Best Practice & Research Clinical Obstetrics & Gynaecology
6The pathogenesis of infertility and early pregnancy loss in polycystic ovary syndrome
Section snippets
The pathogenesis of infertility
Ovarian function in infertile women with PCOS is characterized by disordered folliculogenesis and abnormal steroidogenesis, which are interlinked. Abnormalities in one result in disorders of the other and it has been difficult to identify the initiating abnormality.
The morphological features of the polycystic ovary can be identified on ultrasound examination and include hyperechogenic stromal enlargement and multiple small follicles 2–8 mm in diameter arranged either around the periphery or
Pathogenesis of pregnancy loss
Early pregnancy loss occurs in about 15% of all clinically recognized pregnancies. However, the true miscarriage rate is much higher if the further 15% or more of pregnancies lost before clinical diagnosis are included.52., 53., 54. Although 30–50% of conceptions end in miscarriage, about 1% of women will suffer from recurrent pregnancy loss, defined as three or more consecutive spontaneous miscarriages.
Recurrent miscarriage has many possible underlying causes but no definite aetiology is
Other factors
In the quest to identify the underlying pathogenesis of early pregnancy loss in PCOS, a number of other factors and causes—apart from the endocrinopathy of PCOS—have been investigated. Abnormalities in plasminogen activator inhibitor (PAI) activity have been postulated as a possible cause of recurrent miscarriage probably on the basis of abnormal placentation.89., 90. Increased PAI activity was demonstrated in a group of women with PCOS and miscarriage in a study by Glueck et al.49 These
Conclusions
The pathogenesis of anovulation and early pregnancy failure in women with PCOS has enjoyed considerable attention, both in basic research and in clinical trials, over the past few decades. However, although a large body of information is now available, the exact mechanisms underlying the reproductive dysfunction are still not clearly understood.
Multiple abnormalities have been identified. Folliculogenesis is disturbed and steroidogenesis is often abnormal. Gonadotrophin secretion might be
Summary
PCOS is associated with anovulation and increased early pregnancy loss; its exact pathogenesis remains to be clearly defined. Profound abnormalities in folliculogenesis and steroidogenesis have been identified. Postulated causes include disturbances of gonadotrophin secretion, hyperinsulinaemia, abnormal granulosa and theca cell function; attenuated apoptosis and abnormalities in local regulators.
The mechanism of the reproductive failure was initially thought to be hypersecretion of LH and this
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