Antiphospholipid antibodies and beta 2-glycoprotein-I in 500 women with recurrent miscarriage: results of a comprehensive screening approach

Placentation, antiphospholipid syndrome and pregnancy outcome

The antiphospholipid antibodies (aPLs) are a diverse group of autoantibodies associated with a pattern of disease known as antiphospholipid syndrome (APS). Pregnancy complications secondary to placental insufficiency are key features of this disease. The mechanisms underlying the placental pathology remain unclear. In this article the process of placentation in healthy and pathological pregnancies is reviewed. The evidence for defective placentation in APS pregnancies and involvement of aPLs in this process is summarized. Finally hypotheses based on the interpretation of these studies are discussed.

Anti-beta 2 glycoprotein 1 and anti-annexin V antibodies in women with recurrent miscarriage

While it has been established that anti-phospholipid antibodies (aPL) are associated with recurrent miscarriage (RM), the importance of anti-beta2 glycoprotein 1 (GP1) IgG and anti-annexin V IgG antibodies as risk factors for RM is undefined. We have investigated the prevalence of anti-beta2 GP1 IgG and anti-annexin V IgG antibodies in 54 aPL-positive and 48 aPL-negative women with RM. The prevalence of IgG anti-beta2 GP1 antibodies was not significantly different in persistently aPL-positive women with RM (7%), aPL-negative women with RM (6%) and the normal parous control group (3%). Anti-annexin V IgG antibody prevalence was significantly increased in aPL-positive women with RM compared with aPL-negative women with RM (P = 0.01). The elevations were found in 35%, 19% and 16% of aPL-positive women with RM, aPL-negative women with RM and the control group respectively. No women showed positivity for both anti-beta2 GP1 IgG and anti-annexin V antibodies. Anti-beta2 GP1 IgG antibodies do not appear to be contributory to the investigation of women with RM. Anti-annexin V antibody positivity, although associated with aPL positivity in women with RM, is not an independent risk marker.

Antiphospholipid syndrome and recurrent miscarriages

Sixty percent of recurrent spontaneous abortions are unexplained. Antiphospholipid syndrome is a multisystem disease with the predominant features of venous and arterial thrombosis, recurrent pregnancy loss, foetal death and the presence of antiphospholipid antibodies. Many epidemiological studies focus on antiphospholipid autoantibodies syndrome (APS) as a cause of recurrent spontaneous abortion (RSA). It is found that 7-25% of RSA would have APS as the main risk factor. 'Association not being synonymous with cause', the proportion of abortions due to the APS is difficult to estimate for several reasons: definition of recurrent abortion is variable, the assays for antiphospholipid antibodies are not well standardised, inclusion of patients in the study group according to the antibodies titre is author dependent. Recent studies suggest association of antiphospholipid antibodies syndrome not only with recurrent abortions but also with infertility. New mechanisms are described by which antiphospholipid antibodies could cause placental thrombosis and infarction, acting directly on the surface anticoagulant expressed on trophoblastic cells. Only lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) assays are sufficiently standardised to be usable in routine. Testing for other antiphospholipid antibodies (aPLs) should remain investigational. Several treatments have been proposed: low doses of aspirin, low or immunosuppressive doses of corticosteroids, and preventive or effective dose of heparin, intravenous immunoglobulin.

Thyroid antibodies and fetal loss: an evolving story

This article reviews the literature on thyroid antibodies and miscarriage. In 1990, in a study designed to determine the incidence and etiology of postpartum thyroiditis, a serendipitous finding emerged revealing an association between thyroid antibodies and spontaneous miscarriage. Subsequently, four other studies, performed on three different continents, have confirmed the correlation. Six studies have evaluated the relationship between thyroid antibodies and recurrent abortion, defined as three or more spontaneous miscarriages. The majority of the studies (67%) reported a statistically significant increase in the incidence of thyroid antibodies in the recurrent abortion group as compared to controls. Four intervention trials have evaluated the impact of immunosuppressive therapy in women with thyroid antibodies. Although all of the trials revealed a decrease in the incidence of recurrent abortion, each study was limited by methodological concerns. A recently developed murine model of pregnancy has also demonstrated increased fetal loss in female mice immunized with thyroglobulin when mated with allogeneic males. The implications of these data generated over the last decade are discussed.

