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RECURRENT MISCARRIAGE
-DR. S.Kalaichandran, MBBS , MD, MRCOG,
FRCSC
Introduction:
It is a sad commentary on our society and its ignorance
when a woman who had a miscarriage,instead of getting sympathy and support, is made to
feel that it is somehow her fault. It is all too common to find recurrent miscarriges
leading to divorce.This article is written to give basic information about miscarriages.
The reader is adviced to consult the Family Doctor or the Gynaecologist for specific
problems.
Definition:
A miscarriage is a pregnancy loss under 20 week gestation
from the last menstrual period. A recurrent miscarriage is a term traditionally applied
after 3 successive miscarriages.
Incidence:
arly pregnancy loss is much more common than the average
person understands. Using the very sensitive pregnancy tests that are available now, we
know that 1 in 2 pregnancies end in very early miscarriage. In the past the majority of
these would have been passed off as late or heavy menses. Even after a clinically
diagnosed pregnancy, 1 in 5- 6 pregnancies end in a miscarriage between 4 & 20 week
gestation.
Aetiology:
1.Chromosomal abnormalities in the conceptus
7 out of 10 miscarriages under 12 week gestation are due to chromosomal abnormalities in
the conceptus. This is more common with increase in maternal age. In women over 40 years
of age, 1 in 3 will have a miscarriage on this account. If we include the very early
miscarriages too, 3 out of 4 pregnancies end in miscarriages in this age group.
2. Genetic factors in the couple
In a small number of recurrent miscarriages, genetic defects(translocation) in the parents
may be responsible. One has to consider this when there is a family history of recurrent
miscarriages.
3. Environmental factors
Exposture to noxious or toxic substances are known to be associated with
recurrent miscarriages. Social(!) drugs , cigarettes, alcohol and caffeine are implicated.
Anaesthetic gases, dry cleaning fluids, petroleum products and Isoteretinon(for acne) are
known causes.
4. Medical conditions
Uncontrolled Diabetes and Thyroid disease may cause miscarriages. In a developing country,
chronic diseases,like Malaria or Tuberculosis may be responsible for a significant number
of miscarriages.
5. Auto immune disease
One in ten women with recurrent miscarriages show evidence of auto immune factors on
investigation. They may have overt auto immune diseases like diabetes, thyroid disease,
lupus, colitis, skin and joint diseases or develop these conditions later.
6. Structural defects
One in six to ten women with recurrent miscarriages has a structural defect like uterine
septum or adhesions.
Management:
Miscarriages, like infertility, is a problem of a couple
and they should be seen together. The majority can be reassuared. Of those who had a
successful pregnancy before 3 miscarriages, 70% will have a successful pregnancy. Of those
who had no previous successful pregnancy, a full 60% will have a successful pregnancy.
Education and reassuarance with these good statistical
odds may be all that is needed. Education about smoking, alcohol and drug abuse is also
important ; fortunately this is not a problem among Indian women at present. Counselling
is needed on pre-conceptual folate prophylaxis to prevent neural tube defect and
miscarriages.
Karyotyping may be useful if there is a family history of
recurrent miscarriages or the couple are closely related to each other before marriage as
is often the case in India.
Screening for diabetes, thyroid disease and auto immune
factors will rule out these conditions.
Hystersalpingogram, hystroscopy and laparoscopy will be
useful to assess the anatomy of the uterus and tubes.
Ovum tracking with serial ultrasound scans and serial
serum progestrone assays will help in diagnosing ovulatory factors (corpus luteum
failure).
After all these investigations 50% of recurrent aborters
will be found to have no abnormalities and these should be attributed to chromosomal
defect in the conceptus. |
