Maternal vitamin B-12 and folate status during pregnancy and excessive infant crying.

BACKGROUND The etiology of excessive infant crying is largely unknown. We hypothesize that excessive infant crying may have an early nutritional origin during fetal development. AIMS This study is the first to explore whether (1) maternal vitamin B-12 and folate status during pregnancy are associated with excessive infant crying, and (2) whether and how maternal psychological well-being during pregnancy affects these associations. STUDY DESIGN Women were approached around the 12th pregnancy week to complete a questionnaire (n=8266) and to donate a blood sample (n=4389); vitamin B-12 and folate concentrations were determined in serum. Infant crying behavior was measured through a postpartum questionnaire (±3 months; n=5218). SUBJECTS Pregnant women living in Amsterdam and their newborn child. OUTCOME MEASURES Excessive infant crying, defined as crying ≥3 h/day on average in the past week. RESULTS Multiple logistic regression analysis was performed for 2921 (vitamin B-12) and 2622 (folate) women.Vitamin B-12 concentration (categorized into quintiles) was associated with excessive infant crying after adjustment for maternal age, parity, ethnicity, education, maternal smoking and psychological problems (OR[95%CI]: Q1=3.31[1.48-7.41]; Q2=2.50[1.08-5.77]; Q3=2.59[1.12-6.00]; Q4=2.77[1.20-6.40]; Q5=reference). Stratified analysis suggested a stronger association among women with high levels of psychological problems during pregnancy. Folate concentration was not associated with excessive infant crying. CONCLUSIONS First evidence is provided for an early nutritional origin in excessive infant crying. A low maternal vitamin B-12 status during pregnancy could, in theory, affect infant crying behavior through two potential mechanisms: the methionine-homocysteine metabolism and/or the maturation of the sleep-wake rhythm.