Recurrent pregnancy loss is classically defined as the occurrence of
three or more consecutive pregnancy loss; however, the American Society
of Reproductive Medicine (ASRM) has recently redefined recurrent
pregnancy loss as two or more pregnancy losses. A pregnancy loss is
defined as a clinically-recognized pregnancy involuntarily ending before 20
weeks. A clinically-recognized pregnancy means that the pregnancy has
been visualized on an ultrasound or that pregnancy tissue was identified
after a pregnancy loss.
What Causes Recurrent Pregnancy Loss?
Most pregnancy losses result from chromosomal, or genetic, abnormalities, and are random events. The abnormality may come from
the egg, the sperm, or the early embryo. Approximately 12-15% of all
clinically recognized pregnancies end in miscarriage; however, it is
estimated that at least 30-60% of all conceptions will end within the first 12
weeks of gestation. Up to 50% of the time, the woman doesn’t even realize
that she was ever pregnant. The risk of miscarriage increases with the
number of previous pregnancy losses, but is typically less than 50%.
Advancing maternal age is associated with an increased risk of
miscarriage, which is thought to be due to poor egg quality leading to
chromosomal (genetic) abnormalities. Sometimes, the mother or father
themselves may have a slight irregularity in their genes, but the offspring
could be more severely affected and thus result in miscarriage.
Sometimes, there could be an abnormality in the uterus (the womb) that
leads to miscarriage. The miscarriage may be due to poor blood supply to
the pregnancy or inflammation. Some women may be born with an
irregularly shaped uterus, and some women may develop abnormalities
with their uterus over time.
A woman’s immune system may also play a role in recurrent pregnancy loss. Hormone abnormalities may also impact pregnancy loss, including thyroid disease and diabetes. Abnormalities in a mother’s blood clotting may also affect pregnancy loss.
Generally speaking, environmental factors, stress, and occupational factors do not seem to be related to pregnancy loss.
What Treatment is Available for Recurrent Pregnancy Loss?
The treatment recommendations for patients with recurrent
pregnancy loss are based on the underlying cause of recurrent
pregnancy loss. No matter what the results of the work-up are, the chance
for a successful future pregnancy is high: 77% if the work-up showed no
abnormalities, and 71% if an abnormality was found.
Individuals in whom a karyotypic (a chromosomal or genetic) abnormality is
found are often referred for genetic counseling. There, a specialist can
discuss what the genetic abnormality is and the likelihood of having a
chromosomally normal or abnormal pregnancy in the future. Some affected
couples may choose to undergo prenatal genetic studies during pregnancy
to check the genetic make-up of the offspring with either 1) chorionic villus
sampling (CVS), in which a piece of placenta is biopsied late in the first
trimester or early in the second trimester, or 2) amniocentesis, which
removes some of the amniotic fluid (the fluid that surrounds the baby during
pregnancy) for analysis. In vitro fertilization (IVF) with preimplantation
genetic diagnosis (PGD) can also be done. With this process, the woman
takes shots for several days so that many eggs grow in her ovaries. The
eggs are then retrieved from the ovaries in a minor surgical procedure; one
sperm is then injected into each egg and the embryo is allowed to grow.
One cell of the embryo is then biopsied and the genetic make-up is
analyzed to avoid the transfer of an affected embryo.
If a uterine abnormality is found, surgery may be performed depending on
the defect. If antiphospolipid syndrome is diagnosed, certain medications
that reduce blood clot formation may be given. If thyroid dysfunction or
diabetes are diagnosed, specific medications can be prescribed.
Our experts at Medfemme Women’s Clinic will be happy to help in case
you are suffering from this problem.