The differences in characteristics of uterine leiomyomas and the diverse adverse pregnancy outcomes.

Although previous studies have shown a relationship between uterine leiomyoma and pregnancy outcomes, this relationship is not yet completely understood. Many review articles have addressed this effect, but to date, none has classified this relationship according to the characteristics of the leiomyoma (i.e., type, size, number, and location). This review was conducted to evaluate and classify the relationship between leiomyoma characteristics and the effects of a leiomyoma on pregnancy and prenatal outcomes to facilitate decision-making in preconception and prenatal counselling. We examined articles published in English regarding any leiomyoma characteristics with obstetric outcomes during pregnancy using a collection of subject headings and key terms: 'leiomyomata,' 'myoma,' 'leiomyoma,' 'fibroid,' and 'pregnancy.' Many studies regarding the influence of leiomyoma characteristics on outcomes of pregnancy were identified, and the common conclusion was that the outcomes were dependent on leiomyoma characteristics. Most studies focussed on leiomyoma size, followed by type, location, and number of lesions. Different leiomyoma characteristics are related to diverse pregnancy outcomes. Therefore, it may be possible to predict the extent of the effects of these tumours on pregnancy outcomes by identifying all leiomyoma characteristics.