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Re: mehrere eisprünge pro monat möglich
[ www.FamPlan.de Forum: natuerlich Verhueten , z.b. natürliche Familienplanung (symptothermal) ]
Geschrieben von N. am 19. Juli 2003 01:20:37:
Als Antwort auf: mehrere eisprünge pro monat möglich geschrieben von franziska am 18. Juli 2003 22:37:34:
>gerade ist an der university of saskatchewan/kanada eine studie veröffentlicht worden, die besagt, dass frauen auch mehrere eisprünge pro monat haben können, und dies offenbar gar nicht so selten ist. da wäre naütlich die frage, ob nfp angesichts dieser entdeckungen wirklich soo sicher ist, und nicht nur deshalb funktioniert, weil schwangerschaften ja gar nicht so leicht zustandekommen, bzw. in den ersten zwei wochen doch relativ oft spontan abbrechen. bin ja froh, dass ich schon lange das lea verwende...wie oft hab ich früher schon mal fünfe grade sein lassen, und gedacht: och, ist ja der 23.tag wird schon nix passieren...
>hier jedenfalls zwei pressemitteilungen zur studie:
>Women's Health
>
>No rhythm - women can ovulate more than once a month
>
>advertisement
>Los Angeles Times
>Jul. 16, 2003 09:45 PM
>Women ovulate once a month. Couples' lives, their choice of contraception and even their efforts to combat infertility have been based upon this well- established biological notion. But some researchers say it may not be as ironclad as we've thought.
>Canadian scientists have found that a few women ovulate twice a month; others have the biological potential to do so.
>The discovery might explain why some women who rely on natural family planning methods and others who conscientiously take oral contraceptives still become pregnant, said lead study author Roger Pierson, director of reproductive biology research at the University of Saskatchewan. There may be no "safe" time during their menstrual cycles, he said.
>Reproductive specialists have long theorized that a group of egg sacs, called follicles, begin growing inside the ovary at the beginning of each menstrual cycle. According to that theory, one follicle fully matures, bursts open and releases an egg around the 14th day of a 28-day cycle.
>But the researchers, who tracked activity inside the ovaries with daily ultrasound testing, found that two or three times a month groups of follicles enlarge and one follicle sometimes matures until it is on the verge of releasing an egg. Most of the 63 women studied released an egg just once a month but, in six cases, eggs were released twice. The waves of follicle development occur in healthy women who have a single menstrual period each month, the scientists said.
>The finding suggests that given sufficient hormonal stimulation, or if a woman takes medications known to disrupt the hormones that govern ovulation, mature eggs might be released at more than one point in a woman's cycle, Pierson said. It also might alter the way infertility specialists go about stimulating a woman's ovaries to produce extra eggs for in vitro fertilization, he added.
>But several leading infertility specialists said the discovery might not make much difference.
>"Hormonal stimulations have been tried at various times of the menstrual cycle through trial and error," said Dr. Thomas Toth, director of the in vitro fertilization program at Massachusetts General Hospital in Boston. The greatest successes have come with stimulating the ovaries in the first half of the menstrual cycle. "When stimulation has been applied at other times, it hasn't been as successful."
>Dr. Robert Brzyski, president of the Society for Assisted Reproductive Technology, said that the success of fertility treatments comes down to more than just the timing of the egg's release. Other parts of a woman's reproductive system must also be at the right stage for a fertilized egg to implant in the uterus.
>"You have another entity in the process of getting somebody pregnant, which is the endometrium," said Brzyski, an associate professor of obstetrics and gynecology at the University of Texas Health Sciences Center in San Antonio. For that uterine lining to be ready to nourish a fertilized egg, a woman needs "so many days of estrogen exposure and so many days of progesterone exposure on top of that," he said.
>The study appears in the July issue of Fertility and Sterility.
>
>
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>die Orignial PM der UNI:
>
>Organization: University of Saskatchewan Communications
>Email: communications@usask.ca
>Released: July 8, 2003
>THE FOLLOWING NEWS RELEASE WAS ISSUED BY THE CANADIAN INSTITUTES OF HEALTH
>RESEARCH.
>
>NEW CANADIAN MENSTRUAL CYCLE RESEARCH MAY ALTER MEDICAL TEXTS
>OTTAWA (July 7, 2003) - A Canadian research team funded by the Canadian
>Institutes of Health Research (CIHR) has uncovered evidence that suggests
>the traditionally accepted model of the human menstrual cycle is wrong.
