From all of the participants the investigators will collect hair samples at the crown back of the head (hair will be cut as close as possible to the scalp), the samples will be measured quantitatively about 100 hairs at a length of 2-3 cm. In order to grind the hair samples we will use a mini-Bead beater machine. milled hairs will be incubated overnight in a solution of 1 ml methanol 50, in constant gentle muddling. Afterwards, ethanol will disperse through a stream of nitrogen. The remainder of the suspension will be dissolved at 200 microliter buffer PBS (Phosphate-Buffered Saline) (pH 8.0) and the concentration of estrogen and progesterone will be measured by using the immune method which is available in the endocrine laboratory in Bnai Zion medical center. At the end of the study the investigators will cary out a statistical comparison of progesterone and estrogen levels between the two groups.