NOVAK 2003

Recurrent Pregnancy Loss

CONTENTS Introduction Etiology Evaluation Treatment

INTRODUCTION

70% of pregnancies are lost<viability50%<”””””””””””””””””””””””“ 1st missed period

31% ”””””””””””””””””””“> implantation(by β-HCG)

15% < ’”””””””””””””””””””””” 20 weeks

Definition: ≥3 spontaneous abortions < 20 weeks

= %1:300

Risk of recurrence : >2 abortions = 24%

> 3 = ”””””””””“ 30% > 4 = ”””””””””“ 40-50%

Evaluate RPL after 2 spontaneous abortions if: age > 35 years subfertility/infertility FHMs are seen in both

=1% of pregnancies require evaluation.

ETIOLOGY

1) Genetic = 3.5-5%2) Anatomical = 12-16%3) Endocrine = 17-20%4) Infection = 0.5-5%5) Immunological = 20-50%6) Others = 10%

10-15% of RPL is due to APAS and chromosomal

abnormalities.

GENETIC CAUSES

Mostly due to balanced translocation :Reciprocal translocation normal gametesRobertsonian translocationbalanced gametes

or unbalanced gametes Most embryos with chromosomal

abnormalities do not survive.Live offspring are either carriers of:

Balanced translocation Monosomy/trisomy ( in robertsonian T

).

Monosomic fetuses : may be mosaic

X gametes can only survive ↑in IVF

Trisomic fetuses : may also be mosaic.

include trisomies 13,16,18,and 21 survive

more than monosomic fetuses

We can't exclude chromosomal abnormalities by : negative family history history of a live term birth

The frequency of chromosomal abnormalities is inversely proportional to the number of previous abortions.

Couples with genetic abnormalities are usually with no children .

Parents with history of: spontaneous abortion ± SB ± live birth ( ± anomalies )

are candidates for parental karyotype, but this may be insufficient because:

o aneuploid sperm may be motileo chromosomal abnormality may be in 1

sperm

Other structural chromosomal anomalies include:• Inversion• Insertion• Chromosomal mosaicism• X-linked anomalies (males do not

survive)• Single gene anomalies such as cystic

fibrosis (detected by detailed family history).

HERITABLE THROMBOPHILIAS

1. Hyperhomocysteinemia mutation2. Antithrombin III mutation3. Protein-C and protein-S deficiency4. Factor V Leiden mutation5. Prothombin mutation6. Factor XII deficiency7. Factor XIII and fibrinogen defects

1 -HYPERHOMOCYCTEINEMIA

Homocysteine is derived from dietary methionine. It is metabolized in the presence of methyl-tetra-hydro-folate reductase enzyme (MTHFR) + dietary folic acid, vit B6, vit B12 into:

Cystathione or back into methionine .Hyperhomocysteinemia may be either:

- Congenital due to point mutation in MTHFR (common )

- Acquired due to dietary deficiency of folic acid, vit B6, or

vit B12

Hyperhomocysteinemia is linked to thrombosis and RPL.

2 -ANTITHROMBIN III MUTATION

Antithrombin III inhibits: - thrombin

- factor IXa,Xa,XIa,XIIaAntithrombin III mutation is rare but it is the worst prognostic factor of all heritable thrombophilias. It is associated with RPL and thrombosis.

3 -PROTEIN-C AND PROTEIN-S DEFICIENCY

Protein-C and protein S affect: - X Xa reaction

- prothrombin thrombin reaction

Protein-C and protein S deficiency is linked to placental thrombosis and pregnancy complications.

4 –FACTOR V LEIDEN MUTATION

Factor V prevents interaction with protein-C. Multiple point mutation in the cleavage site of factor V Leiden resistance to protein-C.

Factor V Leiden is associated with

RPL .It is the most common heritable thrombophilia among white people.

5 –PROTHROMBIN MUTATION

It is linked to thrombosis and pregnancy loss.

6 –FACTOR XII DEFICIENCY

Increase in Japanese people and is linked to recurrent pregnancy loss.

7 -FACTOR XIII AND FIBRINOGEN DEFECTS

Both are associated with fetal loss andinvolve other complex mechanisms than simple thrombosis and infarction.

