Animal Studies Mislead Research
Animal studies have led researchers astray on many health issues for pregnant women. From pharmaceutical safety tests to nutritional research to tobacco studies, the animal data have been proven false or inconsistent. For example, animal data have misled researchers and practitioners who are studying substance abuse in pregnant women. In their major review of the research on the effects of substance abuse in pregnancy, faculty members from the Brown Medical School Infant Development Center wrote, “A lingering puzzle, especially with the cocaine literature, is the discrepancy between preclinical (animal) and clinical (human) studies.”7 The real puzzle is why researchers continue to doubt solid human data just because they contradict the results of unreliable animal testing.
Alcohol and Vitamin E
Research on animals has suggested that high doses of vitamin E might prevent some of the devastating effects of alcohol use by pregnant women. This information has been highly publicized despite the danger that it could encourage women to make light of the dangers of consuming alcohol during pregnancy. Additionally, these animal studies convinced clinical researchers to conduct human studies in which pregnant women were given massive doses of vitamin E. Tragically, the women who received the huge doses of vitamin E gave birth to infants with significantly reduced birth weights, and one baby was born severely deformed.8 As is often the case, animal studies proved to be both misleading and dangerous.
Nutrition and Reproductive Health
Human studies have shown that female infants born to undernourished mothers grow up to have decreased fertility. In contrast, intergenerational studies in rats have shown that gestational nutrition has no effect on the reproductive ability of the next generation. When confronted with this misleading animal data, animal researchers from the EPA and the University of Illinois made the following admission about their studies on rats: “[The] data [do] not reflect the intergenerational effects reported in humans. Susceptibility to xenobiotics is well known to vary between species, and even between strains within laboratory species [sic], and it is reasonable to expect similar variability with respect to other environmental influences.” However, these same animal researchers make no apology for offering their misleading results and instead call for more animal studies.9
Drugs for Hypertension
Hypertension in pregnancy can seriously affect the health of a woman and her baby. Unfortunately, animal studies have misled researchers by pointing to false cures—drugs that are actually dangerous to the fetus. Researchers at the U.S. Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) wrote in the journal Reproductive Toxicology about a specific class of anti-hypertension drugs called ACE inhibitors. They stated: “The use of ACE inhibitors (drugs that act directly on the renin-angiotensin system) during the second and third trimester of pregnancy in humans is associated with specific fetal and neonatal injury. The syndrome, termed ‘ACEI fetopathy’ in humans, does not appear to have a similar counterpart in experimental animals.”10 An entire area of hypertension research had to be abandoned because animal tests did not predict the hideous deformities that would result from the use of these drugs.
Other Misleading Studies
The FDA relies heavily on animal testing to determine the safety of drugs that are prescribed to pregnant women. Unfortunately, this process has become a “crap shoot” in which the harmful effects of some drugs are not known until it is too late. The most prominent example of this is the tragedy that resulted from testing the drug thalidomide on animals. Thalidomide was prescribed to pregnant women in the 1960s as a cure for morning sickness. Although experiments on animals had determined that the drug was safe, it caused more than 10,000 severe deformities and thousands of spontaneous abortions in humans. Learn more about the thalidomide tragedy.
Other drugs that were deemed safe by animal tests but later determined to be harmful to pregnant women include the following:
- Accutane: This acne treatment can cause severe birth defects in humans even when it is used in small doses and for brief periods of time.
- Tegretol: This epilepsy treatment increases the risk of birth defects in humans.
- Diethylstilbestrol (DES): This drug was, ironically, prescribed to prevent miscarriages. It actually increased the rate of spontaneous abortions, premature deliveries, and neonatal deaths. DES also caused vaginal and cervical cancer in patients’ daughters and even caused birth defects in the grandchildren of women who used it.
Finally, testing human drugs on animals creates the risk that inaccurate health information will be widely disseminated. For example, a recent newspaper article titled, “Vitamin C May Help Protect Babies of Smoking Moms,” creates the impression that smoking is not harmful as long as it is accompanied by taking doses of vitamin C.11 The article is based on an Oregon Health and Science University study in which researchers injected pregnant monkeys with both nicotine and vitamin C in an effort to determine whether the vitamin negates the detrimental effects of the nicotine on babies. Although responsible physicians would never base their clinical advice on this research, the newspaper article’s headline leads the public to believe that the findings of the study apply to pregnant women. In other words, this research is not merely useless—it might also convince women that it is safe to smoke while pregnant.
1. Hobe J. Schröder, “Models of Fetal Growth Restriction,” European Journal of Obstetric & Gynecology and Reproductive Biology 110 (2003): S29-S39.
2. S. Beaudoin et al., “Development Stages in the Rabbit Embryo: Guidelines to Choose an Appropriate Experimental Model,” Fetal Diagnosis and Therapy 18 (2003): 422-27.
3. A.C. Enders and A.M. Carter, “What Can Comparative Studies of Placental Structure Tell Us?—A Review,” Placenta 25, “Trophoblast Research Supplement,” 18 (2004): S3-S9.
4. Lucy M. Anderson, “Predictive Values of Traditional Animal Bioassay Studies for Human Perinatal Carcinogenesis Risk Determination,” Toxicology and Applied Pharmacology 199 (2004): 162-74.
5. Michael E. Symonds et al., “Current Topic: Limitations of Models Used to Examine the Influence of Nutrition During Pregnancy and Adult Disease,” Arch Dis Child 83 (2000): 215-19.
6. P. Myllynen and K. Vahakangas, “An Examination of Whether Human Placental Perfusion Allows Accurate Prediction of Placental Drug Transport: Studies With Diazepam,” Journal of Pharmacological and Toxicological Methods 48 (2002): 131-38.
