Cytokines in recurrent pregnancy loss

Cytokines seem to play a critical role in the pathogenesis of unexplained recurrent pregnancy loss (RPL). Th1 cytokines have been shown to exert deleterious effects on pregnancy, inhibiting foetal growth and development. On the other hand, Th2 cytokines have been associated with successful pregnancy. The purpose of this study was to evaluate cytokine production in women with RPL. The studied group comprised 29 women with RPL, with at least three consecutive spontaneous abortions. The control group included 27 women with a history of successful pregnancies and no miscarriage. We determined IL-6 and TNF-alpha production in peripheral blood cultured with LPS, as well as IFN-gamma and TGF-beta induced by PHA stimulation. Cytokines were measured by enzyme-linked immunoabsorbant assay (ELISA) using commercial kits (RD, Amersham-Pharmacia). Mann-Whitney test was applied to compare differences between groups. The level of significance was defined at P < 0.05. We observed significantly higher levels of IFN-gamma (355.8 pg/ml versus 98.0 pg/ml; P = 0.01) and a trend toward increased TNF-alpha production (2410.2 pg/ml versus1980.2 pg/ml; P = 0.07) in RPL women as compared to controls. In relation to IL-6 and TGF-beta, no significant difference was detected between RPL and control groups. In agreement with experimental observations, our data support the hypothesis of Th1 cytokine involvement in the pathogenesis of RPL.

Hysteroscopic Metroplasty Improves Gestational Outcome in Women with Recurrent Spontaneous Abortion

STUDY OBJECTIVE

To compare the reproductive outcome in women with recurrent spontaneous abortion (RSA) associated with septate uterus after hysteroscopic metroplasty compared with patients who did not undergo surgery.

DESIGN

Longitudinal evaluation (Canadian Task Force classification II-2).

SETTING

University of Rome, Tor Vergata-affiliated endoscopic unit.

PATIENTS

Forty-eight consecutive women with septate uterus and RSA were enrolled in the study.

INTERVENTIONS

Hysteroscopic metroplasty.

MEASUREMENTS AND MAIN RESULTS

Reproductive outcome in terms of term pregnancy was significantly improved after hysteroscopic metroplasty compared with controls (76% vs. 20%). No differences were found in the prevalence of preterm delivery between groups (4% vs. 5%).

CONCLUSION

Our data suggest that hysteroscopic septum incision can improve pregnancy outcome in patients with RSA associated with septate uterus.

Antiphospholipid antibodies: a major advance in the management of recurrent abortion

Recurrent pregnancy loss is a vexing problem facing many couples and doctors. Repetitive losses affect 2-5% of couples and specific causes are identified in only approximately 50% of patients. Many changes have occurred in this field over the past 20 years and the technology available for the workup of patients has improved. However, the diagnostic yield and pregnancy outcomes of patients with recurrent abortion have not improved significantly over the last two decades. In this regard, the identification of aPL as a new and treatable cause of recurrent abortion represents the major advance in the subject over the past 20 years.

Preimplantation diagnosis of repeated miscarriage due to chromosomal translocations using metaphase chromosomes of a blastomere biopsied from 4- to 6-cell–stage embryos

OBJECTIVE

To evaluate the safety and accuracy of karyotyping the blastomere chromosomes at metaphase in the natural cell cycle for preimplantation diagnosis.

DESIGN

A pilot study.

SETTING

A private infertility clinic and a university laboratory.

PATIENT(S)

Eleven patients undergoing IVF and preimplantation diagnosis.

INTERVENTION(S)

Intact human embryos at the 4- to 6-cell stage and human-mouse heterokaryons were cultured and checked hourly for disappearance of the nuclear envelope. After it disappeared, the metaphase chromosomes were analyzed by fluorescence in situ hybridization.

MAIN OUTCOME MEASURE(S)

Percentage of analyzable metaphase plates and safety and accuracy of the method.

RESULT(S)

The success rate of electrofusion to form human-mouse heterokaryons was 87.1% (27/31), and analyzable chromosomes were obtained from 77.4% (24/31) of the heterokaryons. On the other hand, disappearance of the nuclear envelope occurred in 89.5% (17/19) of the human embryos and it began earlier than that in the heterokaryons. Analyzable chromosomes were obtained and their translocation sites were identified in all blastomeres biopsied from the 17 embryos. After the biopsy, 67.0% of the embryos could develop to the blastocyst stage.