II-ANATOMICAL CAUSES

1 -Congenital causes: incomplete fusion of Mϋllerian ducts incomplete septum resorption (septate, subseptate) cervical anomalies

The most commonest anomalies are septate 60% of spontaneous abortion in the 2nd trimester and sometimes the 1st trimester. Inutero exposure to DES may cause congenital anomalies. The most common lesion in DES is hypopleasia abortion in the 1st or 2nd trimesters.

2 -Acquired causes: fibroid polyps adenomyosis Asherman syndrom cervical incompetence

III- ENDOCRINE CAUSES

Endocrine changes of menstrual cycle

Endocrine factors:1. Luteal phase defect2. Diabetes3. Thyroid disease4. Hyperprolactinemia5. Ovarian reserve

ENDOCRINE CHANGES OF MENSTRUAL CYCLE

Follicular phase and ovulation: - abnormal blastocyst transport

- alteration of uterine receptivity - improper function of CL

From ovulation until 7-9 weeks - failure of CL to produce enough P

- impaired delivery of P to the uterus - inappropriate use of P by the decidua

Near the time of luteal-placental shift - trophoblast unable to produce biologically

active P

ENDOCRINE FACTORS:1- LPD

It is inadequate or inappropriately timed endometrial maturation due to:

- Premature aging of the oocyte

- Dyssynchronous maturation of the endometrium

- PCO : . PCO is present in 80%of RPL

. It is associated with : , obesity

, ↑androgen level affect markers of

uterine receptivity , ↑insulin resistance

2 -DIABETES

DM type II ↑spontaneous abortion

IDDM: - Pregestational glycemic threshold above

which abortion ↑ - Hyperglycemia damage the embryo

- Vascular changes in advanced IDDM ↓placental blood flow.

3 – THYROID DISEASE

Ovulatory disfunction LPD

Pregnancy is associated with ↑ requirement to T4. Hypothyroidism is associated with ↑

spontaneous abortion . Even when T4 is normal, ↑ antithyroid

antibodies may cause ↑ RPL.(Antithyroid antibodies could be markers of a

generalized autoimmune disease .)

4 - HYPERPROLACTINEMIA

Affect reproduction by:

- Direct effect on endometrium

- Indirect immuno-mediator

effect .

5 – DIMINISHED OVERIAN RESERVE

Can be evaluated by:

- Day 3 FSH - Day 3 estradiol

- CC challenge test .

4 - INFECTIONMycoplasmaUreaplasmaChlamydiaβ-streptococcus:

BV is linked to ↑ RPL and PTL in a large study.Viral infection as:

- cyromegalovirus - herpes simplex

Mechanisms of action: - villitis

- mechanisms protecting the fetus from autoimmune rejection↑ infection

- activation of immune reactions PTL, PROM, IUGR.

5 – IMMUNE CAUSES

I. Basic immunologyII. Cellular immunityIII. Humoral immunity

I - BASIC IMMUNOLOGY

1 -Innate responses:1st line defense .

None antigen specific.Mechanisms are :

- phagocytosis - complement fixation ,

- lysis by NK cells .2 -Acquired responses:

Antigen-specific .Modulated by T and B cells.Divided into:

- Primary immune response: on 1st contact with the Ag - Secondary immune response: on subsequent contact with the

Ag. Rapid and strong .

ANTIGEN SPECIFICITY

Regulated by 2 sets of genes present at major histocompatability complex (MHC) located on chromosome 6:

Class I MHC molecules: HLA A, B, C Present at the surface of nearly all cells for intracellular

pathogens .Major ligand for: TCR on CD 8+ cytotoxic and suppressor cells

many receptors on NK cells.

Class II MHC molecules: HLA DR, DP, DQ Present on the surface of antigen-presenting cells as :

Dendritic cells, macrophages- monocytes, B-cells, and tissue specific cells .Protect against extracellular pathogens .Major ligand for: TCR on CD-4+ T- helper cells .

EDUCATION AND HOMING

Fetal bone-marrow derived T-cells move with the blood until they reach the thymus. In the thymus they are divided into :

- Those who will express CD4 co-receptor - Those who will express CD8 co-receptor

And auto-reactivity is eliminated; that is the cells can recognize non-self but not

react against self .

MUCOSAL AND PERIPHERAL IMMUNE SYSTEMS

Peripheral immune system: Located in the blood and spleen.

Responsible for protection against blood-born pathogens.

