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Biomedical subjects

D R Mishell

Publications and source records attributed to D R Mishell.

315 records · Page 18Linked to original sources
PubMedDate not supplied

Intrauterine devices: medicated and nonmedicated.

The main benefits of intrauterine devices (IUDs) are a lack of adverse systemic effects, excellent effectiveness, high continuation rates and the single act of motivation required for use. First year failure rates range from 2% to 3%, but decline steadily thereafter to a cumulative annual failure rate of less than 1% after six years. The risks of IUDs include increased blood loss, uterine perforation, pelvic infection and pregnancy-related complications. The incidence of perforation of the uterine fundus ranges from 1:1000 to 1:2500 insertions, while that of cervical perforation with the copper devices ranges from 1:600 to 1:1000. IUD use is associated with about a three-fold increased incidence of developing acute salpingitis in comparison with use of oral contraceptives and diaphragms. If pregnancy occurs with an IUD in place, there is a three-fold increased risk of spontaneous abortion, a ten-fold increased risk of ectopic pregnancy (5% of all IUD pregnancies) and a possible increased incidence of sepsis during the pregnancy.

Abortion, Septic↗
PubMedDate not supplied

Progestin-only contraceptive rings.

Several progestin-only long acting contraceptives are currently available in the form of implants or injectables. Vaginal rings are another contraceptive option in the final stages of development. These steroid-containing polymer rings are placed in the vagina, providing relatively constant drug release, thus allowing for lower effective doses. Vaginal rings have the advantage of being user-controlled and non-provider dependent, and their use is non-coital related. The first clinical study with medroxyprogesterone acetate vaginal rings was published in 1970. Since then numerous clinical trials testing different steroids and doses have followed. A large Phase III multicenter clinical trial with a levonorgestrel ring, releasing 20 microg/day, was coordinated and sponsored by WHO. The cumulative one-year pregnancy rate was 4. 5%. The principal reasons for discontinuation were menstrual disturbances (17.2%), followed by frequent expulsion of the ring (7. 1%), and vaginal symptoms (6.0%). The finding of erythematous lesions in the vagina in some women has led to the development of a more flexible device. Collaboration with industry should facilitate the manufacture of a redesigned levonorgestrel ring with a higher release rate. The Population Council is also developing a vaginal ring containing Nestorone for 6 months of continuous use. Ovulation inhibition was achieved in over 97% of the segments studied, with rings releasing either 50, 75, or 100 microg/day. No pregnancies occurred in women using the low-dose ring, while one pregnancy each occurred in the intermediate- and high-dose ring groups for a 6-month cumulative pregnancy rate of 0.0, 1.9, and 2.1%. Bleeding irregularities were common. Nestorone is orally inactive; therefore this ring is also excellent for use in lactating women.

Administration, Intravaginal↗