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Biomedical subjects

F Alvarez-Sanchez

Publications and source records attributed to F Alvarez-Sanchez.

27 records · Page 2Linked to original sources
PubMed1981

Pituitary-ovarian function after tubal ligation.

Pituitary-ovarian function was evaluated by measurement of daily serum levels of luteinizing hormone (LH), 17 beta-estradiol, and progesterone in women with a previous history of tubal ligation. Normally menstruating women served as controls. The duration of the proliferative and luteal phase was similar for both groups. The midluteal progesterone level averages did not differ between the two groups. Preovulatory LH and 17 beta-estradiol peaks were significantly lower in the tubal ligation group; average midluteal LH and 17 beta-estradiol levels were also lower. These results reveal that pituitary-ovarian function can be altered following surgical sterilization.

Adult↗
PubMed1980

The menstrual cycle in women using an intrauterine device.

The duration and hormonal characteristics of the menstrual cycles of women using Copper T intrauterine devices (IUDs) were studied. Daily load samples were obtained during both the pre- and postovulatory phases of 30 IUD-associated cycles and the hormone values were compared with those of 15 normally menstruating women not using contraception. The ovulation rate and peak levels of 17 beta-estradiol and luteinizing hormone (LH) were not significantly different between the two groups. The average number of days from the 1st day of menstrual bleeding to the LH peak (the proliferative phase) was longer in the IUD users. The number of days from the LH peak to the onset of menstrual bleeding (the luteal phase) was shorter in the IUD users. Because of the compensating nature of these statistically significant differences, the total cycle length appeared to be unchanged. At the time of menstruation, the plasma levels of both progesterone and 17 beta-estradiol were significantly higher among IUD users. It is concluded that the presence of an IUD does not influence ovarian function, but that ovarian steroid production and endometrial events become asynchronous.

Adolescent↗
PubMed1979

Pregnancies associated with sperm concentrations below 10 million/ml in clinical studies of a potential male contraceptive method, monthly depot medroxyprogesterone acetate and testosterone esters.

A potential male contraceptive approach was evaluated in clinical trials involving monthly injections of depot medroxyprogesterone acetate and either subdermal implants of testosterone propionate or monthly injections of testosterone enanthate. Pregnancies occurred in partners of 9 men with recent sperm counts of 10 million/ml or below. In 5 of the 9 instances, the sperm counts were less than 1 million/ml. It appears that male contraceptive methods involving spermatogenic suppression may require attainment and maintenance of azoospermia. The pregnancy rate cannot be calculated, because the extent of other contraceptive use is uncertain. There were no spontaneous abortions. 6 pregnancies were carried to term, and all progeny were normal, based on physical examination at birth or 3 months after birth.

Contraceptive Agents, Male↗
PubMedDate not supplied

IUDs and PID: a comparative trial of strings versus stringless devices.

An international multicentered clinical trial was designed to determine the possible role of intrauterine device (IUD) marker strings in the etiology of pelvic inflammatory disease (PID). A total of 1265 women were admitted and randomly allocated to receive either a standard TCu200 IUD or a TCu200 IUD without marker strings. These patients were followed-up through 12 months postinsertion. No statistically significant differences were found between the two groups of IUD users with respect to the incidence of PID or other types of infection or inflammation. The 12-month life table termination rates and overall continuation rates were also similar for users of the respective devices, with the exception of removal rates for bleeding/pain, which were significantly higher in the strings group than in the stringless group. However, the number of bleeding/pain complaints ever reported during the study were not statistically different in the two study groups. The study results indicate that the IUD string does not play an important role in the etiology of PID associated with the use of IUDs.

Adult↗
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↗
PubMedDate not supplied

The clinical performance of NORPLANT implants over time: a comparison of two cohorts.

This paper reports on a study that compared the clinical performance of NORPLANT implants in two separate but similar cohorts: 200 NORPLANT users from 1975 through 1978, when the method was first introduced in the clinic, and 212 users in the same population from March 1982 through December 1983. Two different cohorts of Copper T IUD users were included as controls. Continuation rates, at one and two years of use, were significantly higher in the second group of NORPLANT users (88.1 vs. 60.5 and 76.5 vs. 40.8, respectively). Statistically significant differences between the NORPLANT cohorts were observed in discontinuation due to bleeding, amenorrhea, other medical causes, total medical causes, and personal reasons. No differences in clinical performance of the IUD were observed between the two control groups. The higher continuation rate in the second group of implant users is attributed to greater confidence and experience among the clinic staff between 1982 and 1983, and greater knowledge of and familiarity with the method among those in the target population. The study also shows that the first clinical trials of a new contraceptive method may not provide an accurate picture of that method's ultimate performance.

Adult↗