Reproductive failure due to spontaneous abortion and recurrent miscarriage.

The epidemiology, aetiology, diagnosis and clinical management of spontaneous and recurrent abortion and of the failure of embryo implantation are discussed in a retrospective overview of the major studies conducted since 1975 identified through a Medline search. Infertile women who experienced spontaneous single (32%) and recurrent (0.5%) abortion as well as those who became pregnant after induction of ovulation with gonadotrophins (abortion rate 17-31%) and those who underwent assisted fertilization programmes (abortion rate 18-34%) are considered. Causes and treatments are here reported. Medical treatments for immunologically mediated abortion (IMA) are based on prednisolone, heparin, aspirin and intravenous immunoglobulin. Efficacy of the medical treatment of patients with a history of IMA has yet to be completely demonstrated. Genetic disorders are possible causes of both failure in implantation and early abortion; this cause is more prominent with advanced age and currently cannot be treated. Endocrine factors may also be responsible for miscarriage, and correction of hormone abnormalities is discussed. Infections, endometriosis and psychological factors are other possible important causes of embryo loss without specific widely accepted treatments. Prominent areas of research are the identification of genetic preimplantation abnormalities, and pharmacological intervention for abnormal spontaneous uterine contractility. The data here reported are encouraging, but the efficacy of different treatments is still not convincing. The information available is sufficient to develop new diagnostic and therapeutic tools to evaluate their efficacy in reducing spontaneous abortion at an early stage.