CONCLUSION(S)

The natural cell cycle method reported herein requires frequent observation, but it is safe, with no artificial effects on the chromosomes and without loss of or damage to blastomeres, which occurred with the electrofusion method. Using the natural cell cycle method, we could perform preimplantation diagnosis with nearly 100% accuracy.

Diagnosis and Treatment of Recurrent Miscarriage Associated with Immunologic Disorders: Is Paternal Lymphocyte Immunization a Relic of the Past?

Miscarriage is the most common complication of human pregnancy. Although the causes of recurrent miscarriage (RM) are various, immunologic aberrations between mother and fetus might be one of the causes of miscarriage. Immune responses fall into two categories: autoimmune and alloimmune. Currently, no appropriate diagnostic method has been established to identify alloimmune causes. We observed that NK cell activity in women with RM was higher than that in women without a history of miscarriage. Functional or quantitative analysis of NK cells could be used to identify alloimmune causes. Paternal lymphocyte immunization has been the most widely used treatment for alloimmune-mediated miscarriages. However, the latest Cochrane review by Scott reached the current conclusion that lymphocyte immunization therapy provided no significant beneficial effect over placebo in preventing further miscarriage. Approximately 70% of Japanese university hospitals are still performing paternal lymphocyte immunization. Is paternal lymphocyte immunization a relic of the past? Randomized controlled trials based on adequate patient selection in Japan should provide an answer to this question.

The assessment of LIF in uterine flushing--a possible new diagnostic tool in states of impaired fertility

The objective of this study was to assess the LIF (leukemia inhibitory factor) concentration in uterine flushing and serum (ELISA) of women with proven fertility, infertile women and women with recurrent miscarriage. In addition, progesterone level was determined in serum. A decreased production of LIF in the uterine microenvironment was found in states of impaired fertility. With a cut-off point of 8.23 pg/ml for LIF level in uterine flushings we have achieved 86.7% sensitivity and 100% specificity in detection of women with idiopathic infertility compared to fertile controls. No correlation between LIF in serum and uterine flushing was demonstrated, rendering LIF measurements in serum useless for diagnosis of impaired infertility. We conclude that LIF measurement in uterine flushing could be a useful diagnostic tool to predict unsuccessful implantation.

Antibodies to factor XII: a possible predictive marker for recurrent foetal loss

Antibodies to factor XII (FXIIabs) have been demonstrated in some patients with the anti-phospholipid syndrome (APS). The presence of these antibodies were shown to lead to statistically significantly reduced levels of FXII (p = 0.02). In an extension to this study forty female patients with either primary APS (n = 26) or systemic lupus erythematosus (APS positive) (n = 14) were investigated for levels of factor XII, the presence of lupus anticoagulant and antibodies to cardiolipin, beta 2-glycoprotein I and factor XII. Twenty one of the forty patients had a history of foetal loss (> 2, mean = 2.6). Lupus anticoagulant positivity showed a weak association with foetal loss (odds ratio = 1.1). While there was no association between the presence of antibodies to cardiolipin or beta 2-glycoprotein I with foetal loss, antibodies to factor XII showed a strong and statistically significant association (odds ratio = 5.4, p = 0.025).

Abnormal IL-2 receptor levels in non-pregnant women with a history of recurrent miscarriage

BACKGROUND

Immunological abnormalities have been found in pregnant women with a history of recurrent miscarriage. This study compared interleukin-2 receptor (IL-2R) levels in non-pregnant women with a history of recurrent miscarriage with those found in serum from a non-pregnant group with no such history.

METHODS

Group 1 comprised 49 non-pregnant women with a history of recurrent miscarriage (at least three consecutive miscarriages). Group 2 comprised 22 non-pregnant women with no history of miscarriage. Serum IL-2R levels were measured in all patients.

RESULTS

The results obtained showed that although all women were not pregnant at the time of sampling, IL-2R levels were significantly higher in women in Group 1 compared with those in Group 2 (1589 +/- 1289 versus 1082 +/- 823 pg/ml; P < 0.05). Follow-up data were available for 21 women from Group 1. The next pregnancy ended successfully for 14 of these women, while seven miscarried again. The IL-2R levels obtained pre-pregnancy were not significantly different between the two groups (1480 +/- 910 versus 1356 +/- 716 pg/ml).

CONCLUSION

This study has shown that non-pregnant women with a history of recurrent miscarriage have raised IL-2R levels. These increased pre-pregnancy IL-2R levels did not necessarily predict miscarriage for the next pregnancy.

