# Frozen embryos have "better outcome"



## wehavethreecats (Feb 12, 2012)

This news story reports findings from a study which reckons that frozen embryos lead to more pregnancies and less complications at time of birth.

Brief quote from the article: "The scientists think there could be two reasons for the results. One is that only prime quality embryos are likely to survive the freezing process. The other, more popular, theory is that the womb lining is allowed time to settle down and recover from the rigours of IVF hormone treatment."

http://bit.ly/TcGBtH

/links


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## Mudpuffin (Aug 3, 2009)

I only speak from my own personal experience and I know statistical evidence better but for us our 4 non frozen cycles all resulted in BFP though only one resulted in my beautiful daughter howver my body seems to have no response to our fozen cycles all four resulting in BFN.  The logic seems to make sense that only strong embryos survive the thaw though.


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## SWGirl (Aug 19, 2004)

Hmm... I think most clinics get better pregnancy rates and live birth rates from fresh embryos not frozen ambryos.  The clinic where I had my three frozen embryo transfers had a live birth rate of 34% for fresh transfers but about 10% for frozen embryo transfers.  I became pregnant in 2 out of three of my fresh transfers but none out of three of my frozen transfers.


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## wehavethreecats (Feb 12, 2012)

SWGirl and Mudpuffin (great name!)
I have found the abstract for the actual article which the team wrote and looked at it in further detail (I can't get the whole paper as it would cost££). It does seem as though they have only looked at a very narrow range of data which may well explain a result which goes against your experiences. 
The abstract is pasted in below in case you are interested. The key messages i took from this were: 1. they were only looking at singleton pregnancies, which may not be the case for how all clinics report their data. 2. They only were able to include 11 studies in their review (this isn't unusual for this kind of study, but does mean the claims are quite narrow). 3. Although the media article focuses on birth rates a bit, actually the review focuses on complicated birth outcomes, which is of course quite different.

My stats knowledge isn't good enough to interpret the Risk Ratio (noted below as RR), but someone else on here might be able to offer some insights into that.

So I hope that helps explain why it doesn't add up with your experiences... and i guess is a lesson for me to read the actual research before believing what i read in the media !!

x

*Abstract of the original research*
Title
Obstetric and perinatal outcomes in singleton pregnancies resulting from the transfer of frozen thawed versus fresh embryos generated through in vitro fertilization treatment: a systematic review and meta-analysis

Objective
To perform a systematic review and meta-analysis of obstetric and perinatal complications in singleton pregnancies after the transfer of frozen thawed and fresh embryos generated through IVF.

Design
Systematic review.

Setting
Observational studies, comparing obstetric and perinatal outcomes in singleton pregnancies subsequent to frozen thawed ET versus fresh embryo transfer, were included from Medline, EMBASE, Cochrane Central Register of Clinical Trials, DARE, and CINAHL (1984-2012).
Patient(s)
Women undergoing IVF/intracytoplasmic sperm injection (ICSI).

Intervention(s)
Two independent reviewers extracted data and assessed the methodological quality of the relevant studies using critical appraisal skills program scoring. Risk ratios and risk differences were calculated in Rev Man 5.1. Subgroup analysis was performed on matched cohort studies.

Main Outcome Measure(s)
Antepartum hemorrhage, very preterm birth, preterm birth, small for gestational age, low birth weight, very low birth weight, cesarean section, congenital anomalies, perinatal mortality, and admission to neonatal intensive care unit.

Result(s)
Eleven studies met the inclusion criteria. Singleton pregnancies after the transfer of frozen thawed embryos were associated with better perinatal outcomes compared with those after fresh IVF embryos. The relative risks (RR) and 95% confidence intervals (CI) of antepartum hemorrhage (RR = 0.67, 95% CI 0.55-0.81), preterm birth (RR = 0.84, 95% CI 0.78-0.90), small for gestational age (RR = 0.45, 95% CI 0.30-0.66), low birth weight (RR = 0.69, 95% CI 0.62-0.76), and perinatal mortality (RR = 0.68, 95% CI 0.48-0.96) were lower in women who received frozen embryos.

Conclusion(s)
Although fresh ET is the norm in IVF, results of this systematic review of observational studies suggest that pregnancies arising from the transfer of frozen thawed IVF embryos seem to have better obstetric and perinatal outcomes.


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## KittyB (May 1, 2006)

I have just read this article, and I could imagine that only the strongest embryos survive the thaw. However, I'm not sure about this part: 


> When fresh embryos are implanted shortly after harvesting the eggs, a woman's lining may not have fully recovered from the invasive procedure.[/size] [/size]



[/size]From what I can remember of the egg collection process (which I had done without sedation or painkillers), the eggs are collected from follicles in the ovaries via a needle which is passed through the wall of the vagina, not through the cervix. So I'm not sure how much 'damage' the womb lining sustains in the process.


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## wehavethreecats (Feb 12, 2012)

hi KittyB,
yeah that is weird... they purposefully don't go poking needles near where the embryo will be implanted to avoid that kind of possible damage. Am thinking these journalists could do with chatting with a few more people like us who actually know this stuff inside out (literally, haha)

x


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## SWGirl (Aug 19, 2004)

I wonder weather any clinics get better pregnancy rates from frozen embryo transfers than fresh ones.  All the ones I have been to (four of them) all get much better results from fresh transfers.


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## SWGirl (Aug 19, 2004)

Whoops 'whether' not weather.  I can't seem to seem to modify previous messages on an I-pad (I also can't send personal messages).


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## wehavethreecats (Feb 12, 2012)

hi SW Girl,
from the looks of the **** website, all clinics do better with fresh cycles in terms of clinical pregnancies and live births.  This papers is only reporting complications around childbirth (e.g. being born early, small birth weight etc). So fresh is still best for actually getting the BFP you've dreamed of!  
x


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## urbangirl (Jul 28, 2010)

I've read this article now, and, from what I see, when they are talking about the better results being perhaps due to the womb lining having had a chance to recover from the 'invasive procedure' of ivf they are talking about the effects of the IVF drugs on the lining, not needles or anything.
As wehavethreecats says, the article is about birth outcomes, not a higher rate of getting an actual bfp than fresh, though it does say also that risk of the baby dying at birth is reduced by 20%, which is pretty significant.  I think the study is a meta-analysis, where they bring together results from different studies, rather than just one study looking solely conducted to look at outcomes for frozen vs fresh.


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## Totoro (Mar 24, 2011)

This really annoys me. Only the strongest blastos get chosen to be frozen so the chance of them being successful was high anyway. They make it sound like the freezing process somehow magically strengthens the embies and increases the chances of a BFP.  Like someone's going to get to ET and say "oh actually can you freeze them for a bit because it's good for them?"


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