Mucosal immune system: Located in GIT, RT, GUT, lacrimal and

mammary glands. Responsible for protection against exogenous pathogens.

II - CELLULAR IMMUNE RESPONSE

1. Resident cells2. Immune cell education and homing to

the reproductive tract 3. Antigen presentation at the maternal-

fetal interface4. Regulation of the decidual immune

cells

1 -RESIDENT CELLSThe endometrium is populated by: T-cells

NK-like cell Macrophages

Very few B-cells

At implantation, there is a dramatic change in the decidual cells and

70-80% of the cells are called: Decidual granular lymphocytes, or

Large granular, or Decidual NK

If these cells are NK, then implantation site represent the largest accumulation of NK in humans. The function of these cells is unclear.

In animals, peripheral NKT cells (which have the characteristics of both T cells and NK cells) ↑ spontaneous abortion.

Most peripheral immune system T-cells express TCR-αβ .

In the reproductive system T-cells express in addition to this TCR-γδ which ↑ early in pregnancy and are responsible for direct, none MHC restricted immune recognition of Ag within tissues = more protection.

A subset of macrophage called suppressor cells promot anti-inflammatory properties and may be implicated in maintenance of pregnancy.To sum up:

Human decidua is populated by characteristic immune cells. Alteration of these cells may pregnancy loss. Alteration of these cells occur in RPL and not isolated abortion.

2 – IMMUNE CELL EDUCATION AND HOMING

How these cells are selected, educated, and how they home to the reproductive tract is still unknown, but animal studies showed that:These cells may be educated outside the thymusThey may have different mechanisms other than MHCThey may differ from mucosal and peripheral immune systems.In the mucosal immune system, cells select these sites through interaction between:Cell surface molecules on the immune cell= integrins

””””””””””””””””””””””””””“endothelial cell= selectins or vascular wall adhesive molecule (VCAM) == homing.Animal studies showed that:Integrins are expressed in the reproductive tractKnowing the mechanism of selection and homing may aid in ttt of RPL.

3 – ANTIGEN PRESENTATION

In the past trophoblast escape recognition by ↓ expression of MHC Ag .

Now obsolete, although trophopblast cannot express class II MHC molecules and class I MHC HLA: A and B Ags.Extravillous cytotrophoblast cells express class I: C, E and D Ags. These cells are characterized by excessive invasive properties:

They move from the tip of villi deep into the decidua, invade decidual blood vessels, and replace endothelial cells of decidual spiral arteries. Their behavior reflect non-MHC mechanisms as integrin switching and expose the fetus to recognition.

Any cell not expressing Ag is killed by NK. In addition to protection from killing by NK cells, expression of MHC HLA: C, E, and G by the trophoblast may modulate cytokines expression, aid in invasion, and aid in maternal acceptance. G

Ag was linked to disorders of placental invasion . MHC polymorphism was not linked to RPL.

Interferon-γ was believed to ↑ spontaneous abortion by ↑

expresion of class I and class II MHC which ↑ cytotoxic attack of T cells ,

but aborted tissues were not shown to express MHC Ags.

Class II genotypes were linked to adverse pregnancy outcome, RPA, and ↑ susceptibility to disease as autoimmune disease and DM.

4 –REGULATION OF DECIDUAL IMMUNE CELLS

I. Alterations in T- helper cell phenotype

II. Reproductive hormones and immunosuppression

III. Tryptophan metabolism

I –ALTERATION IN T-HELPER CELL PHENOTYPE

Ag-stimulated immune responses involving CD4+ cells can be divided into: T-helper cell subset 1 (TH1)

T-helper cell subset 2 (TH2) based on the character of CD4+ cell and associated cytokine .

Undifferentiated T- helper cells are differentiated into:

TH 1 in the presence of interferon γ (INF-γ). TH 1 is

associated with inflammatory responses and: INF-γ, IL 2, IL 12 .

TH 2 in the presence of IL 4. TH2 is associated with antibody responses and IL 4, 5, 6, 10, TNF-β.

TNF-α is expressed by both T-helper cells.There is a reciprocal relationship between TH 1, TH 2, and

cytokines.

Most researches agree that: TH 1 responses are harmful to the embryo

TH 2 responses are present in most normal pregnancies TH 1 responses are present in some patients of RPL

60-70% of none pregnant patients with history of RPL

show abnormal T-cell responses invitro compared to <3% in controls.The type of CD4+ cellular response to the implanting fetus is controlled not only by the types of cells in the decidua but also by the cytokine enviroment at the maternal –fetal

inteface .

