Maternal dietary diversity and risk of small for gestational age newborn: Findings from a case-control study

An inadequate nutrients intake during pregnancy has been related to an increase of having a small for gestational age (SGA) newborn. A diversity dietary (DD) intake could decrease the risk of SGA delivery, providing the adequate nutrient requirements during pregnancy. The aim of this study was to assess the effect of DD on adequate nutrient intake in a sample of Spanish pregnant women, further to investigate their association on SGA delivery.

A matched case-control study of 518 cases and controls of pregnant women was performed in five hospitals in Eastern Andalusia (Spain). Cases were women with a newborn with SGA. Data about demographic characteristics and diet were collected by trained midwives. DD score (DDS) adjusted by total energy intake was gathered through a validated food frequency questionnaire (FFQ). Nutrient inadequacy was defined as an intake below 2/3 of the recommended dietary intake according to dietary recommendations intake (DRI) for pregnant women. The association between DDS and SGA was assessed by logistic regression models with adjustment for confounding factors.

The prevalence of nutrient inadequate intake decreased across total DDS quintiles (p < 0.05). Women in higher strata of total DDS presented less SGA risk (aOR = 0.50, C.I. 95%: 0.31, 0.80). According to each DDS component, the consumption of high diversity of dairy products showed a significative protection against the risk of having a SGA newborn (aOR = 0.48, C.I. 95%: 0.32, 0.71).

SGA mothers had higher prevalence of nutritional inadequacies and lower DDS compared to their counterparts. Poor total DDS and less variety of dairy products were associated with higher risk of SGA newborn. Efforts to promote DD during pregnancy need to be strengthened to reduce the prevalence of SGA in Spain.