Birth defects after maternal exposure to corticosteroids: prospective cohort study and meta-analysis of epidemiological studies

BACKGROUND

Corticosteroids are first-line drugs for the treatment of a variety of conditions in women of childbearing age. Information regarding human pregnancy outcome with corticosteroids is limited.

METHODS

We collected prospectively and followed up 184 women exposed to prednisone in pregnancy and 188 pregnant women who were counseled by Motherisk for nonteratogenic exposure. The primary outcome was the rate of major birth defects. A meta-analysis of all epidemiological studies was conducted. The Mantel-Haenszel summary odds ratio was calculated for the pooled studies with 95% confidence intervals. A cumulative summary odds ratio was also calculated by combining studies in chronological order. Chi-squared for homogeneity was determined to establish the comparability of the studies.

RESULTS

In our prospective study, there was no statistical difference in the rate of major anomalies between the corticosteroid-exposed and control groups. In the meta-analysis, the Mantel-Haenszel summary odds ratio for major malformations with all cohort studies was 1.45 [95% CI 0.80, 2.60] and 3.03 [95% CI 1.08, 8. 54] when Heinonen et al. ('77) was removed. This suggests a marginally increased risk of major malformations after first-trimester exposure to corticosteroids. In addition, summary odds ratio for case-control studies examining oral clefts was significant (3.35 [95% CI 1.97, 5.69]).

CONCLUSIONS

Although prednisone does not represent a major teratogenic risk in humans at therapeutic doses, it does increase by an order of 3.4-fold the risk of oral cleft, which is consistent with the existing animal studies.

Epidemiology and the medical causes of miscarriage

Human reproduction is extraordinarily wasteful. The reasons for this have taxed all of the contributors to this book. As we move into the 21st century it is sobering to reflect on the fact that we have failed to harness the power of the evolving revolution in molecular medical biology to answer the fundamental question: why is the fate of a fertilized egg so hazardous and so unsuccessful? The following account summarizes our limited knowledge of the epidemiology of miscarriage and then moves on to consider some of the medical causes of miscarriage. The contribution of genetic abnormalities to the problem of pregnancy wastage is discussed elsewhere in this volume.

Obstetric management of antiphospholipid syndrome

The obstetric management of women with antiphospholipid (aPL) syndrome remains controversial. Despite recent advances, the controversies have been fueled by our limited understanding of the multi-factorial causes of aPL-associated pregnancy loss and the lack of data from randomized studies. We have escaped from the narrow confines of the concept of aPL pregnancy loss being purely thrombotic in aetiology and attention is now focused on the adverse effects of aPL on embryonic implantation and trophoblast invasion. Combined treatment with aspirin and heparin has been demonstrated in two randomized studies to lead to a high live birth rate in aPL pregnancies. However, successful pregnancies are characterized by a high rate of perinatal complications and some women are refractory to this treatment combination. In addition to addressing these issues, multi-centre studies, which should perhaps be internet based, are needed to identify those aPL that are causative of pregnancy complications and those that are not, the role of IVIG and the long-term follow-up of both mothers with aPL and their babies.

Thrombophilia in pregnancy

Thrombophilia can be defined as a predisposition to thrombosis. Abnormalities in haemostasis that are associated with clinical thrombophilia include heritable defects, such as mutations in the genes encoding the natural anticoagulants antithrombin, protein C, and protein S, or clotting factors prothrombin and factor V, and acquired defects, such as antiphospholipids. Women with thrombophilic defects have been shown to be at increased risk, not only of pregnancy associated thromboembolism, but also of other vascular complications of pregnancy, including pre-eclampsia and fetal loss. Routine thrombophilia screening of all women attending antenatal clinics is not recommended. Because some thrombophilic defects--for example, type 1 antithrombin deficiency and antiphospholipids--are associated with a high risk of recurrent thrombosis or other pregnancy complications, it is suggested that selected women (those with a personal or confirmed family history of venous thromboembolism or with a history of recurrent fetal loss) are screened for these defects to allow pregnancy management planning.

