Contraceptive Research and Development Looking to the Future (1996) / Chapter Skim
Currently Skimming:
4 Contraceptive Technology and the State of the Science: New Horizons
4 Contraceptive Technology and the State of the Science: New Horizons
Pages 94-124
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 94... ...
Chapter 3 is based on presentations made at the December 1994 Institute of Medicine workshop on Contraceptive Research and Development and the Frontiers of Contemporary Science, conducted as part of this study activity (Institute of Medicine [IOM]
|
From page 95... ...
areas of inquiry or specific targets in the development of contraceptive methods for men, that is, "male methods"; and (3) an area that holds promise for the development of various contraceptive methods for both females and males, "immunocontraception," which subsumes the topic of "mucosal immunity" and its potential for generating new anti-infective and/or contraceptive barrier methods.
|
From page 96... ...
, fibrocystic breast adenomas disease, ovarian cysts, iron-deficiency anemia, dysmenorrhea Progestin-only Changes in cervical 4% 0.5% Protection against Menstrual Unknown mucus and endo- PID, iron-deficiency irregularities metrium, possible anemia, dysmenorrhea ovulation suppression Implants Similar to progestin- 0.09% 0.09% Effective for 5 years Site tenderness, Infection at implant site Levonorgestrel only removal problems, subdermal implants menstrual (Norplant) irregularities, headache, weight gain, acne CONTRACEPTIVE RESEARCH AND DEVELOPMENT
|
From page 97... ...
: Progesterone T Inhibition of sperm 2% 1.5% Diminished menstrual Requirement for Ectopic pregnancy (Progestasert) migration, blood loss and relief of removal and fertilization and dysmenorrhea reinsertion on an ovum transport annual basis; (progesterone is increased cramping responsible for and menstrual flow primary mode of action)
|
From page 98... ...
TABLE 3-1 Continued 98 Unintended Pregnancy Rate Mode of Typical Perfect Disadvantages and Method Action Use Use Advantages Side Effects Dangers Barrier Methods: Spermicide alone Inactivation of sperm 21% 6% May protect against Vaginal irritation None proven bacterial STDs Cervical cap with Mechanical barrier; 18% 11.5% Protection against STDs Cervical irritation, Toxic shock syndrome Spermicide inactivation of sperm vaginal discharge, pelvic pressure, Pap smear abnormalities Diaphragm with Mechanical barrier; 18% 6% Protection against STDs Cervical irritation Toxic shock syndrome, Spermicide inactivation of sperm urinary tract infections Condom Mechanical barrier Male 12% 3% Protection against STDs Latex allergies None Female 21% 5% Protection against STDs, Difficult to insert None including external genitalia CONTRACEPTIVE RESEARCH AND DEVELOPMENT
|
From page 99... ...
(LAM) identification of Only applicable during behaviors, period of lactational the first 6 months including improved infertility using three postpartum maternal and child criteria health Periodic Abstinence Avoidance of coitus 20% 0-1% No commodities Provides no protection Methods: during days when necessary; enhances against STDs fertilization might breastfeeding practices.
|
From page 100... ...
later; or (combined oral contraceptive pills 4 Lo/Ovral, Nordette, containing or Levlen initially, 4 combination of more 12 hours later; estrogen or and progestin)
|
From page 101... ...
women and were determined from: C Ellerton, Expanding access to emergency contraception in developing countries, Studies in Family Planning 26(5) :251–262, 1995, and J Trussell, C Ellerton, Efficacy of emergency contraception, Fertility Control Reviews 4(2)
|
From page 102... ...
serves both to suppress ovulation and change the nature of cervical mucus, making it less permeable to sperm. A fact that is very imperfectly recognized is that COCs have definite non-contraceptive advantages, including protection against ovarian and endometrial cancer, fibrocystic breast disease, benign ovarian cysts, ectopic pregnancies, and symptomatic pelvic inflammatory disease.
|
From page 103... ...
They prevent pregnancy through several modes of action: by inhibiting ovulation; thickening and decreasing the amount of cervical mucus (making it more difficult for sperm to penetrate; creating a thin, atrophic endometrium; and/or premature luteolysis (McCann and Potter 1994)
|
From page 104... ...
All IUDs that have been tested experimentally or clinically induce a local inflammatory reaction in the endometrium that changes the cellular and humoral components of the fluid contents of the uterine cavity; in humans, the entire genital tract then appears to be affected by the inflammatory fluids from the uterine lumen. This in turn affects the function and viability of gametes, thus decreasing the rate of fertilization, either in the altered tubal milieu or in the uterine cavity (Bardin 1996)
|
From page 105... ...
