Understanding your fertility

Professor Joyce Harper
An author, academic, scientist and educator; Founder of Reproductive Health at Work & Co-founder of the UK Fertility Education Initiative, Reproductive Health at Work

Fertility Assessment

From this video you will find out:
  • How does the menstrual cycle work?
  • What is Polycystic ovary syndrome (PCOS), and what are the symptoms and treatment options?
  • What is endometriosis, and what are the symptoms and treatment options?
  • Do ovulation tracking apps really work and how accurate are they?
  • What is the mean age of women at first birth?
  • What are the menopause symptoms?

What you need to know about your fertility?

During this event, Professor Joyce Harper, Author, Scientist & Educator; Founder of Reproductive Health at Work & Co-founder of the UK Fertility Education Initiative, discussed the aspects of understanding your fertility from puberty until menopause. Professor Harper has worked in the fields of fertility, genetics and reproductive science since 1987, written over 230 scientific papers and published three books.

Professor Harper is leading The International Fertility Education Initiative, which has been educating and doing research in the field of fertility education and fertility awareness. Professor Harper published a book called ‘Your fertile years’ last year, which includes all you need to know, so you can make informed decisions about your reproductive life.

The menstrual cycle

Professor Harper started her presentation by explaining and understanding the menstrual cycle. Normally, we all learn that there’s a 28-day cycle, and you ovulate around day 14, but the truth is, it’s not strictly true. There is estrogen and progesterone, and estrogen will rise as the follicle that’s growing the egg rises, so if you’re going through IVF, you’ll have lots of follicles growing, they’ll be producing lots of oestrogens, so that’s why you’ll sometimes have your estrogen checked, and on your ultrasound, they will measure how big those follicles are getting. The progesterone is preparing the womb for implantation, and if no implantation happens, everything will go down. FSH is stimulating the follicle, and the egg to start growing and produce estrogen and progesterone. There is also luteinizing hormone (LH) in the middle to do the final maturation of the eggs, but this is how it would happen in a natural cycle. The 2 key events of the menstrual cycle are period and ovulation, which is a fertile window.

There is a called Natural Cycles which can be used as a contraceptive app or as a plan a pregnancy app. It monitors the women’s period, so when they have a period, they put it in the app, so the app can learn about their menstrual cycles, but it also measures basal body temperature. We know that basal body temperature is what we call a marker of ovulation, it slightly rises on the day you ovulate. That Natural Cycles app had millions of women’s menstrual cycles, and if you look on the Internet, you can find papers and research that was looking at over 600 000 menstrual cycles, it was found that only 13% of the cycles that were analysed were 28 days and the vast majority 65% were 25 to 30 days.

The first take-home message is that if a woman’s not having a 28-day cycle, she doesn’t need to think there’s something wrong. There have been other studies looking at different sets of big data that have shown a very similar result between day 16 and 17 that this is the day that ovulation happens, not day 14.

Polycystic ovary syndrome (PCOS)

Some treatments can be done to help people with PCOS and unfortunately, normally a woman will only realize that she’s got this when she’s trying to get pregnant. It’s really good if we can try to identify this sooner rather than later and deal with some of these symptoms.

  • 1 in 10 women
  • affects menstrual cycle/appearance
  • hormone imbalance – testosterone
  • symptoms
    • mood swings, irritability
  • treatments
    • healthy lifestyle, contraceptive pill, weight loss


This is tissue from the womb, which is found outside the womb, and during your period, these bleed and they bleed into these other areas and create a huge amount of pain and as well as these symptoms.

  • 1 in 10 women
  • 14% of infertile women have endometriosis
  • tissues from the womb found outside the womb
  • During period 
    • depression
    • physical, sexual, psychological and social wellbeing 
  • long-term – causes scar tissue
  • treatment
    • pill, Mirena coil, and/or surgery

Period tracking apps

The next thing Professor Harper talked about was some research that she’s been doing called FemTech, which is a technology for women’s health, it’s mainly digital technology, but not necessarily, there are other non-digital technologies women use for their health. She has taken an interest to take a looking at apps that monitor the menstrual cycle, and there are 2 main types of apps: period tracker apps and fertility apps.

We surveyed women who were using apps, and period tracker apps, and we wanted to know their attitudes, ovulation prediction and the accuracy of the apps in predicting their period, and what they felt about this if their period was earlier or later than the app said. If we look, the biggest response was most of the time, it got it right, only a few said always got it right, there were a few less that said it never got it right, some said rarely, and some said about 50/50. About using the app, the highest answer was to know when my period is arriving, followed by helping me understand my body, and the third answer was to know when I am ovulating.

