The aim of the study is to evaluate the role of uterine natural killer cell(uNK)in recurrent pregnancy losses and the correlation between the numbers of it and embryo toxicity by measuring the level of the Th2 cytokines in normal reproductive profile and in patients with Recurrent Pregnancy Losses (RPL).

Office hysteroscopy examination of the patients at the luteal phase of the natural cycle (day17 to day 20),with endometrial biopsy using pipple curette from the region of the fundus, the biopsy sent to flow cytometry laboratory in South Egypt Cancer Institute to be examined for:

1.1. Phenotypic analysis of uterine natural killer cells:

1.2. Induction and detection of intracellular cytokines by flow Cytometry:

Inclusion Criteria:

1. Women with unexplained recurrent miscarriages (2 or more consecutive).
2. All patients have normal uterine cavity diagnosed by HSG and /or hysteroscopy, normal semen analysis, normal thrombophilic profiles, no history of malformed
3. normal fetus in the previous miscarriages

Exclusion Criteria:

1. Age above forty years old .
2. Antiphospholipid syndrome (lupus anticoagulant and/or anticardiolipin antibodies [IgG or IgM]); other recognised thrombophilic conditions (testing according to usual clinic practice).
3. Intrauterine abnormalities (as assessed by ultrasound, hysterosonography, hysterosalpingogram, or hysteroscopy).
4. Fibroids distorting uterine cavity .
5. Abnormal parental karyotype .
6. Other identifiable causes of recurrent miscarriages (tests initiated only if clinically indicated) e.g., diabetes, thyroid disease and systemic lupus erythematosus (SLE).