The study finds iron and folic acid supplementation (IFAS), as well as iron and folic acid plus essential vitamins and trace minerals (multiple micronutrient supplementation, or MMS) could lower rates of low birthweight babies compared to iron or folic acid alone.
"Our results support the current World Health Organization recommendation that pregnant women should take iron and folic acid supplementation daily," says Ellen Caniglia, lead study author.
“The results also provide compelling evidence that multiple micronutrient supplementation has further advantages over IFAS,” adds Dr Caniglia, an assistant professor of Epidemiology at the Perelman School of Medicine at the University of Pennsylvania.
A six-year study of nearly 100,000 women in Botswana surveyed pregnancies for adverse birth outcomes
These women were asked to follow four routine supplementation strategies carried out before 24 weeks’ gestation: folic acid only, iron only, iron and folic acid supplementation (IFAS), and MMS.
The researchers analysed how the rates of low-birthweight and other complications at birth, such as preterm or very preterm delivery, stillbirth, and neonatal death, varied according to the supplements each woman began taking during her pregnancy.
Women who initiated IFAS had clearly lower rates of most adverse birth outcomes, compared to women who took only iron or folic acid.
Rates of low-birthweight births, for example, were 16.92% in the folic acid-only group and 12.70% in the iron-only group, but only 11.46% in the IFAS group.
Compared to IFAS, women who initiated MMS use saw significantly lower rates of preterm delivery, very preterm delivery, low birthweight, very low birthweight, and caesarean delivery.
The rate of low-birthweight birth, for example, was 10.48% for women on MMS. Similarly, the rate of preterm birth was 12.68% for the women taking IFAS, and 11.63% for those taking MMS.
The study also revealed that among these women, 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 HIV-negative women.
This suggested that supplementation has greater benefits for this population, the researchers stated with Dr Caniglia adding, "We don't really know why this is -- possibly, pregnant women with HIV are more likely to be micronutrient deficient."
IFAS is universally recommended by WHO for pregnant women, yet more than 43% of the women in the study received iron alone, folic acid alone, or no supplement at all, apparently due to these stock shortages.
"This highlights the need for new strategies to improve prenatal supplementation coverage among pregnant women," Dr Caniglia says.
“In conclusion, our findings support IFAS as an essential part of antenatal care to reduce adverse birth outcomes, with greater benefits in women with HIV and women aged 35 years and older,” the study concludes.
“Our findings suggest that MMS might be better than IFAS in terms of the risk of preterm birth, very preterm birth, low birthweight, and very low birthweight.
“We also found no evidence that MMS was harmful for any outcome or any subgroup. These findings might be useful for programmes considering implementation of MMS to improve birth outcomes.”
Source: The Lancet Global Health
Published online: DOI: 10.1016/S2214-109X(22)00126-7
“Iron, folic acid, and multiple micronutrient supplementation strategies during pregnancy and adverse birth outcomes in Botswana.”
Authors: Ellen Caniglia et al