Key messages
-
This updated review assessed special solutions (culture media) that are important for helping embryos develop in assisted reproduction technology (ART) treatments used for women who cannot get pregnant naturally. Currently, we do not know which culture medium gives the best chance of giving birth to a live baby. One study showed that an embryo culture medium called G5 probably leads to more live births than one called HTF, but the other studies did not show clear differences in success rates between different culture media.
-
The evidence is limited because the studies tested different culture media and their results could not be combined. Many studies had weaknesses, such as small numbers of people taking part. More, well-designed studies are needed to find out which embryo culture medium works best.
What is an embryo culture medium?
A woman who cannot get pregnant naturally may use assisted reproductive technology (ART) treatments, such as IVF (in vitro fertilization), in which eggs are fertilized by sperm outside the body. Supporting the embryo this creates to develop (culture) is a very important part of IVF treatment. The embryo is placed in a special solution called an embryo culture medium. This medium provides nutrients and helps the embryo grow in the laboratory until it is transferred to the womb (uterus) or frozen for later use. There are many different embryo culture media.
Why is there no agreement about which culture medium works best?
There is currently no clear agreement on which type of embryo culture medium gives the best chances of having a live baby. The available research does not give enough reliable information to clearly choose one culture medium over another. This makes it difficult for doctors and patients to know which option to use.
What did we want to find out?
We wanted to know whether different types of human embryo culture media affect the chances of having a baby or an ongoing pregnancy (pregnancy confirmed by heartbeat on ultrasound) for women undergoing IVF treatments.
What did we do?
We searched for studies that compared different embryo culture media available for use during IVF treatments. We looked at the results of studies for all the measurements we think are important. We considered the reliability of each study based on how it was designed and conducted. We made a judgement about how certain we were about the evidence for each important measure.
What did we find?
We found 26 relevant studies, eight of which evaluated the most important measures, such as live birth or ongoing pregnancy. Another five studies are in progress, and there are 60 studies that we have not been able to include because they are only published as short summaries without enough information. It was not possible to combine any of the studies' results because no two studies compared the same culture media.
Main results
Eight studies (3315 women) of the 26 studies included in the review reported live birth or ongoing pregnancy.
Most studies did not find a clear difference between the culture media they compared. However, the two largest studies did find some differences that could be important.
One study showed that there was probably a 6% higher chance of having a live birth with G5 compared to HTF (836 women). Another study showed that there may be a 6% higher chance of having a live birth with EmbryoAssist plus GM-CSF (with low HSA (a low concentration of a protein in the blood called albumin)) compared to a version of EmbyroAssist without the GM-CSF (743 women), but we are very uncertain about this result, especially because the treatment was changed during the study.
The same studies found differences in ongoing pregnancy rates. One suggested that G5 probably increases the chance of ongoing pregnancy compared with HTF (836 women). The other suggested that EmbryoAssist plus GM-CSF (low HSA) may increase the chance of ongoing pregnancy compared with EmbryoAssist without GM-CSF (743 women), but we are very uncertain about this result.
The evidence is very limited and unclear, and we could not combine results from different studies. Further well-designed studies are needed to confirm the findings and determine if any specific culture medium improves treatment success.
What are the limitations of the evidence?
-
Many studies included only a small number of women.
-
Some studies had problems with how they were designed.
-
A few studies assigned eggs or embryos (rather than women) to the groups being compared, or transferred embryos from different study groups to the same woman.
-
Most studies did not clearly describe the ingredients in the culture media.
-
Many studies did not report all important measures.
Overall, the evidence was mostly very uncertain because:
-
the studies could not be combined with each other;
-
the studies' results were not precise; and
-
the studies' results were not always worked out in the right way.
How up to date is the evidence?
This review updates one published in 2015. The evidence is current to 28 August 2025.
อ่านบทคัดย่อฉบับเต็ม
Many media are commercially available for culturing pre-implantation human embryos in assisted reproductive technology (ART) cycles. It is unknown which culture medium leads to the best success rates after ART.
วัตถุประสงค์
To evaluate the benefits and harms of different human pre-implantation embryo culture media used for in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles, including intracytoplasmic morphologically selected sperm injection (IMSI).
วิธีการสืบค้น
We searched the Cochrane Gynecology and Fertility Group's Specialized Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, the National Research Register, the Medical Research Council's Clinical Trials Register, and the NHS Centre for Reviews and Dissemination databases on 28 August 2025. We also examined the reference lists of all known primary studies, review articles, citation of relevant publications, and abstracts of major scientific meetings, and we contacted experts in the field for additional studies.
เกณฑ์การคัดเลือก
We included all randomised controlled trials which randomised women, oocytes or embryos and compared any two commercially available culture media for human pre-implantation embryos in an IVF or ICSI programme.
การรวบรวมและวิเคราะห์ข้อมูล
Two review authors independently selected the studies, assessed their risk of bias and extracted data. We sought additional information from the authors if necessary. We assessed the quality of the evidence using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methods. The primary review outcome was live birth or ongoing pregnancy.
ผลการวิจัย
We included 32 studies in this review. Seventeen studies randomised women (total 3666), three randomised cycles (total 1018) and twelve randomised oocytes (over 15,230). It was not possible to pool any of the data because each study compared different culture media.
Only seven studies reported live birth or ongoing pregnancy. Four of these studies found no evidence of a difference between the media compared, for either day three or day five embryo transfer. The data from the fifth study did not appear reliable.
Six studies reported clinical pregnancy rate. One of these found a difference between the media compared, suggesting that for cleavage-stage embryo transfer, Quinn's Advantage was associated with higher clinical pregnancy rates than G5 (odds ratio (OR) 1.56; 95% confidence interval (CI) 1.12 to 2.16; 692 women). This study was available only as an abstract and the quality of the evidence was low.
With regards to adverse effects, three studies reported multiple pregnancies and six studies reported miscarriage. None of them found any evidence of a difference between the culture media used. None of the studies reported on the health of offspring.
Most studies (22/32) failed to report their source of funding and none described their methodology in adequate detail. The overall quality of the evidence was rated as very low for nearly all comparisons, the main limitations being imprecision and poor reporting of study methods.
ข้อสรุปของผู้วิจัย
Embryo culture media are important for embryonic development and subsequent success of in vitro fertilization cycles. Determining which is the most appropriate embryo culture medium has been challenging due to many factors involved in assessing efficiency. Numerous studies have been performed, but no two studies that use an appropriate design and assess clinical outcomes have compared the same culture media.
One study suggested that G5 medium probably increases cumulative live birth compared with HTF medium; however, the overall evidence base remains limited and inconsistent.
We conclude that there is insufficient evidence to support or refute the use of any specific culture medium for human embryo culture. Properly designed and executed randomized trials are necessary.
แหล่งทุน
This Cochrane review had no dedicated funding.
การลงทะเบียน
Protocol (2009) DOI: 10.1002/14651858.CD007524
Original review (2015) DOI: 10.1002/14651858.CD007876.pub2
