Reproductive health: an international perspective.

The twentieth century began with approximately 1.6 billion human beings in the world and, with an increase of 96 million people per year, will end with over 6 billion people. Unless this trend is directly confronted by the world governments and their citizens, there will be nearly 8 billion by 2025 and over 11 billion by 2050. Thus, reproductive health is and will remain an issue of critical importance for all countries to realize and study. Part of this trend is because of the many pregnancies which occur in adolescents around the world. A number of issues have developed this century contributing to the many pregnant teenagers. For example, India has one of the world's largest populations of teenagers--over 23 million, representing over 26% of the total in the world. Effective methods for contraception and sexually transmitted diseases prevention are available, but not to all sexually active humans. However, many barriers to effective contraception exist around the globe. This article discusses some of them and also reviews use of contraceptive methods in various countries. These include oral contraceptives, emergency contraceptives, injectable and implantable contraceptives, intrauterine devices, barrier contraceptives and others. Reproductive health remains a critical, universal issue for all humans in the world. We all must examine the many pitfalls to controlling the world's populations, including lack of sex education, limited access to effective contraceptives, and others. We cannot afford to let the population continue unchecked. Effective strategies are needed at this time; otherwise, the population will continue to run out of control, negatively damaging the world for the coming generations. There is need to leave a positive, and not negative legacy for the next generation.

Bi-directional actions of estrogen on the renin-angiotensin system

Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE activity, was significantly reduced by estrogen treatment, further supporting the biochemical significance of estrogen's inhibition of ACE. In ovariectomized transgenic hypertensive (mRen2)27 rats submitted to estrogen replacement treatment for 3 weeks, ACE activity in plasma and tissue (aorta and kidney) and circulating Ang II levels were reduced, whereas circulating levels of angiotensin-(1-7) (Ang-(1-7) were increased. Ang-(1-7), the N-terminal fragment of Ang II, is a novel vasodilator and antihypertensive peptide. Thus, the net balance of these effects of estrogen on the renin-angiotensin vasoconstrictor/vasodilator system is to promote the antihypertensive effect.