A glioblastoma diagnosis upends everything, often within hours. If you are in your 20s, 30s, or early 40s, one question that rarely comes up in those first conversations is whether fertility preservation before glioblastoma treatment is possible - and what you can do about it before the first chemotherapy dose. The answer, for most patients, is yes. But the window is short, and you need to ask early.
Can you preserve fertility before starting glioblastoma treatment?
Yes, in most cases. Sperm banking can be completed in a single day. Egg or embryo freezing takes roughly 10 to 14 days. You usually have a 4 to 6 week gap between surgery and the start of chemoradiation. That's usually enough time for at least one preservation step if you get a referral right after surgery.
How does glioblastoma treatment affect fertility?
The standard glioblastoma protocol - surgery followed by concurrent radiation and temozolomide chemotherapy, then additional cycles of temozolomide - affects reproductive health in several ways.
Temozolomide and the risk to reproductive cells
Temozolomide (TMZ) belongs to a class of drugs called alkylating agents - drugs that work by attaching chemical groups to DNA and disrupting how cells divide. Reproductive cells, including sperm and eggs, are especially sensitive to this kind of DNA damage. A study examining the impact of temozolomide on gonadal function in primary brain tumor patients found that at six months after treatment, most men showed low sperm motility, abnormally low numbers of normal-shaped sperm, and reduced sperm density. Whether these effects are permanent or reversible varies by individual and by cumulative drug dose.
Radiation and the hypothalamic-pituitary axis
The pituitary gland - a small structure at the base of the brain that controls hormone production, including the hormones governing ovulation in women and testosterone and sperm production in men - sits near many glioblastoma tumor locations. When radiation scatter reaches the pituitary or the hypothalamus above it (a region that works with the pituitary to regulate hormonal cycles), it can disrupt these signals. Research on fertility attitudes in women with glioma confirms that radiation-related disruption of the hypothalamic-pituitary axis is a recognized fertility risk - and that patients often aren't told about it before treatment begins.
Corticosteroids during treatment
Most newly diagnosed glioblastoma patients take dexamethasone - a steroid drug used to reduce brain swelling - during and after surgery. High-dose corticosteroids can temporarily suppress ovulation in women. This effect is generally reversible once the drug is tapered, but during active use it compounds hormonal disruption from chemotherapy and radiation.
Surgery and hormonal signaling
Most glioblastoma tumors develop in the cerebral cortex, away from the pituitary gland. But when surgery involves structures near the base of the brain, direct disruption of hormonal signaling becomes a more specific risk. Even for cortical tumors, the physical stress of surgery can temporarily affect hormone balance in the weeks immediately after the operation.
What fertility preservation options are available before treatment starts?
The American Society of Clinical Oncology (ASCO) has updated its clinical practice guidelines to recommend that healthcare providers discuss infertility risks early with all cancer patients of reproductive age, and that referrals to fertility specialists - often called oncofertility specialists - happen promptly at diagnosis. The following options are standard practice.
For men
- Sperm cryopreservation (sperm banking). The fastest option for male patients. A semen sample is collected and frozen for later use with in-vitro fertilization (IVF) or intrauterine insemination. This can be completed in one to two days and requires no medication or procedure beyond a clinic visit. The National Brain Tumor Society's patient guide on fertility preservation specifically recommends that men bank sperm before any cancer treatment begins.
- Testicular sperm extraction. For men who cannot produce a sample through standard collection, doctors can retrieve sperm directly from testicular tissue under local anesthesia. Some specialized centers also offer freezing of testicular tissue itself, though this remains uncommon.
For women
- Embryo cryopreservation. Doctors retrieve eggs after a 10 to 14 day hormone stimulation cycle, fertilize them with a partner's or donor's sperm in a laboratory, and freeze the embryos. This is the most established method with the best track record for achieving pregnancy later.
- Oocyte (egg) cryopreservation. The same stimulation and retrieval process as embryo freezing, but doctors freeze the eggs unfertilized. This doesn't require a partner or donor sperm at the time of preservation. ASCO now classifies this as standard practice rather than experimental.
- Ovarian tissue cryopreservation. Doctors remove a small piece of ovarian cortex - the outer layer of the ovary - and freeze it. After treatment ends, it can be re-implanted. This option doesn't require a hormone stimulation cycle and can be completed faster than a full egg retrieval cycle, making it useful when the treatment timeline is tight. The Mayo Clinic describes ovarian tissue cryopreservation as now available for women who cannot wait for a full stimulation cycle, though it carries procedural risks that your care team will need to weigh against the urgency of starting cancer treatment.
