Examining male roles in population policies and family planning programs

"This paper will discuss the following: why population policies and programs have traditionally focused on women; what the limitations of current male contraceptives are and why research into new methods [has] proved unfruitful; and why these policies and programs would be more productive if they were to direct more attention toward men."

Hormonal male contraception: progress and prospects for the 21st century

During the second half of the 20th century, progress in developing novel, practical contraceptive methods for men has lagged significantly behind developments for women. Despite the lack of reliable, reversible methods, men throughout the world continue to be strongly involved in family planning but a greater involvement will require more attractive and reliable contraceptive options for men. The closest to fruition are hormonal methods the features of which are reviewed. Landmark WHO contraceptive efficacy studies have established that hormonally-induced azoospermia provides highly effective and reversible contraception for at least 12 months with minimal short-term side effects. Even among the small subgroup of men who remain oligozoospermic during hormonal suppression, good contraceptive efficacy is achieved. The present goals are to develop improved second generation hormonal regimens which provide more uniform azoospermia to obviate the need for monitoring of sperm output and to develop long-acting depot testosterone formulations used alone or with additional gonadotrophin suppressive agents such as progestins or GnRH antagonists. Significant obstacles to progress are the flight of industry from contraceptive R&D dur to the financial deterrent posed by the product liability crisis as well as the low priority accorded male reproductive health. Together those will determine whether the range of contraceptive options available to our children in the 21st century will improve, or whether the historically recent unbalanced increase in reliance on women for family planning will continue.

Effect of testosterone enanthate on serum lipoproteins in man

Sixty-three normal Caucasian men were administered intramuscular testosterone enanthate (TE) 200 mg i.m. weekly for 12 months as part of a male contraceptive trial. This dose of TE caused a 2.5-fold increase in trough serum testosterone concentrations. High density lipoprotein cholesterol (HDL-C) was significantly depressed from pretreatment concentration of 1.19 +/- 0.04 nmol/l to 1.03 +/- 0.04 mmol/l after 12 weeks of treatment, and remained suppressed for the duration of treatment (p < 0.001). There were no changes in serum concentration of total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) or triglycerides (TG) during treatment, but the concentrations of TC and LDL-C were depressed at three months post-treatment. There was a sustained elevation in LDL-C:HDL-C ratio during TE treatment (p < 0.005), from 3.41 +/- 0.15 pretreatment to 3.88 +/- 0.19 after 12 weeks of TE treatment. Sex hormone binding globulin (SHBG), but not testosterone (T) or estradiol (E2), was significantly associated with HDL-C (r = 0.83, p = 0.001). Lipoprotein (a) (Lp(a)) was measured in a subgroup of 33 men: serum concentration fell from 187 +/- 45 mg/l pretreatment to 140 +/- 35 mg/l after 16 weeks of TE treatment (p < 0.01).

Potential of testosterone buciclate for male contraception: endocrine differences between responders and nonresponders

Suppression of serum LH and FSH, by testosterone (T) alone or in combination with other agents, has proved to be the most promising approach to male contraception. T enanthate, the only androgen preparation tested in male contraceptive efficacy trials so far, must be injected every week due to its short terminal elimination half-life of 4.5 days and leads to supraphysiological T serum levels. A new T ester synthesized under WHO and NIH auspices, testosterone buciclate (TB), showed a favorable pharmacokinetic profile, with a terminal half-life of 29.5 days when tested in hypogonadal men. Here we describe the results of the first clinical trial with TB for male contraception. After two control examinations, normal healthy male volunteers were given a single im injection of 600 mg TB (group I; n = 4) and 1200 mg TB (group II; n = 8) on day 0. Follow-up examinations were performed every 2 weeks up to week 32. In both groups mean serum T levels remained in the normal physiological range throughout the study course. Serum levels of dihydrotestosterone (DHT) showed a dose- and time-dependent increase, with serum levels slightly above the normal range in group II for several weeks and a maximal concentration of 3.8 +/- 0.5 nmol/L (mean +/- SE) in week 6. No suppression of spermatogenesis to oligozoospermia was observed in group I. However, in group II, spermatogenesis was suppressed to azoospermia in three of eight volunteers in week 10 that persisted up to weeks 14, 20, and 22, respectively. In these three men, LH and FSH were suppressed by TB injections to the respective assay detection limits, whereas in the other five subjects, mean serum levels were only decreased to values near the lower normal limit for LH and FSH, respectively. In addition, throughout the study course, a significant difference in serum sex hormone-binding globulin was detected between the responders (mean values, 21.2-26.4 nmol/L) and nonresponders (mean values, 36.2-46.3 nmol/L). Serum levels of LH as well as total and free T at baseline and after TB injection were lower in the responders than in the nonresponders. Both subgroups showed similar increases in serum LH and FSH after GnRH stimulation. In a newly introduced GnRH antagonist suppression test, serum LH and T were decreased to significantly lower levels in the responders. These results indicate a different hormonal equilibrium and probably different susceptibility to feedback regulation of the responders compared to the nonresponders.(ABSTRACT TRUNCATED AT 400 WORDS)

