Understanding Treatment: How Do FSH Injections Make You Feel?

October 7, 2025 •

4 min read

In 2022, one out of every 37 babies born in the US was conceived using Assisted Reproductive Technology (ART) [1.6.1]. A key part of many treatments involves follicle-stimulating hormone (FSH). This raises a crucial question for many: how do FSH injections make you feel?

Quick Summary

FSH injections often cause physical sensations like bloating, headaches, breast tenderness, and injection site reactions [1.2.2, 1.3.2]. Emotionally, many report mood swings, irritability, and fatigue due to hormonal shifts [1.2.2, 1.3.2].

Key Points

Common Physical Effects: Expect bloating, abdominal pressure, headaches, and breast tenderness as your ovaries are stimulated [1.2.2, 1.3.2].
Emotional Impact: Hormonal shifts often cause mood swings, irritability, anxiety, and fatigue [1.2.2, 1.3.2].
Injection Site Reactions: Mild, temporary soreness, redness, or bruising at the injection site is normal [1.2.1, 1.3.2].
Serious Risk (OHSS): Ovarian Hyperstimulation Syndrome is a rare but serious side effect. Report severe abdominal pain, rapid weight gain, or shortness of breath to your doctor immediately [1.4.1].
Management is Key: Managing side effects involves staying hydrated, rotating injection sites, resting, and communicating openly with your care team [1.5.2, 1.5.3].
Hormone's Purpose: FSH injections are used to stimulate the ovaries to produce multiple eggs for fertility treatments like IVF [1.8.4].
Individual Experience: Every person's response is different, and symptoms can vary in intensity from person to person and cycle to cycle [1.3.2].

What Are FSH Injections and Why Are They Used?

Follicle-stimulating hormone (FSH) is a naturally occurring hormone produced by the pituitary gland [1.8.1]. Its primary role in women is to stimulate the growth and maturation of follicles in the ovaries, each containing an egg [1.8.3, 1.8.5]. In fertility treatments like In Vitro Fertilization (IVF), doctors prescribe FSH injections (a type of gonadotropin) to encourage the ovaries to produce multiple mature eggs in a single cycle, rather than the usual one [1.7.3, 1.8.4]. This process, known as controlled ovarian stimulation, significantly increases the chances of retrieving viable eggs for fertilization [1.3.4, 1.7.3]. Common brand names for these medications include Gonal-F and Follistim [1.5.5, 1.7.1].

Common Physical Side Effects

The introduction of synthetic hormones can lead to a range of physical side effects as the body adjusts and the ovaries begin to enlarge with developing follicles [1.3.1]. While experiences vary, some feelings are more common than others.

Physical Sensations You Might Experience:

Bloating and Abdominal Fullness: As follicles grow, the ovaries expand, leading to a feeling of pressure, bloating, and mild abdominal discomfort or pain. This is one of the most frequently reported side effects [1.2.2, 1.3.2]. Some temporary weight gain from fluid retention is also possible [1.3.2].
Injection Site Reactions: The daily injections are subcutaneous (under the skin) and can cause temporary redness, soreness, bruising, or irritation at the injection site [1.2.1, 1.3.2].
Headaches: Fluctuating hormone levels are a common trigger for headaches during the stimulation phase [1.2.2, 1.5.5].
Breast Tenderness: Similar to pre-menstrual symptoms, the hormonal changes can cause breasts to feel sore or swollen [1.2.2, 1.9.4].
Nausea and Fatigue: Some individuals report mild nausea and a general feeling of tiredness during their cycle [1.2.1, 1.3.2].

Emotional and Psychological Effects

The fertility treatment journey is inherently stressful, and the hormonal medications can amplify these feelings. The entire IVF cycle can be an emotional rollercoaster, marked by both physical discomfort and psychological stress [1.2.2, 1.2.6].

Common emotional changes include:

Mood Swings and Irritability: Hormonal fluctuations can lead to heightened emotions, irritability, or mood changes that feel more intense than typical pre-menstrual syndrome (PMS) [1.2.2, 1.3.2].
Anxiety: The stress of the treatment process, frequent appointments, and anticipation of the outcome can cause significant anxiety [1.9.3].
Fatigue: Beyond physical tiredness, many report feeling emotionally and mentally drained during the stimulation phase [1.3.2].

Comparison of Common Gonadotropins

While this article focuses on FSH, it's helpful to understand the different types of gonadotropins used in treatment. They all aim to stimulate the ovaries but have different compositions [1.7.1].


