8.96% FDs and 20.73% of bradycardias) when the procedure lasted more than 10 min and/or when more than 3 punctures were attempted (33.33% FDs). These two occurrences are closely related to the gestational age at which the PUBS was conducted, the placental location, the experience of the operators and the condition for which the sample was being taken. Pathological pregnancies (fetal malformation, disease or hypotrophy of the fetus, diseases of the amniotic fluid) had a mortality rate of 11.24% (19/169), whereas fetuses that were presumed to be healthy had a lower risk of 0.58% (1/172).

CONCLUSIONS

The overall mortality (including all fetal and neonatal deaths) appears to be around 5.0% (between 3.84 and 5.87%), but the mortality rate directly related to the procedure seems to be around 1% (between 0.88 and 0.98%). It seems that the fetal mortality rate is closely related to: (a) The state of the fetus and thus to the indication of the procedure. The higher overall mortality rate observed is related to the natural history of the conditions for which the procedure was conducted and the time taken to conduct the procedure and the number of punctures. This depends on the experience of the teams, on the observation of the rule that the attempt should not be prolonged beyond 10 min and no more than 2 punctures should be attempted in any one session.

Fetal blood sampling and pregnancy loss in relation to indication

OBJECTIVE

To assess the relation between the indication for fetal blood sampling and pregnancy loss following the procedure.

DESIGN

Retrospective study.

SETTING

The tertiary referral Fetal Medicine Units at Guy's and University College Hospitals, London.

SUBJECTS

Women undergoing diagnostic fetal blood sampling in four groups: (1) 94 having prenatal diagnosis with normal ultrasound findings; (2) 94 with a structural fetal abnormality; (3) 30 having fetal assessment and (4) 35 with non-immune hydrops.

INTERVENTIONS

Freehand ultrasound guided fetal blood sampling from umbilical cord, intrahepatic vein or fetal heart.

MAIN OUTCOME MEASURES

Pregnancy losses were divided into those within 2 weeks and those 2 weeks after the procedure, obstetric accidents and neonatal deaths.

RESULTS

The 253 patients had fetal blood sampled on 268 occasions. Fifty-one pregnancies were terminated. Overall, 51 of the remaining 202 desired continuing pregnancies were lost, of which 19 (9%) were lost within 2 weeks of the procedure. After exclusion of the pregnancies that were terminated, the procedure-related losses within 2 weeks of sampling were 1 in 76 (1%), 5 in 76 (7%), 4 in 29 (14%) and 9 in 36 (25%) in groups 1, 2, 3 and 4 respectively.

CONCLUSIONS

The risk of fetal blood sampling is increased in abnormal pregnancies, reflecting the underlying pathology and this must be taken into account when counselling patients before the procedure.

Fetal platelet counts in thrombocytopenic pregnancy

Fetal platelet counts were assessed by percutaneous umbilical blood sampling in 64 pregnancies (62 women) with maternal thrombocytopenia. In 33 pregnancies associated with chronic immune thrombocytopenia, 11 of the fetuses had platelet counts below 150 x 10(9)/l and 4 were severely thrombocytopenic (less than 50 x 10(9)/l). In 31 pregnancies with symptomless maternal thrombocytopenia as an incidental finding, 4 fetuses were thrombocytopenic, 1 of them severely. Maternal indices, including antiplatelet antibodies, did not correlate with risk of fetal thrombocytopenia; and in those with repeat measurements there was no evidence of benefit from treatment with either corticosteroids (4 cases) or intravenous immunoglobulin (3 cases). Percutaneous umbilical blood sampling, a safe procedure in experienced hands, provides accurate platelet counts in thrombocytopenic pregnancy, as an aid to decisions on mode of delivery and to assessment of treatments.

Estimation of the risk of thrombocytopenia in the offspring of pregnant women with presumed immune thrombocytopenic purpura

BACKGROUND AND METHODS

The optimal management of immune thrombocytopenic purpura during pregnancy remains controversial because the risk of severe neonatal thrombocytopenia remains uncertain. We studied the outcome of the index pregnancy in 162 women with a presumptive diagnosis of immune thrombocytopenic purpura to determine the frequency of neonatal thrombocytopenia and to determine whether neonatal risk could be predicted antenatally by history or platelet-antibody testing.

RESULTS

Two maternal characteristics were identified as predicting a low risk of severe neonatal thrombocytopenia: the absence of a history of immune thrombocytopenic purpura before pregnancy, and the absence of circulating platelet antibodies in the women who did have a history of the condition. Eighteen of 88 neonates (20 percent; 95 percent confidence interval, 13 to 30 percent) born to women with a history of immune thrombocytopenic purpura had severe thrombocytopenia (platelet count less than 50 x 10(9) per liter at birth), as compared with 0 of 74 (0 percent; 95 percent confidence interval, 0 to 5 percent) born to women first noted to have thrombocytopenia during pregnancy (P less than 0.0001). Among the women with a history of immune thrombocytopenic purpura, 18 of 70 neonates (26 percent; 95 percent confidence interval, 16 to 38 percent) born to those with circulating platelet antibodies had severe thrombocytopenia, as compared with 0 of 18 infants (0 percent; 95 percent confidence interval, 0 to 18.5 percent) born to those without circulating antibodies (P less than 0.02). Thus, the risk of severe neonatal thrombocytopenia in the offspring of women without a history of immune thrombocytopenic purpura before pregnancy and of women with a history of the condition in whom circulating platelet antibodies are not detected was 0 percent (95 percent confidence intervals, 0 to 5 and 0 to 18.5 percent, respectively).

CONCLUSIONS

The absence of a history of immune thrombocytopenic purpura or the presence of negative results on circulating-antibody testing in pregnant women indicates a minimal risk of severe neonatal thrombocytopenia in their offspring.

Prenatal diagnosis of thrombocytopenia absent radius syndrome by ultrasound and cordocentesis

The prenatal diagnosis of thrombocytopenia absent radius (TAR) syndrome, utilizing ultrasound and cordocentesis, is described. To our knowledge, this represents the first prenatal diagnosis of this condition in an index case. The diagnostic evaluation of a fetus with upper extremity limb reduction defects is discussed.