Low levels of serotonin , a neurotransmitter in the brain, have been linked to depression . High levels of estrogen, as in first-generation COCPs, and progestin, as in some progestin-only contraceptives, have been shown to lower the brain serotonin levels by increasing the concentration of a brain enzyme that reduces serotonin. This observation, along with some small research studies  have inspired speculation that the pill causes depression. In 2016, a large Danish study of one million women showed that use of COCPs, especially among adolescents, was associated with a statistically significantly increased risk of subsequent depression, although the sizes of the effects are small (for example, % of the women who took any form of oral birth control were prescribed anti-depressants for the first time, compared to % of women in the control group). 
Chaim Hezekiah Medini , after corresponding with the greatest Jewish sages of the generation, concluded the practice to be Halacha l'Moshe m'Sinai and elaborates on what prompted Moses Sofer to give the above ruling.  He tells the story that a student of Moses Sofer, Lazar Horowitz , Chief Rabbi of Vienna at the time and author of the responsa Yad Elazer , needed the ruling because of a governmental attempt to ban circumcision completely if it included metztitzah b'peh. He therefore asked Sofer to give him permission to do brit milah without metzitzah b’peh. When he presented the defense in secular court, his testimony was erroneously recorded to mean that Sofer stated it as a general ruling.  The Rabbinical Council of America , (RCA) which claims to be the largest American organization of Orthodox rabbis, published an article by mohel Dr Yehudi Pesach Shields in its summer 1972 issue of Tradition magazine, calling for the abandonment of Metzitzah b'peh.  Since then the RCA has issued an opinion that advocates methods that do not involve contact between the mohel's mouth and the open wound, such as the use of a sterile syringe, thereby eliminating the risk of infection.  According to the Chief Rabbinate of Israel  and the Edah HaChareidis  metzitzah b'peh should still be performed.