Imunoglobulinele intravenoase și avortul spontan: o analiză narativă
Intravenous immunoglobulins and spontaneous abortion: a narrative review
Data primire articol: 02 Iunie 2026
Data acceptare articol: 09 Iunie 2026
Editorial Group: MEDICHUB MEDIA
10.26416/Gine.52.2.2026.11628
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Abstract
Spontaneous abortion afflicts 10-20% of clinically recognized pregnancies and remains a major reproductive challenge. While chromosomal abnormalities account for many cases, up to half of recurrent pregnancy losses (RPL) remain unexplained and may involve immune dysregulation. Intravenous immunoglobulin (IVIG) therapy has been proposed as a potential immunomodulatory treatment for women with RPL, particularly those with autoimmune or alloimmune abnormalities. This narrative review synthesizes current evidence regarding the immunological basis of pregnancy loss, the mechanisms of IVIG action, clinical outcomes and controversies surrounding its use.
Keywords
spontaneous abortionimmunomodulatory treatmentautoimmune or alloimmune abnormalitiesRezumat
Avortul spontan afectează 10-20% din sarcinile confirmate clinic și rămâne o provocare majoră în domeniul reproducerii umane. Deși anomaliile cromozomiale sunt responsabile pentru multe dintre aceste cazuri, până la jumătate dintre pierderile recurente de sarcină (RPL) rămân fără o cauză cunoscută și pot implica dereglări ale sistemului imunitar. Terapia cu imunoglobuline intravenoase (IVIG) a fost propusă ca un potențial tratament imunomodulator pentru femeile cu pierderi recurente de sarcină, în special pentru cele care prezintă anomalii autoimune sau alloimune. Această analiză narativă sintetizează dovezile actuale privind baza imunologică a pierderii sarcinii, mecanismele de acțiune ale terapiei cu imunoglobuline intravenoase, rezultatele clinice și controversele legate de utilizarea acestei terapii.
Cuvinte Cheie
avort spontantratament imunomodulatoranomalii autoimune sau alloimune1. Introduction
Spontaneous abortion, defined as pregnancy loss before 20-22 weeks of gestation, afflicts approximately 10-20% of pregnancies, with recurrent pregnancy loss (RPL) occurring in 1-2% of couples(1,2). Although genetic, anatomical, endocrine and infectious causes are well recognized, nearly 50% of RPL cases remain unexplained(3,4). Increasing evidence suggests that immune dysfunction – including autoimmunity, alloimmune intolerance and abnormal natural killer (NK) cell activity – may contribute to pregnancy failure(5,6).
Given its broad immunomodulatory properties, intravenous immunoglobulin (IVIG) has been investigated as a therapeutic option for preventing spontaneous abortion in selected women with RPL(7,8), but the results remain controversial.
2. Immunological basis of spontaneous abortion
Successful pregnancy requires a finely regulated maternal immune response that promotes tolerance toward fetal antigens while maintaining adequate defense mechanisms. Several immunological abnormalities have been associated with miscarriage:
- Autoimmune disorders, particularly antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE), are strongly linked to pregnancy loss(9,10).
- Alloimmune dysfunction, including inadequate maternal tolerance to paternal antigens, may impair implantation and placental development(6).
- Abnormal NK cell activity, especially elevated cytotoxic uterine NK cells, has been observed in women with RPL(11).
- Cytokine imbalance, particularly a shift toward a Th1-dominant inflammatory profile, is associated with early pregnancy failure(12).
- Complement activation, a mechanism implicated in placental injury in autoimmune diseases(13).
These findings provide the rationale for immunomodulatory therapies such as IVIG.
3. Mechanisms of action of IVIG in pregnancy
IVIG is a purified IgG preparation derived from pooled donor plasma. Its mechanisms of action are diverse, and may support pregnancy maintenance.
3.1. Modulation of NK cell activity
IVIG reduces NK cell cytotoxicity and alters receptor expression, promoting a more tolerant uterine environment(14).
3.2. Cytokine regulation
IVIG shifts the immune response from a Th1-dominant to a Th2-dominant profile, which is essential for implantation and placental development(15).
3.3. Fc receptor blockade
By saturating Fc receptors, IVIG reduces the activity of pathogenic autoantibodies and immune complexes, particularly relevant in APS and SLE(16).
3.4. Complement inhibition
IVIG contains anti-idiotypic antibodies that inhibit complement activation, reducing inflammation at the maternal-fetal interface(17).
