RECURRENT PREGNANCY LOSS
Miscarriage is both traumatic and relatively common. Many
pregnancies are lost even before a woman knows that she
is pregnant. It is estimated that 30% of pregnancies are
miscarried. Most pregnancy losses occur prior to eight weeks
gestational age. The presence of a well-formed fetus with
a heart beat at eight weeks is highly encouraging because
only 3% of these fetuses will subsequently miscarry.
Traditionally, three consecutive miscarriages have been
termed recurrent
pregnancy loss (RPL). The definition of RPL has been
widened to include couples with two or three consecutive
pregnancy losses. A cause for RPL can be found in less than
half of the couples evaluated.
We routinely perform an out patient office hysteroscopy
to look inside the uterine cavity for the presence of fibroids,
polyps, congenital malformations and scar tissue. This procedure
is frequently painless and typically takes less than two
minutes to perform. Patients can watch on a video monitor
as we perform the hysteroscopy. Recovery time is less than
10 minutes, and patients can immediately return to work.
Both mothers and fathers are tested for chromosomal abnormalities
called balanced
translocations. In this condition, the total amount
of genetic chromosomal material in the parent's cells are
normal However, the chromosomes are arranged abnormally.
The result is that a fetus could get too much wor too little
genetic information from the affected parent. Because donor
eggs (or donor
sperm) is the only way to correct for balanced translocations,
many couples are willing to cope with multiple miscarriages
until a genetically normal pregnancy is established.
The antiphospholipid syndrome is a relatively common cause
of recurrent pregnancy loss. This abnormal immunologic disease
causes sludging and scarring in the placenta. Mothers who
have antiphospholipid syndrome are at increased risk for
vascular blood clots and pregnancy complications including
high blood pressure (hypertension) and premature delivery.
This disorder can be screened with measurement of anticardiolipin
antibody and lupus anticoagulant in the mother's blood.
We also routinely measure thyroid function hormones, glucose,
and mid-luteal progesterone
levels.
Therapies for treatment of recurrent pregnancy loss are
determined by the underlying disorder found through diagnostic
testing. Structural uterine anomalies can routinely be fixed
with out-patient operative hysteroscopic surgery. Women
with antiphospholipid antibodies are frequently treated
with baby aspirin. Heparin may be added once a normal intrauterine
pregnancy has been established. Many women with unexplained
recurrent pregnancy loss are treated with ovulation
induction medication or empiric luteal
phase progesterone support. Though it is natural that
parents question what role they may have had in causing
a miscarriage, the reality is that miscarriage is not their
fault. Exercise, sexual activity, and eating habits have
not been shown to have any effect on early pregnancy. The
role of maternal caffeine ingestion remains uncertain as
a cause of pregnancy loss.
There has been considerable speculation about the role of
the maternal immune system attacking the fetus in cases
of RPL. One approach has been to immunize mothers with the
blood of their spouse. A recent well done large prospective
study published in The Lancet was terminated early because
immunized women had a higher miscarriage rate than controls.
The role of intravenous immunoglobulin (IVIG) has not been
well studied. However, most published papers utilizing IVIG
have not shown a benefit.
In couples where no cause for RPL is found, the prognosis
is still very good. Among women who have had three consecutive
unexplained miscarriages, there is a 70% chance that the
subsequent pregnancy will be entirely normal. That is because
the majority of all miscarriages are due to sporadic chromosomal
abnormalities of the baby that typically do not recur. We
find it useful to examine the chromosomes of the placenta
from miscarriages. Rarely, a balanced translocation is detected
which has been passed from a parent to the fetus. Far more
common random chromosomal abnormalities are found in 70%
of miscarriages. They typically do not recur. If the placental
chromosomes are abnormal, it adds reassurance to the couple
that the pregnancy was not viable from the moment of conception
onward.
