For many years, the innate immunity was of less interest than the adaptive 
immunity because it was perceived to have secondary importance in the 
functionality of the immune system. During the past decades, with the 
advancement of knowledge about innate immune system, interest in innate immunity 
has grown dramatically and thus its function has been extensively studied. 
Innate immunity plays fundamental roles in the initiation and induction of 
adaptive immune responses. It consists of several cells and receptors including 
natural killer (NK) cells, macrophages (MQs), dendritic cells (DCs) and pattern 
recognition receptors (PRRs). Two decades ago, Toll like receptors (TLRs) family 
was known as one of the important PRRs with unique functions especially in 
protection against invading pathogens. Since the female reproductive tract has 
access to the outside environment and has a unique interaction with different 
pathogens whether invading microorganisms or normal flora, allogenic sperm and 
semi allogenic fetus, it has an essential need for effective immune responses. 
It has therefore been suggested that TLRs may play important roles in the immune 
regulation of the female reproductive tract. In addition, it has been 
demonstrated that immune disturbance may be responsible for some adverse 
pregnancy outcomes such as preeclampsia (PE), recurrent spontaneous abortion 
(RSA) and intrauterine growth restriction (IUGR). Our focus in this review is to 
show the importance of TLRs in pregnancy with emphasis on the expression of 
these receptors in different tissues related to pregnancy.