Reproductive toxicity
Encyclopedia
Chemical substance
In chemistry, a chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. They can be solids, liquids or gases.Chemical substances are...
s, that they will interfere in some way with normal reproduction. It includes adverse effects on sexual function and fertility in adult males and females, as well as developmental toxicity in the offspring. It is usual to take a practical definition, including several different effects which are unrelated to each other except in their outcome of lowered effective fertility. The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) separates reproductive toxicity from germ cell
Germ cell
A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate near the gut of an embryo and migrate to the developing gonads. There, they undergo cell division of two types, mitosis and meiosis, followed by...
mutagen
Mutagen
In genetics, a mutagen is a physical or chemical agent that changes the genetic material, usually DNA, of an organism and thus increases the frequency of mutations above the natural background level. As many mutations cause cancer, mutagens are therefore also likely to be carcinogens...
icity and carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
icity, even though both these hazards may also affect fertility.
One well known group of substances which are toxic for reproduction are teratogens – substances which cause birth defects – of which (S)-thalidomide
Thalidomide
Thalidomide was introduced as a sedative drug in the late 1950s that was typically used to cure morning sickness. In 1961, it was withdrawn due to teratogenicity and neuropathy. There is now a growing clinical interest in thalidomide, and it is introduced as an immunomodulatory agent used...
is possibly the most notorious. Another group of substances which has received much attention (and some controversy) as possibly toxic for reproduction are the so-called endocrine disruptor
Endocrine disruptor
Endocrine disruptors are chemicals that interfere with endocrine in animals, including humans. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders...
s. However many substances which are toxic for reproduction do not fall into either of these groups: lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
compounds, for example, are considered to be toxic for reproduction given their adverse effects on the normal intellectual and psychomotor development of human babies and children.
Many drugs have effects on the human reproductive system: these may be desired (hormonal contraception
Hormonal contraception
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive...
), a minor unwanted side effect (many antidepressant
Antidepressant
An antidepressant is a psychiatric medication used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder. According to Gelder, Mayou &*Geddes people with a depressive illness will experience a therapeutic effect to their mood;...
s) or a major public health problem (thalidomide). However most studies of reproductive toxicity has focussed on occupational or environmental exposure to chemicals and their effects on reproduction. It may be noted that both consumption of alcohol and tobacco smoking are known to be "toxic for reproduction" in the sense that the term is used here.