Intrauterin Growth Retardation is more commonamong twins than singleton. The reduction of intrauterine enviroment and level of transplacental diffusion ofnutrients are main responsible factors. Moreover, anastomosis of vessels between the arterial and venous systems of twins may induce a different irroration and a discordance of growth. Levels of discordane greater than 25% between twin may be associated with a twin¬twin transfusion syndrome, in which the donor is pale and ischemic and the recipient shows hemodynamic troubles within the spectrum of a hyperviscosity syn¬drome. These twins show an additional risk of morta¬lity and morbidity with respect to singleton and con¬cordant twins. The overall number of twins is nowa¬days increased up to 2.5 per thousands livebirths in relation to the diffusion of the pregnancies due to assisted technologies (ART). In faci, both the pharmacological induction of the ovulation and the implantation of in vitro fertilized embryos increase the probability of twinning, dyzygotic as well as monozygotic ones.
|Stato di pubblicazione||Published - 2005|