The paradox of old maternal age in multiple pregnancies.

The study of multiple gestations in older mothers has been furthered by the analyses of large data sets published in recent years. These initial analyses are counterintuitive in that the obstetric and neonatal outcomes of the older mothers (>40 years) are better than those of their younger counterparts (aged 25-29). Currently, it is not clear if older mothers of multiples are advantaged or younger mothers of multiples are disadvantaged. It seems reasonable, however, to conclude that pregnancy after age 40 represents a new obstetric entity, one in which many women will have twins or triplets as a result of assisted reproductive technologies. Further study in this area is clearly warranted, preferably using databases that combine maternal and neonatal data.