Triplet pregnancies are 37% premature, have a 15% pregnancy loss rate, 5% morbidity, and reducing from triplets to twins results in 5–15% fetal mortality. Higher multiple pregnancies are even worse. It is estimated that each triplet pregnancy costs to the system $300,000. Preimplantation Genetic Diagnosis for aneuploidy (PGD-A) can increase implantation and pregnancy rates in women 35 and older, by selecting those embryos with a higher chance of implanting. Thus PGD may allow the replacement of fewer embryos to achieve acceptable pregnancy rates without the risk of multiple pregnancy. As part of an ongoing research study, patients undergoing PGD-A were blindly matched to controls before pregnancy results were obtained. The matching was based on maternal age (39.9 years for both control and PGD-A groups), number of oocytes (13.7 and 14.3, respectively), number of zygotes (8.3 and 8.5, respectively), previous number of IVF cycles (1.4 and 1.7 respectively), and date of retrieval. Of the PGD group we selected those that had only one or two embryos replaced and compared them to their respective controls regarding implantation rates, pregnancy rates and multiple conception rates. The PGD-A method consisted on the biopsy of a single cell per embryo, followed by FISH using probes for 6 to 9 chromosomes (XY, 13, 15, 16, 17, 18, 21, 22). The Control and PGD groups consisted of 108 cycles each. A total of 396 embryos were replaced in the control (average 3.7 embryos) resulting in a 33% pregnancy rate per retrieval (36/108) and an implantation rate of 12% (47/396). There were two triplet pregnancies in the control group. In contrast, 165 embryos were replaced in the PGD-A group (average 1.5), resulting in 30% (32/108) pregnancy rate and a 24% (40/165) implantation rate, with no triplet pregnancies. While there were no differences in pregnancy rates, the implantation rate was significantly higher in the PGD-A group (p<0.001). The present results indicate that offering PGD and replacing a maximum of two embryos, PGD-A can provide similar pregnancy rates as cycles with unlimited embryos replaced, while reducing the risk of triplet pregnancies. The cost to the system is more than compensated. In this case, the cost of 108 PGD-A cycles would be about $324,000 (at $3000 a cycle) compared to $600,000 for two twin pregnancies. Although two-embryo limit was not applied to the control group it is easy to extrapolate that without PGD the pregnancy rate in the control group would had been halved. Thus, in countries with rules and legislations stressing two embryos replaced, PGD-A should be of great help in order to maintain acceptable pregnancy rates in women 35 and older.