7 Myths About IVF We Need To Talk About After Watching 'This Is Us'

On This Is Us, Kate's doctor initially balks at her undergoing IVF because of her weight, before changing her mind and allowing her the procedure at the end of episode 1. So would this happen in real life?

A study in the journal BMC Women's Health in 2015 looked at the IVF procedure and outcomes for 298 IVF cycles for women younger than 38 with a wide range of BMIs (body mass index), though none classified as "underweight." Their body mass index, the scientists showed, had no apparent effect on their IVF cycles, or their pregnancy rates. The eggs retrieved, number of suitable embryos, fertilized eggs and pregnancy rates were essentially the same across all women in the study. But another study in 2018 used a much bigger sample size across the US, involving 51,198 women, and found that the results are a bit more complicated. In that study, women who were labelled overweight or obese were more likely to have low egg levels and low usable embryos.

There are a lot of different factors to consider there, particularly the fact that "obesity" is often an ill-defined term and that other factors affecting fertility, including polycystic ovary syndrome (which Kate also has), have a close relationship with weight as well.

Doctors in Australia are fighting for a change in IVF guidelines that currently recommend clinics don't offer the procedure to women considered obese. To be denied IVF because you're obese, ob-gyn Dr Christine Greves told Health, isn't necessarily fair if doctors would perform the the procedure on women of average weight who had other health issues. “Everything has a risk, a benefit, and an alternative," she said.

Chrissy Teigen and husband John Legend have been open about the fact that both their children have been born via IVF — and that their son Miles was born from a frozen embryo from an early IVF round that was thawed and implanted successfully into her body years later. Freezing "leftover" embryos like this is an option for many couples after an IVF cycle, and there's no evidence that it causes the embryos any harm, fertility expert Dr. Caitlin Dunne wrote in the Huffington Post in 2017. "Freezing does not harm the embryos and they do not get freezer burn," she noted. "Almost all healthy embryos will survive the freezing-warming process. Research suggests that babies born from frozen embryos do not have a higher rate of birth defects compared to fresh embryos."

IVF babies have been the subject of many studies to make sure the process is safe, and the results are pretty clear: being conceived through IVF doesn't seem to affect them in any substantial way. "There is some evidence that IVF babies conceived after fresh embryo transfer are born a little smaller than spontaneously conceived babies," Professor Nick Macklon of the London Women’s Clinic Group wrote. "At this time, however, these differences do not appear to have significant long-term consequences and many IVF babies are now healthy parents of naturally conceived children." A study in 2017 also found that there's "little effect" on future heath if you're born an IVF baby.

It is definitely more likely that you'll have multiple births (twins or triplets, for instance) with IVF than with non-IVF pregnancy, if you decide to get multiple embryos implanted and hope that at least one will "take." However, that isn't a guarantee.

Dr. Victoria Walker of the fertility clinic Institut Marqués told the Evening Standard in 2017, “Only three per cent of natural pregnancies result in the birth of twins. With IVF it can be up to 33 per cent." However, she also pointed out that it's now much more common for fertility clinics to do a single embryo transfer (SET) rather than recommending multiple ones at once. Those can result in twins, but it's far rarer.

IVF doesn't make you "crazy", but if you're prone to mood swings in response to shifting hormones in your natural menstrual cycle, it can produce feelings of irritability and sadness. The reason? The fertility drugs you're given to boost your egg production impact your estrogen levels. "Low estrogen levels can lead to feelings of depression, anxiety or irritability. Bloating, nausea and breast soreness can also occur," Dr. Caitlin Dunne told the Huffington Post.

Two studies, one in 2013 and one in 2016, busted this myth pretty positively: they followed women who'd undergone fertility treatments for any diagnoses of ovarian and breast cancer, and found that IVF provided no apparent rise in risk of developing either. Another study in 2018 of over 250,000 women put it clearly: breast and gynecological cancer risk for women who'd undergone IVF, it said, is "minimal". This is one myth that isn't supported by science at all.

While Hollywood appears to abound with women who successfully got pregnant over the age of 45 — Halle Berry, Brigitte Neilsen, Janet Jackson — for women over the age of 40, IVF does have a lower success rate.

"Over 40, a woman will have a 50 percent miscarriage rate due to declining egg quality and quantity," women's health expert Dr. Sherry Ross told Bustle earlier in 2018. Women doing IVF over age 44 who use their own eggs, according to a study in the UK, only has a 2 percent success rate. If, however, they use donor eggs or eggs frozen when they were younger, their chances are far better — though still not guaranteed.

IVF is one of the wonders of modern technology, but it has also attracted a lot of misconceptions and myths. If you hear anybody spouting these, check them and give them a dose of the facts instead.