IUI, Medications

Medications Commonly Used During IUIs and How They Work

Laura Morrissey, RN, BSN

5 min read

What is an intrauterine insemination (IUI)?

Getting started with fertility treatments often begins with Intrauterine Insemination or IUI. IUI is  the least invasive and least expensive fertility treatment method. 

There are two types of IUIs, medicated and natural. In a medicated IUI, you will take medications to help your body to grow an egg (or a few). In a natural IUI, your body grows the egg to maturity on its own. Once the egg is mature, ovulation is either triggered using a medication or allowed to happen naturally. Then, the IUI procedure is scheduled about 24-36 hours after ovulation. 

During the IUI procedure, the doctor will take a concentrated sperm sample and place it into the uterus using a thin plastic catheter. The IUI not only cuts down the journey that the sperm needs to travel to meet the newly ovulated egg, but also places the sperm into the uterus at the perfect time to be able to fertilize the egg(s) and create a pregnancy. 

After the IUI procedure, you may take progesterone medication to supplement the progesterone that your body is already making. These supplements are taken up until your pregnancy test and will continue if the test is positive.

Ovarian Stimulation Medications

Ovarian stimulation medications are used to stimulate the ovaries to grow an egg or a few eggs to maturity to be ovulated and potentially fertilized during the IUI. There are oral and injectable medications used in medicated IUI cycles. 

Oral Medications

There are two oral medications used to stimulate the ovaries in medicated IUIs: Clomid and Letrozole. Clomid, also known as clomiphene citrate, works by tricking the body into thinking that estrogen levels are low. As a result, the body produces more Follicle Stimulating Hormone(FSH), which stimulates the ovaries to produce one or a few mature eggs that will be triggered to ovulate for possible fertilization during the IUI.

Clomid typically starts with a dose of 50mg taken for 5 days in the first half of your cycle (commonly cycle days 3-7, but this can vary with cycle length).

Clomid 50mg package

The other oral IUI medication used to stimulate the ovaries is called Letrozole or Femara. Letrozole is a type of drug known as an aromatase inhibitor. It works by blocking the conversion of androgen hormones into estrogen, so your body maintains a low estrogen level. Similarly to Clomid, when the body detects low estrogen levels, it produces more follicle stimulating hormone (FSH) to compensate and try to get the ovaries to grow an egg. The ovaries respond to the increased FSH by growing one or a few eggs to maturity to have the opportunity to be fertilized by the sperm introduced during the IUI procedure.

Letrozole typically starts with a dose of 2.5 mg taken for 5 days in the first half of your cycle (commonly cycle days 3-7, but this can vary with cycle length).

Letrozole 2.5mg tablets


Gonadotropins are well known for being used in IVF and egg freezing cycles, but they are also sometimes used in medicated IUI cycles. Typically, gonadotropins are reserved for patients who were unsuccessful using the oral IUI medications. 

The most common gonadotropins are Menopur, Follistim, and Gonal-F. All three of these medications are administered as subcutaneous injections. The injections are taken daily starting on cycle day 2 or 3 of your period and continued until one or a few follicles are measuring of a size that indicates that they likely contain a mature egg. Those eggs are then triggered to ovulate using a trigger shot in preparation for the IUI. During gonadotropin IUI cycles, the medication doses vary but are often kept low so as to not over stimulate the ovaries and create too many mature eggs.

Most clinics have a cut off for how many mature follicles (each containing an egg) can be present in the ovaries to safely proceed with the IUI. If there are too many mature follicles that will ovulate one egg each, the risk of high order multiples (twins, triplets, or greater) becomes too great. This poses a risk to both the mother and the pregnancy. Most clinics will cancel the IUI cycle if 4 or more mature follicles are present, but it's important to discuss your clinic’s rules before getting started.

Trigger Shot

After the ovaries have been stimulated to grow 1-3 mature eggs, a medication known as the Trigger Shot is used to initiate the final maturation of the eggs and kick off the ovulation process. The trigger shot is made up of a hormone called hCG, or Human Chorionic Gonadotropin. The most common trigger shot for an IUI cycle is known as Ovidrel. Ovidrel is a pre-filled syringe of hCG that is injected subcutaneously. Your clinic will provide you with a time to do the injection and then will time the IUI procedure between 24 and 36 hours after the trigger shot. 

Progesterone Supplementation

After the eggs ovulate and the IUI procedure is completed, your doctor will likely instruct you to start taking progesterone to supplement the progesterone that your body is already making naturally. Progesterone supports both embryo implantation and the normal growth and development of the potential pregnancy.

Supplemental progesterone is usually administered vaginally. Vaginal progesterone typically comes in the form of capsules filled with a progesterone cream or gel. The medication may come with a plastic applicator to assist in inserting the capsules deep into the vagina near the cervix. If no applicator is provided, the capsules are inserted manually. Depending on the brand and dosage required, you may be instructed to insert a progesterone capsule anywhere from 1 to 3 times a day. Make sure to clarify your instructions with your clinic before getting started.


As the outer coating of the capsule breaks down in the vagina and the progesterone compound is released, it is normal for some of the white or cream colored medication to leak out. It is highly recommended to wear a panty liner or pad while taking the progesterone and to change it frequently to prevent any exterior skin irritation or discomfort.

The progesterone is usually started the day after the IUI and continued at least through the pregnancy test. If the pregnancy test is positive, your clinic will provide you with instructions for continuing your progesterone supplements. It is often continued through the 7th and 10th week of pregnancy. 

IUIs are often considered the least complicated type of fertility treatment, and a lot of patients start with IUI. But just because the treatment is deemed less complicated, that doesn’t mean there isn’t a lot to keep track of, especially when it comes to medications. Using the Berry app is a great way to make sure you stay on top of everything you need to do. You’ve got this!