The next key message is that if your app is only looking at your calendar, the dates of your menstrual cycle, almost all of the apps tell you the day you’re ovulating, and it is a wild guess. The problem is that after the research, the date they give you is probably going to be just 14 days from the start of your period. If you have a shorter or longer cycle, it could be away from 14 days. Even if you have a 28-day cycle, it’s going to be from day 16 to day 17. It’s good to also use the basal body temperature, and that’s what we call a marker of ovulation.


Women have about 500 menstrual cycles give or take, in their lifetime and normally ovulate 1 egg per month, so that’s about 500 eggs. It’s important to remember that it’s not just the quantity, but the quality of the egg is as important. Men produce about 100 million sperm every time they ejaculate on average, they normally ejaculate about 2 ml of sperm, and an average count is about 50 million sperm per millilitre.

When you’re trying to get pregnant or not get pregnant, the most significant time is ovulation and our fertile window, that’s the time when you’re got to be thinking about that no matter what you’re trying to do. The fertile window is 6 days in your menstrual cycle, it’s the 5 days before ovulation, and that’s because sperm can survive for about 5 days in the female genital tract, and it’s also the day of ovulation because that’s when the egg’s released and it can be fertilized. However, it’s only viable for about 24 hours. Therefore, if we want to look at ovulation, we shouldn’t be looking at dates whether you’re using an app, or a diary, it’s not accurate, there are too many factors that can affect this. As Professor Harper mentioned before, basal body temperature rises very slightly around the day of ovulation, you can check your cervical mucus, but you need to be trained on how to do this, a really easy way is to use an ovulation stick which measures luteinizing hormone, and it rises 24 to 40 hours before ovulation. When you do your late-night injection when you’re having your IVF, it’s equivalent to having that surge of luteinizing hormone, it’s involved with the final maturation of the egg, and you have to have your egg collection about 36 hours later. If you left it at 40 hours, the eggs would become ovulated, so LH hormone is a really easy way to do it.

When it comes to fertility apps, we’ve done some research, and again the recent paper we released showed that over 50% of the apps only looked at dates which are not good, and only 39% looked at dates and basal body temperature, 5% looked at dates and mucus, and 1% looked at dates and luteinizing hormone. We did another study about period tracker apps and ovulation, but our take-home message is that the ovulation day is very varied, and monitoring dates only are inaccurate. If you want to look at your fertility, you need to measure a mark of ovulation.

It’s crucial to understand that men are most fertile from puberty to death. Although, we have to remember that men’s fertility is also decreasing. Female fertility has a limited lifespan and becomes infertile about 8 to 10 years before we go through menopause. It’s due to the quantity and the quality of female eggs.

  • quantity
    • females are born with all the eggs they will have
    • it’s about 1 to 2 million potential eggs at birth
    • 400, 000 eggs at puberty 
    • from puberty – lose up to 1000 eggs each month
    • menopause – all gone

Women are losing up to about 500 to 1000 eggs every month, so they ovulate 1 but the others just die. Even if you’re on any hormonal contraception, you’re only saving 1, the majority will die.

  • quality
    • eggs have fragile chromosomes
    • increase the risk of miscarriage
    • increase risk of chromosomally abnormal child
    • decreased chance of conception

When it comes to checking your ovarian reserve, AMH (Anti-Müllerian hormone) test only looks at the quantity of the eggs, it doesn’t look at the quality, and the graph shown is from Professor’s Harper book where it clearly shows the age and the chance of getting pregnant, your fertility goes down as you get older. By 45, for the majority of women, it’s going to have gone, and the chance of miscarriage goes up mainly because of the chromosome abnormalities. A really important age in reproductive health is age 35, it’s when most women will start to be losing their fertility.

If we look at the data from the OECD, showing the mean age of a woman at first birth, this has got countries along the bottom, and then there’s the age, and you can see that when it goes to age 34, women start to have fertility problems and decrease their fertility. This graph shows that the black diamonds are from 1970, the white diamonds are from 1995, and the blue bars are from 2017, and you can see in almost every country the mean age of women at their first birth has gone up, and if we go across from age 30, you can see that over half of them the mean age of their first birth is actually over the age of 30.

One of the surveys done with one of Professor Harper’s students asked women about their attitudes and knowledge about having children. The graph shows that most women would like to have a child at around the age of 30 mainly because they’re developing their careers. The second most common reason was that they are ready to have children now, but most of them didn’t have a partner who’s ready to have children, and that’s an entirely different issue about men being ready as well.

Modern families

What we call modern families are non-traditional families, so a traditional family would be a man and a woman and then the non-traditional families are becoming much more common now. We can help single women, and same-sex female couples have children, they probably hopefully have eggs and a womb, but they need some sperm which they ideally get from a fertility clinic.

