Miscarriage and Its Associations

Stephen Brown, M.D.


Semin Reprod Med. 2008;26(5):391-400. 

In This Article

Environmental Exposures

Patients who have had miscarriage frequently wonder whether environmental exposures such as cleaning chemicals, heavy metals, drinking water impurities, electromagnetic radiation, low-level x-irradiation, and so forth may have been causal. Unfortunately, the role of such toxins in miscarriage is extremely difficult to study, because exposures of various kinds are common and miscarriage is common. Proving that a given exposure is associated with an increased risk of loss requires documenting that the exposure actually occurred in cases and not in controls. Frequently, objective documentation of exposure is impossible and patient history is relied upon instead, introducing the difficult problem of recall bias.

Confirmed environmental causes of miscarriage include lead, mercury, organic solvents, and ionizing radiation.[61] One can reassure a patient that the doses of environmental toxins required to consistently disrupt early pregnancy are generally sufficient to cause overt harm to the mother as well. One can also encourage worried patients to have their water supply evaluated for potential toxins and to have their own lead and mercury levels checked. Workplace exposures to solvents or other potentially harmful agents can generally be minimized through temporary reassignments.


Several studies using a variety of methods and dating from the 1970s through the 1990s have shown that women who smoke have a modest increase in their risk for miscarriage (see Ref.[62] and references therein.). In most of these studies, the relative risk for miscarriage has been between 1.2 and 2,[63,64] suggesting that women who are concerned about miscarriage should probably quit. Obviously, there are other compelling reasons for this conclusion as well.


The well-known teratogenic effects of alcohol on fetuses that do survive pregnancy would seem to far outweigh any significance for alcohol as a cause of miscarriage. Nonetheless, there is good evidence that even moderate alcohol consumption is associated with an increased risk of miscarriage.[65,66] With this in mind, women who are attempting to conceive should be encouraged to avoid even very early exposure


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.