Human reproductive failure is not a clinical feature associated with beta(2) glycoprotein-I antibodies in anticardiolipin and lupus anticoagulant seronegative patients (the antiphospholipid/cofactor syndrome)

It has been suggested that patients with clinical features suggestive of antiphospholipid syndrome but being lupus anticoagulant (LA) and anticardiolipin (aCL) negative, should be tested for antibodies to beta(2) glycoprotein-I (abeta(2)GP-I), a protein involved in the binding of antiphospholipid antibodies (aPL) to phospholipid surfaces. This was investigated in the present study where a total of 385 women aged </=40 years were included. Of these, 175 were experimental subjects and 210 were controls. The former comprised the following two study groups: 100 spontaneous recurrent aborters (group one), and 75 patients with repeated failure of embryo transfer (group two). Controls included three groups of women: 100 normal healthy parous women with no previous abortion (group three), 60 infertile patients achieving a live birth with their first in-vitro fertilization (IVF)/embryo transfer attempt (group four), and 50 patients with recurrent abortion who tested positive for aPL (LA and/or aCL) (positive controls, group five). Only one patient among recurrent aborters (group one) tested positive for abeta(2)GP-I. All women in groups two, three and four were negative for abeta(2)GP-I screening. As expected, prevalence of patients testing positive for abeta(2)GP-I was significantly higher in group five than among the other groups of patients (P < 0.001). No differences were observed regarding the prevalence of abeta(2)GP-I positive sera in the subgroup of patients having aCL and those having the LA in group five. It is concluded that abeta(2)GP-I screening in first-trimester recurrent abortion or in failure of implantation after IVF is not warranted in patients without aPL as detected by standard antiphospholipid assays.

Habitual abortions in 678 healthy patients: investigation and prevention

The objective of this study of patients with habitual abortion (HA), was to determine their autoimmune profile and to try to prevent new abortions using low-dose aspirin for 7 months with prednisone in the first trimester only, or with low-dose aspirin alone. A total of 678 healthy patients with three or more HA were investigated for antiphospholipid antibodies, antinuclear and antithyroid antibodies. Among these patients, 277 pregnant women were treated, 214 were given prednisone and aspirin (161 autoantibody-negative and 53 autoantibody-positive women), and 63 autoantibody-negative women received aspirin alone. Autoantibodies were present in 33.9% of the patients, in 82.6% of them anticardiolipin antibodies were found to be isolated or associated with antiprothrombin, antithyroid, circulating anticoagulant, antinuclear or anti-beta2 glycoprotein 1 antibodies. In autoantibody-negative pregnant women treated by prednisone and aspirin or aspirin alone, the success rate of live births was 90.7% (146 out of 161) and 74.6% (47 out of 63) respectively (P < 0.01). In autoantibody-positive patients treated with prednisone and aspirin the success rate was 84.9% (45 out of 53) (not significant). Prednisone and aspirin seemed to be as efficient in autoantibody-negative or positive women but better than aspirin alone in autoantibody-negative women. A double-blind trial is in progress to confirm these results.

Antiphospholipid antibodies in infertile couples with two consecutive miscarriages after in-vitro fertilization and embryo transfer

Of 682 women who had undergone in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) with embryo transfer, 84 were successful on two occasions, with 16 of these resulting in miscarriage before 20 completed weeks. Antiphospholipid antibodies (APA) were estimated by enzyme-linked immunosorbent assay in these women (group 1) and compared to two control groups: 42 fertile women with three or more miscarriages (group 2) and 60 women with primary infertility undergoing IVF or ICSI (group 3). An apparently higher prevalence of seropositivity was seen in group 1 women (25%) compared to the group 3 women (6.6%) and it was similar to that seen in group 2 women (21.4%). Therefore the recommendation that women with two consecutive miscarriages after IVF or ICSI should have APA estimations performed routinely may be justified.

