By Dr. Jessie Wai Leng Phoon, MRCOG
Medical Director, GenPrime Fertility Singapore
Last reviewed: January 2026
Being diagnosed with atypical endometrial hyperplasia (AEH) can feel overwhelming—especially if you’re still hoping to have children. Many women are told that hysterectomy is the standard treatment, which immediately raises difficult questions about fertility and future plans.
For carefully selected patients, however, medical (non-surgical) treatment may be an option, allowing time to preserve fertility while closely monitoring the condition.
This article explains what AEH is, the medical treatments available, and what a recent randomised controlled trial from Singapore tells us about outcomes, side effects, and fertility. It is based on a multi-centre clinical trial published in the Journal of Assisted Reproduction and Genetics.
CAH RCT
What is atypical endometrial hyperplasia (AEH)?
AEH is a condition where the lining of the uterus becomes abnormally thick and shows cellular changes that increase the risk of progression to endometrial cancer.
Key points to understand:
- AEH is not cancer, but it is considered precancerous
- The risk of progression to cancer can be as high as 30%
- The standard treatment is hysterectomy
- Some women diagnosed are under 40 and wish to preserve fertility
This is where fertility-sparing treatment may be considered, under strict medical supervision.
Medical options for fertility-sparing treatment
Two commonly used treatments aim to reverse abnormal changes in the uterine lining using progestogens.
Oral progestin: Megestrol acetate
- Taken daily as a tablet
- Acts systemically on the endometrium
- Requires regular follow-up and biopsies
Intrauterine progestin: Levonorgestrel intrauterine system (LNG-IUS)
- A hormone-releasing device placed in the uterus
- Delivers progesterone directly to the endometrium
- Avoids daily medication
Until recently, there was limited high-quality evidence directly comparing these two options in women with AEH.
What did the clinical trial study?
Researchers conducted a multi-centre randomised controlled trial involving women aged 21–40 who wished to preserve fertility.
Participants were randomly assigned to:
- Oral megestrol acetate, or
- A levonorgestrel-releasing intrauterine system
They were followed closely with regular endometrial assessments over 9 months to see:
- How often the condition regressed
- How quickly regression occurred
- Side effects and tolerability
- Fertility and pregnancy outcomes
What were the key findings?
High regression rates with both treatments
By 9 months:
- Almost 90% of patients achieved complete regression
- There was no significant difference between the two treatment groups
This confirms that medical treatment can be effective for selected patients with AEH.
Similar side effects overall
- About three-quarters of patients experienced some side effects
- Irregular bleeding was more common with the intrauterine system
- Nausea, bloating, and mood changes were slightly more common with oral medication
- Weight gain was minimal and similar in both groups
Serious complications were rare.
Fertility and pregnancy outcomes
Among patients who achieved regression and tried to conceive:
- 8 pregnancies were achieved
- 4 resulted in live births
- 4 resulted in miscarriage, including some later pregnancy complications
While successful pregnancies are clearly possible after treatment, the study suggests that women who conceive after AEH treatment may need closer antenatal monitoring.
Does one treatment work faster?
There was a trend toward earlier regression in patients treated with the LNG-IUS, particularly in the first few months.
However:
- This difference was not statistically significant
- Faster regression did not clearly translate into higher live birth rates
Both treatments remain valid options, depending on individual circumstances.
What this means for patients
This study reinforces several important messages:
- Fertility-sparing treatment for AEH can be effective
- Oral and intrauterine progestins perform similarly overall
- Treatment choice should be individualised, considering:
- Side-effect tolerance
- Lifestyle preferences
- Comfort with an intrauterine device
- Need for close follow-up
Medical treatment is not a replacement for hysterectomy in all cases, and strict monitoring is essential.
What happens after regression?
Once the uterine lining has returned to normal:
- Patients trying to conceive may proceed with natural conception or assisted reproduction
- Those delaying pregnancy usually require maintenance hormonal therapy
- Long-term follow-up is necessary, as recurrence can occur
The decision-making process should involve both fertility and cancer specialists.
Questions to ask your doctor
If you’ve been diagnosed with AEH and are considering fertility-sparing treatment, consider asking:
- Am I suitable for medical treatment instead of surgery?
- What are the pros and cons of oral medication vs an intrauterine system?
- How often will I need biopsies or scans?
- How long should treatment continue before reassessment?
- When would you recommend trying for pregnancy?
- What are the risks of recurrence or progression?
A simple next step
If fertility matters to you and you’ve been diagnosed with atypical endometrial hyperplasia, ask for an early discussion about fertility-sparing options.
Understanding the evidence, the limits of medical treatment, and the importance of follow-up can help you make decisions with clarity and confidence.
About the Author
Dr. Jessie Wai Leng Phoon, MRCOG is a leader in fertility innovation and integrated women’s health, blending advanced clinical training with a personal approach to care. A graduate of the University of Auckland, she is an MOH-accredited IVF specialist with expertise across assisted reproduction and minimally invasive surgery. She previously served as Director of KKIVF Centre and the National Sperm Bank, and co-founded Singapore’s pioneering OncoFertility Clinic.