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If you're starting fertility treatment—or even just thinking about it—there's a good chance this question has crossed your mind:
"Will IVF make me gain weight?"

It's a common concern. Between hormone shots, emotional ups and downs, and the physical changes happening in your body, it’s understandable to wonder whether weight gain is part of the package. The good news? A recent study offers real answers—and they’re more reassuring than you might think.

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Where the Worry Comes From

Fertility treatment can feel like a rollercoaster. You're injecting hormones, changing your schedule, avoiding intense workouts, and navigating a minefield of emotions. On top of all that, you may notice bloating or a feeling of heaviness—and naturally, you might assume you’re gaining weight.

You're not alone. Many people going through IVF say they feel “puffier” or “less like themselves.” But here's what science tells us: the actual weight gain during IVF is minimal—if it happens at all.

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The Science Behind It

A recent study followed over 300 people undergoing IVF at a fertility clinic in Israel. Researchers tracked their weight at three points in each treatment cycle: before hormone injections, at the start of stimulation, and after embryo transfer (on pregnancy test day).

Here’s what they found:

Most people gained less than half a kilogram (that’s about 1 pound).
The average weight change was under 1% of body weight.
Even after two or three cycles, the weight shifts stayed tiny.
The changes were the same whether someone had a “normal,” “overweight,” or “obese” BMI.

In other words, this kind of weight change is so small it doesn’t matter clinically—and it usually goes away after treatment ends.

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**So Why Do I Feel Heavier?**

Great question. Even if the scale doesn’t budge much, you might still feel like your body is changing. That’s likely due to:

Bloating from rising estrogen levels
Fluid retention (also called edema)
Progesterone slowing digestion, causing gas or constipation
Anxiety and stress influencing how your body feels—and how you relate to it

These are real, valid experiences. But they’re also temporary, and they’re not the same as putting on fat or truly gaining weight.

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Should I Be Worried About Long-Term Weight Gain?

Not based on this study. In fact, researchers found that even when people felt changes, their actual weight remained stable. Some participants even lost a tiny bit of weight, and no group—regardless of size—had a weight change that would raise any red flags medically.

That said, some people do notice their habits shift during treatment. You might:

Move your body less due to post-retrieval instructions
Reach for comfort food during emotional moments
Feel out of sync with your usual routine

If that’s the case, it’s okay! Be gentle with yourself. IVF is intense, and your body is doing something amazing.

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What You Can Do

If you're worried about body changes during treatment, try these simple tips:

Hydrate: Water helps reduce bloating and keeps things moving.
Eat mindfully: Nourish your body with balanced meals that support hormone regulation.
Walk it out: Light movement like walking or yoga can ease bloating and boost mood.
Talk about it: Whether it’s with your doctor, a therapist, or a friend, you don’t have to carry the stress alone.

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Bottom Line

So, does fertility treatment make you gain weight?

Not in any meaningful way. According to science, most people going through IVF don’t gain significant weight. What you may feel is real—bloating, discomfort, stress—but the number on the scale? It usually stays the same.

More importantly, your body is going through a powerful process. It’s okay if it looks or feels different for a while. You are not alone, and there’s nothing wrong with you.

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Reference

Saar-Ryss B, et al. (2024). Is there any truth in the myth that IVF treatments involve weight gain? Frontiers in Reproductive Health. https://doi.org/10.3389/frph.2023.1327110

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