The Human Fertilisation and Embryology Authority (HFEA) is the body responsible for overseeing fertility services in the UK. They currently have a traffic light system that evaluates evidence for additional treatments that may be offered to you if you undergo fertility treatment. They only use evidence from randomised control trials (RCTs) in their system and they only use a live birth (giving birth to a baby at the end of the treatment) as a way of defining success. In RCTs, a particular drug, food, or other intervention is tested for the effect it has in one group where a control group that isn’t treated is monitored alongside the study group.
Important things to consider
Firstly, we believe that success should be measured not only by the fact you have been able to give birth to a live baby but also by the health of the pregnancy and the health of the baby.
Secondly, the overall body of evidence together with the consensus of professional opinion should be considered, not only RCTs and the HFEA traffic light system is designed to assess the evidence for medical rather than lifestyle interventions.
Thirdly, our courses and programmes include both men and women and there is growing evidence to show that male factors can affect outcomes and there are numerous factors under individual control that can make a difference. When you combine changes in both men and women, marginal gains can accrue so that you really can make a difference, though we don’t currently have good quality studies that demonstrate the full potential of this.
One topic that we cover in our programmes – nutrition – is an area in general where RCTs are difficult to conduct for many reasons. Diet and nutrition research is often based on epidemiological studies (how diseases or ill-health occur in different groups of people and why, often looking at longer-term trends in the population and association with health outcomes ie the Mediterranean diet is associated with better heart health over many years). RCTs looking at diet can be difficult to achieve as those involved in the study need to adhere strictly to the particular diet being studied, it can be hard to sustain, and many other differing individual and lifestyle factors may affect outcomes. For diet and nutrition, we often see an association between a particular type of diet and particular outcomes, rather than evidence of direct cause and effect, as there would be with a randomised control trial (RCT).
It would also be unethical to conduct certain research via RCTs. For instance, if you want to test the consequences of multiple deficiencies on the outcome of fertility treatment and pregnancy, versus correcting those deficiencies prior to treatment, this would mean allowing individuals to enter pregnancy in a state that is overwhelmingly likely to result in harm to mother and baby and the trial would not get ethical approval to proceed. So it is not always possible to conduct RCTs for every aspect of the work that we cover. Studies can sometimes be flawed in that they don’t distinguish between those who start with an underlying deficiency and those who have healthy levels of the nutrients being tested. Having more of something when you already have enough of often won’t be beneficial, which is why studies that look at impact of supplements without knowing truly what is being tested, will always be limited in what they can tell us. Eliminating nutrient deficiencies is a very sound practice for the health of the baby, as an important series of papers published in The Lancet in 2018 tell us. See below for further information.
Despite this, there is a significant body of evidence either through research that shows a positive association with good outcomes in humans or laboratory evidence to show particular nutrients are needed for aspects of reproductive function, for instance, that support the idea that good diet and nutrient chances can increase the chances of having a live birth. Overall, there is a huge body of scientific evidence demonstrating the impact of diet on fertility and pregnancy. From our own clinical experience, we also routinely see the health and fertility of our patients improve as a result of making changes to their diet and lifestyle and we are conducting ongoing research into this.
Along with The Lancet papers, there is also significant evidence and expert consensus on the importance of preconception care including a healthy diet and good nutrient levels for having a healthy pregnancy and a healthy baby.
Finally, fertility issues are often a red flag for other health conditions later in life. Irregular periods and poor sperm health are both linked to poorer cardiovascular disease later in life, for instance. Although we are some way off from proving cause and effect, we believe if we improve underlying health and nutrient status such that we improve these things in men and women, we can improve long term health in the parents too.
So this work is never wasted.
Why this is important for you
We started out courses because it can be difficult to find reliable, evidence-based information with a raft of online resources that can be misleading or overtly incorrect. This is especially true for fertility, where popular crazes include everything from pineapple core to avoiding gluten and dairy.
Interpreting the scientific evidence is further complicated by the fact that humans can survive in a wide range of environments on fairly varied diets, and there is genetic variation and variation in the “good bacteria” in our guts meaning that on an individual level, we may be more or less able to tolerate certain foods than others in the general population. We are moving away from the concept of the “balanced plate” that is the same for everyone and leaning towards individualised recommendations. Our nutritional needs also depend on our lifestyles, including how much exercise we do and how much stress we are under.
So recommending absolutes in terms of the perfect fertility diet for everyone is not always easy and knowing how to translate all the available information into something that will be good for us as an individual can also be challenging. Our courses aim to help you navigate all of this complexity.
- Repeated data from UK annual National Diet and Nutrition Surveys show that a significant percentage of the population have poor dietary intake of key nutrients important for fertility and pregnancy, including iron, zinc, vitamin A, calcium, iodine and magnesium.
- Interventions are not simply about fertility, the focus is on preconception care, the importance of which has been highlighted in a series of linked papers recently by The Lancet (May 2018) of which Professor Judith Stephenson was the senior author (see below). These state that many women enter pregnancy with poor nutrient status that can have negative consequences.
