We asked an ob-gyn if a high BMI really affects the success rate of this fertility treatment.

By Sarah Klein
Updated: September 26, 2018

This Is Us returned last night, and (surprise surprise) we’re already teary-eyed. There’s old and new romance, as viewers travel back in time to Jack and Rebecca’s awkward first date. And of course, heartbreak happens: Kate, who had a miscarriage in season two, is told by a fertility doctor that she’s not a good candidate for in vitro fertilization, or IVF.

“At your weight, the chances of a successful pregnancy is risky … egg retrieval is invasive at your BMI,” the doctor tells Kate and Toby, on Kate’s 38th birthday no less. Not only is the doc not willing to go through an IVF cycle with Kate, but she warns Kate that she'll be “hard-pressed” to find any doctor to take her on as a patient. Distraught, Kate laments the fact that she’s worked hard to shed 40 pounds yet still can’t catch a break.

But her luck changes later in the episode. The doctor summons the couple back to her office to report that after consulting with her colleagues, she’s changed her mind. Despite IVF having a predicted 90% failure rate in Kate’s case, the doctor says she’s focusing on that 10% chance for success.

RELATED: 15 Factors That Affect a Woman’s Fertility

The storyline had us wondering: Is BMI really such an obstacle to a successful pregnancy? Health looked at the latest research and spoke with Christine Greves, MD, an ob-gyn with Orlando Health System in Florida, to get the facts.

For starters, it’s long been known that carrying extra weight can lower female (and male) fertility. Excess weight can alter hormone production and ovarian function. Obesity is also a major risk factor for polycystic ovary syndrome (PCOS), which Kate says she has. PCOS is a hormonal imbalance and a leading causes of female infertility. “Women with PCOS may not ovulate,” Dr. Greves explains, “so they struggle with getting pregnant because of course they need to release an egg.”

Obesity can also complicate IVF, Dr. Greves says. Quick refresher: During in vitro fertilization, a doctor retrieves a woman’s eggs, fertilizes them in a lab to create embryos, and then implants those embryos back into her uterus. A study published in August in the Journal of Assisted Reproduction and Genetics found that women with a BMI above the normal range had a higher risk for IVF cycle cancellation (meaning the process is stopped before eggs are retrieved), lower embryo counts, and lower rates of ongoing pregnancy.

RELATED: 8 Signs You Could Have PCOS

That doesn’t mean a high-risk patient like Kate shouldn’t receive treatment, Dr. Greves says. “Everything has a risk, a benefit, and an alternative,” she explains. With her own patients, Dr. Greves will move forward with treatment “as long as the patient understands the risk and understands that a procedure may not be successful.”

Both the doctor and patient need to accept those risks, however, and some people simply aren’t willing to, she adds. Kate, wanting so badly to be a mom, seems willing to accept the potential dangers to herself and her future baby. “It sounds like the patient’s heart is so big in wanting a child that it let her put her own needs aside,” says Dr. Greves (she hasn't seen the show, it's worth noting).

It’s important to remember that overweight and obese women routinely encounter worse medical care than their average-weight peers. One 2017 article published in the journal Human Reproduction Open argued that denying women fertility treatment because they are obese isn’t fair if the same treatment would be carried out in women with other risk factors. “[I]t excludes a specific patient category on grounds that are not applied to treatment of others with comparable risks,” the authors wrote. “It’s recommended to not be obese and to get healthy before you have a baby, but if that doesn’t happen, it doesn’t mean we think any less of you, it just means your pregnancy may be a little more risky,” Dr. Greves says.

RELATED: 6 Ways to Lose Weight If You Have PCOS

This Is Us viewers will have to wait and see if discrimination or pregnancy complications unfurl for Kate and Toby in future episodes. Until then, it's possible Kate will continue prioritizing her health along with her quest to get pregnant. While she was initially discouraged that her 40-pound weight loss didn't make her a stronger candidate for IVF, every little bit counts. “Even if you lose just five pounds, that will increase your chances of getting pregnant in the next six months,” ob-gyn Diana Bitner, MD, told Health in a prior interview.

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