P–712 Ovulation induction in type 1 anovulation: a comparative study using gonadotrophins and the GnRH pump

Study question Is there a difference in treatment outcome between gonadotrophin releasing hormone (GnRH) pump or hMG for women with Type 1 anovulation undergoing ovulation induction? Summary answer Treatment with GnRH was more efficient compared to hMG, with fewer number of cycles to pregnancy, fewer days of stimulation and fewer cycle cancellations. What is known already Whilst there is a lot of information on ovulation induction in WHO type II anovulation (PCOS), type 1 anovulation is under-represented in research. WHO type 1 anovulation is characterised by low pituitary gonadotrophins and oestradiol. Treatment options used to include induction of ovulation using gonadotrophins (hMG) or the Gonadotrophin hormone releasing hormone (GnRH) pump delivering pulsatile GnRH. Since the withdrawal of GnRH pump, options have become limited. One study reveals that monofollicular cycles are lower and cycle cancellation higher in women with Type 1 anovulation women treated with gonadotrophins. Study design, size, duration: This is a single centre retrospective cohort study. All women with a diagnosis of WHO type 1 anovulation attending the Reproductive Medicine Unit at the University College London Hospital who received ovulation induction treatment using either hMG or GnRH pump between 1993 and 2020 were included in the study Participants/materials, setting, methods 147 women with WHO type 1 anovulation were included in the study. Diagnosis was based on the presence of primary or secondary amenorrhoea in combination with low gonadotrophins and oestradiol. Demographic and clinical data were obtained by reviewing medical records stored within an electronic database. A total of 599 treatment cycles were identified. Statistical analysis between the groups was performed using the independent T test and chi squared test. Main results and the role of chance 147 women with WHO type 1 anovulation underwent ovulation induction. hMG was used in 500 cycles (83.5%) and the GnRH pump in 99 cycles (16.5%). Per cycle started the pregnancy rate in the hMG cycles was 107/500 (21.4%) and in the GnRH pump cycles was 19/99 (19.2%) p = 0.36. Cycle cancellation was significantly greater in hMG than GnRH pump cycles (hMG 137/ 500 27.4% vs GnRH pump 17/99 17.2% p = 0.02). Over response was more common in hMG cycles than GnRH pump cycles (66/130 50.8% vs 3/16 18.8% p = 0.01). A total of 363/500 (72.5%) cycles in the hMG and 82/99 (82.8%) cycles in the GnRH pump group reached ovulation. There was no difference in the pregnancy rate after ovulation (hMG 107/363 29.5% vs GnRH pump 19/82 23.2% p = 0.15). The mean number of treatment cycles to achieve pregnancy was significantly fewer with the GnRH pump compared to hMG (1.8 (min 1 – max 3) vs 2.4 ( min 1 – max 8) p = 0.03).The mean days of stimulation required to reach ovulation was also significantly less with the GnRH pump compared to hMG (16.7 (min 8 – max 34) vs 23.4 (min 7 – max 72) p = <0.001). Limitations, reasons for caution This is a retrospective cohort study and is reliant on the quality and quantity of the data entry at the time of clinical treatment. Wider implications of the findings: Ovulation induction for women with type 1 anovulation is now restricted to a single treatment, namely hMG. hMG is not as effective or optimal as GnRH. Reinstating GnRH in routine clinical practice should be promoted to allow more individualised treatment options and prevent the premature need for in vitro fertilisation.. Trial registration number NA