Autoimmune disease as a cause of reproductive failure

High-risk pregnancy is the most common clinical association with antiphospholipid antibodies; the principal manifestations are pregnancy loss and early preeclampsia. Membership in this family of antibodies is continually growing and includes antibodies against a variety of phospholipids, phospholipid-protein complexes, and phospholipid-binding proteins. The current information in the literature is inadequate to clearly implicate a subgroup of antiphospholipid antibodies or a particular pathophysiologic mechanism as being responsible for poor pregnancy outcomes. It is clear, however, that prevalent diagnostic tests for LA and aCL are extremely useful to identify many of these patients, but are inadequate for diagnosis of all patients with autoimmune pregnancy loss or to elucidate the pathophysiology. Many patients who present clinically with autoimmune-like pregnancy complications currently are negative in tests for LA or aCL, but have antibodies against annexin V, phosphatidylserine, or other relevant antigens. The greatest risk for a complicated pregnancy is conveyed by a subgroup of antibodies that affect the normal function of placental trophoblast. As clinical laboratory tests designed to detect more members of the antiphospholipid antibody family become available, understanding of this complicated disease (APS) will increase.

Placental pathology, antiphospholipid antibodies, and pregnancy outcome in recurrent miscarriage patients

OBJECTIVE

To examine whether there are characteristic histological features in placentas from ongoing pregnancies of patients with a history of recurrent miscarriage, with and without primary antiphospholipid antibody syndrome, in relation to clinical pregnancy outcome.

METHODS

Patients attending a recurrent miscarriage clinic were investigated and treated according to an established protocol. One hundred twenty-one consecutive patients achieving a potentially viable pregnancy (at least 24 completed weeks' gestation), including 60 primary antiphospholipid antibody syndrome-positive cases and 61 primary antiphospholipid antibody syndrome-negative cases were included. After delivery, placental pathologic examination was carried out by a pathologist unaware of the clinical details. Histological sections were examined by two pathologists independently. Pregnancy outcome and placental findings were reviewed in relation to the maternal antiphospholipid antibody status.

RESULTS

Pregnancy outcome was similar in primary antiphospholipid antibody syndrome-positive and primary antiphospholipid antibody syndrome-negative groups regarding gestation at delivery and antepartum obstetric complications. Several histological placental abnormalities were identified in both groups, but most pregnancies were clinically uncomplicated, with no significant placental abnormalities. In cases with pregnancy complications, the placental pathology was primarily that of uteroplacental vasculopathy, such as placental infarction and preeclampsia, but there were no specific placental lesions or patterns of abnormalities characteristic of primary antiphospholipid antibody syndrome-positive patients. A small subgroup of primary antiphospholipid antibody syndrome-positive patients may be at increased risk of development of maternal floor infarction or massive perivillus fibrin deposition.

CONCLUSION

There are no specific histopathologic placental abnormalities characteristic of treated patients with antiphospholipid antibody syndrome and poor reproductive history, but complications of uteroplacental disease are more common.

[Biochemical and sonographic values in early pregnancy in women with a history of early spontaneous abortion]

INTRODUCTION

The aim of this study was to examine interconnections between changes in serum levels of biochemical parameters during pregnancy and sonographic parameters relevant for evaluation of early pregnancy.

MATERIAL AND METHODS

We analyzed serum levels of human chorionic gonadotropin (hCG), estradiol (E2), progesterone (PRG) and prolactin (PRL) using ELISA method, in cases of complicated pregnancies with symptoms of imminent miscarriage, and in patients with uncomplicated pregnancies. We evaluated their impact on mean gestational sac diameter (MSD), crown-rump length (CRL), inner diameter of the vitelline sac (SV), trophoblast (Trf) thickness and embryonic heart rate (STP). All results were correlated using Pearson's test and regression.

RESULTS

Changes in biochemical parameters of pregnancy correlate significantly with dimensions of analyzed sonographic parameters.

DISCUSSION

Levels of chorionic gonadrotropin affect production of ovarian and placental steroidogenesis. Interrelations were also discussed.

CONCLUSION

Changes in biochemical values of pregnancy hormones affect dimensions of analyzed sonographic parameters. During uncomplicated pregnancy, levels of chorionic gonadotropin, progesterone and estradiol affect mean gestation-sac diameter, embryo length, depth of trophoblast invasion and formation and function of vitelline sac, and thus they alter the embryonic heart rate.