Cumulative pregnancy and live birth rates in women with antiphospholipid antibodies undergoing assisted reproduction

The aims of this study were to investigate the influence of antiphospholipid antibodies (APA) on cumulative pregnancy and live-birth rates in patients undergoing assisted reproductive treatment. Serum samples from 173 patients were collected prior to initiation treatment cycle and tested by enzyme-linked immunosorbent assay (ELISA) for the presence of immunoglobulin (Ig)G, IgM and IgA against cardiolipin, phosphoserine, phosphoethanolamine, phosphoinositol, phosphatidic acid, and phosphoglycerol. Fifty-six samples from patients who had at least two failed cycles by assisted reproductive treatment were also tested by a bioassay for the presence of lupus anticoagulants. Both cumulative pregnancy and live birth rates were not affected by the presence of any specific or any number of seropositive APA. There was no association between multiple assisted reproductive treatment failures and APA seropositivity. Neither the serum concentration of any of the 18 APA, nor the number of positive APA was correlated with the number of assisted reproductive treatment failed cycles or affected the probability of pregnancy. No patient was found to be positive for lupus anticoagulants. Using life table analyses, which has been recognized as the most appropriate method available to analyse assisted reproductive treatment results, we conclude that there is no relationship between circulating APA and assisted reproductive treatment outcome. APA do not affect the early process of implantation or maintenance of pregnancy among assisted reproductive treatment patients.

[Anti-beta2 glycoprotein I-beta2 glycoprotein I] immune complexes in patients with antiphospholipid syndrome and other autoimmune diseases

Antiphospholipid syndrome (APS) is defined by the presence of aPL antibodies in patients with thromboembolic phenomena. Some antiphospholipid (aPL) antibodies, such as those directed against beta2-glycoprotein I (beta2GPI), are associated with thromboembolism, possess Lupus Anticoagulant (LA) activity and recognize their target antigen only when bound to specific surfaces or to phospholipids (PL). To ascertain whether both free and antibody-bound beta2GPI circulate in APS, we set up an ELISA to detect [IgG anti-beta2GPI-beta2GPI] immune complexes. In this system, rabbit anti-human beta2GPI antibodies were adsorbed onto plastic plates, incubated with patient plasma, and bound complexes were detected by means of alkaline phosphatase-labeled goat anti-human IgG; each assay was stopped when positive controls consisting of in vitro generated immune complexes reached an Optical Density (OD) of 0.5 at 405 nm. Plasma from 16 patients with APS showed a mean OD405 of 0.291 (range 0.115-0.558), not statistically different from the mean obtained for 15 age- and sex-matched healthy volunteers (mean OD405 = 0.169, range 0.066-0.264). Surprisingly, levels of immune complexes in 14 patients with other autoimmune diseases and no circulating anti-beta2GPI antibodies were statistically higher (mean OD405 = 0.552, range 0.204-0.991) than those of healthy subjects and patients with APS. These data indicate that while autoantibodies to beta2GPI are mainly unbound in plasma of patients with APS, they are complexed with their antigen in patients with other autoimmune diseases, possibly reflecting a higher binding affinity.

Antineutrophil cytoplasmic antibodies and other immunologic abnormalities in patients with habitual abortion

PROBLEM

The immunologic mechanisms of pregnancy loss in habitual aborters with antiphospholipid and antinuclear antibodies have not been fully clarified. The possible association of antineutrophil cytoplasmic antibodies (ANCAs) with recurrent miscarriage was examined.

METHOD OF STUDY

In a prospective, controlled trial of 59 women with recurrent abortion, the prevalence of pANCA (antimyeloperoxidase), cANCA (antiproteinase-3), and immunoserologic abnormalities of systemic lupus erythematosus (SLE) anti double-stranded DNA, anti-SSA, anti-SSB, anti-U1RNP, anti-Sm, anticardiolipin and antinuclear antibodies, LE-cell, lupus anticoagulant, and complement-3 were investigated.

RESULTS

pANCA occurred in 2, and cANCA in 6 of 59 case patients, but neither was observed in the controls (P = 0.09 for cANCA). cANCA levels were significantly higher in patients than in controls (P = 0.028). Six recurrent aborters were identified as having a group of immunoserologic abnormalities characteristic of SLE.

