Clomid (Clomiphene) Side Effects and Risks

Mood Swings, Headaches, Bloating, and Twins

Clomid (clomiphene) side effects are mild for most people. The most common ones include hot flashes, headaches, bloating, mood swings, and breast tenderness.

However, as with any drug, you should be aware of the potential risks before treatment. Clomid may also be sold under its generic name clomiphene or under the brand name Serophene. These medications are all the same drug. 


Many Clomid side effects are the result of how the drug works. Clomiphene tricks the body into thinking there’s not enough estrogen. It does this by blocking estrogen receptors.

This leads the body to release more GnRH, a hormone that tells the pituitary to release more FSH and LH. These hormones stimulate the ovaries and boost ovulation. 

Because most of the estrogen receptors are blocked, this leads to some of clomiphene’s side effects like headaches and vaginal dryness. Most of the other side effects are caused by the ovaries becoming slightly enlarged.

Clomid side effects
Illustration by JR Bee, Verywell 

Not all possible side effects and risks are listed below. If you are experiencing severe side effects, unusual symptoms, or are concerned for any reason, contact your doctor.

Consult with your doctor to get a personalized assessment of your risks for various side effects and to address any questions or concerns you may have.

Hot Flashes

Hot flashes (or, in official 'doctor speak,' vasomotor flushes) are a common side effect of clomiphene. About 1 in 10 women experienced them in clinical studies.

When you’re having a hot flash, you may:

  • suddenly feel extremely warm
  • experience face flush
  • break out in a sweat
  • have a more rapid heartbeat

After a hot flash, you might feel chilled, especially if you broke out in a sweat. Hot flashes are also known as night sweats if they happen while you’re sleeping.

A hot flash can be a bit unnerving the first time it happens. That said, it’s not a dangerous event—just an uncomfortable one.

Bloating and Abdominal Discomfort

Another very common clomiphene side effect is bloating and abdominal discomfort. Research has found it occurred in about 6% of women.

Wearing clothing that isn’t too tight around the waist may help. The bloated feelings should pass once your treatment cycle is over.

Of course, if you experience more than moderate discomfort and cramps, call your doctor. Severe bloating or abdominal tenderness may be a sign of ovarian hyperstimulation syndrome.

(More on this below.)

Weight Gain

Weight gain isn’t as common as bloating, with less than 1 in 100 women reporting weight changes in early clinical studies. But it’s a side effect that you hear often through the infertility grapevine.

What might explain why so few reported weight gain in early research, but so many women online complain about adding on pounds?

One possible explanation is the weight gain is a temporary outcome of bloating. Bloating is common during Clomid treatment, as is retaining water weight. If the weight gain is connected to bloating, then your weight should go back to normal after treatment.

Another possibility is the stress of treatment leads to unhealthy eating. The best way to combat this is to plan your meals and have healthy, fertility-friendly snacks around when you get the munchies.

Mood Swings

Mood swings are another side effect of clomiphene that in early, pre-approval, clinical studies was not frequently reported (less than 1% of women).

However, later studies found that almost half of all women experience mood disturbances on Clomid.

Mood swings may mean feeling more emotionally sensitive, tearful, or even depressed or anxious. Infertility itself can bring on these feelings without drugs. Try to be forgiving and gentle with yourself and practice good self-care during treatment.

Nausea and Dizziness

About 2% of women experience nausea and vomiting while taking clomiphene. Taking the medication in the evening may help.

If the nausea is intense, or you have trouble keeping down food and fluids, be sure to report this to your doctor.

Severe nausea can also be a sign of ovarian hyperstimulation syndrome, a rare but potentially dangerous side effect of fertility drugs.

Breast Tenderness

Breast tenderness is another potential side effect of clomiphene, occurring in 2% of women during clinical trials.

This is another side effect that can have women wondering if they’re experiencing early pregnancy symptoms, but usually it’s just a drug side effect.

Abnormal Menstrual Bleeding

Just over 1% of women in clinical trials reported spotting or abnormal menstrual bleeding.

This can drive some women crazy. They see spotting and think, “Oh, it’s implantation spotting!” But if you’re taking fertility drugs, spotting in the middle of your cycle can be related to the drugs. You shouldn't necessarily assume it's a pregnancy sign.

Contact your doctor, if the spotting is accompanied by other symptoms, such as:

  • abdominal pain
  • nausea and vomiting
  • fever
  • or, something just doesn’t feel right


A little over 1% of women in clinical trials reported headaches.

If you’re experiencing headaches, it may help to take the medication in the evening. This way, you can sleep through them. (If your doctor told you to specifically take the medication in the morning, ask first.)

You should also be sure to get plenty of fluids since mild dehydration can cause headaches.

Vaginal Dryness or Thick Cervical Mucus

This is a frustrating potential side effect of clomiphene, as thick or absent cervical fluid can interfere with achieving pregnancy.

Cervical mucus is needed to help transport the sperm into the cervix. If clomiphene causes thick cervical mucus, this can decrease the chances of getting pregnant.

