A fetus needs optimum blood flow, nutrition and conditions to grow properly. It's why pregnant mothers are cared for so completely; their actions affect their unborn child's development. Using crack while pregnant can do extreme damage to a fetus. Studies published in the 1993 Southern Medical Journal suggest that as many as 10 percent of women use cocaine at some point during their pregnancy.

Low Birth Weight

The fetus gains all of his nutrition from the mother, meaning that what she consumes, the baby does as well. Cocaine passes easily through the placenta. It restricts the flow of oxygen and nutrition to the baby, meaning he isn't able to grow properly. Low birth weight babies are more likely to die during their first month.

Body Abnormalities and Malformations

The reduced oxygen that occurs when using cocaine while pregnant can mean the child is born with facial and head abnormalities, such as a smaller-than-usual head, eyes and ears that weren't able to develop properly, as well as abnormalities in the digestive tract, stomach and genitals.

Developmental Delays

Reduced blood flow and oxygen into the baby may mean her development is disrupted. This can cause the fetus to have later developmental delays in reaching milestones such as crawling, walking and talking. You may also find that she has learning disabilities and that her fine motor skills--the ones that she uses for precise movements--trail other children.

Mental Retardation

By using cocaine throughout a pregnancy, a mother can set up a child with such a constricted amount of blood and oxygen that his brain never develops fully, causing mental retardation. The levels of disability vary from child to child and are on a spectrum of mild to severe, but it could mean the child has impaired intellectual skills and won't be able to function on his own.

Withdrawal

A mother who uses crack habitually throughout pregnancy due to an addiction passes that addiction to the fetus. When born, the baby no longer has access to cocaine and will have the pain of withdrawal in the hospital. Babies who were administered cocaine through the pregnancy tend to be jittery, unpredictable and fussy.

Death

Research performed by the Department of Forensic Medicine at Tohoku University School of Medicine and published in a 1994 Journal of Clinical Forensic Medicine found that infants who tested positive for cocaine at birth had a higher incidence of Sudden Infant Death Syndrome.