2. DEFINITION
Sequence of three or more consecutive spontaneous abortion before
20 weeks.
It may be primary or secondary (having previous viable birth).
3. ETIOLOGY
• FIRST TRIMESTER ABORTION:
• Genetic factors[3-5%]: Parental chromosomal abnormalities is a
proven cause of recurrent abortion.
• The most common abnormality is a balanced translocation.
• Risk of miscarriage in couples with a balanced translocation is greater
than 25%.
• However, the chance of successful pregnancy even without treatment
is 40-50%.
5. • Infection: Genital tract infection may be responsible for sporadic
spontaneous abortion but its relation to recurrent abortion is a not
ending doubt.
6. • Inherited thrombophilia causes both early and late miscarriages due
to intravascular coagulation and thrombosis.
• Protein C resistance is the most common cause.
• Protein C is the natural inhibitor of coagulation.
7. • Immune factors ( 10-15%):
• Autoimmunity—Presence of autoantibodies causes rejection of early
pregnancy (15%) in the second trimesters mainly.
• Causes of miscarriage are: (a) inhibition of trophoblast proliteration
and function, (b) release of local infammatory mediators (cytokines)
through complement pathway, (c) spiral artery and placental
intervillous thrombosis and (d) decidual vasculopathy with fibrinoid
necrosis.
9. • SECOND TRIMESTER MISCARRIAGE:
• Anatomic abnormalities are responsible for 10–15% of recurrent
abortion.
• The causes may be congenital or acquired.
• Congenital anomalies may be due to defects in the Müllerian duct
fusion or resorption (e.g. unicornuate, bicornuate, septate or double
uterus).
• Acquired anomalies are: intrauterine adhesions, uterine fibroids and
endometriosis and cervical incompetence.
10.
11. • OTHER CAUSES OF SECOND TRIMESTER MISCARRIAGE :
• Chronic maternal illness – uncontrolled diabetes,
hemoglobinopathies, chronic renal disease, inflammatory bowel
disease , systemic lupus erythematosus.
• Infection – Syphilis, toxoplasmosis and listeriosis.
• Unexplained.
12. INVESTIGATIONS FOR RECURRENT MISCARRIAGE
• A thorough medical, surgical and obstetric history with careful clinical
examination should be carried out to find out the possible cause or
causes as mentioned previously.
• Careful history taking should include—(i) The nature of previous
abortion process. (ii) Histology of the placenta or karyotyping of the
conceptus, if available. (iii) Any chronic illness and bacterial vaginosis.
13. • Diagnostic tests:
• (1) Blood-glucose (fasting and postprandial), VDRL, thyroid function test, ABO and
Rh grouping (husband and wife), toxoplasma antibodies IgG and IgM.
• (2) Autoimmune screening—lupus anticoagulant and anticardiolipin antibodies.
• (3) Ultrasonography—to detect congenital malformation of uterus, polycystic
ovaries and uterine fibroid.
• (4) Hysterosalpingography in the secretory phase to detect—cervical
incompetence, uterine synechiae and uterine malformation.
• (5) This is supported by hysteroscopy and/or laparoscopy.
• (6) Karyotyping (husband and wife).
• (7) Endocervical swab to detect chlamydia, mycoplasma and bacterial vaginosis.