Types of pregnancy loss in recurrent miscarriage: implications for research and clinical practice.

<bold>Background: </bold>In recurrent pregnancy loss, there is much debate about cause and association, as exact pathophysiological mechanisms have not been elucidated. The aim of this study was to assess whether recurrent pregnancy loss (RPL) patterns differ according to causal/associated conditions, suggesting differing disease processes.<bold>Methods: </bold>Following investigation, 427 women with RPL were classified into the following 'diagnostic' groups: idiopathic, oligomenorrhoea, antiphospholipid syndrome (APS) and 'possible' APS. A total of 323 subsequently conceived, and underwent serial ultrasonography in early pregnancy; of these, 87 (26.9%) miscarried, and the types of pregnancy loss for the four diagnostic groups were allocated to either embryo loss (fetal heart never seen) and fetal loss (fetal heart seen prior to pregnancy loss).<bold>Results: </bold>Overall, there were 75 embryonic losses and 12 fetal losses. The fetal loss rates in each group were similar: idiopathic 5.1%, oligomenorrhoea 3.4%, 'possible' APS 4.9% and APS 4.8%.<bold>Conclusions: </bold>Serial ultrasound helps to discriminate type of pregnancy loss and demonstrates that embryo loss is more common than fetal loss. More importantly, pregnancy loss patterns do not seem to differ between diagnostic groups in a treated population. The fetal loss rate in each of the diagnostic groups is similar to that in other reported populations. [ABSTRACT FROM AUTHOR]