Monash discovery may help unlock the key to infertility in older women

May 18, 2017
Securin is important for both egg divisions but in old eggs, it appears that there is insufficient securin remaining to ensure meiosis II takes place normally. Credit: Monash Biomedicine Discovery Institute

Findings from new research led by the Monash Biomedicine Discovery Institute (BDI) and University College London may finally resolve, and potentially provide answers, as to why older women have higher incidences of miscarriage and have babies with chromosomal abnormalities.

Female fertility declines rapidly after the age of 37—with women over 42 having only a five per cent chance of having a baby without fertility treatment. The problem is that as a woman ages, her also age—increasing the chances of chromosomal abnormalities. This leads to an increase in conditions such as Down's syndrome, where the egg has three copies of chromosome 21. However most chromosomal abnormalities in eggs lead to embryos that either fail to implant in the womb, or miscarry soon after implantation. In women over 40 most miscarriages are caused by the wrong number of chromosomes being present in the egg.

In a paper published today in Nature Communications, Professor John Carroll from the Monash BDI, together with an international team of collaborators, reveal a fault in how the egg controls the levels of a protein called securin. In the final stages of just before ovulation, it undergoes two specialised cell divisions known as meiosis I and meiosis II. Securin is important for both divisions but in old eggs, it appears that there is insufficient securin remaining to ensure meiosis II takes place normally.

Most chromosome abnormalities occur in the first egg division (meiosis I) but it is known that a substantial number of abnormalities also occur during meiosis II. Dr Ibtissem Nabti and Professor Carroll's experiments help explain why things go wrong in this second division. In these older women the chromosomes in their eggs start to fall apart because there is insufficient securin to control the process. Dr Nabti, formerly from University College London, is currently at the Abu Dhabi campus of New York University.

The discovery opens the way to improving an older woman's chances of having eggs with fewer chromosomal abnormalities through regulating the processes that control securin levels in the two divisions of the egg or controlling the protein that securin regulates (a protein called separase).

According to Professor Carroll, new therapeutic approaches to improving egg quality in older women is very important at a time when the age at which are having their first baby is increasing.

"It is immensely challenging because any treatments need to be safe for the egg and subseqents embryo and would usually need to be applied while the egg is in the ovary," Professor Carroll said.

"It may one day be possible to perform treatments in-vitro (in the laboratory) but human in-vitro egg maturation is not yet very successful."

The research team is working with Monash IVF to improve in vitro maturation and identify new targets that may be able to better control prevent the degradation of Securin, according to Professor Carroll.

"Now that we have an idea of at least one of the causes of the increased incidence of and miscarriages in , we can attempt to find ways to prevent this happening," Professor Carroll said.

Explore further: A more detailed understanding of cell divisions giving rise to sperm and egg cells could lead to infertility treatments

More information: Nature Communications (2017). DOI: 10.1038/ncomms15346

Related Stories

A more detailed understanding of cell divisions giving rise to sperm and egg cells could lead to infertility treatments

May 17, 2017
Researchers have shown that a recently identified protein, called Speedy A, plays an essential role in the early stages of meiosis—a special type of cell division that produces sperm and egg cells.

Ladies, this is why fertility declines with age

April 3, 2017
Researchers at the University of Montreal Hospital Research Center (CRCHUM) have discovered a possible new explanation for female infertility. Thanks to cutting-edge microscopy techniques, they observed for the first time ...

Women's wellness: pregnant later in life

January 10, 2017
Are you considering pregnancy after 35? Understand the issues for older mothers - and know what it takes to have a healthy pregnancy.

Could ovarian stimulation cause an increase in oocyte chromosome abnormalities?

July 4, 2011
Ovarian stimulation undertaken by women of advanced maternal age (over 35 years) receiving fertility treatment may be disrupting the normal pattern of meiosis – a critical process of chromosome duplication followed by ...

Recommended for you

Hormone discovery marks breakthough in understanding fertility

December 12, 2017
Scientists at The University of Nottingham have shown, for the first time, that a naturally occurring hormone plays a vital part in regulating a woman's fertility, a discovery that could lead to better diagnosis and treatment ...

Study reveals Viagra to be 'ineffective' for fetal growth restriction

December 8, 2017
A University of Liverpool led international clinical trial has found an anti-impotence drug to be ineffective at improving outcomes for pregnancies complicated by fetal growth restriction.

Obese first-time mums more likely to have premature babies

December 4, 2017
Obese women are up to three times more likely to have a premature child during their first pregnancy, according to a study from University College Dublin.

Stillbirth is not just stillbirth—more information is needed

December 4, 2017
Forty two babies are stillborn in Australia every week, and 60 per cent of them are recorded as "unexplained".

First baby from a uterus transplant in the US born in Dallas

December 2, 2017
The first birth as a result of a womb transplant in the United States has occurred in Texas, a milestone for the U.S. but one achieved several years ago in Sweden.

Living in a 'war zone' linked to delivery of low birthweight babies

November 28, 2017
Mums-to-be living in war zones/areas of armed conflict are at heightened risk of giving birth to low birthweight babies, finds a review of the available evidence published in the online journal BMJ Global Health.

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

michael_frishberg
not rated yet May 18, 2017
"Now that we have an idea...we can attempt to find ways to prevent this happening," Professor Carroll said.
Does anyone ask why 'treating' this is a good idea?
Why should women be able to have children into their 50's if their body isn't fertile anymore?
MarsBars
not rated yet May 19, 2017
Why should women be able to ...

Are you a woman, Michael? No?
Then please take a back seat.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.