A weighty issue
How a woman’s weight impacts the risk of miscarriage
A miscarriage is a devastating experience for couples, perhaps even more so for those who have struggled with infertility and gone through the initial joy of a successful fertility treatment. Statistics have shown that in both natural and IVF conception, about one in six pregnancies will end in a miscarriage before the 20th week, with the rate being higher in older couples.
Understandably, couples are frightened of miscarriages and would rather not think or talk about it. However, it is important for couples to understand why miscarriages happen, as well as what they can do to reduce their risks.
Although the exact reason for a miscarriage is often unexplainable, it can occur due to a number of reasons. These include chromosomal abnormality, improper implantation of the egg and maternal health problems or trauma. The mother’s age also plays a significant role, as does her lifestyle, which includes exposure to stress, smoking, drug use, malnutrition, excessive caffeine, radiation and toxins.
Another well-studied factor than increases a woman’s risk for miscarriage, is her weight. As these studies indicate, if the mother is obese or underweight, this increases her risk of not only infertility, but miscarriage as well, regardless of the method of conception.
According to researchers at the Department of Obstetrics and Gynaecology, University of Adelaide, Australia, being overweight increase a woman’s risk of miscarriage by 29%, while being obese can increase the risk by 71% or more. However, for women undergoing assisted reproduction, researchers at the Assisted Fertilization Center, Brazil concluded that maternal obesity could increase the risk of miscarriage by up to 1330%.
Obesity also compounds miscarriage rates in women with PCOS. The Department of Obstetrics and Gynecology, Faculty of Medicine, Erciyes University, Turkey found that the miscarriage rate in obese women with PCOS is about nine times higher than average.
And while miscarriage is often the result of an unhealthy fetus, researchers from the Department of Obstetrics and Gynecology, Stanford Hospital and Clinics, CA, USA found that the risk of miscarriage of a healthy fetus is significantly higher in obese women (with BMIs of 25 or more).
While obesity has been identified as a risk factor for spontaneous miscarriage, the mechanism for it remains unclear. But a study by The Academic Unit of Reproductive and Developmental Medicine, The University of Sheffield and Sheffield Teaching Hospitals, Sheffield, UK points to the endocrinological changes in obesity as possibily causing complex adverse effects including circulating adipokines, sex steroids and insulin resistance.
Women who are underweight, with a BMI of under 20, also face an increased miscarriage risk. A study by researchers at the German Cancer Research Centre found that pregnant women who were underweight faced a 70 % higher risk of having a miscarriage.
Therefore, it can be concluded that among intrauterine environmental factors, nutrition appears to play the most critical role in influencing placental and fetal growth. Since maternal undernutrition or overnutrition during pregnancy can impair fetal growth, women must adopt healthier diets and incorporate exercise to lower their risk of miscarriage.
If you have any concerns regarding miscarriage, especially after IVF, please do not hesitate to consult with your fertility consultant for advice.
A journalist who came to interview me a few years ago asked me a question: ‘What makes you become interested in reproductive science and inspired you to become a Fertility Specialist?’
I was quite taken aback by this question. I knew where this question was coming from: Being a daughter of a Professor in Chinese Literature, one who had thought that I would end up in field related to Sociology, Literature or Humanity. A doctor and a Fertility Specialist from such family, hmmm….an unlikely species.
I searched my mind long and hard, everyone who knew me knows that I have a passion for literature and social science. But why reproductive science? And why Fertility?
The answer became clear suddenly: I have the privilege to know a couple who was my parents’ neighbours and friends, whom I have have fondly called Uncle Chong Lek & Aunty Sam. This couple are both Professors in the field of Genetics. At the age of 9, I used to listen to Uncle Chong Leh and Aunty Sam, who came to join us for a meal or a tea, and shared on their field of research and findings. I was fascinated and in awe, even at the tender age of 9.
How fascinating it is that we are governed by our genes which determined how we look like or the colour of our skin? How did these DNA coding became the essential aspect of life forms ?
At that time, we have not discovered the secret of nurture versus nature in modifying our gene expression.