Medication Type	Composition	Source	Primary Action
rFSH (e.g., Gonal-F, Follistim)	Contains only Follicle-Stimulating Hormone (FSH)	Recombinant (Lab-created)	Stimulates follicle growth [1.7.1].
hMG (e.g., Menopur)	A mix of FSH and Luteinizing Hormone (LH)	Urinary (Purified from the urine of postmenopausal women)	Stimulates follicle growth with LH support [1.7.1, 1.7.5].
hCG	Human Chorionic Gonadotropin	Recombinant or Urinary	Acts like LH to trigger the final maturation and release of eggs [1.7.3, 1.7.4].

Understanding Ovarian Hyperstimulation Syndrome (OHSS)

A rare but serious side effect of FSH injections is Ovarian Hyperstimulation Syndrome (OHSS) [1.2.5]. This is an exaggerated response to the hormone medication, causing the ovaries to swell and leak fluid into the abdomen [1.4.1, 1.4.6]. It affects a small percentage of patients, with severe cases occurring in approximately 1-2% of those undergoing stimulation [1.3.5, 1.4.2].

Symptoms of OHSS:

Mild to Moderate OHSS: Symptoms include abdominal bloating, mild to moderate pain, nausea, vomiting, diarrhea, and tenderness near the ovaries [1.4.1].
Severe OHSS: This is a medical emergency. Symptoms include rapid weight gain (more than 2.2 pounds in 24 hours), severe abdominal pain, shortness of breath, decreased urination, and severe, persistent nausea and vomiting [1.4.1]. If you experience severe symptoms, contact your doctor immediately [1.2.1].

Risk factors for OHSS include having Polycystic Ovary Syndrome (PCOS), being under age 35, having a large number of follicles, and high estrogen levels before the trigger shot [1.4.1, 1.4.2].

Tips for Managing Side Effects

While some discomfort is expected, there are ways to manage the side effects and make the process more tolerable.

Stay Hydrated: Drinking plenty of fluids, especially those with electrolytes, can help with bloating and overall well-being [1.3.3].
Manage Injection Pain: Rotate injection sites to prevent skin irritation [1.5.3]. Applying an ice pack to the area before the injection can help numb the skin and reduce discomfort [1.5.2].
Rest: Listen to your body and get plenty of rest to combat fatigue [1.5.2]. Your doctor may recommend avoiding strenuous exercise as your ovaries enlarge [1.3.1].
Wear Loose Clothing: Comfortable, loose-fitting clothes can help ease discomfort from bloating [1.5.2].
Communicate: Keep an open line of communication with your fertility care team. They can offer support and make adjustments if side effects become severe [1.3.1].

Conclusion

FSH injections are a cornerstone of modern fertility treatment, but they are not without their side effects. Physically, you can expect sensations like bloating, headaches, and localized soreness. Emotionally, the combination of hormones and the stress of the process can lead to mood swings and anxiety [1.2.2, 1.3.2]. Most of these effects are mild and temporary [1.3.2]. However, it is vital to be aware of the signs of serious complications like OHSS and maintain close contact with your medical team throughout the journey [1.4.4]. Understanding what to expect can empower you to navigate the process with greater confidence.

For more information from an authoritative source, you can visit ReproductiveFacts.org [1.3.5].

Frequently Asked Questions

The most common side effects include headache, bloating, abdominal pain or fullness, mood swings, breast tenderness, and redness or soreness at the injection site [1.2.1, 1.2.2, 1.3.2].

Temporary weight gain of five to six pounds is not unusual, largely due to hormonal shifts and fluid retention. This typically resolves within two weeks after egg retrieval [1.3.1, 1.3.2].

Yes, it is very common to experience mood swings, irritability, and heightened emotions due to the hormonal medications used during ovarian stimulation [1.2.2, 1.3.2].

Ovarian Hyperstimulation Syndrome (OHSS) is an exaggerated response to fertility medication. A mild form occurs in 10-20% of cycles, but the severe form, which requires medical attention, happens in only about 1-2% of cases [1.3.5, 1.4.2].

To minimize discomfort, you can apply an ice cube to numb the skin before injecting, rotate the injection location daily, and ensure you're using the correct subcutaneous technique as shown by your nurse [1.3.3, 1.5.2].

As your ovaries grow, you may be advised to avoid high-impact or strenuous activities. Your clinic will provide specific guidelines, but gentle activity is usually fine [1.3.1].

Most mild side effects like bloating and moodiness are temporary and tend to resolve after the egg retrieval procedure and as your hormone levels return to normal [1.3.2, 1.3.1].