Clomid (Clomiphene Citrate) Treatment and Side Effects

How Clomid Works, Why It's Prescribed and Possible Side Effects

Twins sitting on a bed, perhaps conceived with Clomid treatment
About 10% of pregnancies conceived with Clomid will result in twins. Donnie Ray Jones / Flickr

Clomid is an ovulatory stimulating drug used to help women who have problems with ovulation. It is the most commonly used and best well-known fertility drug. Because Clomid can be prescribed by a gynecologist, and doesn't require a fertility specialist, it's also the very first fertility treatment tried for most couples.

Clomid is taken as a pill. This is unlike the stronger fertility drugs, which require injection.

Clomid is also very effective, stimulating ovulation 80 percent of the time.

Clomid may also be marketed under the name Serophene, or you may see it sold under its generic name, clomiphene citrate. 

Note: Clomid can also be used as a treatment for male infertility. This article focuses on Clomid treatment in women.

When Is Clomid Used?

If a woman has irregular cycles, or anovulatory cycles (menstruation without ovulation), Clomid may be tried first.

Clomid is used when there are problems with ovulation but no problems with male infertility or blocked fallopian tubes.

(If fallopian tubes are blocked, stimulating ovulation would be pointless. The egg and sperm can't meet if the tubes are blocked.)

Clomid is often used in treating polycystic ovarian syndrome (PCOS) related infertility.

It may also be used in cases of unexplained infertility or when a couple prefers not to use the more expensive and invasive fertility treatments.

(However, it's important to remember that the more expensive treatment is sometimes the most appropriate.)

Clomid may also be used during an IUI (intrauterine insemination) procedure.

It is rarely used during IVF treatment. With IVF, injectable ovulation meds are more frequently chosen.

How Is Clomid Taken?

You should follow the directions your doctor gives you.

Every doctor has a slightly different protocol.

With that said, the most common dosage of Clomid is 50 mg taken for five days, on Days 3 through 7 of your cycle. Some doctors prefer you take the pills on Days 5 through 9 of your cycle. 

Does it really matter if your doctor suggests the Day 3 to 7 protocol or the Day 5 to 9 one? Not really.

Ovulation and pregnancy rates have been shown to be similar whether the drug is started on day two, three, four, or five.

Don't feel concerned if your doctor tells you a different protocol to follow than your friend.

If 50 mg doesn't work, your doctor may increase the medication. Or, they may give it another try at 50 mg.

You might think that more is always better, but higher doses, especially at or above 150 mg, can actually make conception more difficult. (See below, under side effects.)

What are Clomid's Common Side Effects?

Clomid's side effects aren't so bad, as far as fertility drugs are concerned.

The most common side effects are hot flashes, breast tenderness, mood swings, and nausea.

Once the medication is stopped, the side effects will leave, too.

Possible side effects of Clomid include:

  • Enlarged and tender ovaries (14%)
  • Hot flashes (11%)
  • Abdominal tenderness, due to enlarged and tender ovaries (7.4%)
  • Bloating (5.5%)
  • Breast tenderness (2.1%)
  • Vaginal dryness or thicker cervical mucus (percentage of occurrence not available)
  • Nausea and vomiting (2.2%)
  • Anxiety and insomnia (1.9%)
  • Vision disturbances (1.6%)
  • Headache (1.3%)
  • Abnormal uterine bleeding (spotting) (0.5%)
  • Mood swings and fatigue (0.3%)

Read more about Clomid side effects and risks:

The side effect you're probably most familiar with is the risk of multiples.

You have a 10 percent chance of having twins when taking Clomid. Triplets or quadruplets are rare, happening less than 1 percent of the time.

One of the more annoying side effects to comprehend is that Clomid can decrease the quality of your cervical mucus. This can cause problems with sperm being able to move easily through the cervix, making conception more difficult.

Clomid can also make the lining of your uterus thinner and less ideal for implantation.

This is why "more" is not necessarily better when it comes to Clomid dosage and use.

How Successful Is Clomid?

Clomid will jump-start ovulation in 80 percent of patients. But ovulating doesn't guarantee pregnancy will occur.

About 40 to 45 percent of women using Clomid will get pregnant within six cycles of use.

Using Clomid for more than six cycles is not generally recommended.

If six cycles go by, and pregnancy is not achieved, other alternatives may be considered.

More on fertility treatment:


Medications for Inducing Ovulation: A Guide for Patients. American Society of Reproductive Medicine. Accessed February 3, 2008.

General Infertility FAQ. InterNational Council on Infertility Information Dissemination, Inc. Accessed February 3, 2008.

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