- Fertility issues are usually a red flag for other health concerns that need to be addressed.
- Furthermore, very little attention is traditionally given to the male partner and there is a significant body of evidence to demonstrate the impact of diet, lifestyle and nutrient status on male fertility and treatment outcomes. (https://publichealthmatters.blog.gov.uk/2018/07/16/health-matters-your-questions-on-reproductive-health-and-pregnancy-planning/). Recent research from the recurrent miscarriage team at Imperial has shown that the partners of women who have suffered recurrent miscarriage are more likely to have DNA fragmentation in sperm than women who have not had a miscarriage, for example. Well conducted trials demonstrate that DNA fragmentation can be improved with dietary and nutritional interventions, including nut consumption and various anti-oxidant supplements
- All couples should undergo a programme of preconception care to optimise health, weight and nutrient status prior to trying to conceive – this is well-established advice. Tommy’s, for instance, has just updated its recommendations to include preconception care and there is a body of research looking at preventable causes of miscarriage in relation to nutrition.
- Diet and nutrient status in the year before women conceive have an impact on the lifetime health of the baby, and both obstetric and long-term outcomes for the child can be affected by the preconception diet and lifestyle of both the father and the mother via effects on sperm and oocyte health, include epigenetic mechanisms.
- The environment in which an egg matures prior to ovulation affects egg quality and IVF outcomes and we cover this information in our courses
- There is a huge research focus and body of evidence on environmental influences on fertility and reproduction – this is starting to be more widely adopted in health services.
- Certain nutrient deficiencies and ratios of micronutrients impact the risk of pregnancy complications such as gestational diabetes (GDM). Women who develop GDM have significantly higher risk of subsequent health problems such as cardiovascular disease, we well as a significantly increased risk of stillbirth, adding another dimension to the preventive medicine component of improving diet, nutrient status and underlying health before pregnancy.
- The UK Iodine Group, chaired by Prof John Lazarus focusses on iodine during pregnancy, it aims to raise awareness amongst GPs and gynaecologists of this potential risk factor, as many women enter pregnancy with poor iodine status. Even mild deficiencies impact outcomes and studies show that this is not correctable if supplementation starts after conception.
- Poor preconception mental health is associated with increased odds of experiencing any pregnancy complication, having a non-live birth, and having a low birth weight baby after controlling for maternal age, race/ethnicity, marital status, education, health insurance status, income, and number of children in the household. Preconception interventions constitute an opportunity to optimise mental as well as physical health, and good diet and physical activity are also important foundations for mental wellbeing.
Extracts from The Lancet series of papers on preconception care, May 2018:
Preconception health 1: Judith Stephenson, Nicola Heslehurst, Jennifer Hall, Danielle A J M Schoenaker, Jayne Hutchinson, Janet E Cade, Lucilla Poston, Geraldine Barrett, Sarah R Crozier, Mary Barker, Kalyanaraman Kumaran, Chittaranjan S Yajnik, Janis Baird, Gita D Mishra. Before the beginning: nutrition and lifestyle in the preconception period and its importance for future health Lancet 2018; 391: 1830–41
Preconception health 2: Tom P Fleming, Adam J Watkins, Miguel A Velazquez, John C Mathers, Andrew M Prentice, Judith Stephenson, Mary Barker, Richard Saffery, Chittaranjan S Yajnik, Judith J Eckert, Mark A Hanson, Terrence Forrester, Peter D Gluckman, Keith M Godfrey. Origins of lifetime health around the time of conception: causes and consequences Lancet 2018; 391: 1842–52
Preconception health 3: Mary Barker, Stephan U Dombrowski, Tim Colbourn, Caroline H D Fall, Natasha M Kriznik, Wendy T Lawrence, Shane A Norris, Gloria Ngaiza, Dilisha Patel, Jolene Skordis-Worrall, Falko F Sniehotta, Régine Steegers-Theunissen, Christina Vogel, Kathryn Woods-Townsend, Judith Stephenson. Intervention strategies to improve nutrition and health behaviours before conception Lancet 2018; 391: 1853–64
“The nutritional status of both women and men before conception has profound implications for the growth, development, and long-term health of their offspring.”
“Health and nutrition of both men and women before conception is important not only for pregnancy outcomes but also for the lifelong health of their children and even the next generation. The preconception period can be seen in three different ways: from a biological standpoint as the days and weeks before embryo development; from the individual perspective as the time of wanting to conceive; and through a population lens as any time a women is of childbearing age. This Series of three papers highlights the importance and summarises the evidence of preconception health for future health and suggests context-specific interventions. It also calls for a social movement to achieve political engagement for health in this particular phase in life.”
“Observational studies show strong links between health before pregnancy and maternal and child health outcomes, with consequences that can extend across generations, but awareness of these links is not widespread. Poor nutrition and obesity are rife among women of reproductive age, and differences between high-income and low-income countries have become less distinct, with typical diets falling far short of nutritional recommendations in both settings and especially among adolescents.”
