Environmental Medicine Integrating a Missing Element into Medical Education (1995) / Chapter Skim
Currently Skimming:
Case Study 53: Reproductive and Developmental Hazards
Case Study 53: Reproductive and Developmental Hazards
Pages 872-892
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 872... ...
Ed of the 3 million infants born during the 1980s, approximately 7% were low birth weight, 5% were preterm, 2% to 3% had major congenital anomalies, and an unknown number have developmental or functional problems in childhood. Ed The extent to which environmental or occupational exposures affect these statistics is unknown.
|
From page 873... ...
While collecting information forthe health assessment, ATSDR finds that birth certificates for the county do not reveal an excess of adverse pregnancy outcomes in the water-service area compared with the rest of the county. However, because only 20% of all birth defects are typically reported on birth certificates, the agency advises that birth certificate studies alone cannot rule out an increase of birth defects; furthermore, vital records do not provide data on spontaneous abortions.
|
From page 874... ...
O Many chemical agents are suspected of causing adverse reproductive or developmental effects; however, strong evidence exists for only a few. O Folic acid supplements administered during the periconceptual period may prevent fetal CNS anomalies.
|
From page 875... ...
Table 1 lists some environmental oroccupational agents suspected to cause decreased female reproductive capacity or adverse developmental effects in the fetus. Some therapeutic agents reported to affect female reproductive capacity include steroids, alkylating agents, methotrexate, levodopa, quinacrine, appetite suppressants, opioids, antipsychotics (e.g., phenothiazines)
|
From page 876... ...
Agents associated with adverse female reproductive capacity or developmental effects in human and animal studies. Agent Human Outcomes Strength of AnimalOutcomes Strength of Association Associatiotn in Humans in Animals Anesthetic gases1 Reduced fertility, spontaneous abortion 1,3 Birth defects 1,3 Arsenic Spontaneous abortion, low birth weight 1 Birth defects, fetal loss 2 Benzo(a)
|
From page 877... ...
Chemical exposures to males can cause adverse pregnancy outcomes by several mechanisms.
|
From page 878... ...
Destruction of the basic stem-cell spermatogonia usually causes permanent infertility; damage during subsequent stages of the maturation process is potentially reversible. Chemical exposure to the male can cause adverse pregnancy outcomes not only by damaging the sperm, which can produce an abnormal zygote, but possibly also by transmission of toxic agents in seminal fluid.
|
From page 879... ...
pyrene None NA Testicular damage 1 Cadmium Reduced fertility 1 Testicular damage 2 Carbon disulfide Decreased sperm count, decreased sperm motility 2,3 Testicular damage 1 Carbon monoxide None NA Testicular damage 1 Carbon tetrachloride None NA Testicular damage 1 Carbaryl Abnormal sperm morphology 1 Testicular damage 1 Chlordecone Decreased sperm count, decreased sperm motility 2 Testicular damage 2 Chloroprene Decreased sperm motility, abnormal morphology, decreased libido 2 Testicular damage 1 Dibromoch loropropane (DBCP) Decreased sperm count, azoospermia, hormonal changes Dimethyl dichlorovinyl phosphate (DDVP)
|
From page 880... ...
may cause early pregnancy loss by interfering with tubal transport or implantation. Heavy metals such as lead or copper have been found to inhibit implantation in experimental animals by interfering with uterine hormone-binding mechanisms.
|
From page 881... ...
Some chemical toxicants cause severe effects on the embryo and have no effect on the pregnant woman; others affect the embryo only at maternally toxic doses. Traditional theory contends that a threshold exists for defects of organogenesis because the embryo can usually repair damage caused by low levels of exposure.
|
From page 882... ...
High maternal exposures, such as those caused by the ingestion of PCB-contaminated rice oil in Japan in 1968, have led to disease in infants, either through exposure in utero or through breast feeding.-Chemical exposures by routes other than maternal ingestion have not been reported to produce adverse health effects in breast-fed infants. Table..
|
From page 883... ...
Even it a trial involving removal from exposure has been undertaken, it is important to remember that infertility may be a problem of the couple, rather than due solely to the man or the woman. For example, a submaximal sperm count in association with abnormalities of cervical mucus can lead to infertility, when neither condition alone would prevent conception.
|
From page 884... ...
Potentially comparable effects on females have not been elucidated because parameters that affect female reproductive capacity cannot be easily measured. Chemical exposures should be strictly controlled or eliminated for all females of reproductive age.
|
From page 885... ...
a) "Can adverse reproductive effects such as spontaneous abortion and birth defects be caused by drinking and using contaminated water?
|
From page 886... ...
Because most organic solvents (including TCA) are excreted relatively rapidly, breast feeding can be resumed several days after an acute maternal exposure.
|
From page 887... ...
Infertility associated with chemical exposures has thus far been linked primarily to effects on the male. This may be partially because semen can be measured and analyzed and thus provides a ready means of assessing reproductive health in men exposed to potential toxicants.
|
From page 888... ...
The procedure provides advice on specific Dublic health issues that arise from actual or potential exposure to a hazardous substance. When a rapid response is required, a health consultation is a more limited method of addressing concern about potential adverse health effects than is an ATSDR public health assessment.
|
From page 889... ...
Recommendations forthe use of folic acid to reduce the number of cases of spine bifida and other neural tube defects.
|
From page 890... ...
Arizona Arizona Teratogen Information Service. Arizona Health Sciences Center, Tucson, AZ.
|
From page 891... ...
266-2900 New Jersey Teratogen Information Network, University of Medicine and Dentistry of New Jersey. Serves primarily New Jersey: (609)
|
From page 892... ...
Polifka, Ph.D. Teratogen Information System (includes Shepard's Catalog of Teratogenic Agents)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.