Maternal iron intake during pregnancy and the risk of small for gestational age

Abstract

Studies of iron and its association with the risk of small for gestational age (SGA) show inconsistent results. Consuming iron supplements during pregnancy is controversial because of possible risks. This study assessed the association between iron intake and the risk of having an SGA newborn and whether iron intake is associated with gestational diabetes. A case-control study of 518 pairs of Spanish women who were pregnant and attending five hospitals was conducted. Groups were matched 1:1 for age (±2 years) and hospital. Cases were women with an SGA newborn at delivery.Controls were women with normal-sized newborns at delivery. Data were gathered on demographic characteristics, socio-economic status, adverse habits (like smoking), and diet. A 137-item food frequency questionnaire was completed. Iron intakes were categorized in quintiles (Q1-Q5). Crude odds ratios (ORs) and adjusted ORs (aORs) with 95% confidence intervals (CIs) were estimated by conditional logistic regression.No significant relationship was found between dietary iron intake and SGA. A protective association was found for women receiving iron supplementation >40 mg/day and SGA versus women not taking supplements (aOR = 0.64, 95% CI [0.42, 0.99]).This association was identified in mothers both with (aOR = 0.57, 95% CI [0.40, 0.81]) and without (aOR = 0.64, 95% CI [0.64, 0.97]) anaemia. In women in the control group without anaemia, iron supplementation >40 mg/day was positively associated with gestational diabetes (aOR = 6.32, 95% CI [1.97, 20.23]). Iron supplementation in pregnancy may prevent SGA independently of existing anaemia but may also increase the risk of gestational diabetes.

Nutrients that modulate gestational diabetes mellitus: A systematic review of cohort studies Jan 2019‐Jan 2020

“…Martínez‐Galiano et al 25 suggest that iron is fundamental for placental growth and embryonic organogenesis within the first 12 weeks, but any excess of iron after the end of this period may result in the disruption of glucose metabolism. This study showed no link between iron supplementation and the development of GDM in patients with anaemia.…”

Factors associated with fetal growth restriction and small for gestational age newborns

“…The only protective factor for the occurrence of FGR during the third trimester in our study was iron supplementation. Iron is an important micronutrient in pregnancy because of its role in the growth, haematopoiesis, and development of the fetus [28]. Previous studies have also confirmed that iron supplements have a protective effect against SGA, even in women without anemia [28,29].…”

“…Iron is an important micronutrient in pregnancy because of its role in the growth, haematopoiesis, and development of the fetus [28]. Previous studies have also confirmed that iron supplements have a protective effect against SGA, even in women without anemia [28,29]. However, there are also studies that didn't find any association between iron supplementation and SGA [30,31].…”

Nutrition in Reproductive Health: Nutritional Conditioning Factors during Pregnancy and Its Impact on Health

“…Nut consumption during early pregnancy is associated with long-term childhood neuropsychological development. A maternal diet with significant consumption of pastries during pregnancy, consisting mainly of baked and sugary products, combined with a longer period of breastfeeding, can lead to the development of food allergies, suggesting a harmful effect of trans fat in the baby [58][59][60][61][62][63][64][65][66][67][68]. The maternal diet can even cushion the risk of other risk factors for neonatal pathology [63].…”

“…The systematic intake of micronutrient, iron, and multivitamin supplements in all pregnant women is not recommended as it has not been found to be exempt of risks. This advice must be adapted to the real needs of each woman [65,76,77]. However, folic acid supplementation by all pregnant women from the preconception stage for preventing neural tube defects does have support, although it has also been associated with adverse effects during pregnancy [78,79].…”