What Causes Lack Of Nutrition In The Womb?

Newborns come in a variety of sizes, but babies whose weight falls below the 10 percentile for gestational age are classified as having intrauterine growth retardation, or IUGR. Around 5 percent of all newborns have IUGR, according to doctors with the American Academy of Family Physicians. Intrauterine growth retardation can be symmetrical, with all organs being proportionately smaller than normal, or asymmetrical, where the head and brain are proportionately larger than the abdomen. A number of medical conditions can cause lack of nutrition in the womb and lead to decreased growth in a fetus.

Maternal Factors

Poor weight gain and inadequate maternal nutrition during pregnancy is a major cause of IUGR in both developing and developed countries. Maternal nutrition can affect fetal growth in a number of different ways. Mothers who weigh less than 100 pounds pre-pregnancy, women who don't get enough protein during pregnancy, and women with nutritional deficiencies such as low levels of B12, iron and essential fatty acids are all more likely to have babies with IUGR. Low maternal weight plus poor weight gain in the second trimester also serve as strong predictors of IUGR, Indian researchers reported in the November 2009 issue of the "Indian Journal of Medical Research." Cigarette smoking, excess alcohol intake or drug use can all cause IUGR. Maternal health problems such as diabetes, heart disease, kidney disorders or high blood pressure can also lead to IUGR.

Placental Insufficiency

Nutrition for the developing fetus goes from the placenta, which attaches to the uterine wall, through the umbilical cord to the fetus. Maternal disorders that affect blood flow through the placenta include high blood pressure, placenta previa, which is an abnormally placed placenta that may cover the opening from the uterus to the birth canal, or placental abruption, where part of the placenta detaches from the uterine wall before delivery. A smaller-than-normal placenta or a problem with the umbilical cord, such as a two-vessel cord rather than a normal three-vessel cord, can all cause IUGR in a fetus.

Multiple Pregnancy

Multiple pregnancy can also cause IUGR. Identical twins or higher-order multiples, which means triplets or more babies, are most likely to have IUGR. Identical twins may develop twin-to-twin transfusion syndrome, where one twin gets too much of the blood supply and the other, who is likely to have IUGR, gets too little. In high-order multiples, a pregnant woman may not provide enough nutrition to provide for all the fetuses, or one or more fetuses may not get an adequate blood supply through the placenta. Complications such as high blood pressure or pre-eclampsia in pregnancy can also reduce blood flow throughout the pregnancy, increasing the chances of IUGR.

Fetal Disorders

Congenital problems such as trisomy 13, 18 or 21, or Turner syndrome can all cause IUGR. Infections during pregnancy such as rubella, syphilis, herpes, toxoplasmosis or cytomegalovirus can also lead to IUGR.