Twin pregnancies: eating for three? Maternal nutrition update.

The incidence of multifetal pregnancies has increased, mainly because of assisted reproduction treatments. This trend is reflected in increased maternal and neonatal morbidity and mortality. While the optimum maternal nutrition and weight gain patterns for singleton pregnancies is well documented, there is a paucity of information for twin pregnancies. Although it is assumed that optimum nutritional requirements and weight gains would be greater for twin than for singleton gestations, research is needed to establish the optima. This article is a collation of available recommendations for maternal nutrition and weight gain patterns in twin pregnancies.