Birth Defects and Congenital Anomalies | Research & Clinical Trials

Predicting a drug's likelihood of causing birth defects

When pregnant women need medications, there’s often concern about possible effects on the fetus. Although some drugs are clearly recognized to cause birth defects (thalidomide being a notorious example), and others are generally recognized as safe, surprisingly little is known about most drugs' level of risk. Researchers in the Boston Children's Hospital Informatics Program (CHIP) have created a preclinical model for predicting a drug's teratogenicity (tendency to cause fetal malformations) based on characterizing the genes that it targets.

The model used bioinformatics and public databases to profile 619 drugs already assigned to a pregnancy risk class, and whose target genes or proteins — over 7,000 in all — are known. For each drug, CHIP investigators Asher Schachter, MD, MMSc, MS, and Isaac Kohane, MD, PhD, identified the number of targeted genes likely to be involved in fetal development, using telltale search terms like "genesis," "develop," "differentiate," or "growth." The drugs targeting a large proportion of genes associated with fetal development tended to be in the higher risk classes.

Based on the developmental gene profile, the researchers created a model that showed 79 percent accuracy in predicting whether a drug would be in Class A (safest) or Class X (known teratogen). "We can't provide a yes/no answer,” says Schachter, “but we found a pattern that can predict which are riskier."

Schachter and Kohane believe their model may be of interest to drug developers and prescribing physicians, and might provide useful information to incorporate in drug labeling. (Reproductive Toxicology, March 2011)