Cytokines may affect reproduction by regulating: Type of cytokine expressed

Concentration of cytokine expressed Differential stage of effector cell.

Cytokine alteration can be detected in: Endometrium

Decidual immune cells Peripheral blood lymphocytes

Animal studies showed that the only factor absolutely essential for implantation is :

” Leukemia inhibitory factor .“

II- REPRODUCTIVE HORMONES

Many mechanisms are present to avoid fetal recognition by the mother.

Maternal immune responses to the fetus can be detected and

if these mechanisms are regulated, this may help to treat RPL.

Increased reproductive hormones during pregnancy is known to suppress maternal immunity, but the overall immune responses during pregnancy appears to change little, while local immune suppression at the maternal-fetal interface may be vital .

PROGESTERONE

Progesterone is partially responsible for pregnancy maintenance .Progestrone suppress T-cell activity by altering K-channels in cell depolarization which affect:

gene expression intracellular Ca

And both may be none receptor mediated, resulting in: TH 2 responses

LIF expressionBoth will help in maintenance.Recently it was found that progesterone can inhibit CD 8+ T cell proliferation and cytokine secretion.

ESTROGEN

Estrogen modulate immune reactions.

In male animals :

Estrogen improve immune responses after hemorrhage, trauma and thermal injury.

Estrogen protect against chronic renal allograft rejection In humans:

Estrogen ↓ delayed-type hypersensitivity

Estrogen ↑ TH 2 responses .

III – TRYPTOPHAN METABOLISM

Tryptophan is important for T-cell activity and proliferation. Local alterations in tryptophan metabolism may either :

activate or fail to suppress maternal immune response.

In animals: - Tryptophan rich diet ↑ spontaneous abortion

- Inhibition of indolamine 2,3 dioxygenase enzyme (IDO) loss

of allogeneic fetuses but not syngeneic .In humans:

- IDO is expressed in the decidua . - As GA ↑ alteration in maternal serum tryptophan level

Both= potential local immune regulation.

HUMERAL IMMUNITY

I. Antiphospholipid antibody syndromeII. Antithyroid antibodiesIII. Blocking antibody deficiency theoryIV. Novel HLA-linked alloantigen

ANTIPHOSPHOLIPID ANTIBODY SYNDROME

In the past , it was thought that these antibodies were against: cardiolipin and phosphatidylserine. Now it is believed to be against a protein cofactor : β2 glycoprotein-1Which assist antibody association with phospholipid.

%3-5

CHARACTERISTICS OF APAS:

Prolonged aPTT Thrombosis Obstetric complications: Abortion Stillbirth PTL PROM IUGR Preeclampsia

SAPPORO CRITERIA FOR APAS DIAGNOSIS(1998)

clinical and ≥ laboratory criteria must be present to diagnose APAS: ≥ clinical criteria:

≥1 episode of thrombosis in artery, vein, or small vessel obstetric complication:

≥3 spontaneous abortions ≥ 10 weeks ≥1 fetal death ≥ 10 weeks

≥1 preterm labor ≥ 34 weeks for preeclampsia or placental insufficiency

laboratory criteria: 2 results must be (+)ve on ≥ 2 occasions with ≥ 6 weeks in

between+ ve ACA (Ig G or Ig M medium to high level)

+ ve LAHistory of systemic lupus erythromatosus=less favorable outcome.

MECHANISMS OF ACTION

I. ↓ prostacyclin, ↑ thromboxane thrombosis placental infarction

II. Inhibition of syncytiotrophoblast formationIII. Increase β2 glycoprotein 1

rapid atherosclerosis in decidual artries inhibit trophoblast adhesion to

endothelial cells ↓annexin V = placental antithrombotic

molecule To summarize:Pathological evidence of APAS are often equivocalCharacteristic criteria “””””””””””””””””” lacking

””””””””””””””””””””””””””””””””””””””””“present in other lesions

ANTITHYROID ANTIBODIES

ControversialOne study link it to RPLOther study no link

BLOCKING- ANTIBODY DEFICIENCY THEORY

Studies using mixed lymphocyte culture with paternal stimulator cells suggest that HLA-sharing between the two parents may cause blocking-antibody deficiency.