Let your doctor know if this happens during treatment. He can consider whether clomiphene is the right drug for you, or find a way to treat or bypass the problem (like with IUI treatment).

You may want to try using a sperm-friendly lubricant to make sex more comfortable.

Blurred Vision

A frightening, but usually not dangerous, side effect of clomiphene is blurred vision. It occurred in 1.5% of women during clinical trials.

Vision disturbances may include...

  • blurred vision
  • seeing flashing lights
  • seeing floaters 

This is more likely at higher doses. 

If you experience vision changes, be sure to contact your doctor right away. The symptoms should go away once the medication is stopped.

(And, obviously, you should take care in driving or operating dangerous equipment if you experience visual side effects.)

Additional Risks

While side effects are usually physical or emotional discomforts experienced while taking a drug, a drug's risks are what may occur beyond what you feel. With that said, here are the possible risks to Clomid:

Twin or multiple pregnancy: The risk of getting pregnant with twins or more may be the most well-known side effect of clomiphene. Data from the National Birth Defects Prevention Study, 1997–2005, shows 11.7% of pregnancies were twin pregnancies and 1.1% were triplets or quadruplets.

To reduce the chances of having twins, your doctor should always start you on the lowest dose first, before trying higher doses.

Ovarian Hyperstimulation Syndrome (OHSS): Usually mild with clomiphene treatment, but in rare cases, the severe form can occur. Without treatment, severe OHSS can be life-threatening.

If you experience nausea, severe abdominal or pelvic pain, sudden weight gain, or severe bloating, contact your doctor immediately.

Irreversible vision disturbances: Extremely rare, only in those who continue treatment after vision disturbance began. In those who discontinued treatment, vision disturbance stopped after three days.

Ovarian cysts: 15.4% of women will develop an ovarian cyst during treatment. The cyst is typically benign (not cancer), and it should go away on its own not long after the treatment cycle is over. If the cyst does not go away, the doctor should follow up and reevaluate. In rare cases, it may require surgical intervention.

Ovarian cancer: Some studies have found an increased risk of ovarian cancer if clomiphene is taken for a year or longer. It's unclear if this is caused by clomiphene or infertility itself.

Strategies to Reduce Side Effects

You can't completely avoid potential side effects of Clomid or eliminate all risks, but there are things you or your doctor can do to help possibly reduce them. 

  • Start on the lowest dose possible: More doesn't necessarily mean better. Your doctor is likely to start you at the lowest dose, but if the first cycle fails, they may encourage you to try again at the same dose. You might think a higher dose would be better, but this isn't necessarily true. 
  • Take the pill in the evening: If you're getting headaches, taking Clomid before bed may help.
  • Monitor your diet: Weight gain can occur while taking Clomid, but most of that weight gain should be temporary. Weight gain that comes from bloating and water retention will go away. However, the weight you gain from stress eating while taking Clomid will stay. 
  • Practice good self-care: Mood swings on Clomid are real. They aren't "just in your head." The best way to cope with this side effect is to take good care of yourself. Get enough sleep, eat well, and seek the support of friends and family.
  • Dress in layers: If you're experiencing hot flashes, dress in layers. This way, if you suddenly feel overheated, you can take something off and cool down a little quicker. Drinking something cold can also help you cool down.    
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9 Sources
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  1. Rebar RW. Ovulatory Dysfunction. Merck Manual Professional Version. Updated January 2019.

  2. U.S. Food and Drug Administration. Clomid (clomiphene citrate tablets USP). Sanofi-aventis U.S. LLC. Updated October 2012.

  3. Blenner JL. Clomiphene-Induced Mood Swings. J Obstet Gynecol Neonatal Nurs. 1991;20(4):321-327. doi:10.1111/j.1552-6909.1991.tb01695.x

  4. Usadi RS, Merriam KS. On-label and off-label drug use in the treatment of female infertility. Fertil Steril. 2015;103(3):583-594. doi:10.1016/j.fertnstert.2015.01.011

  5. Reefhuis J, Honein MA, Schieve LA, Rasmussen SA. Use of clomiphene citrate and birth defects, National Birth Defects Prevention Study, 1997-2005. Hum Reprod. 2011;26(2):451-457. doi:10.1093/humrep/deq313

  6. Schram CA. Outdated approach to a common problem. Can Fam Physician. 2016;62(9):713-716.

  7. Purvin VA. Visual disturbance secondary to clomiphene citrate. Arch Ophthalmol. 1995;113(4):482-484. doi:10.1001/archopht.1995.01100040102034

  8. Frattarelli JL, Dempsey MS. Characteristics of baseline ovarian cysts in clomiphene citrate ovulation cycles. Fertil Steril. 2004;82(4):979-981. doi:10.1016/j.fertnstert.2004.02.145

  9. Brinton LA, Moghissi KS, Scoccia B, Westhoff CL, Lamb EJ. Ovulation induction and cancer risk. Fertil Steril. 2005;83(2):261-274. doi:10.1016/j.fertnstert.2004.09.016