When should the antagonist be started in an IVF cycle ?

hello I'm doctor Anil gory and valo

consultants and reproductive medicine

surgery an assisted conception and

Homerton Fertility Center and today I'm

going to talk to you about the use of an

antagonist we have traditionally

believed that you start antagonists

between a 5 day 6 day 7 started if on a

fixed protocol rather than on a flexible

protocol and that is what the earlier

metallus analysis that showed that a

flexible protocol would give poorer

results in the past many years we have

got better at the Antechinus protocol

our cycles are safer have equal success

rate and we have lowered the risk of

ovarian hyperstimulation now let's have

a look at how different studies are

coming the question is when do you start

the antagonist now this is very much a

retrospective analysis and not a

randomized controlled trial but gives us

an idea into what's going on with the

large number of antagonist cycles which

have been done and this was looking at

cycle day estrogen levels lead follicle

count analysis of over 27,000 cycles

which to decide the optimal start date

of an antagonist and this was published

in April 2018 infertility the criteria

when to start the antagonist was not

standardized it was a retrospective

cohort study from 20 centers 55% had

observations on lead follicle size

extrusion and the start of the

antagonist and what did you see have a

look at the graph it showed that the

maximum pregnancy rates were achieved

when the antagonist was started with a

lead follicle being between 14

and 15 on nine millimeter again the day

of stimulation around day six of

stimulation an extrusion of between 500

to 599 picogram per liter if you start

an antagonist after follicle size was 16

millimeter pregnancy rates dropped by

25% if you started before day 5 or after

day 8 pregnancy rates also declined

fertilization was highest when the

extrusion was in the optimal range

estrogen seems to be an independent

predictor of success rates in this study

but the under gonna start there are very

high levels of Ito also demonstrated

that there could be lower weight babies

the later you start the antagonist you

may lose the receptivity window and also

if you start the antagonist very early

when the extrusion is very low it may

affect the mitotic activity or

follicular cells again this is all

presumption and that is what they the

authors are doing is they're saying well

why is it that the pregnancy could be

lower if you started earlier or we

started later why do the pregnancy rates

start declining at the end this is a

very large sample size 44 percent did

not have adequate details but it tells

us few things in an antagonist cycle if

you want to fine tune your success rates

look at the cycle day look at the

follicle size look at the e2 levels

these should not be ignored so even

though this study is a very large

retrospective data it starts getting us

thinking are we all right to just use

one fixed protocol or should we start

managing and if you start looking at

some of the protocols which I use

especially one which

it looks at poor responders you'll see I

start using protocols that delay the

start of an antagonist using different

drugs and what it allows us to do is

allows us to allow follicle growth to

occur whether or not this can stand the

test of research I don't know but

sometimes our personal observations do

suggest that we may see a better

pregnancy rate anyway thank you very

much if you like these videos please

share them let this knowledge flow these

are reviews of papers which I do once or

twice a week between me and my team

thank you very much