The place of beta 2 glycoprotein 1 in the assessment of antiphospholipid syndrome

beta 2 glycoprotein 1 (beta2GP1) is a phospholipid-binding protein implicated in the development of antiphospholipid antibodies, associated with thromboembolic complications and fetal morbidity and death, and is thought to corrrelate better than anticardiolipin (aCL) assays. We analysed the role of beta2GP1 in assessing 86 patients being investigated for antiphospholipid syndrome. Thirty-nine patients had 3 tests: [lupus anticoagulant (LA), aCL and beta2GP1], and a further 46 had aCL and beta2GP1. Sixty-one patients had completely negative tests. Five patients had beta2GP1 as the only positive result. 80% of this group had recurrent miscarriage suggesting that beta2GP1 may be an useful adjunct to aCL and LA testing in patients with a significant obstetric history.

Diagnostic studies for thrombophilia in women on hormonal therapy and during pregnancy, and in children

OBJECTIVE

To review the role of acquired and inherited prothrombotic risk factors that increase the risk of thrombosis in oral contraceptive users, during pregnancy, and in neonates, infants, and children; and to determine by the consensus opinion of recognized experts in the field which risk factors should be determined in which individuals at which time.

DATA SOURCES

Review of the medical literature and current clinical practice by a panel of experts in the field of thrombophilia.

DATA EXTRACTION AND SYNTHESIS

The experts made an extensive review of the published literature and prepared a draft manuscript, which included preliminary recommendations. The draft manuscript was circulated to participants in the College of American Pathologists Conference XXXVI: Diagnostic Issues in Thrombophilia prior to the conference. The manuscript and recommendations were then presented at the conference for discussion. Recommendations were accepted if a consensus of the 26 experts attending the conference was reached. The results of the discussion were used to revise the manuscript into its final form.

CONCLUSIONS

This report reviews the options for testing for thrombophilic states in women using oral contraceptives, during pregnancy, and in neonates and children. General guidelines for testing in these clinical situations are provided, along with citation of the appropriate supporting literature.

Clinical utility of factor V leiden (R506Q) testing for the diagnosis and management of thromboembolic disorders

OBJECTIVE

To review the current state of the art regarding the role of the clinical laboratory in diagnostic testing for the factor V Leiden (FVL) thrombophilic mutation (and other protein C resistance disorders), and to generate, through literature reviews and opinions of recognized thought-leaders, expert consensus recommendations on methodology and diagnostic, prognostic, and management issues pertaining to clinical FVL testing.

DATA SOURCES, EXTRACTION, AND SYNTHESIS

An initial thorough review of the medical literature and of current best clinical practices by a panel of 4 experts followed by a consensus conference review, editing, and ultimate approval by the majority of a panel of 28 additional coagulation laboratory experts.

CONCLUSIONS

Consensus recommendations were generated for topics of direct clinical relevance, including (1) defining those patients (and family members) who should (and should not) be tested for FVL; (2) defining the preferred FVL laboratory testing methods; and (3) defining the therapeutic, prophylactic, and management ramifications of FVL testing in affected individuals and their family members. As FVL is currently the most common recognized familial thrombophilia, it is hoped that these recommendations will assist laboratorians and clinicians caring for patients (and families) with this common mutation.

An analysis of the pattern of pregnancy loss in women with recurrent miscarriage

OBJECTIVE

To describe the pattern of pregnancy loss in women with a history of recurrent miscarriage (RM).

DESIGN

Retrospective, observational study.

SETTING

A tertiary referral center for RM.

PATIENT(S)

Five hundred thirty-eight subjects with RM.

INTERVENTION(S)

Women with antiphospholipid syndrome were treated with clexane and aspirin; some patients with uterine anomalies underwent corrective surgery, and some cases of retarded endometrium were treated with hMG.

MAIN OUTCOME MEASURE(S)

Pregnancy outcome, including the stage of pregnancy at which pregnancy loss occurred.

RESULT(S)

In women with a prothrombotic state, the miscarriage rate before the detection of fetal heart activity (early loss) in the untreated group (50%) was significantly higher than in the treatment group (17.5%). In women with a uterine anomaly, the early loss rate and the later loss rate (after detection of fetal heart activity) were both increased. Women with retarded endometrium, women with >/=6 losses, and older women (>/=41 years) are more likely to have a further early loss but not a later loss.