>The discovery by University of Saskatchewan researchers may lead to the
>design of new, safer and more effective contraception and may improve
>success with assisted reproductive technology for women who are having
>trouble conceiving.
>"This collaborative discovery is an important step forward in understanding
>the human menstrual cycle," said Dr. Michael Kramer, Scientific Director of
>the Institute of Human Development and Child and Youth Health of the
>Canadian Institutes of Health Research. "It provides a new model for ovarian
>function during the menstrual cycle which could have profound implications
>for infertility diagnoses and treatment in women."
>The team's findings were published in the July 6th issue of the prestigious
>scientific journal Fertility and Sterility. A companion paper published in
>Biology of Reproduction is available on-line.
>Previous research has shown that a group of 15 to 20 follicles grew during
>the menstrual cycle, and that one follicle from the group was selected to
>ovulate while the others died off.
>University of Saskatchewan researchers have found that this process occurs
>in "waves". In response to hormone surges, women experience two to three
>periods of follicular development each month, though only one egg is
>selected for ovulation.
>"This work is particularly exciting to us because of the impact it will have
>on women taking oral contraceptives and undergoing fertility treatment,"
>says Dr. Roger Pierson, Director of the Reproductive Biology Research Unit
>at the U of S. "It also shows that we have not fully understood the basic
>biological processes that occur during menstrual cycles. We are literally
>going to have to re-write medical textbooks."
>For instance, up to 40 per cent of women may not be able to use natural
>family planning methods, he said. That's because for women who experience
>two or three waves of dominant follicle growth per month there is no "safe"
>time to have intercourse during the cycle -- there may always be a follicle
>capable of ovulating.
>The study involved 63 women with normal menstrual cycles who underwent
>ultrasound every day for a month. "This study is a real tribute to the
>altruism of Saskatchewan women," Dr. Pierson said. "As I've gone around the
>country talking about this work, people just can't believe the dedication of
>our research volunteers."
>Dr. Pierson says further research is needed to see if the same number of
>waves occurs consistently every month and to determine why a particular egg
>is selected to ovulate.
>Other team members are Angela Baerwald, the lead author on the article who
>just received her Ph.D. in clinical reproductive biology from the U of S,
>and veterinarian Dr. Gregg Adams, a professor with the Western College of
>Veterinary Medicine at the University of Saskatchewan.
>The study was done through an unusual collaboration. In clinical studies,
>Dr. Pierson noticed follicular development occurring at a time when the
>textbooks said it shouldn't happen. He consulted Dr. Adams, who developed
>the follicular wave model in cows with Dr. Pierson at the University of
>Wisconsin in the 1980s.
>"What Roger was seeing in women seemed very similar to what is happening in
>horses and cows that develop follicles in waves," said Dr. Adams. "And
>that's exactly what we found -- that humans are not so very different from
>other species."Soweit ich den Artikel verstehe, geht es nicht darum, dass entdeckt wurde, dass Frauen mehrere Eisprünge haben können (was nur innerhalb einer bestimmten Zeit von ca. 24 Stunden sein kann - Zwillinge!), sondern dass Follikel wellenartig produziert werden. Letzendlich reift nur ein Ei heran, welches dann befruchtungsfähig ist (Zitat obiger Artikel: "Dr. Pierson says further research is needed to see if the same number of waves occurs consistently every month and to determine why a particular egg is selected to ovulate.").
Ist das in der Tat eine neue Entdeckung?
Außerdem ist kritisch zu bedenken, dass es sich bei der Untersuchung um eine Stichprobe von nur 63 Frauen handelte!
Was die Sicherheit von NFP anbelangt, verweise ich auf die vielen unterschiedlichen internationalen Studien und deren Erkenntnisse. Offensichtlich hat sich die Methode bewährt (gewissenhafte Anwendung vorausgesetzt!).
Gibt es zur Sicherheit von LEA bereits empirische Studien? Der Pearl-Index von 2,5-3,7 dieser Methode entspricht den Herstellerangaben, meines Wissens...
N.
[ www.FamPlan.de Forum: natuerlich Verhueten , z.b. natürliche Familienplanung (symptothermal) ]
Lifestyles long love : Kondome mit extra schlanker Taille, für sichereren Sitz ... mehr Infos bei http://www.famplan.de/kondome ]