There is renewed public interest in barrier methods, since they constitute the only category of contraceptives now available that can reduce the risk of transmission of sexually transmitted diseases (STDs)
|
From page 106... ...
A thicker material is now being tested in clinical trials under the aegis of the National Institute of Child Health and Human Development (NICHD) (American Health Consultants 1995; Contraceptive Technology Update June 1995)
|
From page 107... ...
Periodic Abstinence Methods (PAM) : Calendar Rhythm, Cervical Mucus/ Ovulation, and Symptothermal Methods These methods provide instruction about the timing of ovulation during the ovulatory cycle and the days of potential fertilization of the ovum, and require abstinence at those times (Queenan and Labbok 1992)
|
From page 108... ...
The term "fertility awareness method," on the other hand, generally applies when either periodic abstinence or a barrier method is used only for pregnancy avoidance during the fertile phase, as that is identified using any of the three periodic abstinence methods listed above. Thus, periodic abstinence may be a part of practicing a fertility awareness method or of natural family planning, but the philosophies behind the two approaches are different.
|
From page 109... ...
When standard COCs are used for emergency contraception, they are called ECPs (emergency contraceptive pills)
|
From page 110... ...
The categories reviewed are: (1) improved methods for women, including improved oral contraceptives, new delivery systems, postcoital methods, and better barrier methods; and (2)
|
From page 111... ...
. As indicated earlier in this chapter, depending on a woman's age and health status, these benefits can include protection against ovarian and endometrial cancer, pelvic inflammatory disease, fibrocystic breast disease, ovarian cysts, ectopic pregnancy, iron-deficiency anemia, dysmenorrhea, and osteoporosis.
|
From page 112... ...
Absent positive incentives, some companies currently in the field might dismantle their contraceptive research teams and devote the freed-up resources to other, less risky areas of research and development. There is also the matter of negative stimuli, one of which is the fact that the USFDA considers all oral contraceptives as belonging to a single class of drugs.
|
From page 113... ...
Already available in some European countries, this new device seems to have fewer side effects -- for instance, cramping, blood loss, and increased risk of pelvic inflammatory disease -- than traditional IUDs and has a very low pregnancy rate (WHO 1994b)
|
From page 114... ...
Better Barrier Methods Mechanical Barriers The barrier methods of contraception that are now available are either mechanical (male and female condoms, diaphragms, and cervical caps) , chemical (spermicides and other formulations)
|
From page 115... ...
While some spermicides, specifically nonoxynol-9, can kill HIV and bacteria in laboratory studies, there is concern that, as a detergent, it may also kill cells and irritate the vaginal epithelium, thereby possibly elevating susceptibility to HIV transmission. This has led many researchers to suggest that research should now focus on noncytotoxic rather than cytotoxic methods of stopping sexually transmitted pathogens.
|
From page 116... ...
. Indeed, the gel simply increases the buffer capacity of vaginal fluids sufficiently to overcome the neutralizing action of semen and cervical mucus.
|
From page 117... ...
.6 The compound has been licensed for that purpose in France, Sweden, and the United Kingdom, and is being manufactured in China. In the United States, RU 486 is in phase III clinical trials under the aegis of the Population Council (IOM 1993)
|
From page 118... ...
. The potential of the antiprogestins goes well beyond emergency contraception.
|
From page 119... ...
One implant delivers an agonist of luteinizing hormone releasing hormone (LHRH) that suppresses sperm production; the other implant, required to compensate for resulting diminution of testosterone, the androgen that governs sexual function, supplies a synthetic androgen (MENT)
|
From page 120... ...
While toxicology studies have not been completed, these plant compounds show particular promise because they seem to work by interfering in sperm maturation in the epididymis, thus offering a potential contraceptive without side effects involving male sex hormones. CONCLUDING COMMENT At the outset of this chapter, we stated that there was reasonable probability that a number of improvements in existing contraceptive technologies could become available in the next decade.
|
From page 121... ...
How frequently is emergency contraception prescribed? Family Planning Perspectives 26(6)
|
From page 122... ...
The Lactational Amenorrhea Method: A new postpartum introductory family planning method with program and policy implications. Advances in Con traception 10:93–109, 1994.
|
From page 123... ...
1994. Van Look PFA, H von Hertzen.
|
From page 124... ...
4. Oral contraceptives are packaged specifically for emergency contraception use in Bulgaria, Finland, Germany, Hungary, Jamaica, Malaysia, the Netherlands, Nigeria, Pakistan, Poland, Singapore, states of the former Soviet Union, Sweden, Switzerland, the United Kingdom, Uruguay, and Zimbabwe (Camp 1994)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.