Table 3.

Changes in placental morphology in the human and animal placenta related to maternal nutritional state

Species	Population studied/experimental conditions	Placental weight/volume	Fetal weight	Villi	Capillaries	Pathology	Reference
Human	Undernourished population	NA	NA	NA	NA	Fewer cells of larger volume. Increased fat, protein, potassium, zinc, copper, hydroxyproline and decreased selenium concentrations	43
Human	Five country studies: severe anemia associated with malnutrition	Increased placental weight	Varying: low-high	NA	NA	NA	2
Human	Two urban populations: high and low-med maternal nutritional status	Decreased placental weight	Lower birthweight	Decreased peripheral villous mass and peripheral villous surface area, no differencies in stem villi	Decreased peripheral villous capillary surface area	Increased subchorionic fibrin component and infarction, lower proportion of connective tissue and syntitiotropho-blast, decreased number of syntitiotrophoblast knots	3
Human	Lower socio-economical class	Decreased placental weight	Higher percentage of low-birth weight babies and infant death	Reduction of surface area	NA	No changes in placental water, protein, DNA, ash and hemoglobin, lower level of hydroxyprone and fat	33
Human	Lower socio-economical class	Decreased placental weight, reduced placental weight and surface area	Decreased fetal weight	NA	NA	Ill-defined cotyledons, eccentric attachment to the cord, presence of hemorrhage	44
Human	Lower socio-economical class	Decreased placental weight	Decreased fetal weight	NA	NA	Increased villous and intervillous fibrinoid necrosis, decreased number of vascular-syntitial membranes, increased number of syntitiotrophoblast knots	45
Human	Malnutrition	Decreased placental weight		Higher level of stromal villi fibrosis	Reduced villi vascularity	Degenerative changes at peripheral placental regions (infarction, calcification, deposition of fibrinoid)	46
Human	Iron-deficient anemia				Increased numbers of capillaries per villous cross section	Increased numbers of villous macrophages and of proliferating MIB-1-positive cells compared to control group	47
Human	Anemia/undernutrition	No differences	No differences	Reduction of surface area, volume of intermediate and terminal villi, stem villi	Reduction of surface area, no differences in volume	Reduction of trophoblast and stroma, unchanged intervilli space volume	37
Human	Prospective study in poor women regarding maternal pre-pregnancy weight and weight gain	Maternal pre-pregnancy weight is an important determinant of placental weight	Increased IVS and non-parenchimal volume components with increasing pre-pregnancy weight	No correlations with villi surface area	Maternal pre-pregnancy weight is an important determinant of placental vasculariation (direct correlation)	Volume of fibrin correlated positively with maternal pre-pregnancy weight	48
Human	Maternal anemia			Reduced villous surface area - alters disproportionately to volume			27
Sheep	Undernutrition: sheep, twin pregnancies	No differences	reduced	NA	No alteration in placental vascular architecture as measured by Doppler systolic/diastolic ratio	NA	49
Sheep	Fed 50% of energy requirements in early and late gestation	Reduction in placental weight at 80 days, but an increase in placental weight at 145 days of gestation	No effect	NA	NA	Reduction of fetal component of placenta	38
Sheep	Fed 70% of protein requirements and 70% global food consumption in early pregnancy	No differences. More smaller placentomes and fewer larger placentomes in 70% protein group compared to 70% global group	No differences	NA	No changes in Doppler and echocardiographic parameters reflecting vascular resistance	NA	50
Sheep	Restricted at 70% of control feed allowance, singleton and twin pregnancies	No differences	No differences	No changes	No changes	NA	51
Sheep	Moderate restriction	Higher placental weight	Different effects, depending on time of restriction	NA	NA	NA	15
Guinea-pig	70% of ad libitum fed control from periconceptual period till day 30 and till day 60 post conception	Lower placental weight	Lower fetal weight	Reduced the total placental surface area for exchange and surface density of trophoblast at day 30 and day 60 of gestation	Reduced capillaries volume at day 60.	The arithmetic mean barrier thickness for diffusion was increased by maternal food restriction at both gestational ages (day 30, +37%, and day 60, 40%)	16