CONCLUSION(S)

An understanding of the patterns of pregnancy loss provides further insight into the mechanism of the reproductive failure, which has implications for treatment.

Trophoblastic beta1-glycoprotein and hemostasis system in pregnant women with antiphospholipid syndrome

Clinical and laboratory studies were carried out in 38 pregnant women with antiphospholipid syndrome. Increased functional activity of platelets and decreased protein-producing function of the placenta were observed starting from the early terms of gestation. These disorders were followed by the development of hypercoagulation in the plasma component of hemostasis, appearance of intravascular blood clotting markers, and inhibition of AT III and protein C. This led to the progress of disorders in the microcirculatory bed, fetoplacental insufficiency, decrease in trophoblastic beta1-glycoprotein level, chronic hypoxia, and fetal death. Infection accelerated this process. Measurements of trophoblastic beta1-glycoprotein every 2 weeks help to diagnose fetoplacental disorders, predict the course of pregnancy, and evaluate the efficiency of drug therapy.

[Celiac disease and spontaneous abortion]

BACKGROUND

Over the last ten years it has become clear that the clinical expression of celiac disease is more heterogeneous than was thought in the past. Although celiac disease is a relatively frequent disease (1/170-200), it is only diagnosed in a small percentage of adult cases compared to the real situation because it is manifested with few symptoms or in an atypical form, or occasionally is completely silent. Gynecological problems have been reported in women with celiac disease, in particular delayed menarche, early menopause, sterility, recurrent abortion and fetal intrauterine growth retardation. The main aim of this study was to investigate the association between celiac disease and abortion, and in particular to evaluate whether patients suffering from recurrent spontaneous abortion might present an atypical or subclinical form of the disease.

METHODS

During the period 1997-1998 a series of laboratory tests were carried out at the Department of Obstetrics and Gynecology and at the Institute of Medicine B of Verona University, in a sample of 184 women (149 from the Obstetrics Clinic and 35 from Internal Medicine B ). These tests included circulating anti-gliadin (AGA) and anti-endomysium (EMA) antibodies and total serum immunoglobulins. In positive cases, further diagnostic tests were performed using small bowel biopsy specimens.

RESULTS

In our selected sample of cases, 5 women (2.7%) were positive for immunological screening against IgA-EMA and for bowel biopsy (confirmed diagnosis of celiac disease). Four of these women (2.1%) formed part of a group of patients with a positive history of spontaneous abortion and one (0.5%) was from the control group.

CONCLUSIONS

An analysis of the cases that emerged from this study and those reported in the literature shows that tests to identify the celiac disease should be extended to the population with a risk of developing this disease. These subjects should include those with a family history or clinical symptoms, in particular women with a history of multiple abortions. In these cases, there are grounds for suspecting an atypical form of celiac disease.

[Recurrent spontaneous abortion of alloimmunologic etiology--diagnosis and immunotherapy]

Alloimmunologic mechanisms have been implicated in a number of heretofore unexplained recurrent spontaneous abortions (RSA) and various forms of immunotherapy have been introduced to treat couples suffering from this condition. The treatment most widely used has been immunization using allogenic leukocytes from the partner. This immunotherapy is offered by many medical centers in the USA and elsewhere, although its efficacy remains controversial. Published trials and meta-analyses of published and unpublished studies have yielded conflicting results (success rate 57%-87%). The multicenter study performed under the auspices of the American Society of Reproductive Immunology concluded that contradictory results of investigations could be caused by the heterogeneity of study groups. Because of controversy about the efficacy of allogeneic leukocytes immunization for treatment of RSA, intravenous immunoglobulin as an alternative treatment have been sought. Small number of randomized, controlled trials of IVIG for treatment of RSA have been published. Although these results show that IVIG is effective in the treatment of RSA (live birth rate of 61-85%), it still is not clear what the ideal dosage is, and how frequently and how long IVIG therapy should be given.

[Spontaneous abortions in Sneddon's syndrome]

Following the publications on the connection between Sneddon's syndrome and the antiphospholipid++ syndrome, the attention of researchers concentrated on the reproductive problems of women comprising the greater part of patients suffering from Sneddon's syndrome. One of the main indications of these almost coinciding syndromes are miscarriages for no obvious reason. It is supposed that the general mechanism is thrombosis. In a group of 38 patients with Sneddon's syndrome 32 (84%) are women. Twenty-eight of them have altogether given bright 43 times. Seven of them have suffered miscarriages for no obvious reason and three have habitual miscarriages. Three women have sterility problems.

