The few state WIC agencies that used abnormal postpartum weight change as a nutrition risk criterion for postpartum women (see Table 4-1) used cutoff points that ranged from maternal weight loss of greater than 0.9 kg/month to a 6-month postpartum weight of 18 kg less than the postpartum weight at 6 weeks, or an increase in weight of at least 10 percent in women who were at desirable weight at 6 weeks postpartum.

Detection of abnormal maternal postpartum weight change requires repeated measurements of maternal weight over a relevant time period, which may sometimes not be possible in WIC program settings.

Although there is a theoretical basis for benefit from participation in the WIC program, no risks have been documented, and there is no standard definition for this change in either lactating or postpartum women. Therefore, the committee recommends discontinuation of use of abnormal postpartum weight change as a nutrition risk criterion for postpartum women by the WIC program.

A summary of anthropometric risk criteria as predictors of risk and benefit for infants and children appears in Table 4-3.

The term low birth weight (LBW) is used to describe a weight of less than 2,500 g at birth. Infants and children with LBWs can be broadly categorized into two subgroups: (1) those who are born preterm, that is, at less than 37 weeks of gestation and (2) those who are growth retarded in utero and who are born SGA (see the section Small for Gestational Age). Because weight at birth is a function of both duration of gestation and interuterine growth of the fetus, an LBW infant can be both preterm and SGA.