According to the Journal of Obstetrics and Gynecology Canada, the impact of obesity on women’s fertility is highly complex. The most understood correlation in this area is between obesity and the menstrual cycle. Essentially, they say cycle irregularity is more common in women with a higher BMI (body mass index).
The JOGC also says that in some studies, obesity is associated with reduced response in fertility treatments, but other studies report no difference in IUI or IVF patients who are considered obese. When it does occur, the exact mechanism by which obesity lowers IVF success rates is unknown.
The science of fatness and fertility is not totally clear. But as fat positive fertility coach Nicola Salmon tells Ovry, the main issue fat women face when trying to become pregnant is not the way their bodies respond to treatment, but the way medical professionals respond to their bodies.
Anti-fat bias is rampant in our culture and throughout our medical system, and the tendency of doctors to over-rely on weight loss as a cure-all is prevalent in fertility spaces as well.
Nicola was diagnosed with PCOS (Polycystic Ovary Syndrome) when she was 16 years old. When she was receiving the diagnosis, her doctor told her that she would never be able to get pregnant with PCOS. One of the ways she could manage her illness, the doctors told her, was to lose weight.
From then on, “I associated weight loss with the ability to get pregnant,” Nicola says.
Despite these early experiences, Nicola says she and her husband conceived both of their children fairly easily. One of the main struggles she faced during her first pregnancy was anxiety—the myths and stories she had been told directly by her doctors, and the ones passed on through our cultural mindset about being fat and pregnant, significantly impacted the way she viewed her body. This caused Nicola a lot of stress.
When her eldest son was about six months old, Nicola realized she didn’t want this anxiety about her body to be passed on to her kids.
“My relationship with my body and food was incredibly disordered, and I didn’t want them to absorb those negative messages. This was when I made a commitment to quit dieting, to stop weighing myself, and to embark on a journey to heal my relationship with my body and food.”
This was also when Nicola started to do extensive research on fatness and fertility, and the harm caused to larger people by mainstream ideas on the topic. As someone who was already working in the fertility space, Nicola wanted to confront the damage done to her by this mindset, as well as the damage she feels she did by perpetuating it.
Nicola saw very little evidence to support the restrictive diets sometimes prescribed by fertility specialists to their fat patients. Diets in general have an alarmingly high failure rate, and most people regain the weight they’ve lost, if not more. Of course, despite this staggering reality, the blame is almost always placed on the individual who is dieting, instead of the diet itself.
This means that fat women looking for fertility care are likely to be treated as broken right out of the gate. Depending on how high the patient’s BMI, doctors will typically recommend weight loss (whether by diet or by surgery). The patient’s mental health is not always taken into consideration.
The biggest myth Nicola faces in her practice is the one she faced herself as a teenager: that fat people cannot or should not become pregnant. This myth is harmful because it means folks delay or never start their journey to have a family because they believe it would be too dangerous. Instead, they put it off until they’ve lost “sufficient” weight, a goal they might never achieve.
This myth exists because there is a foundational belief in our society that fat is unhealthy, and that fat people are lazy and unmotivated. Instead of viewing health as a multifaceted and highly personal thing, we tend to oversimplify it, and our attitude towards fatness is just one way this oversimplification manifests.
“When we look at the research around pregnancy loss for folks in bigger bodies, the majority of it either shows no correlation between BMI and pregnancy loss, or a statistically insignificant correlation,” Nicola says.
The idea that fat is inherently bad, and that losing fat is inherently good, leaves a lot of people in the dust. The BMI (Body Mass Index) is used to categorize people by their weight (and at times used to restrict access to fertility care) but it’s highly problematic in its history and modern application. It was never meant to be used to assess the health of an individual.
Nicola says that a more pressing concern than a high BMI is the anti-fat bias people face when accessing maternity systems or simply existing in the world as a fat pregnant person. This causes undue stress and anxiety, which we know can lead to complications in pregnancy.
In terms of what Nicola would like people to know about their own fertility journeys, she says she hopes they can recognize they are worthy of accessing care and evidence-based support.
“I would tell them their worth is not dependent on the size of their body,” she says. “They do not need anyone’s permission but their own to pursue their dream of growing a family.”