Background and Objective: Choline, an essential nutrient, has many important roles during pregnancy. However, most women do not consume the Adequate Intake (AI), and choline is not currently part of standard prenatal regimens. A large body of rodent research has demonstrated that maternal choline intake beyond amounts in standard rodent chow is important for offspring cognition throughout the lifespan, especially attention and memory. There is preliminary evidence to suggest the translation of these effects to humans, although important gaps in our knowledge remain, two of which are addressed by this dissertation. First, no prior studies have experimentally manipulated maternal choline intake and followed the children to school-age; the first chapter of this dissertation presents the results of a test of executive functioning administered to the 7-year-old children of women who participated in a controlled choline feeding study. Second, although a small body of rodent research suggests that maternal choline intake may be important for offspring socioemotional function, no human studies have evaluated the effects of maternal choline intake on infant socioemotional outcomes; chapters 2 and 3 of this dissertation, respectively, present results from a study of maternal choline supplementation on indices of infant temperament and affect regulation during the first year of life. Methods: Childhood Study: Third-trimester pregnant women were recruited to take part in a randomized controlled feeding trial. Women were randomized to consume either 480 mg/day (approximately the AI) or 930 mg/day choline until delivery. An ancillary follow-up study was conducted when their children were 7 years old to assess attention, memory, and executive functioning. This thesis presents the results of the Tower of London, an executive function task of planning and problem-solving. Infancy Study: Second-trimester pregnant women were recruited to take part in a randomized controlled supplementation trial. Women were randomized to consume either 25 mg/day or 550 mg/day choline, plus usual diet, until delivery. An ancillary follow-up study was conducted when their infants were 5–13 months old to assess attention, memory, and socioemotional functioning. This thesis presents the results of the Infant and Early Childhood Behavior Questionnaires and the Face-to-Face Still Face Paradigm. Results: Childhood Study: In the childhood study (N = 20), children whose mothers consumed 930 mg/day choline performed better on a task of planning and problem-solving skills as compared to children whose mothers consumed 480 mg/day choline, indicative of superior executive functioning. Infancy Study: In the infancy study, there was no effect of maternal choline supplementation on parent-report measures of infant temperament (N = 25) across the first year of life or on a laboratory measure of affect regulation at 7 months of age (N = 16). Conclusions: Childhood Study: Maternal choline supplementation at approximately 2x the AI has significant beneficial effects on child executive functioning at 7 years of age compared to the AI. Infancy Study: Maternal choline supplementation in addition to usual diet does not have an effect on infant temperament or affect regulation. However, interesting patterns emerged indicative of a more adaptive affective response in the infants born to women in the higher choline supplementation group. These preliminary data indicate that the current AI for pregnant women may not be sufficient for offspring self-regulation and support the conclusion that choline should be added to a standard prenatal vitamin regimen.