Single men and same-sex male couples are increasingly having children now. They normally have the sperm, but they need eggs and a womb, so it’s a bit more complicated, but we can certainly help them.

  • single women and same-sex female couples
    • need sperm
    • ideally from a fertility clinic
  • single men and same-sex couples
    • need an egg and a womb

Fertility for people who do not align or identify as their sex assigned at birth, so there may be non-binary or maybe transitioning they need:

  • an egg, sperm and a womb
  • it’s especially important if they’re medically transitioning (may be hormonal and/or it may be surgery)
  • AFAB (assigned female at birth)
    • may or may not wish to keep having periods
    • if they keep their womb – they may or may not wish to carry a pregnancy
  • AMAB (assigned male at birth) – can freeze sperm


  • fertile window
  • most should be pregnant within 6 months
  • infertility – no pregnancy after 1 year

The International fertility education initiative recommends for people over 35 to only leave it to 6 months, don’t wait for a 1 year, leave it to 6 months and then it’s up to you but maybe start getting some tests.

The menopause

  • no more menstrual cycle
  • no more periods
  • no more pre-menstrual syndrome
  • no more mood swings
  • no more need for contraception

We did a lot of research, and one of the studies we’ve been doing was on: before the age of 40, how informed did you feel about menopause, and unfortunately, the majority felt not informed at all. The next one was some knowledge, and women should not be reaching this stage of their life not understanding what menopause is. The age women go through the menopause means they’ve gone for 1 year without having a period and remember they’re going to lose their fertility about 8 to 10 years before that, so the average age in the UK that women are post-menopausal is age 51, but this can start in your late 30s. It’s important that at these stages, we have educated women about the symptoms and treatments available for menopause, so they go into this really with knowledge.

In conclusion, we need to ensure that everyone is educated about everything from the menstrual cycle to the menopause

- Questions and Answers

Does a painful period mean I have endometriosis or not necessarily?

Not necessarily, some checks need to be done, my message to everybody is that if you feel that the pain in your period is not acceptable, don’t suffer in silence. Please, go and see your doctor and ideally be referred to a gynaecologist as soon as you can. There are treatments for this, and leaving it long-term can cause scar tissue and can lead to higher levels of infertility. There are treatments available, and it’s best to go and see your gynaecologist as soon as you can.

Are the LH test strips accurate, or what is the surest method to tell when we ovulate?

Everyone will have their view. For me, I think the LH strips. There’ll be different makes, and I haven’t looked at all the different makes or validated them, but the LH strips should be pretty accurate, I know there are some very cheap ones you can buy I don’t know how good they are, but there are brands that have been around for decades. I think you could go for one of the really good brands, and when you know when you’re going to be ovulation each month roughly, then you need to use a few. In the first few months, you might have to use quite a lot to check when you’re ovulating, but as you get used to it, you could just use a few of them around the right time.

Does going through IVF for repeated rounds reduce the best eggs as time and rounds progress?

There’s no evidence for that. As I said, you would lose up to a thousand each month anyway in IVF, we think it’s a lot if you’ve produced 30 eggs, that’s such a small number. These are normally going to die anyway, and the quality, I wish we had the answers for the quality, but we just don’t.

I read a study that suggested chromosome abnormalities are only responsible for 5% of miscarriages, and immune issues are primarily the cause. What is your feedback on this?

I’ve not seen that 5% at all, when I give a bit longer talks, I have a table that shows the number of miscarriages that are due to chromosome abnormalities by age certainly if you’re 16, the chance is low even in a 16-year-old it’s as low as 5%, I’m not sure. I’d have to go and check the data, but once you get over 35 and over 40 and over 45, the chance of the chromosome abnormalities being responsible for your miscarriage is hugely increased, so I would have to have a look at that paper I think they were probably looking at a subgroup of people and not looking at the general population, it’s certainly very high, it’s one of the main causes of miscarriage.

Is there any way in which the quality of eggs can be tested? I’m 43 and my AMH is 10.3.

Unfortunately not. There is a method to check the chromosomes of eggs and embryos, but it’s very complicated. One issue at 43 is you might not get that many eggs, and in my view, to start doing these procedures where you start checking the chromosomes has issues.

There are differing views about the value of various vitamins to improve fertility health, e.g., Vitamin C and D. What’s your view, and how do they help?

