Miscarriage(abortion)

DEFINITION:

• Abortion is the expulsion or extraction from its mother of an embryo or fetus weighing 500 g or less when it is not capable of independent survival (WHO).
• This 500 g of fetal development is attained approximately at 22 weeks (154 days) of gestation.
• The expelled embryo or fetus is called abortus.

TYPES:

TYPES	SYMPTOMS	UTERINE SIZE	CERVIX(EXT.OS)	ULTRASONOGRAPHY
Threatened	Vaginal bleeding present Pelvic pain	Gestational age	Closed	Fetus alive Retroplacental hemorrhage
Inevitable	Vaginal bleeding present Pelvic pain	Same or	Open with palpable conceptus	Fetus often dead Retroplacental hemorrhage
Incomplete	Vaginal bleeding(may be heavy)		Open	Products of conception partly retained
Complete	Vaginal bleeding(trace or absent)		Closed	Uterine cavity empty
Missed	Vaginal bleeding(trace  or brownish in color)		Closed	Blighted ovum or fetus
Septic	Vaginal discharge:purulent, foul smelling with features of sepsis	Variable, may be larger	Open	Products of conception retained Presence of foreign body (±) Free fluid in peritoneal cavity/ POD

INCIDENCE:

• 75% miscarriages occur before the 16th week
• 80% occur before the 12th week of pregnancy

ETIOLOGY:

GENETIC FACTORS:

• Autosomal trisomy(50%)→trisomy 16 (30%).
• Polyploidy22%
• Monosomy X (45, X)(20%).
• Structural chromosomal rearrangements2–4%
• Mosaic, double trisomy4%

ENDOCRINE AND METABOLIC FACTORS(10-15%):

• Luteal Phase Defect (LPD)
• Deficient progesterone
• Thyroid abnormalities: Overt hypothyroidism, or hyperthyroidism
• Diabetes mellitus

ANATOMICAL ABNORMALITIES (3–38%):

Cervico–uterine factors:

• Cervical incompetence
• Congenital malformation of the uterus

Causes of fetal loss are:

• Reduced intra-uterine volume
• Reduced expansion uterus
• Reduced placental vascularity when implanted on the septum
• Increased uterine irritability and contractility.

INFECTIONS (5%):

• Viral: Rubella,cytomegalovirus, variola, vaccinia or HIV.
• Parasitic: Toxoplasma, malaria
• Bacterial: Ureaplasma, chlamydia,Syphilis ,brucella.

IMMUNOLOGICAL DISORDERS (5-10%):

• Antiphospholipid antibody syndrome (APAS)
• Immune factors:T-helper 1(Th1):Recurrent miscarriage have more Th1 response
• Autoimmunity

MATERNAL MEDICAL ILLNESS:

• Cyanotic heart disease
• Hemoglobinopathies

PREMATURE RUPTURE OF THE MEMBRANES:

• Paternal factors

Thrombophilias: 

• Inherited thrombophilia
• Protein C resistance (factor V Leiden mutation)
• Protein C deficiency 
• Hyperhomocysteinemia

ENVIRONMENTAL FACTORS:

• Cigarette smoking
• Contraceptive agents
• Drugs, chemicals, noxious agents(anesthetic gases, arsenic, aniline, lead, formaldehyde)

Miscellaneous:

• Electromagnetic radiation
• Hair dyes, watch television and fly in airlines

UNEXPLAINED (40–60%):

• Increased maternal age

COMMON CAUSES OF MISCARRIAGE:

First trimester:

• Genetic factors (50%)
• Endocrine disorders (LPD, thyroid abnormalities, diabetes)
• Immunological disorders (autoimmune and alloimmune)
• Infection
• Unexplained.

Second trimester: 

•  Anatomic abnormalities
• Cervical incompetence (congenital or acquired)
• Müllerian fusion defects (bicornuate uterus, septate uterus)
• Uterine synechiae.
• Uterine fibroid
• Maternal medical illness
• Unexplained

MECHANISM OF MISCARRIAGE:

Don’t Forget to Solve all the previous Year Question asked on Miscarriage(abortion)