 The purpose of the Antiretroviral Pregnancy Registry Registry is to detect any major teratogenic effect involving any of the Registry drugs when administered to pregnant women. Registration is voluntary and confidential with information obtained from the health care provider. A Registry-assigned identifier allows for follow-up capability. Information on subjects is provided to the Registry prospectively prior to the outcome of pregnancy being known through their health care provider, with follow-up obtained from the health care provider after the outcome is determined. Providers are strongly urged to enroll their patients as early in pregnancy as possible to maximize the validity of the data. In addition, the Registry is very interested in assembling a group of providers who are willing to make a commitment to report all of their sites antiretroviral pregnancy exposures to the Registry, thereby assuring all cases can be considered prospective. Providers are encouraged to contact the Registry for more information about this group. The Registry is informed in its analysis by other data, for example, retrospective reports and clinical studies. 