Home Tags Posts tagged with "human reproduction"
human reproduction
A new study has concluded that women may be able to better gauge their own fertility based on the age their mother went through the menopause.
Women whose mothers had an early menopause had far fewer eggs in their ovaries than those whose mothers had a later menopause, a Danish team found.
Women with fewer viable eggs have fewer chances to conceive.
The study, of 527 women aged between 20 and 40, was reported in the journal Human Reproduction.
Researchers looked at two accepted methods to assess how many eggs the women had – known as their “ovarian reserve” – levels of anti-Mullerian hormone (AMH) and antral follicle count (AFC).
Women are born with all the eggs they will ever have. These are released from the ovary cyclically, usually one every month after puberty, until menopause.
The AFC and AMH give readings doctors an idea of how many yet-to-be released eggs remain in the ovary.
Women whose mothers had an early menopause had far fewer eggs in their ovaries than those whose mothers had a later menopause, a Danish team found
In the study of female healthcare workers, the researchers found both AMH and AFC declined faster in women whose mothers had an early menopause (before the age of 45) compared to women whose mothers had a late menopause (after the age of 55).
Average AMH levels declined by 8.6%, 6.8% and 4.2% a year in the groups of women with mothers who had early, normal or late menopauses, respectively.
A similar pattern was seen for AFC, with annual declines of 5.8%, 4.7% and 3.2% in the same groups, respectively.
Past research suggests there is about 20 years between a woman’s fertility starting to decline and the onset of menopause. So a woman who enters the menopause at 45 may have experienced a decline in her fertility at the age of 25.
Lead researcher Dr. Janne Bentzen said: “Our findings support the idea that the ovarian reserve is influenced by hereditary factors. However, long-term follow-up studies are required.”
Also, having fewer eggs does not necessarily mean that the woman will go on to have fewer babies.
Dr. Valentine Akande, a consultant gynaecologist and spokesman for the British Fertility Society, said the findings were helpful, but that women should not be overly concerned if their mother did have an early menopause.
“There is a huge amount of variation among women. Some will have more eggs and some will have less.
“Whilst it is assumed that lower egg number is associated with more challenges at getting pregnant this study did not look at that.
“Currently there is no test that can accurately predict fertility.
“The advice remains the same – the younger you start trying for a baby the more likely you are to be successful.”
He said, in general, women are most fertile between the ages of 18 and 31.
French academics in an IVF clinic found that time-lapse photography has shown that embryos of smoking women develop more slowly.
Experts took regular pictures of an egg from the moment it was fertilized until it was ready to be implanted into the mother.
At all stages of development, embryos from smokers were consistently a couple of hours behind, a study showed.
The lead researcher, from Nantes University Hospital, said: “You want a baby, quit smoking.”
French academics in an IVF clinic found that time-lapse photography has shown that embryos of smoking women develop more slowly
Smoking is known to reduce the chances of having a child. As eggs fertilized through IVF initially develop in the laboratory before being implanted, it gave doctors a unique opportunity to film the embryos as they divide into more and more cells.
Researchers watched 868 embryos develop – 139 from smokers.
In the clinic the embryos of non-smokers reached the five-cell stage after 49 hours. In the smokers it took 50 hours. The eight-cell stage took 62 hours in smokers’ embryos, while non-smokers’ embryos reached that point after 58 hours.
Senior embryologist and lead researcher, Dr. Thomas Freour, said: “Embryos from smoking women, they behave slower, there is a delay in their development.
“On average it is about two hours, it is significant and nobody knew that before.”
This study cannot say what impact the slower development has, or if this affected the chances of having a child.
Dr. Thomas Freour speculated that “if they go slower, maybe something is starting to go wrong and they wouldn’t implant.”
His advice was simple: “You should quit smoking, it couldn’t be easier. What else can I say? You want a baby, quit smoking.”
The findings were presented at the European Society for Human Reproduction and Embryology (ESHRE) meeting in Turkey.
Falling asleep straight after sex shows that you and your partner are truly in love, a new study has shown.
Research by evolutionary psychologists at the University of Michigan and Albright College in Pennsylvania, found the tendency to drop off to sleep first after sex is associated with greater partner desire for bonding and affection.
Daniel Kruger, a research fellow at the University of Michigan, and lead author of the study, said: “The more one’s partner was likely to fall asleep after sex, the stronger the desire for bonding.”
The study was published in the Journal of Social, Evolutionary, and Cultural Psychology.
The research team examined 456 participants, who completed anonymous online surveys assessing experiences and desires with one’s partner after sex.
Participants then indicated “who falls asleep after sex?” and “who falls asleep first when going to bed not after sex”.
Participants whose partners nodded off immediately after sex had stronger desires for post-coital cuddling and chatting.
“Falling asleep before one’s partner may be a non-conscious way to foreclose on any commitment conversation after sex,” says co-author Susan Hughes, associate professor of psychology at Albright College in Reading, Pennsylvania.
The study also looked at who were more likely – men or women – to fall asleep first.
Despite the common stereotype, the researchers did not find it more common for men to fall asleep first after sex. Women, however, were more likely to fall asleep first when sex hadn’t taken place.
“Perhaps men stay awake longer as an artifact of mate guarding – making sure the woman doesn’t leave them for another partner,” says Susan Hughes.
“Men may also stay awake longer in an attempt to entice their partner into having sex.”
Research on post-coital behaviors are few, the study authors say.
“The vast majority of the research on the evolutionary psychology of human reproduction focuses on what’s before and leading up to sexual intercourse,” says Susan Hughes.
“But reproductive strategies don’t end with intercourse; they may influence specific behaviors directly following sex.”
A 30-year Scandinavian study suggests that oral contraceptives may alleviate painful periods for some women.
Estimates suggest more than half of women have suffered from the condition, called dysmenorrhoea, at some point.
The Swedish study, reported in the journal Human Reproduction, found women on the pill reported slightly less severe period pains.
Oral contraceptives are not currently officially licensed for this purpose.
A 30-year Scandinavian study suggests that oral contraceptives may alleviate painful periods for some women
The researchers, from Sahlgrenska Academy at Gothenburg University, followed groups of hundreds of 19-year-olds, recruiting some in 1981, some in 1991, and the rest in 2001.
Five years after an initial health questionnaire, the women were contacted again to see if anything had changed.
Dr. Ingela Lindh, who led the study, said: “We found there was a significant difference in the severity of dysmenorrhoea depending on whether or not the women used combined oral contraceptives.”
While it was hard to quantify precisely this difference in pain levels, on average it represented a change from “severe” to “moderate” pain in every third woman in the group taking oral contraceptives.
Dr. Ingela Lindh said that the impact of painful periods should not be underestimated.
She said: “Painful periods occur frequently, particularly in young women where as many as 50% to 75% suffer from dysmenorrhoea.
“It can have a detrimental effect on these women’s lives, causing regular absenteeism from school and work, and interfering with their daily activities for several days each month.
“Effective management of dysmenorrhoea is beneficial for both the women affected and society.”
One US survey suggested that the condition could cause 600 million lost working hours in the US each year.
However, earlier efforts to detect any link between the pill and period pain had proved fruitless, with a 2009 Cochrane Review concluding there was limited evidence for pain improvement.
At present, the European Medicines Agency, which oversees drug licensing across the EU, does not include the treatment of period pain as a licensed use for oral contraceptives.
Dr. Ingela Lindh said that the new information from her study should be included in contraceptive counseling sessions.
