Rates of twinning before and after fortification of foods in the US with folic acid, Texas, 1996 to 1998.

Several investigators have reported a 40% increase in the prevalence of twinning among women who have taken folic acid or multivitamins containing folic acid at the time of conception. Given that infant morbidity and mortality are greatly increased among twins, such a large increase in twinning could have serious implications. We undertook this study to determine if US fortification of enriched cereal-grain products with folic acid was associated with an unexpected increase in the prevalence of twinning in the state of Texas. We examined 1 003 207 deliveries conceived in Texas, between 1 January 1996 and 31 December 1998. We compared the prevalence of twin deliveries conceived before, during and after fortification with folic acid, mandated to begin on 1 January 1998. Comparing pregnancies conceived in 1997 with those conceived in 1996, we observed a 2.4% yearly increase in twinning, 1.024 [0.98, 1.07]. Comparing pregnancies conceived in 1998 with those conceived in 1997, we observed a 4.6% yearly increase in twinning, 1.046 [1.00, 1.09]. These increases were adjusted for maternal age, race, education, parity and season of conception. The size and pattern of these increases are consistent with the ongoing increase in twinning of 1-4% per year which began in the US prior to fortification.

Declining levels of erythrocyte folate during the postpartum period among Hispanic women living on the Texas-Mexico border.

Hispanic women have higher parity and shorter interbirth intervals than women of other ethnic groups. Thus, they are more likely to become pregnant relatively soon after giving birth, which may place these women at risk of low or deficient levels of specific nutrients. Folic acid is of particular concern because recent studies suggest that maternal use of folic acid supplements may be associated with better reproductive outcomes. The purpose of this study was to assess folic acid levels in postpartum Hispanic women. Using a cross-sectional design, we measured erythrocyte folate values for 188 low-income Hispanic women 1-12 months postpartum who were receiving services at the Women, Infants, and Children (WIC) clinics in El Paso, Texas. An interview was administered to collect information on diet, vitamin use, and method of infant feeding. Mean erythrocyte folate levels decreased from >1300 ng/ml during the first 4 months postpartum to a low of 1017 ng/ml by 12 months postpartum, for an overall decrease of approximately 23% (p = 0.004). Use of postpartum vitamin supplements was significantly associated with higher folate levels. However, only 35% of mothers used vitamins beyond 1 month postpartum. Study results suggest that these mothers may be at risk of developing low or deficient levels of folic acid during the postpartum period. Educational campaigns targeting these women as well as other groups of postpartum women should encourage them to comply with the U.S. Public Health Service recommendation that women of childbearing age consume 0.4 mg of folic acid daily.