CONCLUSIONS

Immunologic mechanisms detectable in SLE may operate in a subgroup of habitual aborters with suspected immunologic cause. ANCAs occur more frequently in patients with recurrent miscarriage than in controls.

Pregnancy complications in women with recurrent miscarriage associated with antiphospholipid antibodies treated with low dose aspirin and heparin

OBJECTIVE

To study the obstetric course of women with a history of recurrent miscarriage associated with antiphospholipid antibodies, lupus anticoagulant and anticardiolipin antibodies, treated with low dose aspirin and low dose heparin.

DESIGN

Prospective observational study.

SETTING

University based tertiary referral clinic.

POPULATION

One hundred and fifty pregnant women with a history of recurrent miscarriage associated with persistently positive tests for antiphospholipid antibodies.

METHODS

Lupus anticoagulant was detected using the dilute Russell's viper venom time together with a platelet neutralisation procedure. IgG and IgM anticardiolipin antibodies were detected using a standardised enzyme linked immunosorbent assay. An IgG anticardiolipin level > or = 5 per litre units and an IgM anticardiolipin level > or = 3 per litre units was considered positive. Aspirin (75 mg daily) was commenced at the time of a positive pregnancy test and heparin (5000 units subcutaneously 12 hourly, or enoxaparin 20 mg daily) was started when fetal heart activity was demonstrated on ultrasound. Treatment was stopped at the time of miscarriage or at 34 weeks of gestation.

RESULTS

One hundred and seven pregnancies (71%) resulted in a live birth. Forty-one pregnancies (27%) miscarried, the majority in the first trimester. One woman had a stillbirth, and one a premature baby who died in the neonatal period. One pregnancy was terminated for a fetal anomaly. Gestational hypertension complicated 17% (18/108) of ongoing pregnancies and antepartum haemorrhage 7% (8/108). Twenty-six babies (24%) were delivered before 37 weeks of gestation. Fifty women (46%) were delivered by caesarean section. The median birthweight of all live born infants was 3069 g (range 531-4300); however 15% (16/108) of the infants were small for gestational age.

CONCLUSION

Combination treatment with aspirin and heparin leads to a high live birth rate among women with recurrent miscarriage and antiphospholipid antibodies. However, successful pregnancies are prone to a high risk of complications during all trimesters. Close antenatal surveillance and planned delivery of these pregnancies in a unit with specialist obstetric and neonatal intensive care facilities are indicated.

Antiphospholipid antibodies and reproduction: the antiphospholipid antibody syndrome

In women who have a diagnosis of APS (both clinical and laboratory criteria) the chance for successful pregnancy is reduced. In these cases, treatment appears to be a clear option, particularly in the case of prior thromboembolic events. The current preference of treatment for women with RPL and aPL antibodies is subcutaneous heparin and aspirin. This treatment should begin with a positive pregnancy test and continue postpartum. It is unclear, at this time, what treatment, if any, is required for women who do not meet all the criteria for diagnosis of APS, but who are known to have aPL antibodies. In some cases, these women were tested because of a prior false-positive test for syphilis, with subsequent identification of aPL antibodies. More recently, women undergoing IVF were tested and found to have an increased incidence of aPL antibodies. It was suggested that aPL antibodies are associated with infertility and failure to implant. However, a summary of published reports indicate that positive aPL antibodies in patients undergoing IVF do not influence ongoing pregnancy rates. This subject, however, remains an area of active investigation because aPL antibodies were shown to interact with the syncytiotrophoblast and cytotrophoblast layers and could, theoretically, after implantation.

Thyroid autoantibodies are not associated with recurrent pregnancy loss

OBJECTIVE

Approximately 1% of all women have recurrent pregnancy loss, defined as >/=3 spontaneous losses of pregnancy; however, a cause is determined in only 50% of cases. Recent studies have associated the presence of thyroid autoantibodies during the first trimester of pregnancy with spontaneous abortion in the current pregnancy among women without a history of recurrent abortion. The objective of this study was to determine whether circulating thyroid autoantibodies were associated with recurrent pregnancy loss.

