Does the collection of more eggs increase your chance of pregnancy from IVF?

Written by Dr Christos Venetis
05 Jul

New research indicates that egg quantity is an important determinant of IVF success

One of the success factors many women and couples focus on when undergoing IVF treatment is the number of eggs retrieved at the oocyte pick up (OPU) stage of the cycle. But does this number (high or low) affect the likelihood of pregnancy from the IVF cycle?

IVFAustralia fertility specialists, together with the University of NSW, recently investigated the hypothesis of whether a higher number of eggs (oocyte yield) lead to more Day 3, chromosomally normal (euploid) embryos?

The results of the study were presented at the 33rd Annual Meeting of the European Society of Human Reproduction and Embryology (ESHRE) this week.

The number of eggs collected and the chance of IVF success

In this study, including more than 700 IVF cycles across 3 IVF clinics, Australian fertility doctors and scientists determined that a higher number of eggs retrieved (egg yield) in an IVF treatment cycle is independently associated with more chromosomally normal embryos available for transfer. This means that more eggs can lead to more chromosomally normal embryos irrespective of the woman’s age as well as the intensity of ovarian stimulation (dose of gonadotrophins).

The presence of more chromosomally normal (euploid) embryos translates to a higher cumulative chance of a live birth after that stimulated IVF cycle. This is because chromosomally normal embryos are known to have the greatest potential for a pregnancy that will lead to a live birth and represent a clear predictive factor for IVF success.

The effect of the woman’s age

Another interesting finding of this study was that the benefit of egg yield decreased significantly with advancing female age. The study indicated that to produce 1 and 2 euploid embryos, 5 and 14 oocytes would be required at age 34. However 10 and 24 oocytes would be required at age 38. Hence, the older a woman is the more eggs have to be retrieved in order to increase the chance of obtaining an additional chromosomally normal (euploid) embryo.

Will multiple embryo transfers increase the cumulative chance of pregnancy?

The cumulative pregnancy rate refers to the chance of a pregnancy after a single stimulated IVF cycle including both fresh and frozen embryo transfers resulting from that cycle. This research helps to explain why cumulative pregnancy rates after IVF seem to improve in cycles with a higher egg yield. The more chromosomally normal embryos there are, the more transfers are possible, with an inevitably better cumulative chance of pregnancy and live birth. Chromosomally abnormal (aneuploid) embryos are unlikely to develop as pregnancies, and, if they do, sadly frequently result in miscarriage.

A number of studies (1, 2) published recently suggest that cumulative live IVF birth rates increase significantly with the number of eggs retrieved. This association is not evident in the initial fresh cycle of treatment, where birth rates might be even inferior when a high number of oocytes is obtained (1, 3). This is most likely due to an adverse effect of intense ovarian stimulation on the receptivity of the endometrium as has been convincingly demonstrated (4, 5). However, a positive association of a higher number of eggs with IVF outcome is evident when we consider the cumulative IVF birth rate from one stimulated IVF cycle.

The egg quality vs. egg quantity debate

This study also provides evidence that aiming for a higher egg yield during ovarian stimulation does not seem to compromise the quality of the eggs obtained. This has been debated for years but recently accumulated evidence suggests that a detrimental effect of intense ovarian stimulation on egg quality is unlikely. On the contrary, obtaining a higher number of eggs will probably lead to a higher number of competent eggs and, as the present study has shown, to more chromosomally normal (euploid) embryos.

Is there an optimum number of eggs collected?

While this study does provide strong evidence in the ongoing debate over the importance of egg numbers as determinants of IVF success, any attempt to propose an optimum number of egg collected needs to take into account many other parameters such as:

  • Individual patient characteristics (such as age and ovarian reserve)
  • The indication for treatment
  • Whether one is interested in the pregnancy rate after just the fresh embryo transfer or the cumulative pregnancy rate after both fresh and frozen embryo transfers
  • The number of embryos transferred (single vs. multiple embryos transferred)
  • The protocols followed in the laboratory, and
  • Most importantly, the patient’s wishes.

It should not be overlooked that aiming for a high number of eggs (usually more than 15) can increase the risk of ovarian hyperstimulation syndrome (OHSS), a potentially serious complication of ovarian stimulation. However, newer IVF protocols can substantially reduce this risk, allowing fertility specialists to maximize the results from a single IVF cycle and thereby reduce the financial, physical and emotional cost of fertility treatment. Increasing the oocyte yield should always be performed safely which means an individualised approach should be discussed with your fertility specialist.

