Kourtney Kardashian, Chrissy Teigen shed light on bloating during IVF. Here's what fertility experts say.

Kourtney Kardashian and Chrissy Teigen are calling attention to the bloating that can occur while undergoing fertility treatments — and why invasive questions about it need to stop.

In a leaked teaser for Hulu's The Kardashians, oldest sister Kourtney, 42, reveals that she and fiancé Travis Barker, 46, are pursuing in vitro fertilization (IVF) in order to have a baby together; the reality star is already a mom of three, while the drummer has two teens. The clip, which has since been removed from social media, also showed Kardashian complaining to mom Kris Jenner that she'd "gained so much weight" during the IVF process, prompting unsolicited comments wondering whether she might be pregnant.

“I’m, like, it’s so rude to comment on people when you have no idea what they’re going through,” said Kardashian, who has repeatedly shut down pregnancy speculation on Instagram over the past few months.

Her experience echoes that of Teigen, 36, who last month shared the news that she and husband John Legend, 43, are trying to conceive another child via IVF. The couple, parents to daughter Luna and son Miles, lost their son Jack in 2020, just 20 weeks into the pregnancy. Like Kardashian, the Cravings author has had to field nosy questions about her body.

"The bloating is a bitch, so I humbly beg you to stop asking if I’m pregnant because while I know it’s said with excited, good intentions, it just kind of sucks to hear because I am the opposite of pregnant!" Teigen told fans in a candid Instagram post.

As both stars speak out over prying questions about women's bodies and their fertility plans, they're also shedding light on a common but often-overlooked side effect of IVF: weight gain.

Why bloating and weight gain occur during an IVF cycle

Dr. Jenna Turocy of Columbia University Fertility Center in New York City, tells Yahoo Life that bloating is a common side effect of hormone medication, including birth control. In the case of an IVF cycle, in which injectable fertility medications are used to stimulate the ovaries, high estrogen levels "can cause some women to feel bloated, retain fluid and gain weight."

"I do tell women prior to starting an IVF cycle to expect to feel some bloating and discomfort, particularly toward the end of the cycle when the hormones are the highest and ovaries are the biggest," Turocy adds.

There can be other contributing factors affecting a patient's weight. Though Dr. Wael Salem, a reproductive endocrinologist at CCRM Fertility in San Francisco, attributes most weight gain to "fluid retention ... as a result of multiple follicles growing and ovulating at once," he points out that elevated hormone levels may also increase appetite. Turocy, meanwhile, cites the comfort that eating might bring during such a high-pressure process.

"IVF can also be an extremely stressful period in a women’s life," she says. "This, combined with mood swings (another common side effect of medications), can lead to some women to overeat if they are natural overeaters when stressed."

When is weight gain a red flag?

For a small percentage of women — less than 5 percent, according to Salem — significant discomfort and weight gain could signal a condition called ovarian hyperstimulation syndrome (OHSS), which happens when a woman's ovaries swell and leak fluid into the body, according to the Cleveland Clinic, leading to rapid weight gain.

"Worsening abdominal pain and excessive weight gain are both clinical symptoms of OHSS," says Turocy. "OHSS is an excessive response to medications where the ovaries become enlarged with multiple follicles and blood estrogen levels are very high. Overstimulated ovaries release chemicals into the bloodstream that cause blood vessels to become leaky so women accumulate fluid in places like the abdomen, resulting in bloating, discomfort and weight gain."

Generally speaking, adds Salem, "if you’re gaining more than one to two pounds per day, have severe abdominal pain or are noticing a decrease in the amount of urine, you should contact your doctor."

He notes that fertility specialists will also monitor patients who may be at risk of OHSS and tailor medications to reduce symptoms. Salem is a proponent of "highly personalized" IVF stimulation protocol (the medications used to grow eggs), so that precise considerations can be made to create a best-case "Goldilocks" result: a good number of eggs, but not so many that ovaries are overstimulated or OHSS occurs.

Can anything help bloating?

Bloating is typically part of the IVF process, but certain things can help offset the side effect, from a tailor-made stimulation protocol to good hydration.

"I encourage women, particularly those who are at risk for developing large overstimulated ovaries that can cause discomfort, to drink lots of electrolyte-containing fluids like Gatorade, coconut water and Smart Water during their IVF cycle," says Turocy. "It’s also a good idea to avoid alcohol and caffeinated drinks such as coffee, which can worsen dehydration."

And in cases in which weight gain is caused by stress-related overeating, Turocy suggests finding soothing alternatives, such as light exercise, acupuncture or meditation.

How long will it last?

The good news is that any IVF-induced bloating should be short-lived. Fluid retention will typically hit its peak near the end of the cycle — and for those with OHSS, around four to seven days after a hormone trigger shot — but reduce once stimulation ends.

"This is temporary and once a woman has stopped medications, hormones levels will return to baseline levels," says Turocy. "Most women will quickly lose any extra fluid accumulated and will go back to their normal body weight within two weeks."

That in itself, however, may also be short-lived if the egg retrieval and implantation are successful. Like IVF, another hormone-disrupting experience is bound to cause bloating, particularly in the first trimester, and weight gain: pregnancy.

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