Firstborns' behaviors during a mother's second pregnancy.

Distress and autonomy behaviors were examined in 80 preschool children of pregnant mothers and nonexpectant mothers. Four groups of only children participated: three groups of 20 children of expectant mothers who were in their early, middle, or late stages of pregnancy and a comparison group of 20 children of nonexpectant mothers. The groups were balanced for age (young: 18 to 36 months; old: 37 to 60 months) and sex. At 12 weeks, young firstborn girls were more dependent than either young boys or older girls and boys. Firstborns in the middle pregnancy group were more dependent at 20 weeks than at 24 and 28 weeks; however, boys reacted more to separation and expressed more anger than did girls. During the late phase of pregnancy, boys reacted to separation more negatively than girls did only at 28 weeks. Old firstborns were generally more autonomous than young firstborns; however, by the 32nd week of pregnancy, the groups did not differ. Compared with children in the comparison group, those in the early pregnancy group showed fewer reactions to separation, and those in the middle pregnancy group were less dependent at 24 and 28 weeks. At 38 weeks of pregnancy, late pregnancy boys reacted less to separation and expressed less anger than did comparison group boys. Late pregnancy girls were angrier than boys in both the comparison and pregnancy groups.