Patients wishing to know more about this study, including how to increase their chance of pregnancy from IVF treatment, should speak with their local fertility specialist:

Fertility specialists in QLD, fertility specialists in NSW, fertility specialists in VIC, fertility specialists in TAS, fertility specialists in Singapore


1. Ji J, Liu Y, Tong XH, Luo L, Ma J, Chen Z. The optimum number of oocytes in IVF treatment: an analysis of 2455 cycles in China. Hum Reprod. 2013;28(10):2728-34.
2. Drakopoulos P, Blockeel C, Stoop D, Camus M, de Vos M, Tournaye H, et al. Conventional ovarian stimulation and single embryo transfer for IVF/ICSI. How many oocytes do we need to maximize cumulative live birth rates after utilization of all fresh and frozen embryos? Hum Reprod. 2016;31(2):370-6.
3. Sunkara SK, Rittenberg V, Raine-Fenning N, Bhattacharya S, Zamora J, Coomarasamy A. Association between the number of eggs and live birth in IVF treatment: an analysis of 400 135 treatment cycles. Hum Reprod. 2011;26(7):1768-74.
4. Venetis CA, Kolibianakis EM, Bosdou JK, Lainas GT, Sfontouris IA, Tarlatzis BC, et al. Estimating the net effect of progesterone elevation on the day of hCG on live birth rates after IVF: a cohort analysis of 3296 IVF cycles. Hum Reprod. 2015;30(3):684-91.
5. Venetis CA, Kolibianakis EM, Bosdou JK, Tarlatzis BC. Progesterone elevation and probability of pregnancy after IVF: a systematic review and meta-analysis of over 60 000 cycles. Hum Reprod Update. 2013;19(5):433-57.

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Related Articles

Conceiving in your 40s, what are the chances?

I was recently asked to comment in a Sun Herald article on 26th August (also published online here: Sydney Morning Herald) on Collette Dinnigan, who pregnant at the age of 46, has called on women not to leave it too long to try for a baby.

It is always news when a high profile personality such as Ms Dinnigan, has a child, particularly when the personality in question is a bit older.  The difficulty is that these occasions, while very happy for the people involved, give a misleading picture of the actual likelihood of conception in these circumstances.  Remember that high profile personalities such as Ms Dinnigan, are human beings who quite rightly value their privacy and so very rarely (quite understandably) talk to the press when things aren’t going so well.  It was therefore, a particularly courageous action of Ms Dinnigan, while celebrating her own happiness, to so publicly, point out the difficulties that may face other women, seeking the same fulfilment.

What then, are the issues for women in their forties who are planning to have a child?

The main difficulty is that conceiving is simply harder at that age and, even once a woman does conceive, the risk of miscarriage is higher.  Surprisingly, although we have very good data about the effects of age on IVF conception (more shortly), we don’t have very good statistics about the effects of age on conceiving naturally. The limited available data about natural conception comes from old population studies or studies of unique populations, such as the Hutterites of North America, who do not use contraception.  Interestingly these data, such as they are, seem to be entirely consistent with the more modern and abundant IVF data.  Generally, in one year of trying, 75% of women under 30 years and 66% of 35-year-old women but only 44% of 40-year-old women will achieve a live baby naturally.

The main explanation for this, is that women are born with a finite number of eggs, and from that moment onwards, the number of eggs is declining all the time, until women go through their menopause at around 50-51.  Nonetheless, women in their 40s do still ovulate each month.  What is it about their eggs that cause all these problems?

A common misunderstanding with some women is that the fact she looks and feels young, and leads a healthy lifestyle, means that her eggs will be healthier. I regularly see women who have taken enormous care with their fitness and their health.  The rest of their body is in great shape, completely fit and ready to carry that longed-for pregnancy.  Sadly, despite this, the eggs still can’t do it.  The effects of time are remorseless and, sadly, there is no wonder drug to fix it.

Scientists have shown that eggs from older women are more likely to have an abnormal makeup making pregnancy less likely, miscarriage more common and increasing the risk of Down Syndrome, a condition where a child is born with an extra chromosome number 21.

Nor is IVF a cure for this problem. For women, in their early 40s, IVF is still a good thing to try and gives significantly higher success rates than trying naturally.    However, IVF success rates fall sharply after the age of 40 and by the time a woman is 45 are close to zero.