- Ovarian suppression with GnRH agonists. GnRH agonists are drugs that temporarily put the ovaries into a low-activity state during chemotherapy, with the goal of reducing direct gonadal damage. ASCO notes that the evidence for this approach is unclear, and it should not replace the established preservation methods above when those are feasible.
How much time is there between surgery and the start of chemoradiation?
The standard glioblastoma treatment plan involves a 4 to 6 week recovery and planning period after surgery before concurrent chemoradiation begins. Within that window, you typically have enough time for sperm banking (1 to 2 days) and often enough for egg or embryo freezing (10 to 14 days for ovarian stimulation and retrieval).
The fertility referral needs to happen in the first week after surgery - within days, not weeks. Once TMZ begins, the window for meaningful preservation closes quickly. Research on fertility preservation in primary brain tumor patients found that the gap between surgery and the start of radiation is generally sufficient to allow at least basic preservation steps when the referral happens promptly. The critical variable is the speed of the referral, not a biological limit on what is possible.
In reality, the pressure of a GBM diagnosis means this conversation often doesn't happen when it should. Research in this area suggests that fewer than half of young cancer patients get fertility counseling before treatment begins. If your oncology team hasn't raised this topic, raise it yourself - at your first appointment after surgery.
How to request a fertility referral and what to expect
Ask your neurosurgical or neuro-oncology team directly for a referral to a reproductive endocrinologist or oncofertility specialist - a doctor who specializes in fertility preservation for cancer patients and understands the time pressure involved. Many major cancer centers have dedicated oncofertility programs. The Dana-Farber Cancer Institute Adult Fertility Preservation Program is one example of a team that works with oncology to fit fertility procedures into your treatment schedule.
At your first meeting with a reproductive specialist, you can expect:
- A review of your current hormone levels through a blood test
- An assessment of ovarian reserve for female patients using an ultrasound scan
- A discussion of which preservation method fits the available time window
- Direct coordination with your neuro-oncology team to ensure fertility procedures don't delay the start of chemoradiation
If your center doesn't have an oncofertility program, ask for a referral to a reproductive clinic with experience treating cancer patients. Bring your treatment plan and the proposed start date for chemoradiation so the reproductive team can design a plan that fits within that window.
Questions about pregnancy after glioblastoma treatment
For patients who complete initial treatment and reach a period of disease stability, pregnancy may be possible. The American Brain Tumor Association has noted that while evidence on pregnancy after GBM treatment is limited, successful pregnancies have been reported in survivors - particularly those with favorable tumor biology who achieve longer periods off active treatment.
We don't know if pregnancy speeds up glioblastoma recurrence, though this remains understudied and individual circumstances vary widely. Any decision about attempting pregnancy after treatment must involve your neuro-oncologist, a reproductive specialist, and often a maternal-fetal medicine specialist who can assess the risks based on your specific treatment history and current disease status.
Fertility is one item in a broader first-month strategy. If you are still building your overall plan - covering molecular testing, second opinions, and treatment sequencing decisions - reviewing what the first 30 days after a GBM diagnosis should include can help you organize those priorities alongside the fertility question. For patients who want an independent read on their full treatment picture from an experienced team, you can arrange a remote second opinion through Art of Healing Cancer in parallel with the clinical process at your local center. Age also shapes how oncologists approach the full GBM treatment protocol, from surgical extent to radiation dosing - understanding how age affects GBM treatment decisions gives useful context for the conversations ahead.
What if the fertility window was missed before treatment started?
If treatment has already begun, or if the pre-treatment window passed without a referral, there may still be options. Post-treatment hormone testing and a reproductive assessment can clarify whether natural fertility has been preserved. Some patients retain or recover fertility after treatment ends, depending on the specific drugs used, cumulative dosing, and individual biology. Reproductive endocrinologists who specialize in post-cancer fertility can evaluate your situation after treatment is complete.
Preserving sperm or eggs during a period of remission or between treatment cycles may also be feasible in some cases, depending on your ongoing treatment schedule. The American Brain Tumor Association has described the role of oncofertility teams as extending well beyond the pre-treatment window, with support and guidance available at multiple points in treatment, not just at diagnosis.
If you are mapping out your care strategy and want a team to review what is realistically available at your current stage, you can upload your MRI and treatment reports at the Glioblastoma Center patient-journey page to request a structured review of your options.
When to talk to your doctor
Raise fertility preservation at your first appointment after surgery, or as soon as you're planning treatment - ideally within the first week after surgery. The referral to a reproductive specialist needs to happen within days. If you are a caregiver managing this process on behalf of a young patient and this conversation hasn't happened, ask the care team directly whether a fertility referral has been arranged. A brief delay in raising this can meaningfully narrow what options remain available.
This article is for general information and is not a substitute for medical advice. Always consult your oncologist or care team about your specific situation.