ESTRING (estradiol vaginal ring) PLACEMENT. The exact position of ESTRING (estradiol vaginal ring) is not critical, as long as it is placed in the upper third of the vagina. When ESTRING (estradiol vaginal ring) is in place, you should not feel anything.he soft, flexible ring is placed in the upper third of the vagina (by the physician or the patient). ESTRING (estradiol vaginal ring) should be removed after90 days of continuous use. If continuation of therapy is indicated, the flexible ring should be replaced.
Fertilization takes place in the fallopian tube, more specifically the juncture of the ampulla and isthmus (ampullary-isthmic junction). The ovaries will ovulate and expel a mature ovum due to a surge in the Leutenizing Hormone.
In self-fertilization, the gametes come from the same individual. Fertilization includes the union of the cytoplasm of the gametes (called plasmogamy) followed by the union of the nuclei of the two gametes (called karyogamy). Among many animals, such as mammals, fertilization occurs inside the body of the female. Among fish, eggs are fertilized in the water. Among plants, fertilization of eggs occurs within the reproductive structures of the parent plant, such as the ovules of gymnosperms and angiosperms. See Note at pollination.