mism. These are conceptualized as relatively stable characteristics of individuals that are generally protective of the individual’s health and that function as coping resources (Lachman and Weaver, 1998; Thoits, 1995). They can be more broadly conceptualized as resilience resources, along with social support and other values, beliefs, and personality traits, which function similarly. Studies to date on personal resources and preterm birth have shown some interesting results. In a prospective study of 553 nulliparous African American pregnant women at less than 26 weeks of gestation, Edwards et al. (1994) found that two specific questions from a standard self-esteem measure predicted gestational age and preterm birth, and one item predicted infant head circumference. Jesse et al. (2003) found that the same standard self-esteem measure predicted a lower risk of preterm birth (RR = 0.865) in 120 pregnant women studied at 16 to 28 weeks of gestation, but that the effect became marginally significant when other variables were controlled for in the analyses. Rini et al. (1999), using the same standard measure used by Jesse et al. (2003), combined with standard scales of mastery and optimism into a broader personal resources factor, reported that self-esteem again predicted birth weight but not gestational age in more than 200 pregnant women assessed in midpregnancy. The findings of these studies are contradictory as to whether self-esteem influences preterm birth independently of birth weight. In addition, there is little discussion in the literature of the mechanisms by which such an effect would occur. It is possible that women with higher levels of self-esteem take better care of themselves during pregnancy, which has plausible pathways to fetal growth and to the use of health care for the management of risk factors for preterm birth and intrauterine growth restriction. However, these pathways remain to be fully explicated and tested.
Other pertinent studies have evaluated mastery, which is a sense of efficacy over one’s environment (Copper et al., 1996), and dispositional optimism, which refers to expectations for positive life outcomes in future (Lobel et al., 2000). In general, however, those studies did not find an association of these factors with preterm birth (see also the work by Rini et al. ). However, Misra et al. (2001) report that locus of control was an independent predictor of preterm birth (unadjusted OR = 2.22; adjusted OR = 1.75 after controlling for biomedical factors). Women who perceived that they could influence the health of their children at birth had lower rates of preterm birth.
In sum, the few available studies on self-esteem, mastery, optimism, and perceived control in women expecting infants do not consistently predict preterm birth. It may be that these factors are more related to fetal growth and low birth weight or that these factors are more relevant to particular subgroups of pregnant women, such as populations of women who are socioeconomically disadvantaged. There is a need for the develop-