So, what’s the good news?  Well despite all of the above, many women do conceive in their forties, either by IVF, or naturally, and have very happy healthy families.  It is obviously better to have your family earlier, if you can, but all hope is not lost, just because you’re past 40.  Conception and early miscarriage are the big problems but, if you do conceive and get past the first few weeks, by far the most likely outcome will be a healthy child.  While the risk of Down Syndrome is increased, most of the other problems that affect young children are not increased by being conceived a later maternal age.

Finally, many women worry that by having their children later, their long term health and emotional development may be affected.  On the contrary, we now know that the children of older mums grow up to be as healthy and bright as any other child.

Snapshot of Fertility in Australia

There have been a number of happy and high profile stories in the press recently about older celebrities giving birth to healthy children. Stories like this used to be extraordinary, but they certainly seem to be on the increase. While this trend is supported by data that shows the fertility rate and numbers of births are increasing for women over 30 and especially for women in their early 40s, women and couples should understand the risks associated with having children later in life.  IVF Australia, Melbourne IVF and Queensland Fertility Group, have teamed up to create their latest infographic - “Fertility and Age in Australia” which explores some of these issues.
 Fertility in Australia infographic

Paternity, Maternity, Equality

Conceiving a baby in a same sex relationship

IVFAustralia, and its partner clinics Melbourne IVF, Queensland Fertility Group and TasIVF, are proud supporters of ‘rainbow families’. IVFAustralia were an Official Supporter of Sydney’s Gay and Lesbian Mardi Gras this year, and we’ve seen the number of same sex couples accessing our donor program double in the last year.
 
In 2011, a survey of 3,835 LGBT people found 33% of women and 11% of men had children1 - but close to 40% reported wanting to have children or have more children. This so-called ‘gayby’ boom is thanks to changes in community attitudes and laws, including better access to Assisted Reproductive Treatments for lesbian and single women.
 
So, if you’re hoping to experience the joy of starting a family within a gay or lesbian relationship, what do you need to consider?

How long will it take to conceive?

Generally speaking, we’d expect a healthy woman with no fertility issues to fall pregnant through IVF or Artificial Insemination within six months. You can prepare for pregnancy by improving your diet, doing regular exercise and other lifestyle factors.
 
When you access the donor program there are a few extra decisions you need to make.
 
Do you choose a known donor, or an anonymous donor? In a lesbian relationship, do you want to implant an embryo with eggs from one mother into the other? Should you store some sperm from the same donor for later, in case you’d like a related sibling? For two dads, the process of finding a surrogate can also be complex.

How do we choose a donor?

Our fertility clinics offer access to both Australian and US* donor sperm. The access fee for US donor sperm is higher, but the waiting list is also shorter as there is a shortage of local donors (gay men, we’d love to hear from you!)
 
When you’re using donor sperm or eggs, there are a few legal, emotional and ethical factors to consider and a counsellor will help you work through these concerns so you can make the best decisions for your family’s future.

Are there any legal issues?

Each state has different laws about parental recognition and access, so it’s worth seeking specialist advice before you start.
 
For example, in Victoria, the Victorian Assisted Reproductive Treatment Act (2008) removed discrimination against lesbian and single women with regard to fertility treatment, recognised parenting status for non-birth mothers and also effectively legalised ‘altruistic’ surrogacy. It also recognises lesbian couples as equal parents of their child or children as long as they were in a de facto relationship.

What else should we be prepared for?

30 years of research2 has shown that the children of same-sex parented families do just as well as the children of heterosexual parents socially, educationally, physically and emotionally.

The issues your children will face as they get older are just the same as the issues facing any children conceived using donor sperm or eggs: Where did I come from? Should I contact my donor? You need to be prepared for these questions at some point.
 
In the meantime, we hope we can help you fulfil your dream of having a baby, and that you will experience the joys of pregnancy, birth and parenthood.

What should be my next steps?

If you would like to learn more about the fertility treatments available for same-sex couples in your regions, visit one of our websites. 


 * IVFAustralia and Queensland Fertility Group patients only.

1 Leonard et al. (2012) Private Lives 2: The Second National Survey of the Health and Wellbeing of GLBT Australians, The Australian Research Centre in Sex, Health and Society, Melbourne
2Rainbow Families Council of Victoria (2010) Rainbow Families and the Law, RFC, Melbourne, http://www.rainbowfamilies.org 

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