Prescription of teratogenic medications in United States ambulatory practices

PURPOSE

The purpose of this study was to identify the potentially teratogenic medications most frequently prescribed to women of childbearing age and the specialty of physicians who provide ambulatory care to women who use such medications. In addition, we evaluated rates of contraceptive counseling to explore awareness of the risks associated with teratogenic medication use.

SUBJECTS AND METHODS

The prescription of teratogenic medications and provision of contraceptive counseling on 12,681 visits made by nonpregnant women, 14 to 44 years of age, to 1880 physicians in US ambulatory practice (National Ambulatory Medical Care Survey) between 1998 and 2000 was analyzed.

RESULTS

Use of a potentially teratogenic, class D or X, medication by a woman of childbearing age is documented on 1 of every 13 visits made to US ambulatory practices. These include anxiolytics (4.1 million annual prescriptions), anticonvulsant medications (1.4 million annual prescriptions), antibiotics like doxycycline (1.4 million annual prescriptions), and statins (0.8 million annual prescriptions). Isotretinoin accounts for less than 5% of potentially teratogenic prescriptions (0.5 million annual prescriptions). Internists and family/general practitioners provide ambulatory care to 45% of women prescribed potentially teratogenic medications, psychiatrists provide ambulatory care to 20% of women prescribed potentially teratogenic medications, and dermatologists provide ambulatory care to 20% of women prescribed potentially teratogenic medications. Contraceptive counseling was provided on less than 20% of visits that documented use of a potential teratogen by a woman of childbearing age. Women using low-risk (class A or B) drugs received contraceptive counseling as frequently as women using potential teratogens (P = .24).

CONCLUSION

Potentially teratogenic medications are prescribed to millions of women of childbearing age each year. Physician awareness of the teratogenic risk associated with class D or X medications seems low.

Trends in environmental lead exposure and troubled youth, 1960-1995: an age-period-cohort-characteristic analysis

Beginning in the mid-1980s and extending into the early 1990s, the United States experienced a wave of increased youth violence and teenage pregnancy. Nevin (2000) proffers a cohort-based explanation that these trends can be attributed to corresponding trends in gasoline lead exposure during the youths' early years. He contends that the increased consumption of adversely impacted their intelligence levels (IQs). This decreased their intellectual ability, resulted in poor decisions made during their teen and young adult years, and in turn, led to disproportionally high level of criminal involvement and unwed pregnancies among this cohort. The present study evaluates Nevin's causal model by testing the connection between trends in lead exposure and youthful problem behavior with age-period-cohort-characteristic (APCC) models. Our research finds no support for this cohort explanation.

Recent developments in low-level lead exposure and intellectual impairment in children

In the last decade children's blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 Mu g/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 Mu g/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently less than 10 Mu g/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children's cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1-4%), whereas social and parenting factors account for 40% or more.