What if there’s complications during my stem cell treatment?

At Stem Cell Mexico, you are monitored by nursing and medical staff during and after your procedure, often with an overnight stay; procedures are performed in a medical setting located next to a full-service hospital, so emergency and specialist care are available if needed; and you leave with written instructions, warning signs and direct contact information for the team. Most side effects, such as soreness, swelling, mild fever or fatigue, are temporary and managed with simple measures. If a complication appears after you return home, you contact our team and, when necessary, seek care locally, bringing your medical report and cell documentation so your local doctors understand exactly what you received.

This guide explains which complications can occur, how each is handled during your stay and after you return home, and how to prepare so that any problem is managed quickly and safely.

How common are complications?

Large analyses of randomized trials provide reassurance:

• A systematic review in EClinicalMedicine (Thompson and colleagues, 2020) of 55 randomized trials with 2,696 patients receiving intravascular MSCs found an increased risk of temporary fever but no increase in acute infusion toxicity, infections, thrombotic events, malignancy or death.
• A 2026 analysis in Stem Cells Translational Medicine (Hum and colleagues) of 42 randomized trials with 2,280 patients receiving umbilical cord MSCs found the same pattern and recommended continued long-term monitoring.

These results come from controlled settings with screened patients, quality-controlled cells and monitoring, which is the model we follow.

The first 24 to 72 hours: what is normal and what is not

Knowing what to expect helps you tell a normal recovery from a complication. In the first day or two after an intravenous infusion, it is normal to feel tired, have a mild headache or a low-grade fever, and want to rest. After an injection, it is normal for the treated area to be sore, swollen and stiff, sometimes more on the second day than the first, and for small bruises to appear at needle sites. These effects should gradually improve from the third day onward. What is not normal is a fever that keeps rising or lasts more than two days, pain that becomes progressively worse after the third day, spreading redness or warmth around an injection site, new neurological symptoms, or difficulty breathing. Keeping a simple log of your temperature and symptoms during the first days makes it easier to describe them accurately if you contact the team.

Complications during your stay and how they are managed

Fever, chills or headache after an infusion

The most common reaction. Nurses monitor temperature, and paracetamol and cooling measures are used as needed. Fever usually resolves within one to two days. If fever is high or persistent, the team evaluates for infection or other causes.

Pain flare or swelling after an injection

Managed with rest, elevation, paracetamol and, after the first two days, short applications of ice or heat as instructed. Severe or worsening pain is examined promptly.

Allergic reaction

Rare. Staff are trained to recognize early signs, such as hives, itching, swelling or difficulty breathing, and emergency medications and equipment are available.

Fainting or dizziness (vasovagal reaction)

Some people feel faint during needle procedures or after fasting. Lying down, fluids and monitoring usually resolve it quickly.

Sedation effects

Nausea, drowsiness or a temporary drop in blood pressure or oxygen levels are monitored and treated by trained personnel.

Bleeding or bruising

Pressure and observation; more significant bleeding is evaluated, particularly in patients on blood thinners.

Condition-specific events

Patients with specific conditions may experience related events, such as autonomic dysreflexia in spinal cord injury, seizures in people with epilepsy, or blood pressure and rhythm changes in heart disease. These are anticipated in the treatment plan, and staff are briefed on each patient's needs.

When hospital care is needed

If a complication requires imaging, specialist evaluation or hospital admission, care is coordinated with the adjacent hospital. Your coordinator helps communicate with your companion and family.

Complications after you return home

What to watch for

• High or persistent fever, chills or feeling very unwell.
• Increasing redness, heat, swelling or discharge at an injection site after the first few days.
• Pain that worsens instead of gradually improving.
• New weakness, numbness, loss of bladder or bowel control, or severe headache (especially after spinal procedures).
• Chest pain, shortness of breath, calf pain or swelling (possible blood clot).
• Signs of an allergic reaction.

What to do

1. For emergencies, such as chest pain, difficulty breathing, signs of stroke or severe allergic reaction, call your local emergency number or go to the nearest emergency department immediately.
2. For non-emergency concerns, contact our team by phone, WhatsApp or email using the details in your discharge instructions. The medical team will review your symptoms and advise next steps.
3. Share your documentation with your local doctor: medical report and the list of procedures performed.
4. Follow up as advised; the team stays in contact to track your recovery.

Communication with your companion and family

During your stay, a companion or family member is often the first to notice changes such as confusion, unusual drowsiness or difficulty breathing. Make sure your companion knows the warning signs and has the coordinator's contact information. If you are admitted to the hospital for any reason, the coordination team helps keep your family informed, assists with logistics such as changing flights or lodging, and ensures that medical information is shared with your consent. After you return home, involving a family member in follow-up calls can help ensure that instructions are understood and followed.

Why preparation matters

Many complications are prevented or caught early through preparation:

• Complete disclosure of medications, supplements and conditions allows the team to anticipate problems.
• Following pre-treatment instructions reduces bleeding and interaction risks.
• Travel planning, with return flights after your discharge check-up, avoids being in transit if an early reaction appears.
• A companion can help notice symptoms and communicate with staff.
• Travel and medical insurance that covers care abroad is worth considering, because most health plans do not cover elective treatment in another country.

Reporting adverse events

Responsible practice includes documenting and reviewing adverse events. Ask your provider how complications are recorded and reviewed. The U.S. Food and Drug Administration encourages patients who experience problems after a regenerative medicine product to report them through its MedWatch program, which helps regulators detect safety signals. The International Society for Stem Cell Research (ISSCR) also encourages patients to ask how complications are managed before agreeing to any treatment.

What we do to minimize complications

• Eligibility screening and exclusion of patients with unacceptable risk.
• Pre-treatment testing on arrival.
• A single documented cell source: Wharton's jelly MSCs from a COFEPRIS-licensed laboratory under GMP standards, with quality and safety testing before release.
• Image-guided procedures with sterile technique, and fluoroscopy-guided spine procedures in a hospital-level environment.
• Monitoring and observation with trained nursing staff.
• Written discharge instructions, warning signs and direct contact information.
• Structured follow-up after you return home.

Long-term follow-up

Some questions about safety can only be answered over time. Clinical trials of MSCs have followed patients for months to a few years without signals of increased cancer, abnormal tissue growth or serious infections, but rare late effects cannot be completely excluded. That is why follow-up continues after your immediate recovery. Our team checks in at intervals to review your progress and any new symptoms. Keep your regular medical appointments, inform any new doctor that you received cell therapy, and keep your treatment documentation in a safe place so it is available whenever it is needed.

What about financial responsibility?

Ask before treatment how costs are handled if a complication requires additional care. Policies differ between providers and depend on whether the complication is related to the procedure. Clear answers in advance avoid stressful surprises. It is also wise to keep receipts and medical records from any care you receive afterward, in case they are needed for insurance or follow-up.

Questions to ask during your evaluation

• What complications are most likely with my procedure, and how are they handled?
• What medical resources are available on site and nearby?
• Who do I contact after I return home, and how quickly will I get a response?
• What documentation will I receive for my local doctors?
• How are costs handled if a complication requires additional care?

Bottom line

Complications after MSC therapy are uncommon and usually mild, but a responsible clinic plans for them: monitoring during your stay, immediate access to hospital resources, clear warning signs, direct contact after discharge and complete documentation for your local doctors. A medical evaluation can help determine whether this type of regenerative treatment is appropriate and safe for your condition, goals and medical history.