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.
A discovery about how cells die could lead to ways to protect fertility in women having cancer treatment, researchers suggest.
Australian scientists found two specific proteins caused the death of early egg cells in the ovaries.
Blocking them meant cells survived the effects of radiotherapy, according to the study published in the journal Molecular Cell.
The researchers from the Walter and Eliza Hall Institute, Monash University and Prince Henry’s Institute of Medical Research looked at egg cells called primordial follicle oocytes, which provide each woman’s lifetime supply of eggs.
A discovery about how cells die could lead to ways to protect fertility in women having cancer treatment
They found that, when the DNA of cells is damaged through chemotherapy or radiotherapy, two proteins called Puma and Noxa cause the eggs to die.
This causes many female cancer patients to become infertile.
Low numbers of egg cells can also lead to a woman going through an early menopause.
When these cells were manipulated so they did not have the Puma protein, they did not die after being exposed to radiation therapy.
Prof. Jeff Kerr, from Monash University, who worked on the study said: “This might ordinarily be cause for concern because you want damaged egg cells to die so as not to produce abnormal offspring.”
But he added: “To our great surprise we found that not only did the cells survive being irradiated, they were able to repair the DNA damage they had sustained and could be ovulated and fertilized, producing healthy offspring.
“When the cells were also missing the Noxa protein, there was even better protection against radiation.”
Prof. Clare Scott, from the Walter and Eliza Hall Institute of Medical Research, who also worked on the lab and animal research, added: “It means that in the future, medications that block the function of Puma could be used to stop the death of egg cells in patients undergoing chemotherapy or radiotherapy.
“Our results suggest that this could maintain the fertility of these patients.”
The researchers said that the discovery could also mean it would be possible to slow the loss of egg cells from the ovaries, thereby delaying early menopause.
U.S. doctors have discovered that women who go through a premature menopause are more likely to suffer a potentially fatal brain haemorrhage or a cerebral aneurysm.
This occurs when part of the artery weakens and swells.
The artery can then burst and cause a stroke or death, with half of those suffering a cerebral aneurysm likely to die.
The new U.S. research is part of a growing body of evidence pointing to the staggering toll on a woman’s overall health associated with early menopause — a concern because more women are being diagnosed with the disorder.
Most scientists define a premature menopause, or premature ovarian failure (POF), as occurring when a woman’s ovaries stop working before the age of 40, though some studies include women up to the age of 45.
As well as cerebral aneurysm, they are also at greater risk of heart disease – they are 50% more likely to die and 80% more likely to suffer from heart disease than women who go through the menopause between the ages of 52 to 55.
A study last year by Imperial College London found that women who had early menopause were also twice as likely to have a poor quality of life in health terms.
U.S. doctors have discovered that women who go through a premature menopause are more likely to suffer a potentially fatal brain haemorrhage or a cerebral aneurysm
Another study, by the Mayo Clinic in the U.S., found that affected women had a greater risk of dying early, developing heart disease, neurological disorders, including Parkinson’s and Alzheimer’s, psychiatric disorders and osteoporosis.
Women were particularly likely to die early or develop heart disease if they’d not been taking HRT following their early menopause, said the researchers.
“These recent studies are telling us what we have suspected for some time, but until now no one has done the work to quantify it,” says Dr. Kevin Harrington, a consultant gynaecologist at the Bupa Cromwell Hospital in London.
The trigger for all this is dramatically falling levels of the hormone oestrogen.
“Oestrogen plays a very important role in maintaining the health of all the connective tissues in the body,” Dr. Kevin Harrington says.
“This includes blood vessels, skin, ligaments and bones.”
The deteriorating quality of the blood vessels in the brain is responsible for conditions such as strokes. Low oestrogen affects connective tissues in the eyes and mouth, too, which is why these patients are more prone to gum disease, tooth loss and cataracts.
The thyroid gland can also be affected, says Dr. Kevin Harrington.
This is possibly because auto-immune diseases are thought to be a major cause of premature menopause.
“It may be the kind of person whose body produces antibodies that attack the ovaries is also prone to producing antibodies that attack the thyroid.”
Lifestyle may be to blame. The Imperial College study found a link with smoking.
Further research last year also suggested a link between premature menopause and PFCs – chemicals found in non-stick pans and food packaging. The women with the highest levels of PFCs in their body had the lowest levels of oestrogen in their blood.
Genetics may play a part, too, with women more likely to go through early menopause if their mother did. However, doctors say more research is needed.
Furthermore, the success in treating cancer in children, adolescents and women of child-bearing age might lie behind some cases of POF – for instance, premature menopause can be a side-effect of chemotherapy and radiotherapy.
Clearly early diagnosis is key, yet despite improved recognition of POF, campaigners say much more could be done.
A recent British Menopause Society report noted some doctors were still unaware of the need to protect prematurely menopausal women against future illness and called for the creation of a national register of all such patients to ensure they receive correct advice and care.
Campaigners are also calling for HRT to be made free of prescription charge for women who’ve suffered a premature menopause.
