Estrogen negative feedback on the anterior pituitary greatly decreases the secretion of FSH, which inhibits follicular development and helps prevent ovulation.Another primary mechanism of action of all progestogen-containing contraceptives is inhibition of sperm penetration through the cervix into the upper genital tract (uterus and fallopian tubes) by decreasing the water content and increasing the viscosity of the cervical mucus.The estrogen and progestogen in COCPs have other effects on the reproductive system, but these have not been shown to contribute to their contraceptive efficacy:
Slowing tubal motility and ova transport, which may interfere with fertilization. Endometrial atrophy and alteration of metalloproteinase content, which may impede sperm motility and viability, or theoretically inhibit implantation. Endometrial edema, which may affect implantation.Insufficient evidence exists on whether changes in the endometrium could actually prevent implantation. The primary mechanisms of action are so effective that the possibility of fertilization during COCP use is very small. Since pregnancy occurs despite endometrial changes when the primary mechanisms of action fail, endometrial changes are unlikely to play a significant role, if any, in the observed effectiveness of COCPs. Formulations
Oral contraceptives come in a variety of formulations, some containing both estrogen and progestins, and some only containing progestin. Doses of component hormones also vary among products, and some pills are monophasic (delivering the same dose of hormones each day) while others are multiphasic (doses vary each day).
Pupillary hippus, also known as pupillary athetosis, is spasmodic, rhythmic, but regular dilating and contracting pupillary movements between the sphincter and dilator muscles. Pupillary hippus comes from the Greek hippos meaning horse, perhaps due to the rhythm of the contractions representing a galloping horse.It is particularly noticeable when pupil function is tested with a light, but is independent of eye movements or changes in illumination. It is usually normal, however pathological hippus can occur.Pathologic hippus, the phenomenon of increased oscillation or their amplitude, is associated with aconite poisoning, altered mental status, trauma, cirrhosis, and renal disease; suggesting a common pathway of frontal lobe dysfunction. A retrospective study of 117 hospitalized patients with hippus noted an increased 30-day mortality when compared to controls and adjusted for other factors. See also
Athetosis
Anisocoria - condition characterized by an unequal size of the eyes pupils. == References ==