Larger studies showed that HLA heterogeneity is not necessary for successful pregnancy, although complete sharing of the whole genome (occur in isolated groups of people and is very rare) is associated with ↑ spontaneous abortion. Thus, HLA-typing is rarely required.

NOVEL HLA-LINKED ALLOANTIGEN SYSTEM

Studies showed that this substance is actually CD 46 which is a placental complementary receptor responsible for protecting the placenta from complement -mediated attack.

Conclusion:Successful pregnancy may not require an intact maternal immune system.Evidence:Successful pregnancy can occur in:

Agamma-globulinemic women Severe immune deficiency Animals lacking T and C cells Animals with congenital absence of the thymus

OTHER FACTORS VEGF Apoptosis Uterine receptivity Endometrial mucin Cellular and extracellular matrix adhesion properties Soluble intercellular adhesive molecules.

Environmental factors:o Medications:

Antiprogestogens Antineoplastic agents Anhalation anesthetics Ionized radiation prolonged organic solvents

o Heavy metalso Alcoholo Coitus cause abortion only if the cervix is abnormal or

incompetent

EVALUATION

PRECONCEPTION EVALUATION

History Physical examination Laboratory investigations

POSTCONCEPTIONAL EVALUATION

Β-hCG U/S Α-fetoprotein

HISTORY

History of previous pathologic studies or karyotyping of the abortus tissues.

60% of abortions < 8 weeks are due to chromosomal abnormalities. Most common anomalies are trisomy 16 or monosomy 45X. Documentation of aneuploidy in the abortus tissues does not affect future fertility.

GA of previous abortion: Most RPL occur at the same GA every time.

Menstrual history may detect oligomenorrhia or endocrine abnormalities.

The timing of coitus in relation to fertilization may detect dyssynchronous fertilization or old ovum.

Subfertility or infertility= 33% in RPL couples. Abortion may occur before

the 1st missed period and is diagnosed as subfertility. Personal or family history of thrombosis or renal

abnormalities. Family history of pregnancy loss or obstetric complications. Drug intake or environmental exposure.

PHYSICAL EXAMINATIONGeneral examination :

Obesity Hirsuitism and acanthosis Brest examination and glactorrhea Thyroid

Pelvic examination: Anatomy: uterus size, shape, DES

cervix vagina

Trauma Infection

Estrogenization

LABORATORY ASSESSMENT

Standard investigations:I. Parental peripheral blood Karyotyping II. Hysteroscopy / HSGIII. Luteal-phase endometrial biopsy at

day 24IV. Thyroid function tests ± prolactinV. Platelet/ complete blood pictureVI. ACA+LA (aPTT or Russel viper venom)

LABORATORY ASSESSMENT UNDER INVESTIGATION

• Ovarian reserve: day 3 FSH, CC challenge test• PCO: LH, A• ATA• Autoantibodies : antiphospholipid,

antiphosphatidylserine, anti-β2 glycoprotein 1 • Nk cells activity• TH 1, TH 2• Hypercoagulability; aPTT• Hyperhomocysteinemia: fasting and after

methionine loading (dangerous to the fetus). • Cervical cultures: mycoplasma, ureaplasma,

chlamydia

EXPERIMENTAL STUDIES Mixed lymphocyte culture

Parental HLA-typing Serum or site-specific autoantibodies & alloantibodies Others:

- Suppressor cell

- Cytokines - GF

- Embryotoxic factor - Oncogenes

POSTCONCEPTIONAL EVALUATIONIf become pregnant psychological supportConfirm: - intrauterine pregnancy

- viability Because of ↑ % of ectopic and molar pregnancyPregnancy complications

Only ↑ in APAS and intrauterine infections .Monitoring:

Β-hCG Not always ↓ before abortion If missed period Β-hCG until= 1500mIU/ml U/S Every 2 weeks GA of abortion If no FH activity until 6-7 weeks terminate and karyotype Maternal serum α-fetoprotein At 16-18 weeks.

Karyotyping of the abortus tissues: - Suggest chromosomal abnormalities in the

parent - Prevent other costly investigations ↓ cost

Difficulties:

- Difficult culturing of inflamed or necrotic cells

- Contamination with maternal cellsRecent advances:

Genomic hybridization technology: Used on archived and paraffin-embedded

tissues Karyoyping of nucleated fetal RBCs in

maternal blood

TREATMENT

TREATMENT

Most ttt are experimental, use only with informed consent. Most patients conceive irrespective of ttt.