Prospects for new hormonal male contraceptives

Overpopulation is a paramount global crisis, as it underlies virtually all major worldwide problems, including poverty, malnutrition, and warfare. It is imperative that proliferation be curbed by expediting reductions in fertility. This article discusses the demand for and acceptability of male contraceptives and the process of spermatogenesis. Endocrine control of spermatogenesis, and potential sites for disruption of male fertility, including steroid combinations and GnRH agonists and antagonists are reviewed also. Risks and benefits of these approaches are considered.

The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men

A preliminary assessment of the contraceptive efficacy of a daily mild increase (1-2 degrees C) in testicular temperature during waking hours is reported in nine couples using two techniques of non-surgical fixation of the testes close to the inguinal canal. With technique 1, immobilization was achieved by passing the penis and the empty scrotum through a hole made in close-fitting underwear; there was one pregnancy, from a man who stopped the heating after 7 weeks, for 42 cycles of exposure in three couples. With technique 2, immobilization was achieved by adding a ring of soft material surrounding the hole in the underwear; there was no pregnancy for 117 cycles of exposure in six couples. Reversibility and safety were assessed. These preliminary results suggest that a daily mild increase in testicular temperature could be a potential contraceptive method for men.

Possible physiological bases for contraceptive techniques in the male

Aspects of the physiology of the testis and epididymis are discussed which might be relevant to future methods of contraception in the male. These include the blood-testis barriers, both at the tubular and vascular level, testicular and scrotal thermoregulation and maturation of spermatozoa in the epididymis. Possible adverse consequences of interfering with spermatogenesis are also considered, such as reduced endocrine responsiveness of the testis, increased incidence of genetic abnormalities and abnormal development of embryos produced by sub-fertile males.

Male contraception: hormonal, mechanical and other

Methods of male contraception that have been developed so far have mainly focused on the inhibition of spermatogenesis through suppression of the hypothalamo-pituitary secretion of gonadotrophins, and simultaneous supplementation with androgens. These methods include the use of combinations of progestogens or luteinizing hormone-releasing hormone antagonists and testosterone derivatives, or high dose testosterone. Though effective contraception can be obtained, side-effects and/or the high cost of treatment limit the widespread use of these approaches. Inhibition of sperm maturation in the epididymis, or direct interference with spermatogenic cells or the cells of Sertoli by e.g. gossypol have been abandoned because of toxic side-effects. Voluntary sterilization by vasectomy is the most commonly used method of male contraception, but its surgical nature, problematic reversibility and suspected link with subsequent prostate cancer render the method far from ideal. Non-surgical vas occlusion may overcome some of these problems, but data on long-term side-effects and reversibility are lacking. New contraceptive developments should focus on interfering with highly specific aspects of spermatogenesis such as unique enzymatic processes and intercellular communication through cytokines, or application of antibodies against antigens of the epididymis or the spermatozoa. Only through better understanding of normal and pathological spermatogenesis will it be possible to develop an acceptable male contraceptive.

The value and use of different contraceptive methods

Reductions in the rates of maternal and child mortality as well as in demographic growth are directly linked to contraceptive usage. The development and availability of safer, improved contraceptives which are convenient to use could be expected to be used by a larger group of individuals and thus make an impact on reproductive health as well as on population growth rates. Such arguments have been used to support contraceptive research. This article deals with some of the developments that have occurred as a consequence of such efforts.