Assisted reproductive technology and the risk of poor pregnancy outcome

Introduction As the very purpose of assisted reproductive technology (ART) is to assist infertile people in creating a healthy baby, anything short of this is basically a poor outcome. The majority of such poor outcomes are failure to achieve pregnancy and early pregnancy loss, but these are not dealt with in this chapter. Neither are the rare life-threatening situations, such as ovarian hyperstimulation syndrome, or other maternal morbidity that is more common after assisted than after natural conceptions [1]. This chapter will deal with perinatal outcomes, i.e. outcomes of pregnancies that have surpassed the early hurdles and have evolved far enough to result in a birth, internationally defined as the separation from its mother of a fetus weighing 500 g or more [2]. Although fetal weights vary widely, especially among pregnancies that end too early for one reason or another [3], this almost invariably implies a gestational age of at least 20 weeks. In Australia, where every fetus with a gestational age of 20 weeks or more is registered as a birth, fetuses of 500 g or more at 20 weeks account for less than 1 in 100 000 births [4]. Also, most studies on perinatal outcome after ART apply a 500 g, if not a 1000 g, cut-off point, with some using or adding gestational age limits ranging between 20 and 28 weeks. This can create considerable variation among studies particularly for an outcome such as perinatal death [5].