P-577 A randomized trial to compare the live birth rate following the progestin-primed ovarian stimulation versus the antagonist protocol in women with anticipated high ovarian responses
Authors: Ng E , Chen Z  Q , Zhang Y , Li H , Wang J  Y , Wang L , Ai A 
Published: July 2024

Study question

Is there difference in the live birth rate following the progestin-primed ovarian stimulation (PPOS) versus the antagonist protocol in women with anticipated high ovarian responses?

Summary answer

The live birth rates of the first frozen embryo transfer following PPOS and the antagonist protocol were comparable in women with anticipated high ovarian responses.

What is known already

Progestin when given orally inhibits the pituitary LH surge during ovarian stimulation when taken orally i.e. progestin-primed ovarian stimulation. Two randomized trials showed similar number of oocytes for PPOS and the antagonist protocol in oocyte donation cycles. However, there is still no randomized trial to compare the live birth rate between PPOS and the antagonist protocol.

Study design, size, duration

This is a randomized controlled trial of 784 infertile women conducted from June 2020 and October 2021.

Participants/materials, setting, methods

Infertile women aged &lt;43 years undergoing the first IVF cycle in a tertiary fertility center and having antral follicle count &gt;15 randomly assigned in a 1:1 ratio into two groups: PPOS group and the antagonist group. Medroxyprogesterone 10 mg daily was given from the start of ovarian stimulation until the day of ovulation trigger in the PPOS group. The primary outcome was the live birth rate of the first frozen embryo transfer.

Main results and the role of chance

784 women were randomly assigned into two groups: PPOS group (n = 392) and antagonist group (n = 392). Embryo transfer was either cancelled or postponed in 62 (62/392, 15.8%) women in the PPOS group and 65 (65/392, 16.6%) in the antagonist group because of no transferable embryos or no frozen embryo transfer within 6 months following randomization. The two groups were similar in demographic characteristics and number of oocytes obtained/fertilized, the number of cleaving embryos, number of good quality embryos at day 3, number of blastocysts developed and number of embryo/blastocyst frozen. There was no statistically significant difference in the live birth rate of the first frozen embryo transfer cycle between the progestin-primed ovarian stimulation and antagonist groups based on both intention to treat [37.5.0% (147/392) versus 32.7% (128/392), RR 1.148 (95% CI = 0.949–1.390), P = 0.16] and per protocol analysis [44.5% (147/330) versus 39.1.% (128/327), RR 1.138 (95%CI = 0.950–1.364), P = 0.16]. Both groups showed comparable clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and cumulative live birth rates.

Limitations, reasons for caution

Women with anticipated high ovarian responses were recruited and the results may not be extrapolated to the general population seeking IVF. This is not a blind study although the live birth rate as the primary outcome is objection. The duration of the study is 6 months since randomization.

Wider implications of the findings

In situations in which fresh embryo transfer is not required such as oocyte/embryo freezing for fertility preservation, oocyte donation or preimplantation genetic testing, the PPOS protocol may be preferred over the antagonist protocol.

Trial registration number

NCT04414761