STUDY DESIGN

Sera from 74 nonpregnant women with a history of recurrent pregnancy loss and from 75 healthy, fertile control subjects of similar gravidity were tested for thyroglobulin and thyroid peroxidase antibodies by means of radioimmunoassay kits. All women had a third-generation thyroid-stimulating hormone assay performed. Samples were obtained >/=6 months after a pregnancy.

RESULTS

Twenty-two of the women with a history of recurrent pregnancy loss (29.3%) and twenty-eight of the control subjects (37%) had positive results for either one or both of the thyroid autoantibodies (P >. 05). Mean thyroid-stimulating hormone levels and the proportion of women with abnormal thyroid-stimulating hormone values did not differ between the 2 groups.

CONCLUSION

Women with a history of recurrent pregnancy loss are no more likely than are fertile control subjects to have circulating thyroid autoantibodies. Testing for antithyroid antibodies is not clinically useful in the evaluation of patients with a history of recurrent pregnancy loss.

Antiphospholipid antibodies and reproductive outcome: the current state of affairs

Antiphospholipid antibodies were first linked to pregnancy loss more than 20 years ago, and the condition known as antiphospholipid syndrome is perhaps the most convincing 'immunologic' disturbance other than anti-erythrocyte and anti-platelet alloimmunization disorders. Specific criteria for the antiphospholipid syndrome have been delineated, the anticardiolipin assay has been standardized, and authorities agree on laboratory criteria defining lupus anticoagulant. Nonetheless, considerable confusion exists regarding antiphospholipid syndrome and related reproductive problems. The state of affairs primarily derives from two problems: the first is the premature introduction of non-standardized antiphospholipid assays into clinical use without rigorous standardization and prior to convincing proof of clinical utility. As a result, well-intending, but less well-versed clinicians sometimes make the diagnosis of antiphospholipid syndrome in women who are negative for lupus anticoagulant and anticardiolipin antibodies. This is especially confusing in the face of of growing evidence that the relevant in vivo antiphospholipid antigen is formed by a complex between beta 2-glycoprotein 1 and phospholipids. A second major problem is that of unwarranted discrepancies in the clinical and laboratory features of patients considered to have a diagnosis of antiphospholipid syndrome. This problem is most apparent in the case selection for pregnancy-loss treatment series and trials. Many series have included women with predominantly pre-embryonic and embryonic pregnancy losses, while others included a large majority of patients with one or more second or third trimester pregnancy losses. Some treatment trials purposefully excluded patients with a history of thrombosis or systemic lupus erythematosus, features found in nearly 50% of patients in other series. Though most authorities require the presence of either lupus anticoagulant or medium-to-high titer IgG anticardiolipin antibodies to make a diagnosis of antiphospholipid syndrome, in some series no more than half of the study patients had lupus anticoagulant and as many as 20% had only IgM anticardiolipin antibodies. It is very unlikely that patients with such disparate clinical and laboratory findings have the same autoimmune syndrome, and a stated or implicit diagnosis of antiphospholipid syndrome in such a wide variety of women is scientifically unsound and clinically dangerous. The relationship between antiphospholipid antibodies and poor reproductive outcomes must be approached through rigorous scientific study and appropriate treatments established by well-designed clinical trials.

Antiphospholipid antibodies or not? The role of beta 2 glycoprotein 1 in autoantibody-mediated pregnancy loss

Antiphospholipid antibodies are a family of autoantibodies including lupus anticoagulant and anticardiolipin antibodies that appear to react with negatively charged phospholipids. These antibodies induce thrombosis and pregnancy complications including recurrent stillbirth, recurrent miscarriage, pre-eclampsia and intra-uterine growth retardation. Recent evidence indicates that antiphospholipid antibodies do not bind directly to phospholipid but rather to phospholipid-binding proteins or to a combination of phospholipid and phospholipid-binding proteins. This opens the possibility that antiphospholipid antibodies may be pathogenic by disrupting the function of phospholipid-binding proteins rather than membrane phospholipid. The antigenic role of one phospholipid-binding protein, beta 2 glycoprotein, has been studied in the greatest detail and is reviewed. Despite being highly conserved and expressed at high levels, the physiological function of beta 2 glycoprotein 1 remains unknown. However, a number of putative roles have been proposed which allow speculation as to the mechanism by which antiphospholipid antibodies may disrupt haemostasis and pregnancy.