Frequency of etiological factors and cost effectiveness of the work up for patients with history of recurrent pregnancy loss

OBJECTIVE

To assess the frequency of the etiological factors during the evaluation of patients with recurrent abortions. The cost effectiveness of the most frequent positive findings will be assessed.

STUDY DESIGN

This is a retrospective study in which 97 patient charts were evaluated and only 90 charts were included in this study. The diagnostic studies for every patient including hysterosalpingogram, endometrial biopsy, cervical cultures for Chlamydia and ureaplasma, and chromosomal karyotyping for the couple were assessed. The cost analysis was based on the CPT coding for each test.

RESULTS

The frequency of the tests with highest positive findings were hysterosalpingogram, endometrial biopsy, cervical cultures, and immunologic studies. Chromosomal karyotyping has a low positive yield in evaluation of these patients.

CONCLUSION

In evaluating patients with recurrent miscarriages, treating physicians should take into consideration the tests which have a high positive yield as a first step. Chromosomal karyotyping should be evaluated in specific situations.

Contemporary issues for spontaneous abortion. Does recurrent abortion exist?

Most of the time, spontaneous abortion is a random event and represents the natural selection process. Although a recurrent factor may be present and may cause one or more abortions for a given couple, such instances are rare. Well-substantiated causes include parental chromosomal abnormalities (e.g., translocation), antiphospholipid syndrome, PCOD, and maternal age greater than 40 years. Müllerian duplication defects are most likely a cause of pregnancy loss for some women. A growing body of evidence refutes the role of corpus luteum defect as a common cause of recurrent abortion. Other causes are numerically infrequent in occurrence. It is likely that cigarette smoking and alcohol consumption contribute to pregnancy wastage. Although some therapies for the causes listed herein have been proven effective by randomized controlled trials, most have not. Given the excellent outcome demonstrated for most couples with unexplained recurrent abortion in the absence of treatment, it is difficult to recommend unproven therapies, especially if they are invasive and expensive. Instead of examining the environment in which pregnancy has occurred or been planned, clinicians have simply counted the number of spontaneous abortions among couples in an attempt to determine who should be evaluated. The former approach would seem most appropriate and proactive.

Relation between decreased anandamide hydrolase concentrations in human lymphocytes and miscarriage

BACKGROUND

Endocannabinoids such as anandamide are thought to have adverse effects on pregnancy and embryonic development. The activity of the degradative enzyme anandamide hydrolase may therefore be crucial for prevention of excessive concentrations of anandamide in the uterus, and thus prevention of pregnancy failure or female infertility. We tested this hypothesis in a preliminary study, and then used the results to find out whether anandamide hydrolase activity could predict miscarriage in a group of pregnant women.

METHODS

We assessed anandamide hydrolase activity in peripheral lymphocytes from 50 healthy, pregnant women at weeks 6-11 of gestation by a specific radiochromatographic method. The expression of the enzyme at the protein level was measured by ELISA with specific polyclonal antibodies. In a further study, we measured anandamide hydrolase concentration in 120 women who were 7-8 weeks pregnant and compared these findings with subsequent pregnancy outcome.

FINDINGS

In the first study, seven of the 50 women had a miscarriage. Anandamide hydrolase activity was lower in the seven women who miscarried than in the 43 who did not (60.43 pmol/min per mg protein [SD 29.34] vs 169.60 pmol/min per mg protein [30.20]; difference 109.17 pmol/min per mg protein [95% CI 26.64-191.70]; p<0.0001 by the Mann-Whitney test). Enzyme activity correlated with enzyme concentration, and a threshold concentration represented by an optical density (after ELISA) of 0.15 absorbance units at 450 nm separated the women who had miscarriages from those who did not. In the second study, 15 women had anandamide hydrolase concentrations below the threshold, and 105 had concentrations at or above the threshold. All 15 women in the low anandamide hydrolase group had miscarriages, compared with one of the 105 women with high concentrations (p<0.0001 by Fisher's exact test).

INTERPRETATION

Decreased anandamide hydrolase activity and expression in peripheral lymphocytes is an early (<8 weeks of gestation) marker of spontaneous abortion, and may prove useful as a diagnostic tool for large-scale, routine monitoring of gestation. Our results also suggest that endocannabinoids might be critical in regulating the lymphocyte-dependent cytokine network associated with human fertility and successful pregnancy.