Back

Successful Ovulation and Pregnancy Using Pulsatile GnRH Pump in Lean PCOS

Case Studies 5 min 9

Font Size

Created On: 01/09/2026

See All

Poster abstract

Ovulation induction in lean polycystic ovary syndrome (PCOS) can be challenging, particularly when conventional therapies fail to achieve predictable, monofollicular development. A 28-year-old woman with lean PCOS and normal baseline luteinizing hormone (LH) remained infertile despite treatment with clomiphene citrate and letrozole + human menopausal gonadotropin (HMG). Following unsuccessful gonadotropin cycles complicated by multifollicular development, treatment was changed to pulsatile gonadotropin-releasing hormone (GnRH) pump therapy.

After individualized adjustment of GnRH pulse dose and frequency, the patient achieved single dominant follicle development, ovulation, and successful pregnancy during the second treatment cycle without ovarian hyperstimulation syndrome (OHSS). Pregnancy progressed well, and both maternal and neonatal outcomes were favorable following cesarean delivery for vasa previa.

This case highlights pulsatile GnRH therapy as an effective second-line therapy for carefully selected women with lean PCOS who do not conceive with conventional ovulation induction.

Complaints

The patient reported oligomenorrhea and primary infertility for 2 years.
Irregular menstrual cycles were reported since menarche at 14 years of age, with cycle intervals varying from 1-7 months and menstrual bleeding lasting approximately 5 days.
She remained unable to conceive despite prior hormonal treatment and ovulation induction therapy.

Anamnesis

Introduction

PCOS, a common endocrine disorder, is characterized by ovulatory dysfunction, hyperandrogenism (excess androgen activity), and polycystic ovarian morphology (PCOM). It impacts approximately 6–10% of females of reproductive age and remains the most common cause of anovulatory infertility.

The condition results from dysregulation of the hypothalamic-pituitary-ovarian axis, leading to abnormal follicular development and chronic anovulation. For women with PCOS seeking pregnancy, ovulation induction is a key treatment strategy. Letrozole, clomiphene, and gonadotropins are commonly used. However, treatment resistance and risks such as multiple pregnancy and OHSS remain concerns.

Pulsatile GnRH therapy mimics physiological GnRH secretion and regulates follicle-stimulating hormone (FSH) and LH release. Although mainly used for congenital hypogonadotropic hypogonadism, evidence for its use in PCOS remains limited.

Medical History

A 28-year-old woman with PCOS presented with oligomenorrhea, menstrual irregularity, and difficulty conceiving. She had received long-term therapy with ethinylestradiol/cyproterone acetate. She had no history of childbirth and had attempted conception for 2 years. Before presentation, she underwent two cycles of clomiphene-triggered ovulation at another hospital:

First cycle: Clomiphene citrate 50 mg/day for 5 days
Second cycle: Clomiphene citrate 100 mg/day for 5 days

Neither cycle resulted in the development of a dominant follicle, prompting presentation to the reporting hospital for further fertility treatment. This case highlights an alternative ovulation induction strategy in a lean woman with PCOS who failed standard fertility treatment.

Examination

(a) Physical Examination

The patient had a body mass index (BMI) of 18.35 kg/m².
Clinical assessment revealed no signs of hyperandrogenism, with hirsutism, acne, and alopecia all absent.
Gynecological assessment showed normal external genitalia, vagina, and cervix.
The uterus was normal in size and positioned anteverted (tilted or bent forward).

(b) Ultrasonographic Examination

Transvaginal ultrasonography demonstrated normal uterine dimensions with bilateral PCOM.
In each ovary, more than 12 follicles (2–9 mm diameter) were present.

(c) Hormonal and Metabolic Evaluation

Hormonal assessment showed no biochemical evidence of hyperandrogenism or thyroid dysfunction. Metabolic parameters were within normal limits, with no signs of insulin resistance.

Diagnostic Assessment: Based on the presence of oligomenorrhea and bilateral PCOM, with other endocrine disorders excluded, the patient was diagnosed with PCOS.

Treatment

(a) Letrozole + HMG Therapy

The patient received four cycles of letrozole combined with HMG.
Ovulation occurred during the first cycle, but pregnancy was not achieved.
The following three cycles were cancelled because of multiple follicular development.

(b) Pulsatile GnRH Pump Therapy

Following unsuccessful conventional ovulation induction, subcutaneous pulsatile gonadorelin therapy was initiated on cycle day 3.
The initial regimen was 10 μg per pulse every 90 minutes, followed by adjustment to 10 μg every 120 minutes and subsequently 15 μg every 120 minutes according to hormonal and follicular responses.
In the second cycle, 15 μg per pulse every 120 minutes was continued.
Ovulation was induced using 250 μg recombinant human chorionic gonadotropin (rhCG), and dydrogesterone was initiated for luteal-phase support.

Results

(a) Ovulation

Ovulation was achieved during the first cycle of pulsatile GnRH pump therapy, although pregnancy did not occur.
During the second GnRH treatment cycle, a 19 × 18 mm dominant follicle developed in the left ovary.

(b) Pregnancy

On cycle day 28, 20 days after the trigger, HCG was 1260.3 IU/L and progesterone was 15.29 ng/mL, depicting biochemical pregnancy.
At 41 days post-trigger, transvaginal ultrasonography verified an intrauterine pregnancy with positive fetal heart activity.

(c) Pregnancy Follow-Up and Delivery

The patient received regular prenatal care, and fetal development remained in good condition.
No gestational diabetes mellitus, hypertensive disorders, or cardiac disease were reported during pregnancy.
Vasa previa was detected by color Doppler ultrasonography at 26 + 3 weeks, prompting cesarean delivery at 35 + 6 weeks.
Maternal and neonatal outcomes were good.

Key Learnings

Lean PCOS can present with normal LH levels despite significant ovulatory dysfunction.
Failure of conventional ovulation induction should prompt consideration of alternative fertility strategies.
Pulsatile GnRH therapy promotes physiological ovulation with a low risk of multifollicular development and OHSS, making it a promising second-line option for selected women with refractory PCOS-related infertility.
Individualized adjustment of GnRH pulse dose and frequency is essential for successful treatment.