3.5. Enhancement of regulatory T cells
Regulatory T cells (Tregs) are essential for maternal tolerance; IVIG has been shown to increase their number and function(18).
These mechanisms collectively support the hypothesis that IVIG may benefit women with immunemediated pregnancy loss.
3.6. Anti-immunoglobulin antibodies – anti-idiotype and anti-F(ab)2 antibodies
Idiotype anti‑idiotype networks create a natural regulatory loop in which antibodies neutralize each other’s antigen‑binding sites, dampening excessive immune activation. Anti‑idiotype antibodies can mimic fetal antigens and induce tolerance by promoting regulatory T‑cell expansion and reducing Th1‑type inflammation(19). Anti‑F(ab’)2 antibodies further down‑regulate autoreactive B‑cell clones by binding to their antigen‑binding fragments, limiting harmful autoantibody production(20). Together, these mechanisms reduce NK‑cell cytotoxicity, complement activation and inflammatory cytokines at the maternal-fetal interface. This immunomodulation explains why IVIG – rich in anti‑idiotype and anti‑F(ab’)2 antibodies – may help restore immune tolerance in women with recurrent spontaneous abortion of suspected immune origin(21).
4. Clinical evidence for IVIG in preventing spontaneous abortion
4.1. IVIG in autoimmune-related pregnancy loss
In APS, standard therapy consists of low-dose aspirin and heparin, which significantly improve the outcomes(22). IVIG has been used as an adjunct in refractory cases, with some studies reporting improved live birth rates(23).
4.2. IVIG in unexplained recurrent pregnancy loss (uRPL)
This is the most debated indication. Early uncontrolled studies suggested live birth rates of 70-80% with IVIG(7). However, randomized controlled trials (RCTs) have produced mixed results:
- Some RCTs found no significant benefit compared with placebo(24).
- Others demonstrated improved outcomes in specific subgroups, such as women with more than three miscarriages(25).
A 2021 metaanalysis concluded that IVIG may improve live birth rates in selected high-risk women, but heterogeneity across studies limits firm conclusions(26).
4.3. IVIG in alloimmune disorders
Women with abnormal alloimmune profiles (e.g., low blocking antibodies, high Th1/Th2 ratios) may benefit from IVIG, although these tests lack standardization(27).
4.4. Timing and dosage
Protocols vary widely:
- Early pregnancy administration (peri-implantation) appears more effective(24).
- Doses range from 0.2 g/kg to 1 g/kg, given monthly or biweekly(28).
Lack of standardization complicates the interpretation of results.
5. Safety and adverse effects
IVIG is generally well tolerated. Common adverse effects include headache, fever and chills, while rare complications include thromboembolic events, aseptic meningitis and hemolysis(29).
In pregnancy, IVIG is considered relatively safe, with no evidence of teratogenicity(30).
6. Controversies and limitations
6.1. Heterogeneity of patient populations
Studies include women with autoimmune, alloimmune and unexplained RPL, making comparisons difficult(7,12).
6.2. Lack of standardized immunological testing
Markers such as NK cell levels or cytokine ratios vary by laboratory and lack universal cutoffs(11,12).
6.3. High cost and resource use
IVIG is expensive and requires infusion facilities, raising concerns about cost-effectiveness(32).
6.4. Ethical considerations
Major reproductive societies, including ASRM and ESHRE, do not recommend routine IVIG use outside research settings due to insufficient evidence(33,34).
7. Future directions
Future research should focus on:
- Identifying reliable biomarkers to select women who may benefit(21,35).
- Standardizing IVIG protocols (dose, timing, duration)(25).
- Conducting large RCTs targeting immunologically defined subgroups(25).
- Exploring alternative immunotherapies (e.g., intralipid therapy, TNF-a inhibitors, Treg-based therapies)(36,37).
8. Conclusions
Intravenous immunoglobulin is a promising but controversial therapy for preventing spontaneous abortion, particularly in women with recurrent pregnancy loss of suspected immunological origin. While mechanistic studies support its potential benefits, clinical evidence remains inconsistent due to heterogeneous study designs and patient populations. At present, IVIG should be considered only in selected high-risk cases or within clinical research protocols. Continued investigation is essential to clarify which women may truly benefit and to establish standardized treatment guidelines.
Autor corespondent: Dan Navolan E-mail: navolan@yahoo.com
CONFLICT OF INTEREST: none declared.
FINANCIAL SUPPORT: none declared.
This work is permanently accessible online free of charge and published under the CC-BY.
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