CA2 and abortion: The results of previous studies have shown that Nigella sativa can cause an abortion by inducing menstruation cycles20, 26, 27; and thymoquinone as the main constituent of the essential oil of Nigella sativa,28 possesses spasmolytic effects by the means of blocking Ca2+ channels, it inhibits the automatic movement of the uterine smooth muscle in guinea pigs and rats and has anti‐oxytocic effects.29