Host defenses and bacterial resistance.

The amount of knowledge and understanding about the human immune system has expanded rapidly in the past several decades. The ability of the physician to care for pregnant women, specifically those with infectious diseases, can be enhanced through a basic understanding of host defenses and the normal alterations of these defenses encountered during pregnancy. A general understanding of bacterial resistance to antimicrobial agents will also aid the practitioner in selecting the appropriate setting and agent when prescribing these drugs.