Human infertility has become an important and common problem in the world, especially in developed countries. Infertility is estimated to affect between 8 and 12 percent of couples of reproductive age worldwide, with 9 percent currently cited as the probable global average. In human pregnancy, in order to preserve the fetus and mother for successful pregnancy, there is a need for a wide adaptation between the innate and acquired immune systems (Zumla et al., 2014). The function of these two systems during pregnancy is in the opposite direction, so that acquired immunity is suppressed during normal pregnancy, however, innate immunity dependents on phagocytic and neutrophils increases over time (Peterson et al., 2020). Uniquely, polymorphonuclear neutrophils (PMNs) play a role in both fertility preservation and adverse abnormalities. PMNs play a role in various stages of reproduction such as fertilization and implantation in the beginning of pregnancy, maintaining the health of the fetus and mother during pregnancy as well as successful delivery and maternal health after delivery (Giaglis et al., 2016a). On the other side, abnormal function of PMNs has been reported in severe pregnancy abnormalities such as recurrent fetal loss (RFL) (Girardi et al., 2006), preeclampsia (PE) (Gupta et al., 2005b) and gestational diabetes mellitus (GDM) (Stoikou et al., 2017). In humans, pregnancy, activation of circulating PMNs and increased tendency for reactive oxygen species (ROS) production, degranulation and phagocytosis are evident (Sacks et al., 1998). In fact, these PMNs are associated with an increased tendency to form NETs, which is increased during pregnancy and reach the highest level in term (Giaglis et al., 2016b). The process of NETosis, which means the release of neutrophil contents, requires several signals, including histone citrullination by PAD4 enzyme, reactive oxygen species (ROS), neutrophil elastase (NE), and Myeloperoxidase (MPO) enzymes (Fuchs et al., 2007, Kaplan and Radic, 2012, Martinod et al., 2013). NE and MPO are stored in azurophilic granules of naive neutrophils. NE is a neutrophil-specific serine protease that destroys bacteria, and MPO catalyzes the oxidation of halides. Maternal circulating neutrophils also show an increased cell-free (cf)-DNA level during pregnancy. These neutrophils are associated with the tendency to form spontaneous NETs, which are stimulated by granulocyte-colony stimulating factor (G-CSF) and modulated by sex hormones (Giaglis et al., 2016b). Recently, neutrophil extracellular traps (NETs) have been implicated as a potential mechanism promoting inflammation in pregnancy disorders (Redman et al., 1999). NETs appear to play an important role in fertility as well as recurrent fetal loss (RFL) at different stages of the reproductive cycle (Hahn et al., 2012). During pregnancy, the placenta can release inflammatory cytokines and activated neutrophils to form NETs, which may lead to pregnancy loss by obstructing the intervillous space and creating hypoxic conditions (Hahn et al., 2006). Therefore, in this review, the role of neutrophils in pregnancy and the relationship between patients, pregnancy complications and neutrophil extracellular traps will be discussed.