As I progressed in pursuing my acaedemic advancement, I find myself becoming more and more inclined to science related subjects. I was, genetically inclined to arts, but an exposure to this lovely couple had altered my genetic expression…..I became who I am, a doctor, then a Gynaecologist and then a Fertility Specialist, who works closely with scientists. Being involved in Fertility work, my practice is closely related to understanding of chromosomes and genes.
Nature or nurture?
An introduction to epigenetics
Many people believe that children are more the product of nurture than nature, meaning that the environment in which a child is brought up in has a greater effect on his or her well-being, personality and traits than the child’s genes. Yet, there are those who believe that a child’s inherent nature can’t be changed, despite the amount of nurturing received. Now, however, this debate has become academic, enter – epigenetics.
What is epigenetics?
Epigenetics is a new and complex science that looks at how lifestyle and environmental factors can affect a baby’s genes. In particular, it studies how the millions of markers in our genes can change our traits at a cellular and physiological level. Although the sequence of the genes we’re born with can’t be changed, it is believed that the way that they’re activated or expressed can be altered – for better or for worse. Furthermore, it is possible that these traits can then be passed down by an individual through the generations.
How it affects IVF patients
Most IVF patients who receive donated eggs and sperm feel that their baby won’t be taking much after them, as they don’t share the same DNA. However, according to epigenetics, this doesn’t have to be the case. In epigenetics, factors such as the uterine environment, stress levels and pregnancy diet can have a direct influence on the way that a baby’s genes are expressed. Therefore, in epigenetics, it is thought that IVF patients have a degree of control over how their egg/sperm-donor child might turn out, if they adopt healthy lifestyle choices.
But can the IVF procedure itself cause negative epigenetic consequences? According to a small Danish study conducted in 2010, it is possible. The study suggested that, “Babies born via assisted reproduction (i.e. IVF) had a slightly higher chance of getting childhood cancer.” As alarming as it sounds, the study was inconclusive and the risk appears to be minimal at best.
The importance of eating well
Through the decades, scientists have established a link between a healthy maternal diet and the well-being of babies. However, the effects can also be seen in reverse. For example, during the Dutch famine of 1944, thousands died of malnutrition due to Nazi blockades and a prolonged and harsh winter. The babies born during this period were not only underweight, but their genes were damaged.
Decades later, the Dutch Famine Birth Cohort Study would reveal that the offspring of children who were born during the famine were equally susceptible to being underweight and contracting illnesses like diabetes, obesity, cardiovascular disease and microalbuminuria. It is as if their genes had been ‘programmed’ with the adverse effects of malnutrition.
A greater power
Although epigenetics is yet to be scientifically proven, it certainly offers promise. True, it can’t be said for certain that the positive lifestyle changes you adopt before and during pregnancy can influence your baby’s genes. However, science notwithstanding, parents who have struggled to conceive possess a greater, innate power that rivals nature itself – love. And this love, coupled with positive thinking, has been known to conquer and surmount the greatest of odds.
The link between Vitamin D and fertility
Caucasian women love showing off a sun-kissed tan, so much so they would dedicate a good portion of their holidays to sunbathing. We Asian women, however, are the exact opposite, preferring to keep out of the sun, sometimes taking considerable pains to do so. This aversion to the sun is largely due to the desire to maintain a fair complexion, but is driven in part by concerns over harmful UV rays. This penchant for shunning the sun, however, has had an undesirable side effect on Asian women, as we are known to have lower levels of Vitamin D despite living in tropical climates.
Few people realise that vitamin D plays a significant role, not only in their general health, but their fertility as well. It has been shown that people living in countries with strong seasonal contrasts have always had fewer pregnancies during winter and more in summer, resulting in a baby boom around spring. Scientists have discovered that this ebb and flow has to do with exposure to the sun.
Over the years, this link between Vitamin D and fertility has been extensively investigated, but it has been further detailed in a systemic review published in 2012 by the European Journal of Endocrinology. The review, by Elisabeth Lerchbaum and Barbara Obermayer-Pietsch from the Medical University of Graz, Austria, assessed studies that evaluated the relationship between vitamin D and fertility in women and men, as well as in animals.