Prednisone and aspirin in women with autoantibodies and unexplained recurrent fetal loss

BACKGROUND

Recurrent fetal loss has been well described in women with antiphospholipid antibodies. Such women also often have other autoantibodies commonly found in patients with systemic lupus erythematosus. Treating them with prednisone and aspirin may reduce the risk of fetal loss.

METHODS

We screened 773 nonpregnant women who had the unexplained loss of at least two fetuses for antinuclear, anti-DNA, antilymphocyte, and anticardiolipin antibodies and for the lupus anticoagulant. Of 385 women with at least one autoantibody, 202 who later became pregnant were randomly assigned in equal numbers to receive either prednisone (0.5 to 0.8 mg per kilogram of body weight per day) and aspirin (100 mg per day) or placebo for the duration of the pregnancy. The women were stratified according to age (18 to 34 years or 35 to 39 years) and the week of gestation at which the previous fetal losses had occurred (< or = 12 or > 12 weeks). The primary outcome measure was a successful pregnancy.

RESULTS

Live infants were born to 66 women in the treatment group (65 percent) and 57 women in the placebo group (56 percent, P=0.19). More infants were born prematurely in the treatment group than in the placebo group (62 percent vs. 12 percent, P<0.001). The major side effects of therapy in the mothers were hypertension (treatment group, 13 percent; placebo group, 5 percent; P=0.05) and diabetes mellitus (15 percent and 5 percent, P=0.02).

CONCLUSIONS

Treating women who have autoantibodies and recurrent fetal loss with prednisone and aspirin is not effective in promoting live birth, and it increases the risk of prematurity.

Inherited thrombotic disorders: an update

Significant advances in identification of etiologies of inherited thrombosis have been recently reported. A point mutation in coagulation factor V (factor V Leiden) results in resistance to activated protein C and probably represents the most common genetic risk factor for venous thrombosis. A metabolic disorder, homocysteinemia, is now known to be an important risk factor for both arterial and venous thrombosis. Many patients with recurrent thrombosis will have more than one genetic risk factor identified. Recognition of these new disorders should permit a diagnosis to be achieved in at least half of patients evaluated for inherited thrombosis.

Human autoantibodies recognizing human and mouse preimplantation stages

PROBLEM

To find out whether autoantibodies against human preimplantation stages are present in some human sera and, if so, whether the antibodies could be capable to affect the egg development and/or to trigger an activation of the complement system at the procedures of assisted conception.

METHODS

1. Immunohistochemistry on blots of human preimplantation stages. 2. Immunohistochemistry on paraffin sections of human and mouse preimplantation stages. 3. Culture of mouse morulae to analyze complement activation.

RESULTS

1. Some human sera contained autoantibodies against human preimplantation stages. 2. Human-mouse cross-reacting antibodies against preimplantation stages occurred. 3. Immune complexes, formed on mouse preimplantation stages, activated the complement systems in egg cultures, resulting in a damaging of the eggs.

CONCLUSION

The presence of natural autoantibodies to preimplantation stages may be associated with reproduction failure, caused by a direct effect by the autoantibodies and/or an activation of the uterine complement system by the immune complexes formed.

Psycho-neuro-cytokine/endocrine pathways in immunoregulation during pregnancy

PROBLEM

Some mammalian pregnancy failure is thought to occur by immunological or immunologically modifiable mechanisms. The original model wherein spontaneous abortion was proposed to represent rejection of the conceptus as an allograft has been supplanted by a model of maternal paraimmunological natural effector cell toxicity to fetal trophoblast more closely related to tumor rejection. The problem is to integrate current information concerning the role of immunological, paraimmunological, endocrinological, and stress-triggered neural factors that determine whether or not abortion will occur.

METHODS

Review of existing data.

RESULTS

An integrated model is proposed.

CONCLUSION

Immunological factors play an important role in abortion processes and prevention of abortions. The existence of abortogenic mechanisms and their regulation appears to be based upon optimizing survival of the species. Two new conceptual models provide a useful framework for further investigation of human pregnancy failure and its treatment.