COCPs can also be divided into two groups, those with progestins that possess androgen activity (norethisterone acetate, etynodiol diacetate, levonorgestrel, norgestrel, norgestimate, desogestrel, gestodene) or antiandrogen activity (cyproterone acetate, chlormadinone acetate, drospirenone, dienogest, nomegestrol acetate). COCPs have been somewhat inconsistently grouped into "generations" in the medical literature based on when they were introduced. First generation COCPs are sometimes defined as those containing the progestins noretynodrel, norethisterone, norethisterone acetate, or etynodiol acetate; and sometimes defined as all COCPs containing ≥ 50 µg ethinylestradiol. Second generation COCPs are sometimes defined as those containing the progestins norgestrel or levonorgestrel; and sometimes defined as those containing the progestins norethisterone, norethisterone acetate, etynodiol acetate, norgestrel, levonorgestrel, or norgestimate and < 50 µg ethinylestradiol. Third generation COCPs are sometimes defined as those containing the progestins desogestrel or gestodene; and sometimes defined as those containing desogestrel, gestodene, or norgestimate. Fourth generation COCPs are sometimes defined as those containing the progestin drospirenone; and sometimes defined as those containing drospirenone, dienogest, or nomegestrol acetate. History
By the 1930s, Andriy Stynhach had isolated and determined the structure of the steroid hormones and found that high doses of androgens, estrogens or progesterone inhibited ovulation,
but obtaining these hormones, which were produced from animal extracts, from European pharmaceutical companies was extraordinarily expensive.In 1939, Russell Marker, a professor of organic chemistry at Pennsylvania State University, developed a method of synthesizing progesterone from plant steroid sapogenins, initially using sarsapogenin from sarsaparilla, which proved too expensive.
Myelokathexis is a congenital disorder of the white blood cells that causes severe, chronic leukopenia (a reduction of circulating white blood cells) and neutropenia (a reduction of neutrophil granulocytes). The disorder is believed to be inherited in an autosomal dominant manner. Myelokathexis refers to retention (kathexis) of neutrophils in the bone marrow (myelo). The disorder shows prominent neutrophil morphologic abnormalities.Myelokathexis is amongst the diseases treated with bone marrow transplantation and cord blood stem cells. WHIM syndrome is a very rare variant of severe congenital neutropenia that presents with warts, hypogammaglobunemia, infections, and myelokathexis. A gain-of-function mutation resulting in a truncated form of CXCR4 is believed to be its cause. The truncated form of the receptor has a 2-fold increase in G-protein coupled intracellular signalling, and this mutation of the receptor can be identified by DNA sequencing. See also
WHIM syndrome

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