Recurrent Pregnancy Loss
Repeated miscarriages, or recurrent pregnancy loss, is defined as having two or more consecutive miscarriages. Of couples trying to conceive, approximately 5% have 2 consecutive miscarriages, and 1% have 3 or more consecutive losses.
There are various causes for recurrent miscarriages. The majority of miscarriages (60-70%) are due to chromosomal abnormalities within the embryo. These chromosomal abnormalities can be either numerical (abnormal number of chromosomes) occuring randomly during fertilization or structural (one partner has a chromosome in which one piece is transferred to another chromosome). These patients with a chromosomal translocation pass their abnormal chromosomes to their offspring leading to miscarriages.
Problems of the uterus are known to cause repeated miscarriage. The most common is a septate uterus, a congenital (inborn) defect where the uterus is partially divided into two sections by a wall of tissue. There are also acquired problems of the uterine cavity (endometrium) that have been associated with repeated miscarriages such as scarring called Asherman Syndrome. Uterine scarring may have been a result of previous uterine surgery or infection. Fibroids and polyps may also play a role in recurrent pregnancy loss.
Medical conditions associated with an increased risk of repeated miscarriages include:
- Antiphospholipid antibody syndrome, an autoimmune disorder associated with blood clots.
- Poorly controlled diabetes mellitus.
- Polycystic ovary syndrome, condition with irregular menstrual cycles and increased levels of male hormones.
- Abnormal thyroid function.
Testing for recurrent pregnancy loss usually involves:
- A thorough medical history.
- A complete physical and pelvic examination.
- A pelvic ultrasound.
- Blood tests looking for thyroid problems, abnormal sugar levels, antibodies related to the immune system and a chromosomal analysis to check for genetic abnormalities.
- An imaging study such as an hysteroscopy, hysterosonography or hysterosalpingogram looking for uterine problems.
Treatment depends on the specific cause for the recurrent pregnancy loss. Unfortunately, in approximately 50% of couples with repeated miscarriages, a cause cannot be found.
Treatment for recurrent pregnancy loss may be:
- Medical – medications used to treat hormone or immune problems.
- Surgical – corrective uterine surgery to remove polyps, fibroids or septum may increase the chance of a successful future pregnancy.
- Assisted reproduction – in vitro fertilization with preimplantation genetic testing to select for genetically normal embryos.