Recurrent Pregnancy Loss
In all women, 15-25% of all clinically-diagnosed pregnancies end
in spontaneous miscarriage and recurrent pregnancy loss (RPL)
affects 2-4% of reproductive-aged women. The definitions for the diagnosis
of RPL are:
- Two consecutive first trimester or early second trimester miscarriages
with fetal heartbeats
- One or more second or third trimester miscarriages that are not
explained by an obvious correctable source
Recurrent pregnancy loss causes anxiety and fear in couples
seeking to build their families after several miscarriages.
It is important to note that successful outcomes will occur for more
than two-thirds of all couples with RPL, regardless of their reproductive
histories.
RPL has many possible causes, but in up to 50% of cases no specific
medical cause can be detected. This is termed idiopathic or unexplained
RPL. Your physician at RMACT will thoroughly investigate all possible
etiologies, including genetic, hormonal, anatomic, immunologic, microbiologic
and thrombophillic (blood clotting disorders) causes. These will be
explained below.
Unexplained RPL can lead to intense emotions such as frustration,
anger, guilt and depression. Often patients blame themselves inappropriately.
It is important to keep in mind that these feelings are normal, and
there are many resources available in our office to support you personally
and emotionally. Patients should be reassured that exercise, sexual
intercourse or eating unhealthy foods do not cause miscarriages.
Treatment plans vary by the diagnosis made. Any correctable conditions
should be aggressively treated. In those cases where no specific diagnosis
can be made, studies have shown that weekly monitoring and support
of early pregnancy supplementation of progesterone and estrogen if
indicated, can improve the miscarriage rate and empower patients.
Causes of Recurrent Pregnancy Loss
- Parental genetic causes: In the general population, approximately
1% of people have stable structural abnormalities of their chromosomes.
This group of conditions likely does not impact the health of that
individual but can lead to the production of abnormal sperm and
eggs. These types of abnormalities typically involve having a piece
of one chromosome break off and reattach itself to the wrong chromosome
and are called translocations.
Studies on couples with translocations have shown a high number
of miscarriages. Treatment options for RPL include genetic counseling,
early amniocentesis or chrorionic villi sampling (CVS) or the use
of donor sperm or eggs. Recent studies have shown that patients
with recurrent loss due to genetic factors may benefit from an advanced
treatment option called pre-implantation genetic diagnosis (PGD),
which involves the biopsy of an embryo derived from IVF (using your
own sperm and eggs) to study the chromosomes of that embryo and
find the chromosmally normal one. Using this technique, we can select
the normal embryos for transfer and increase the implantation rates
while decreasing the miscarriage rate.
- Embryo genetic causes: This is the mostly likely reason
for pregnancy loss which is secondary to improper development of
the early embryo. This occurs when the normal complement of 46 chromosomes
is not present and therefore a healthy child cannot develop. For
couples with RPL, chromosomal analysis of the miscarriage itself
can provide useful information.
- Hormonal or systemic causes: Approximately 10% of RPL patients
will have a hormonal disorder associated with their losses. This
includes untreated hypothyroidism (and possibly hyperthyroidism).
Patients with known thyroid disease will need to have their TSH
levels followed closely and will likely need to have their doses
adjusted during pregnancy. Unrecognized or poorly controlled diabetes,
and even pre-diabetes, increases the miscarriage rate. This rate
is reduced to a normal level once sugar and insulin control is normalized.
Lastly, deficiencies of progesterone, the hormone that supports
early pregnancies, can lead to miscarriages. This is sometimes termed
luteal phase deficiency. Treatment involves supplementing with progesterone
during the first trimester.
- Anatomic causes: Developmental anomalies of the uterus
are called mullerian anomalies. The most common abnormality associated
with RPL is the septate uterus, where a fibrous ridge of tissue
protrudes into the endometrial cavity, or womb. Removal of this
uterine septum by minimally invasive surgery called hysteroscopy
has been shown to improve delivery rates. Other mullerian anomalies,
such as bicornuate and unicornuate uterus, are associated more with
later-trimester losses or preterm birth and are much less amenable
to surgical repair.
- Auto-immune causes: Anti-phospholipid syndrome is a very
specific diagnosis with strict diagnostic criteria. It involves
your immune system attacking the placenta or placental blood vessels
that can lead to miscarriages and poor pregnancy outcomes. Treatment
includes blood-thinning injections and low doses of aspirin. Historical
treatments with steroids or with infusions of immunoglobulins to
treat a suspected or theoretical immune system problem do not have
any benefit and have been shown to worsen maternal and fetal outcomes
in pregnancy.
- Infectious causes: There have been some studies in the
past that have implicated asymptomatic infections of the uterus
with RPL. These may include mycoplasma, ureaplasma, Chlamydia and
others, but current data does not support these associations to
be a strong cause of RPL.
- Thrombophillic causes: This class of blood-clotting disorders
is called thrombophillias, meaning "love of clotting" in Latin.
It is associated with RPL by causing small clots to form in placental
blood vessels that impair the full implantation and function of
the placenta. Thrombophillias can also cause blood clots anywhere
in your body and may have serious health consequences. Blood tests
will help your physician diagnose these conditions and formulate
a treatment plan.
- Lifestyle causes: Tobacco use has a detrimental effect
on pregnancy outcomes and increases the rate of miscarriage. Smoking
greater than 15 cigarettes per day increases the miscarriage rate
approximately 1.5 times. Alcohol consumption beyond 10 drinks per
week may increase the miscarriage rate by a factor of 2 compared
to non-drinkers. Smoking and drinking to excess may worsen the effects
of each alone. In addition Obesity has been associated with markedly
higher miscarriage rates and poor pregnancy outcomes.
For more information about Recurrent Pregnancy Loss (RPL), contact
us.
www.asrm.org/Patients/FactSheets/recurrent_preg_loss.pdf
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