5 Undiagnosed Medical Conditions that Commonly Cause Weight Gain in Women

Weight gain

You’ve tried everything to lose weight! You exercise religiously and watch what you eat. Still, the pounds won’t budge. It’s a frustrating problem, especially when you’re doing everything right to prevent weight gain. Could something else be going on?

There are a number of medical conditions that commonly cause weight gain and some of these conditions have few or no symptoms. That’s why it’s a good idea to get a check-up and blood work if you’ve given diet and lifestyle a try without success. Some of these conditions, like polycystic ovarian syndrome and an underactive thyroid gland, are more common in women too. So, rule out these and other health problems, before assuming you can’t lose weight. Treating them could make the difference and help you get on track to a leaner, healthier body. Here are five of the most common problems that cause weight gain and may go undetected.

An Underactive Thyroid Gland & Weight Gain

It’s not surprising that an underactive thyroid gland causes weight gain since your thyroid gland is the master regulator of your resting metabolism. An underactive thyroid, also known as hypothyroidism, is common, especially in women after menopause. The most common cause of hypothyroidism in women is Hashimoto’s thyroiditis, an autoimmune condition where the immune system attacks the thyroid. Fortunately, it’s treatable with thyroid replacement therapy.

Other than weight gain, other symptoms you might experience with hypothyroidism include:

  • Dry skin
  • Feeling cold much of the time
  • Hair loss
  • Brain fog
  • Fatigue
  • Constipation
  • Depression

However, you can have an underactive thyroid with few symptoms other than weight gain. The best way to find out how well your thyroid is working is through a blood test that measures how much thyroid hormone your thyroid is producing. Your doctor can order such a test and make further recommendations based on the results.


Depression can cause weight gain or weight loss, but weight gain is a common problem with mild depression. Some people who are depressed try to make themselves feel better by eating comfort foods. Then, after eating sugar and high-calorie food, they don’t have the energy or motivation to exercise. Plus, medications used to treat depression can cause weight gain too. In addition, levels of the stress hormone cortisol are often higher in those who are depressed or despondent. If insomnia accompanies depression, as it often does, that makes weight gain even more likely.

Polycystic Ovarian Syndrome

Another common condition that typically affects women before menopause is polycystic ovary syndrome, a condition where multiple cysts pop up on the ovaries. In fact, about one in ten premenopausal women have this condition and many don’t know it. Polycystic ovarian syndrome is caused by an excess of hormones called androgens and many of the effects from it, including weight gain, are caused by too much androgen, a type of male sex hormone Although women have androgens circulating in their body too, women with polycystic ovarian syndrome have too much. Other effects of too much androgen include increasing acne outbreaks and hair growth on the face.

How do you know if you have it? There isn’t one definitive test for polycystic ovarian syndrome, however, blood tests, pelvic exam, and an ultrasound may be helpful for making the diagnosis. Some doctors recommend certain types of oral contraceptives for people with polycystic ovarian syndrome. Losing as little as 10% of body weight can also make a difference. If you’re premenopausal and gaining weight, particularly around the middle or are having increased hair growth on the face and other body parts or having fertility issues, it’s worth talking to your physician about the possibility that you  have this condition.

Sleep Apnea

Sleep apnea is a condition where you stop breathing for short periods of time throughout the night. These periods of paused breathing may occur many times over the course of sleep. People who have sleep apnea often feel tired during the day and their partner may say they snore frequently. It’s a serious condition because it can lead to elevated blood pressure and heart problems, so it’s important to get it diagnosed and take it seriously.

Although sleep apnea is more common in people who are obese and store a lot of fat around their upper chest and neck, there’s evidence that sleep apnea can cause further weight gain. One reason is sleep apnea interferes with sleep. When you don’t sleep enough, appetite hormones, leptin and ghrelin, don’t reign in appetite as effectively. Plus, you’re less likely to feel like exercising or moving around.

If you snore at night or have a thick or fat neck, check with your physician and make sure you’re not one of the many people who suffers from sleep apnea.

Medications Used to Treat Medical Weight Gain Conditions

Many medications commonly cause weight gain. Some of the most likely culprits are steroids, hormone replacement therapy, birth control pills, anti-depressants, some medications used to control blood sugar, beta-blockers, anti-seizure medications, migraine medications, and antihistamines. If you’re taking new medications and gaining weight, check with your physician and see if your prescriptions could be playing a role. Medication-associated weight gain is quite common. It’s possible that your physician may have another medication that works in the same way but is less likely to cause weight gain.

The Bottom Line

These aren’t the only health conditions that can cause weight gain, but these are some of the most common that cause weight gain in women. Once you get a clean bill of health, reevaluate your lifestyle and eating habits. Are you getting enough sleep and managing stress? Getting this part of the equation right matters too. See if you can make small tweaks to your lifestyle that will deliver better results. Also, be patient. It takes time to change your physique and your health but it’s well worth the effort when it comes to your health.



  • com. “Are Your Meds Making You Gain Weight?”
  • Clin Obes. 2017 Dec;7(6):354-359. doi: 10.1111/cob.12208. Epub 2017 Aug 11.
  • gov. “Polycystic Ovarian Syndrome”
  • com. “Does Sleep Apnea Cause Weight Gain? Here’s What You Need to Know”
  • org. “Polycystic Ovarian Syndrome”
  • Indian J Endocrinol Metab. 2016 Jul-Aug; 20(4): 554–557. doi: 10.4103/2230-8210.183454.
  • Int J Obes (Lond). 2009 Mar; 33(3): 335–341.Published online 2009 Jan 13. doi: 10.1038/ijo.2008.273.


Related Articles By Cathe:

5 Science-Backed Reasons Why Weight Gain Is A Problem As You Age

5 Ways Psychological Stress Leads to Weight Gain

6 Surprising Reasons You Gain Weight in the Winter

How Meditation Can Help You with Weight Training

How Mindfulness Meditation Can Help You with Weight Training

How Lack of Quality Sleep Limits Muscle Growth

Hi, I'm Cathe

I want to help you get in the best shape of your life and stay healthy with my workout videos and Free Weekly Newsletter. Here are three ways you can watch and work out to my exercise videos:

Get Your Free Weekly Cathe Friedrich Newsletter

Get free weekly tips on Fitness, Health, Weight Loss and Nutrition delivered directly to your email inbox. Plus get Special Cathe Product Offers and learn about What’s New at Cathe Dot Com.

Enter your email address below to start receiving my free weekly updates. Don’t worry…I guarantee 100% privacy. Your information will not be shared and you can easily unsubscribe whenever you like. Our Privacy Policy