Supplementing pregnant women with a comprehensive micronutrient supplement may reduce complications at birth, according to a new study conducted in Botswana, published in The Lancet Global Health (DOI:10.1016/S2214-109X(22)001-126-7).

Led by researchers at the University of Pennsylvania with investigators at the Botswana-Harvard AIDS Institute Partnership and Harvard T.H. Chan School of Public Health, the study was the largest of its kind including a substantial cohort of pregnant women with HIV. Lead researcher Ellen Caniglia, ScD, from the University of Pennsylvania, commented in a statement: “Our results support the current World Health Organization recommendation that pregnant women should take iron and folic acid supplementation daily, but also provide compelling evidence that multiple micronutrient supplementation has further advantages over IFAS [iron and folic acid supplementation].”

The observational cohort study surveyed pregnancies for adverse birth outcomes at eight hospitals in Botswana from July 2014 to July 2018, and 18 hospitals from August 2018 to December 2020. It assessed four routine supplementation strategies in women presenting before 24 weeks’ gestation: iron only, folic acid only, IFAS, and MMS [iron and folic acid, plus vitamins A, C, D, E, B1, B2, B3, B6, B2; and iodine, selenium, zinc and copper)]. The analysis included 96,341 women with singleton pregnancies; known HIV status (22.5%), age, and delivery site; haemoglobin measured within seven days of presenting to antenatal care; and weight within 31 days of presentation.

Women who initiated iron-only (37.7%) or folic acid only (11.8%) supplementation had higher risks of stillbirth, preterm birth, very preterm birth, low and very low birthweight, and neonatal death compared with women who received IFAS, with greater difference in women with HIV and those aged 35 years and older. Compared with IFAS, women who initiated MMS had lower risks of preterm and very preterm births, and low and very low birthweight.

Among the women with HIV, the differences in rates of adverse outcomes between MMS and IFAS, and between IFAS and folic acid or iron alone, were generally larger than those seen in pregnant women without HIV infection. In the statement, Caniglia noted, “We don’t really know why this is—possibly, pregnant women with HIV are more likely to be micronutrient deficient.”