“Micronutrient supplementation started in pregnancy can correct important maternal nutrient deficiencies, but it is not sufficient to fundamentally improve child health; dietary interventions in pregnancy can limit weight gain, but they are also insufficient in improving pregnancy outcomes.”
“Parental environmental factors, including diet, body composition, metabolism, and stress, affect the health and chronic disease risk of people throughout their lives, as captured in the Developmental Origins of Health and Disease concept. Research across the epidemiological, clinical, and basic science fields has identified the period around conception as being crucial for the processes mediating parental influences on the health of the next generation. During this time, from the maturation of gametes through to early embryonic development, parental lifestyle can adversely influence long-term risks of offspring cardiovascular, metabolic, immune, and neurological morbidities, often termed developmental programming. We review periconceptional induction of disease risk from four broad exposures: maternal overnutrition and obesity; maternal undernutrition; related paternal factors; and the use of assisted reproductive treatment. Studies in both humans and animal models have demonstrated the underlying biological mechanisms, including epigenetic, cellular, physiological, and metabolic processes. We also present a meta-analysis of mouse paternal and maternal protein undernutrition that suggests distinct parental periconceptional contributions to postnatal outcomes. We propose that the evidence for periconceptional effects on lifetime health is now so compelling that it calls for new guidance on parental preparation for pregnancy, beginning before conception, to protect the health of offspring.”
“The consequences of maternofetal iron deficiency also fit a critical period model in which repletion after an undetermined timepoint does not rectify structural impairments to developing brain structures. In experimental rodent models, dietary restriction of iron from the beginning of gestation can induce a 40–50% decrease in brain iron 10 days after birth and preconception zinc deficiency compromises fetal and placental growth and neural tube closure.”
“Adolescence might represent a particularly sensitive period as unhealthy life-style behaviours—eg, smoking, poor diet, and eating disorders—often originate in the teenage years. These preconception risk factors can set patterns that have a cumulative effect on health into adulthood and for future generations, as shown by mounting evidence of the long-term effects of poor maternal nutrition and obesity for the child.”
” Our analysis in the UK shows that many women of reproductive age will not be nutritionally prepared for pregnancy, since they do not meet even the lower reference nutrient intake (RNI) amounts, which applies especially to young women and mineral intake. 77% of women aged 18–25 years had dietary intakes below RNI daily recommendations for iodine and 96% of women of reproductive age had intake of iron and folate below daily recommendations for pregnancy (data not shown). Adequate folate concentration in pregnancy (red blood cell folate concentration above 906 nmol/L) for prevention of neural tube defects is hard to achieve through diet alone. Folic acid supplements or fortified foods are effective alternatives. In a cohort of over 1·5 million women in China, folic acid supplementation 3 months before pregnancy (n=1 182 967) was associated with significantly lower risk of low birthweight (OR 0·74, 95% CI 0·71–0·78), miscarriage (OR 0·53, 0·52–0·54), stillbirth (OR 0·70, 0·64–0·77), and neonatal mortality (OR 0·70, 0·63–0·78) than in women who did not take folic acid before pregnancy (n=352 009). In several countries (including Canada, Chile, Oman, Jordan, Costa Rica, South Africa, USA) a decrease in neural tube defects has been observed following mandatory folic acid fortification, typically of wheat flour or cereal grain products, in the country or region. A mild degree of iodine deficiency in pregnancy has been linked to lower intelligence quotients in offspring, although the balance between the benefit and risk from iodine supplementation before or during pregnancy remains unclear.”
Science is evolving
It’s important to remember that the evidence is constantly evolving. Science is a journey, a constant quest for knowledge, and rarely do we arrive at a fixed destination. It is important to remember this when considering scientific evidence in any area.
Take home message
There is overwhelming research confirming the benefit of good diet and nutrition when you are trying to conceive and when going through fertility treatment. We believe the balance of evidence does show that adopting the range of changes we recommend in both men and women, including correcting multiples deficiencies, can improve your chances of having a healthy baby, but the evidence comes from a range of studies rather than individual RCTs.
We cannot of course, guarantee that you will have a baby after making changes to your diet and lifestyle. No-one can guarantee you success in having a baby but making improvements to your diet, lifestyle, nutrient status, and underlying health will put you in the best possible place for success for the factors that you have under your control.
The courses offered by Balance Fertility are designed to provide information to take to your treating doctor to help optimise underlying health, identify and correct any nutrient deficiencies, and improve the modifiable factors that are known to affect fertility, pregnancy and reproductive health. There are no guarantees as to specific outcomes and certain factors including age and underlying medical conditions may limit the potential for dietary and lifestyle interventions to improve outcomes in terms of symptoms and/or results from fertility treatment. Courses are designed for information purposes only and are not a replacement for medical treatment. If you have any concerns about your health, medication or symptoms, please consult your treating doctor.