Infection is considered a rare cause of recurrent miscarriage.Most patients with a history of recurrent miscarriage do not benefit from an extensive infection workup.Approximately 10% of human malformations result from environmental causes.
Women with poorly controlled diabetes are at a significantly increased risk of miscarriage and fetal malformation.
However, screening for occult diabetes in asymptomatic women is not necessary unless the patient presents with an elevated random glucose level or exhibits other clinical signs of diabetes mellitus or if there is an unexplained loss in the second trimester.
Although the presence of antithyroid antibodies may represent a generalized autoimmune abnormality, which could be a contributing factor in miscarriages, screening for thyroid disease is not useful unless the patient is symptomatic.
Early pregnancy loss is defined as the termination of pregnancy before 20 weeks' gestation or with a fetal weight of below 500 g.
Most spontaneous miscarriages are caused by an abnormal (aneuploid) karyotype of the embryo.
At least 50% of all first-trimester spontaneous abortions (SABs) are cytogenetically abnormal.
Although preimplantation genetic screening (PGS) of a removed blastomere for aneuploidy would theoretically increase the likelihood of embryonic implantation, reports in the literature have been conflicting with regard to the efficacy of this technique.
However, couples in whom pregnancy loss can be attributed to a balanced translocation may benefit from specific genetic testing by preimplantation genetic diagnosis (PGD).
Tests for antiphospholipid antibodies (APLAs), signaling the presence of the autoimmune disease antiphospholipid antibody syndrome (APS), have reportedly been positive in 10-20% of women with early pregnancy losses.
Three classes of clinically significant APL antibodies have been identified: anticardiolipin (a CL), lupus anticoagulant (LAC), and anti-β2 glycoprotein I antibodies.
Data from uncontrolled, retrospective reviews have suggested that resection of the uterine septum increases delivery rates, although a prospective, controlled trial did not show that surgical correction of uterine abnormalities benefits pregnancy outcomes.