Here’s what the review, entitled ‘Vitamin D and fertility: a systematic review,’ found:
- Vitamin D receptors (VDR) and vitamin D metabolising enzymes are present in the reproductive tissues of both men and women.
- Laboratory mice deprived of VDR tend to suffer significant gonad (sex gland) insufficiency, decreased sperm count and motility, and abnormalities in the microscopic structure of tissues in the testis, ovary and uterus.
- Vitamin D is involved in female reproduction including IVF outcome (clinical pregnancy rates) and polycystic ovary syndrome (PCOS).
- In PCOS women, vitamin D supplementation might improve menstrual frequency and metabolic disturbances.
- Vitamin D might influence steroidogenesis of sex hormones (estradiol and progesterone) in healthy women.
- In men, vitamin D is positively associated with semen quality and androgen status.
- Vitamin D treatment might increase testosterone levels.
While the results are encouraging, the researchers emphasise that vitamin D supplementation alone can’t improve fertility issues. However, what is certain is that it is a safe and inexpensive treatment that can be a boon to conception. So if you’re trying to conceive, don’t shy away from the sun! Instead, aim to get about 15 minutes of sun each day and take care not to overexpose yourself to UV rays.
In my next post, I’ll be discussing another topic related to fertility and nutrition – the findings of the Dutch Famine Birth Cohort Study. Stay tuned!
The importance of micro-nutrients to conception
The adage goes, “You are what you eat,” and the same is true for fertility. But when you’re trying to conceive, you want to rely on much more than just an old saying. Statistics show that around 11% to 20% of couples experience subfertility. Of this, 10% can be classified as unexplained infertility, while 60% are classified as anovulatory subfertility. In my experience, couples today also find their infertility issues compounded by their hectic lifestyles.
Factors such as stress; unhealthy body weight; excessive smoking, alcohol and caffeine intake; exposure to toxins, as well as recreational drug use, can all play a role in affecting fertility. But even those who maintain a healthy weight, manage their stress and abstain from unhealthy habits may neglect a very important factor – nutrition. Fortunately, there is now hard evidence in the form of scientific proof that shows you can indeed improve your fertility by eating right, particularly by including micro-nutrients in your daily diet.
While macro-nutrients, like protein, unsaturated fats and carbohydrates can be easily obtained from the foods that you eat, micro-nutrients like vitamins, minerals and trace elements are often left out due to an unbalanced and unhealthy diet. Realising that micro-nutrient deficiencies are not uncommon in women of reproductive age, Dr Rina Agrawal, a consultant and associate professor in reproductive medicine and obstetrics/gynaecology at the University Hospital at Warwick University, conducted a study on the role of micro-nutrients in improving pregnancy rates.
The study, which involved 58 suitable candidates consisting of subfertile women with an average age of 32.3 years (range 19–40), investigated whether subfertile women undergoing ovulation induction using standard treatment regimens have higher pregnancy rates when given multiple micro-nutrient (MMN) nutritional supplements, as compared with folic acid alone. The findings of the pilot study unveiled that the women on MMN supplementation had a higher pregnancy rate of 66.7%, as compared with 39.3% for those on just folic acid.
This therefore suggests that additional MMN supplementations, such as vitamins B6, B12, folates, vitamin E, multivitamins, iron, zinc, copper and selenium, does improve female fertility. In addition to finding that the women on MMN supplementation had a higher chance of pregnancy compared to their peers, the women on MMN supplementation also required significantly fewer attempts to become pregnant, as compared with women on folic acid. But there are also other benefits to taking MMN supplements, including reduced reproductive risks ranging from infertility to miscarriage, and fetal structural defects to improved embryogenesis or placentation.
You may need only small amounts of micro-nutrients, but they are no doubt essential. Each vitamin and mineral plays a specific role in ensuring that your bodily systems function in top form, and needless to say they are vital to your overall wellbeing. In order to get more micro-nutrients from your daily diet, you should eat a wide variety of foods from the different food groups. It is also best to avoid eating fast foods and processed foods that are of low nutritional quality. Instead, opt for fresh fruits and vegetables, legumes, nuts and seeds, whole grains, lean meats, fish and low-fat dairy products.
Stay tuned to find out more about foods that can boost fertility.