Lately, the role of GnRH agonist as luteal phase support has been recommended by various studies though the mechanism is still debatable. It has been postulated that GnRH agonist might support the corpus luteum by stimulating the secretion of luteinizing hormone by pituitary gonadotroph cells, or by acting directly on the endometrium through the locally expressed receptors.

Therefore, this study was designed to evaluate effects of the additional of single-dose GnRH agonist to the routine progestogens use for luteal phase support on IVF outcome as compared to progestogens only. The biochemical pregnancy rates, clinical pregnancy rates, live birth rates and miscarriage rate between these regimes were compared. The hypothesis of this study was women with addition of GnRH agonist as luteal phase support have higher biochemical pregnancy rate, clinical pregnancy rate and live birth rate compare to patient with progestogens only luteal phase support.

This was a retrospective study on selected patients who underwent IVF treatment under MAC (Medically Assisted Conception) Unit, University Kebangsaan Malaysia Medical Centre for the period of June 2015-June 2018. Their medical records were reviewed, and data analysed.

The sample size was calculated using Power & Sample Size Calculator by Dupont & Plummer 1998 for dichotomous response version 3.1.2 [6]. Based on this formula, a is the type I error probability for a two-sided test allowable about 5% in this study. The power of certainty is the percentage of estimated power of this study. On the other hand, p0 is the probability of the outcome for GnRH agonist used as luteal phase support by Zafardoust et al. [7] which is 30% (0.30). The p1 is the probability of the outcome in an experimental subject which expected in this study based on similar objective of higher rate of implantation with GnRH agonist. The investigators set the p1 is 0.50 as overall literature suggest that at cumulative successful of implantation post GnRH is around 30-50%. The m is the ratio of control to experimental subjects which is 1 to 1 in this study. Generated sample size from this program is 93 for one arm which result in total sample size is 186. The investigators then added 10% of additional sample for any bias or loss of data during follow up which concluded total sample size to be at least 200 samples (100 patients each arm).

All women who underwent control-ovarian stimulation (COH) regime using either gonadotrophin combination with GnRH antagonist protocol or mild stimulation protocol using oral letrozole or clomiphene citrate were included in this study. All women underwent follicle tracking by transvaginal ultrasound until dominant follicle size reached (>18mm). IM Ovitrelle (6500 IU) was given and proceed with oocyte retrieval (OR) at least 35-36 hours under transvaginal ultrasonography guidance. The 17-gauge single -lumen needles used for oocyte retrieval under sedation.

ICSI were performed according to local protocol. Zygotes were cultured up to day 5 in G1 medium (Vitrolife). On day 5, embryos were graded according to previously described criteria. One or two embryos were transferred, depending on the morphological score and the developmental stage of the embryo, as well as the age of the patient.

Regardless the ovarian stimulation protocols, these women were assigned into two group; progestogens with additions of GnRH agonist and progestogen only for luteal phase support. Both groups were given routine progestogen support for two weeks duration started from the day of embryo transfer. This includes oral progestogen (Tablet Duphaston 10mg tds), vaginal progestogen (vaginal utrogestan 400mg bd) or intramuscular (IM Proluton 250 mg weekly) as prescribed by attending clinician .

In the first group, there were additional GnRH agonist administrated as a single dose of 0.2 mg decapeptyl given at day 3 after ICSI. The other group with no GnRH agonist given was the control group.

Inclusion Criteria:

• underwent ICSI
• given progestogens plus GnRH agonist or progestogens only as luteal phase support.

Exclusion Criteria:

• different luteal phase support
• frozen embryo transfer and
• missing medical records data

Data women underwent IVF treatment under MAC (Medically Assisted Conception) Unit, University Kebangsaan Malaysia Medical Centre for the period of June 2015-June 2018 were reviewed.