Preliminary Study Suggests Smoking While Pregnant May Increase Chromosomal Abnormalities in Fetal Cells

March 11, 2005 — A preliminary report suggests that maternal smoking during pregnancy is associated with increased chromosomal abnormalities in fetal cells, according to a study in the March 9 issue of the Journal of the American Medical Association.
Maternal smoking during pregnancy has many consequences during and after pregnancy, such as infertility, coagulation problems, obstetric complications such as extrauterine pregnancy and placenta previa, and intrauterine growth retardation, according to background information in the article. However, only indirect data have been published on a possible genotoxic (effect of damaging DNA, possibly causing genetic mutation) effect on pregnancy in humans.

Researchers found that when comparing genetic data between smokers and nonsmokers (controls) there were important differences for the proportion of structural chromosomal abnormalities (smokers: 12.1 percent; controls: 3.5 percent) and to a lesser degree for the proportion of metaphases (a phase of cell division) with chromosomal instability (smokers: 10.5 percent; controls: 8.0 percent), and for the proportion of chromosomal lesions (smokers: 15.7 percent; controls: 10.1 percent). Statistical analysis found a certain chromosomal region was most affected by tobacco, and noted that this region has been implicated in hematopoietic (pertaining to the formation of blood or blood cells) malignancies.

It has been suggested that the increase of chromosomal lesions and structural abnormalities or the very existence of an increased chromosomal instability resulting from the genotoxic effect of tobacco could be indicative of an increased cancer risk and that fragile sites could be responsible for the chromosomal instability observed in cancer cells,
An increase of chromosomal instability is associated with an increase in the risk of cancer, especially childhood malignancies.

Mother's Depression Associated with Increased Risk of Child's Antisocial Behavior

February 9, 2005 — Significantly higher levels of antisocial behavior were found in seven-year-old children whose mothers were depressed during the child's first five years of life, according to an article in the February issue of Archives of General Psychiatry, a journal of the American Medical Association.

"Children of depressed mothers have elevated conduct problems, presumably because maternal depression disrupts the caregiving environment," according to background information in the article. Researchers have identified three possible explanations for the association between a mother's depression and antisocial behavior (ASB) in their children: 1) depressed women are likely to have antisocial personality traits related to depression, 2) are likely to bear children with antisocial men, 3) and the children of depressed mothers may inherit a genetic predisposition for antisocial disorders.

Julia Kim-Cohen, Ph.D., from King's College London, and colleagues investigated the association between maternal depression and children's ASB. Participants were members of the Environmental Risk (E-Risk) Longitudinal Twin Study, which examined how genetic and environmental factors affected the development of 1,116 sets of twins in England and Wales. The mothers categorized the timing of their depression as: never depressed (n = 728), depressed only before twins' birth (n = 68), depressed only after twins' birth (n = 193), and depressed before and after twins' birth (n = 124). Children's ASB at ages five and seven was determined from mother and teacher reports.

The researchers found that children of mothers who were depressed during the child's first five years of life had significantly higher ASB levels at 7 years of age. A mother's depression taking place after the children's birth was associated with children's ASB, although depression before the children's birth was not. Maternal depression combined with symptoms of antisocial personality disorder in mothers posed the greatest risk for children's ASB.

It was found that familial liability for ASB accounted for approximately one-third of the observed association between maternal depression and children's ASB," the authors write. However,findings also suggested that children exposed to maternal depression were significantly likely to have conduct problems through a risk process that operates environmentally over any contributions of their parents' antisocial personality.