For patients with a previous child or pregnancy with
a chromosomal abnormality,
preimplantation genetic diagnosis
(PGD)
can reduce the risk of certain abnormalities in the
patient’s next pregnancy. This may be an attractive
alternative to CVS or amniocentesis for some people,
as they may be able to avoid termination of an
abnormal pregnancy.
Trisomy 21 or Down’s Syndrome seen in
this karyotype of a 9 week miscarriage may be
avoided by preimplantation genetic diagnosis (PGD)
performed at CRH. PGD may not only improve the risk
of miscarriages due to a chromosomal abnormality,
but can also prevent the birth of a malformed infant
with an abnormal karyotype. PGD can also decrease
the risk of miscarriage due to maternal age over 35.
CRH is a leader in ART and has a proven success
rate.
There are many causes of recurrent miscarriage.
These include:
-
genetic (chromosomal) abnormalities
-
hormonal imbalances
-
structural or anatomical problems, such as
fibroids, polyps or scar tissue
-
autoimmune disorders, such as lupus or diabetes
-
clotting disorders
-
environmental factors, including smoking
-
decreased egg quality (most often as a result of
normal aging) or sperm quality
An
accurate diagnosis can be made by checking specific
blood tests for estradiol and progesterone levels or
abnormal patterns of blood clotting; performing
simple x-rays or ultrasounds of the uterus;
obtaining a biopsy of the uterine lining to assess
its development; looking for pregnancy-related
antibodies; or culturing the cervix for infection.
Traditional treatments options, which are often
started in early pregnancy and sometimes continued
until delivery, may include:
-
surgical correction of anatomic problems of the
uterus through simple outpatient surgery
-
hormonal (i.e., estradiol, progesterone)
supplementation
-
baby aspirin or other blood thinners
-
antibiotics
-
steroids (i.e., prednisone)
Approximately
5%
of the population will experience
recurrent pregnancy loss
(RPL), defined as three or more miscarriages.
RPL is distressing for patients and
frustrating for physicians. In many cases, the cause
is not apparent and often requires intensive
clinical and laboratory investigations.
Now, a procedure called PGD offers
hope of normal pregnancy to women who have
experienced the anguish of unexplained recurrent
miscarriages. PGD is performed after a couple has
created embryos through in vitro fertilization.
Before implanting the embryos, CRH tests a single
cell from each embryo for a variety of conditions.
We then implant in the woman’s womb only those
embryos which are chromosomally normal.
After two or three miscarriages, couples often have
no explanation for the continued loss, especially
when both partners have had their chromosomes
analyzed and no abnormalities were found. Even when
both partners have normal chromosomes an embryo can
be produced with abnormal numbers of chromosomes, a
condition called aneuploidy. In the relatively
complicated process of making gametes, sometimes
mistakes are made; and some individuals may make
these same mistakes on a regular basis. If an error
occurs that leads to the egg or sperm having an
extra or missing chromosome, the resulting embryo
will also carry the same aneuploidy.
However, recurrent aneuploidy does not explain, but
a small fraction of RPLs. Thus, the evaluation of
these patients should first rule out genetic,
anatomic, endocrine, and immunologic causes for
recurrent miscarriage. The evaluation typically
includes a physical examination; pelvic
ultrasonography, hysterosalpingography, or saline
hysterosonography to evaluate the uterus; testing
for thyrotropin, antithyroid antibodies, prolactin,
lupus anticoagulant, anticardiolipin, and
antiphosphatidylserine antibodies; karyotyping
(chromosomal analysis) of both partners and fetal
tissue if available; and possibly an endometrial
biopsy (biopsy of the lining of the uterus) and
screening for genetic blood clotting disorders.