Genetic causesAnatomical causesEndocrine causesInfectionImmunological ttt

immune-stimulation immune-suppression

Antithrombotic ttt

TREATMENT OF GENETIC CAUSES

Antithrombotic ttt for inherited thrombophiliasPreimplantation genetic diagnosis in known heritable disordersDonor oocyte or sperm in robertsonian translocationsRecently :

PGD+antithrombotic ttt+ ART for all unexplained RPL

TREATMENT OF ANATOMICAL CAUSESHysteroscopic resection/metroplasty ± laparoscopyU/S guided transcervical metroplastyFluoroscopic guided septum resectionLaparoscopic excision of endometriotic lesionsCervical cerclage .

TREATMENT OF ENDOCRINLOLGICAL CAUSES

Ovulation inductionThyroid hormone replacementInsulin-sensitizing agents for overt DMBromocriptine

TREATMENT OF INFECTION

Empiric antibiotics for immunosuppressive patientsSpecific antibiotic ttt for known infections to both partners with posttreatment culture before attempting conception.

TREATMENT OF IMMUNOLOGICAL CAUSESImmunostimulating ttt

leukocytes others

Immunosuppressive ttt I.V. immunoglobulin

progesterone others

cyclosporine nifedipine

corticosteroids LDA

LEUKOCYTES

Large studies uselessComplications:

Graft versus host reaction Severe IUGR Fatal fetal thrombocytopenia Autoimmune/isoimmune complications

May benefit 1 : 11 patientsRoutine use unjustified

OTHERS

I. I.V. injection of syncytiotrophoblast microvillous plasma membrane vesicles.

II. 3rd party seminal plasma suppositories.

INTRAVENOUS IMMUNOGLOBULINIndicated in:

APAS Inappropriate cellular immunity

Possible Mechanisms of action: ↓ autoantibodies ↑autoantibodies clearance T-cell regulation Complement inactivation ↑ T-cell suppressor function ↓ T-cell adhesion to extracellular matrix ↓ TH1 cytokine production

Side effects: nausea myalagias hypotension headache anaphylaxis

Disadvantages : expensive invasive time consuming require multiple I.V.D.

PROGESTERONE

Partially responsible for maintenance .Inhibits TH1 responses shift to TH2

responsesVaginal progesterone:

Is better than systemic treatment ↑ local suppression ↑ intrauterine concentrations ↓ adverse effects.

OTHERS

Cyclosporine Nifedipine Plasmaphoreses Corticosteroids:

Prednisone + low dose Aspirin same pregnancy outcome as controls, but :

↑ HTN ↑ DM ↑ PTL

ANTITHROMBOTIC TREATMENT

For APAS and thrombophilic disordersTreat hypercoagulabilityStart before conception continue although pregnancyUnfractionated heparin 5000 IU S.C. twice/day

+low dose Aspirin 75-80mg/day. Monitoring by aPTT/week.Risks:

PTL PROM IUGR Preeclampsia Abruptioplacenta Stillbirth Gastric bleeding Ostiopenia

Recently: low molecular weight heparin(LMWH) Indications:

APAS Non-APAS patients with thrombophilia Patients without thrombophilia =unexplained RPL

Advantages: Less bleeding Less osteopenia More antithrombotic ratio More patient compliance:

- less frequent doses - less frequent monitoring

The role of LDA alone:Studies useful for APAS and RPLStudies useful in unexplained RPLRoutine use alone cannot be justified.

Other antithrombotic treatment: Vit B6, B12, folate Protein C concentrate

Both for hyperhomocysteinemia whether congenital or aquired.

PROGNOSIS Depends on cause and number of abortions.

Even if >4 abortions, successful birth rate may reach 60%

Genetic causes 20-80% live birth Anatomical causes 60-90% “””””””””” Endocrine causes > 90% “””””””””” Infection 70-90% “””””””””” APAS 70-90%

“”””””””””FHM documentation:

It has a prognostic value depending on the cause :

FHM documentation in 77% of live birth ””””””””””””””””””””””“in 86% of APAS before

abortion ””””””””””””””””””””””“in 3% of unexplained RPL