When I was writing the book again, I read every paper, listened to every webinar I could about vitamins, and wished to find a magic pill that would help people. There’s a fantastic research group in the US that has done amazing work on this, and I read everything and spoke to them. The most important thing is to have a healthy diet, and there’s a lot of research about the Mediterranean diet, which is lots of fresh fruit and vegetables, not too much red meat, and lots of fish. Alcohol, smoking, eating fast food, and eating convenience foods, those things seem to have a negative effects. Regarding a specific vitamin, I think the significant thing is to be very careful with vitamins. I originally did biochemistry, and we were taught you should always be very careful about vitamins. Some of them can be toxic, and some of them don’t work with other vitamins, it’s not just a case I’ll just take this big pill every day, and it will make me great. You can overdose on some vitamins, so I think you have to be careful. Vitamin D is a big one, go and get a test and find out if you’re deficient, we all seem to be deficient in vitamin D. I think it’s really important to find out if you’re deficient but not just you, you and your partner. We always need to remember there are 2 that make a baby. There is so much evidence now about the health of the man, their health can have a long-term effect not just on our fertility but also on the health of the future child.  

I’ve got PTSD from undergoing IVF. Are there any useful resources for overcoming trauma from fertility treatments?

I think many of us have PTSD after IVF, whether we have a child from it or not. It’s certainly something that people have recognized, so please look around from whatever country you’re in. There should be people that have recognized this. We surveyed people that hadn’t had children and who had wanted to, we’ve done a survey on men and women and the main reason people stop fertility treatment is emotional distress. It’s very hard to go through the treatment, so please look around and try to find someone you can discuss this with and hopefully can help you and support you. I’ve had 2 sessions of counselling just for this, and how I felt about it, you’re not alone for sure.

Do donor eggs from a young donor have the same quality, or some might not be of good quality?

All egg donors should be under 35 years. The majority of eggs should be hopefully of good quality. There will be some people who don’t have good quality eggs, and we can’t tell that from, unfortunately, just looking at the egg. Some of us go through IVF at under 35 and can’t get pregnant, and it’s probably because our eggs are not as good. Those graphs are showing you sort of big numbers, but there will definitely be people in their 20s or even younger who don’t have good eggs, so just as it could happen to someone who’s not a donor, it can happen to someone who is a donor.

Does IVF/ICSI in some way bypass the ‘natural’ chromosome miscarriages, so that there are more births of babies with chromosome-related problems or diseases?

There’s no data. People have followed and looked at the births from IVF and ICSI for many years. There’s a fabulous team in Belgium who have been following these from the 90s, but there is no evidence that there are more babies with chromosome abnormalities. They understand this because there is a thought that you could maybe more of the embryos are implanted that the womb would normally reject, but there is no data, and people do look at this all the time. They look at it with frozen embryos, they looked at it with biopsied embryos, it’s really important to monitor the children that we’re creating through these treatments and to check that everything’s okay. There doesn’t seem to be any difference in any of the data.
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Professor Joyce Harper

Professor Joyce Harper

Joyce Harper, BSc, PhD is an author, academic, scientist and educator. She is a Professor of Reproductive Science at University College London in the Institute for Women’s Health, where she is Head of the Reproductive Science and Society Group. She is a Director of the Embryology and PGD Academy which delivers an online certificate in clinical embryology, founder of Global Women Connected and Reproductive Health at Work. She has worked in the fields of fertility, genetics and reproductive science since 1987, written over 230 scientific papers and published three books. She started her career as an embryologist and then moved into reproductive science and genetics. Now she is researching fertility and reproductive health education, FemTech, IVF add-ons, gamete donation and menopause. Joyce is a passionate educator at all levels, from the public to PhD students. She is invited to numerous international meetings, including key note and plenary lectures. She regularly appears on TV, radio and in the press. She gives talks for companies to understand fertility issues in the workplace, including menopause. In 2022, she is giving free talks in UK schools to discuss fertility education. She is the founder of Reproductive Health at Work, helping companies ensure that the reproductive health needs of their staff are catered for https://joyceharper.com/repro-at-work/ She is co-founder of the UK Fertility Education Initiative (www.fertilityed.uk) and the founder of the International Fertility Education Initiative (www.eshre.eu/ifei). Her latest book, Your Fertile Years, What you need to know to make informed choices, has been published by JOHN MURRAY PRESS, SHELDON PRESS and signed copies can be ordered from www.joyceharper.com. She is a cold-water swimmer and an ambassador for This Girl Can. Further information – www.joyceharper.com Follow-on Twitter, Instagram, TikTok and LinkedIn - @ProfJoyceHarper
Event Moderator
Caroline Kulczycka

Caroline Kulczycka

Caroline Kulczycka is managing MyIVFAnswers.com and has been hosting IVFWEBINARS dedicated to patients struggling with infertility since 2020. She's highly motivated and believes that educating patients so that they can make informed decisions is essential in their IVF journey. In the past, she has been working as an International Patient Coordinator, where she was helping and directing patients on their right path. She also worked in the tourism industry, and dealt with international customers on a daily basis, including working abroad. In her free time, you’ll find her travelling, biking, learning new things, or spending time outdoors.
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