Miscarriage can be
caused by many factors; below are the 8 common
causes.
•
Chromosome or genetic abnormalities
in the pregnancy:
There are 46 chromosomes (23 pairs) in the cells
of your baby. The chances of a miscarriage are
higher if there is a chromosome abnormality i.e.
there is one extra chromosome in every cell of
your baby's body. This 47th chromosome is responsible
for abnormalities such as Down's syndrome, Edward's
syndrome or Patau's syndrome. Turner's syndrome
occurs if there is one less sex chromosome (45
in total). Genetic abnormalities such as thalassaemia
major also become a factor for causing a miscarriage.
Most
chromosomal abnormalities discovered
in a miscarriage are not inherited
ones but occur because of a defect
in the cell division that formed
the particular egg or sperm. Because
of this most miscarriages are isolated
events not likely to repeat. There
are instances however, where the
defect is an inherited disorder
– this is when the abnormality of
chromosome is an abnormality of
structure rather than abnormality
of number. For miscarriages due
chromosomal abnormalities at least
95% are due to abnormalities of
chromosome of number. |
|
•
Structural deformity in the fetus:
Structural deformities include defects of the
brain, heart, spine, intestinal tract and kidneys.
Fetal organs develop largely in the first trimester
and all the key organs are formed by the 14th
week of pregnancy. Any major defect can develop
in this time frame and lead to a risk of miscarriage.
For example a fetal heart not developing properly
can cause the heart activity to stop, even if
it was beating previously. Sometimes an embryo
fails to progress in its growth and an ultrasound
examination will reveal a sac without a visible
fetus – this is known commonly as missed abortion.
Such pregnancies are not viable to begin with,
and will eventually lead to bleeding and expulsion
of the pregnancy sac.
•
Inadequate pregnancy hormones
causing an inadequate placental implantation:
In some pregnancies the placenta fails to implant
properly into the uterine wall. This is sometimes
caused by lower levels of progesterone, a pregnancy
hormone produced by the ovary and later the placenta.
Inadequate levels of hCG, another pregnancy hormone
produced by the placenta have also been associated
with a miscarriage. Bleeding from the placenta
may occur and cause a miscarriage to result.
•
Viral infections:
In early pregnancy if you contract an infection
and have a high fever, you are at risk of a miscarriage.
Most fevers are controllable with proper medication;
your doctor's advice is necessary as to which
medication is safe and suitable. Infections such
as parvovirus, coxsackie virus and cytomegalovirus
can result in miscarriages.
| Pregnancies
that are conceived within 3 months
of a live birth have a high chance
of miscarrying. |
|
•
Maternal disease occasionally causes miscarriage:
Unregulated diabetes increases the risk for miscarriage
– a poor adherence to diet and the incorrect use
of insulin may result in a pregnancy loss. Hypothyroid
or underactive thyroid has been associated with
miscarriage just as excessive levels of thyroxin
produced by an overactive thyroid. Celiac disease,
another illness if left untreated, can result
in a miscarriage.
•
Auto-antibodies in the mother's
blood:
These auto-antibodies can cross into the developing
fetus and placenta and cause the woman to miscarry.
Women with SLE or systemic lupus are at higher
risk of miscarrying.
•
Maternal diet:
Severe malnutrition can contribute to this loss.
But food alone is not the cause - if a mother
lacks in nourishment or eats poorly the embryo
is not miscarried. Instead habits such as drinking
and smoking increases the rate. One study showed
that 5 cigarettes a day increased the possibility
and drinking alcohol twice a week increases the
chance of miscarrying. There are mixed reviews
on caffeine intake so it is prudent to limit its
consumption.
•
Abnormalities of the uterus:
The presence of fibroids or an abnormally shaped
uterus may lead to a miscarriage. Defects in the
body of the uterus and in the cervix may cause
a miscarriage. Sometimes such defects may result
from prior surgical procedures such as severe
postpartum bleeding in a previous pregnancy. Fibroid
tumors may distort the shape of the uterine cavity
and interfere with the growth of the embryo –
this happens when the fibroid is on the inside
of the uterus lining or muscle. Mostly, fibroids
do not interfere with pregnancy.
| Often
the cause of miscarriage is never
determined because most women who
have miscarried do not have a repeat
miscarriage. |
|
