It is a definitely a good clinical practice to try putting only 2 good quality embryos in any woman who is less than 35 years of age. Infact if you have a very good blastocyst and a good endometrium , there are many clinics which we are trying to put only a single blastocyst to avoid the incidence of twins. In an occasional incidence when the woman is more than 35 years of age, we could implant 3 embryos but never ever more than 3 embryos. The chances of preterm deliveries happens to be more when we put more embryos. So this can be a high risk not only for the mother but also for the babies as the chances of preterm deliveries is much higher with multiple pregnancy.