Recurrent Pregnancy Loss (RPL) is defined as more than 3 consecutive first trimester losses or miscarriages. The incidence is approximately 2% of reproductive aged women. There are various causes of RPL including anatomic, endocrine, genetic, immunologic and infectious disorders. The causes can generally be categorized as a) problems with the embryos and b) problems with the environment that support the embryo.
Anatomic causes can include things such uterine polyps, fibroids or congenitally abnormal uteri. This can be diagnosed by several methods including hysterosalpingogram (HSG), sonohysterogram or fluid ultrasound (FUS), or hysteroscopy. Anatomic problems other than congenital disorders can typically be treated by minor surgery.
Endocrine disorders can involve problems such as an underactive or overactive thyroid gland, elevated prolactin levels, diabetes or insulin resistance. The disorders can be diagnosed with simple blood tests and can be treated rather easily through diet and medication.
Genetic problems can come from the parents or the fetus itself. Parental disorders can be diagnosed with a blood chromosome test called a karyotype. Fetal genetic problems can be diagnosed by biopsying an early stage embryo and testing a single cell with a test called comparative genomic hybridization (CGH). This is done during in vitro fertilization, and only genetically competent embryos are transferred to the uterus, thus reducing the risk of miscarriage greatly.
Immunologic causes result when the maternal immune system rejects the implantation process. There are several reasons for this, including rejection of the maternal aspect of the pregnancy, as well as rejection of the paternal aspect of the pregnancy. Good screening tests for immune disorders include natural killer cell (NK Cell) assay and antiphospholipid antibodies (APA).
In rare cases, certain bacteria have been implicated in RPL. These include bacteria such as mycoplasma and ureaplasma. These can easily be diagnosed with cervical cultures and treated with antbiotics.