This week I am excited to launch my fourth book Fertile; I wrote it because I want to encourage women to learn to nourish themselves prior to becoming pregnant and it is full of ways to improve your health and fertility before conceiving. Many health and diet books on the market are not written with fertility in mind. I have also seen books on fertility that focus on a list of ‘Fertility Foods’; I think this is slightly misleading. It is not about eating a limited list of 'super' food in excess; more about adopting an approach to eating that is sustainable and avoids obsession around food. This week is also Eating Disorder Week and I wanted to highlight the impact of eating disorders on fertility. This is an area I feel passionately about as being a healthy weight can impact on your ability to conceive, the health of the pregnancy, baby and the mother’s emotional health. Women are often conflicted about their weight; wanting to be pregnant and wanting to stay slim. Often having spent their whole life maintaining a weight they are happy with, it can be daunting to put on weight or exercise less. Or, once pregnant, to see the body grow and change before your eyes. For most women this is a joy but for some it can trigger anxiety and fears about their weight. I recently met with Dr Joan Brunton, Consultant Psychiatrist in adult eating disorders at the Priory Group, in order to get her expert take on the subject. I hope you’ll find our interview enlightening and read Joan’s final answer as offering both hope and positivity for women suffering from eating disorders. Emma: What percentage of women of childbearing age are affected by eating disorders? Joan: Eating disorders affect 3-4% of women of childbearing age. Emma: Do eating disorders cause long term damage to fertility? Joan: They have a significant impact on fertility which is usually reversible with weight restoration and normalisation of eating patterns. Emma: What is the major impact on fertility and what is the mechanism behind this? Joan:One of the key features of anorexia nervosa is the stopping of periods. Around 80% of women will not ovulate regularly below a BMI of 18.5 and the BMI at which periods stop if people exercise excessively tends to be higher. Women need reserves of fat to maintain a pregnancy so if the brain picks up that you do not have enough, it switches off the hormones which cause you to ovulate which leads to periods stopping. It is the body cleverly protecting the potential mother and baby from the dangers of conceiving at a low weight. Emma: I think that there is more emphasis by fertility clinics towards women who are overweight and not enough towards underweight women. What is your view on this? Joan:Fertility clinics often tend to concentrate on the risks of pregnancy to overweight women but becoming pregnant at low weight also carries significant risks including miscarriage, still birth, pre term labour and an increase in birth defects. Pregnancy can also have a significant psychological effect on the mother if she has not had treatment for the eating disorder. Women can develop severe anxiety problems as their 'out of control' body grows and grows. Post natal depression is also common, plus relapse into a more serious eating disorder if women are not well supported post birth. Emma: What would you like to see changed? Joan: It is imperative that patients with anorexia receive treatment so that periods return naturally, rather than forcing their depleted bodies to ovulate using strong medications used in fertility treatments. I have heard stories of fertility clinics boasting about 'getting anorexic patients pregnant' at low weights but they do not see the long term effects on the mother or baby. Emma: What about other eating disorders how do they impact on fertility? Joan: Other eating disorders such as bulimia also often lead to irregular periods. This issue is less well researched than anorexia nervosa but there is a link to polycystic ovaries. Other abnormal eating behaviours such as vomiting and bingeing lead to huge swings in insulin to which the ovaries are very sensitive. Stabilising eating can help women switch from non-ovulating PCOS to ovulating PCO. Emma: What about excessive exercise? I am increasingly concerned about young women over exercising or doing intense work out regimes and have seen an increase in women coming with no periods. It is worrying. Joan: Excessive exercise also switches off ovulation as in evolutionary terms the brain thinks someone who is running around all the time without fat reserves won't be able to support a pregnancy. Emma: And final words of wisdom? Joan: Many of the ideals society places on women actually run contrary to their biology and put their fertility at risk. Thankfully, the vast majority of these problems can be reversed with careful treatment and I have seen many women go on to have families, but the key issue is not to rush this treatment and don't fight your biology!