What is Controlled Ovarian Hyperstimulation?
Controlled ovarian hyperstimulation, commonly called COH, is a key part of many fertility treatments at CNY Fertility and other fertility clinics.
In a typical menstrual cycle, a woman naturally develops one mature follicle and ovulates one egg. With COH, medications gently stimulate the ovaries to mature multiple follicles during a single cycle. This increases the number of eggs available for fertilization and may improve the chances of a successful pregnancy.
While COH is often part of IVF, it may also be used with timed intercourse, intrauterine insemination (IUI), egg and embryo freezing, or donor cycles, depending on the treatment plan.
Why Would Someone Use COH?
COH can be helpful when a couple is trying to conceive and:
- Ovulation is irregular
- There is unexplained infertility
- There is mild male factor infertility
- IVF is planned, and multiple eggs are needed
- A patient wants to freeze multiple eggs or embryos for future use
COH with IUI vs. IVF
For people with unexplained infertility, COH with IUI can increase success rates by improving the odds that multiple eggs and sperm meet at the right time. This approach doesn’t correct a specific underlying cause, but rather increases opportunity and probability.
However, COH with IUI is not recommended when:
• Sperm parameters are severely low
• Fallopian tubes are blocked
• Maternal age makes success unlikely with IUI (over 41 in most cases)
COH with IVF is a more effective next step. when:
• You are over 38 to 40
• Unexplained infertility has persisted for several years
• Tube issues or moderate-to-severe male factor are present
• Time sensitivity or fertility preservation is a priority
How Controlled Ovarian Hyperstimulation Is Performed
A COH cycle typically follows a predictable schedule, although dose and medication type will be personalized. Fertility specialists will closely monitor the process to protect against overstimulation.
A typical cycle may include:
1. Baseline Ultrasound and Labs
Performed early in the cycle (day 2 to 4) to confirm that there are no ovarian cysts and establish base hormone levels.
2. Stimulation Medications
Medications may include oral meds such as Clomid (clomiphene) or Femara (letrozole) and/or injectable gonadotropins such as Gonal-F, Menopur, or Follistim. These medications stimulate multiple follicles to grow.
3. Monitoring Visits
Ultrasound monitoring measures follicle growth, and blood tests track estradiol and other hormones. This helps personalize dosing and prevent overstimulation.
4. Trigger Shot
Once follicles reach the optimal size, a trigger shot (typically hCG or a GnRH agonist) helps eggs complete final maturation and allows timing of egg retrieval or insemination.
5. Timed Insemination, Intercourse, or Egg Retrieval
• IUI or intercourse usually happens about 36 hours after the trigger
• For IVF, egg retrieval is scheduled during this window
What Medications Are Used?
COH may include one or a combination of:
• Oral medications (Clomid or Femara)
• Injectable FSH or FSH+LH gonadotropins
• GnRH antagonists to prevent premature ovulation
• Trigger medication for egg maturation
Medication choice depends on diagnosis, ovarian reserve, comfort level, response to medications in a previous cycle, and cost considerations.
COH Success Rates: What to Expect
Success varies based on age, diagnosis, sperm quality, how long you’ve been trying, and whether COH is paired with IUI or IVF.
For unexplained infertility, research shows that COH with IUI gives pregnancy rates of approximately 5 to 15 percent per cycle in women under age 36.
Results typically decline with age and with moderate-to-severe male factor infertility.
Because success is cumulative, many physicians recommend up to three cycles before considering IVF. Over the age of 38 to 40, IVF is often statistically more effective sooner :
- IVF has a much faster time to pregnancy because of its higher per-cycle success rate. For those under 35, success rates are generally around 50% per treatment.
- IUIs generally have a success rate of around 5-15% per cycle. If an IUI is to be successful, it most often happens in the first three or four treatment cycles.
COH vs OHSS: Understanding the Difference
Controlled ovarian hyperstimulation and ovarian hyperstimulation syndrome (OHSS) sound similar, but they are very different.
• COH is the supervised medical process used to stimulate egg development
• OHSS is a possible complication when the ovaries respond too strongly
OHSS can involve ovarian swelling, bloating, nausea, and fluid shifts. It is more common in individuals with PCOS or a very high AMH.
Modern monitoring and medication strategies, including GnRH antagonist protocols and Lupron triggers, significantly reduce the likelihood of moderate or severe OHSS.
Cost of COH at CNY Fertility
Costs vary depending on the clinic you choose, the medication you’ll need, monitoring, and whether COH is used for IUI, IVF, or egg freezing. Medications and clinic choice are often the most significant variable expenses.
Nationwide, IVF cycles commonly cost 15,000 to 30,000 dollars, including medications.
CNY Fertility offers significantly more accessible pricing compared with national averages, as well as medication discount partnerships to help lower out-of-pocket cost.
| Treatment Type Using COH | National Average Cost | CNY Fertility Cost | What’s Included At CNY |
|---|---|---|---|
| COH for IUI Cycle | $2,500–$5,000 per cycle | ~$1,793–$3,213 (depending on meds and monitoring) | Includes monitoring, trigger shot timing, and IUI procedure. Meds vary widely by response and protocol. |
| COH for Egg Freezing (Oocyte Cryopreservation) | $10,000–$18,000 per cycle (plus annual storage) | $5,795 including medications (plus annual storage $600 a year) | Includes COH in-house monitoring, egg retrieval, anesthesia, and freezing. Medications ar additional but discounted. |
| COH for Embryo Creation and Freezing (no transfer yet) | $15,000–$25,000 (with lab add-ons billed separately at most clinics) | $7,895 (including medications and one year of storage) | Includes monitoring, egg retrieval, ICSI, assisted hatching, cryopreservation. Medications additional. |
| COH for Full IVF Cycle (retrieval + fresh transfer) | $20,000–$30,000+ | $7,295 (with fresh embryo transfer)- $9,835 (Frozen Embryo Transfer) | Includes medications, retrieval, fertilization, assisted hatching, ICSI, fresh or frozen transfer, and cryopreservation of remaining embryos. |
Controlled Ovarian Hyperstimulation: The Takeaway
Controlled ovarian hyperstimulation can be an effective next step when you’re ready for more support in growing your family. By stimulating the ovaries to produce more mature follicles, COH increases the likelihood of fertilization and improves success rates across many treatment paths, including IUI and IVF.
At CNY Fertility, COH protocols are personalized, cost-conscious, and monitored with care so patients feel supported, informed, and safe throughout treatment. To learn if COH is right for you, schedule a consultation today.
