Figure 2
From: Preconception care: nutritional risks and interventions
Pre pregnancy underweight and risk for preterm birth: evidence from observational studies Citations to the included studies: Abenhaim 2007 [55], Chen 2009 [56], Driul 2008 [57], Johnson 2009 [58], Kosa 2010 [59], Murakami 2005 [60], Ronnenberg 2003 [61], Salihu 2009 [62], Wise 2010[63], Chen 2010 [64], Gilboa 2008 [65], Han 2010 [66].