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The protein source in embryo culture media influences birthweight: a comparative study between G1 v5 and G1-PLUS v5
Insights
Embryo culture media containing human serum albumin (HSA) significantly impacts birthweight Z scores and the incidence of large-for-gestational age (LGA) babies. This finding highlights the importance of protein source in assisted reproductive technologies.
Area of Science:
- Reproductive Medicine
- Neonatal Health
- Embryology
Background:
- Previous studies suggest variations in birthweights based on embryo culture media.
- G1-PLUS culture media has been anecdotally linked to increased birth and placenta weights.
Purpose of the Study:
- To investigate whether the protein source or human serum albumin (HSA) in embryo culture media influences subsequent singleton birthweight.
- To compare birthweight outcomes between embryos cultured in G1 v5 and G1-PLUS v5 media.
Main Methods:
- Retrospective analysis of 1097 singleton births from fresh embryo transfer cycles.
- Inclusion criteria: women <40 years, BMI <30 kg/m², singleton pregnancies, born after 28 weeks gestation.
- Exclusion criteria: vanishing twin, pregnancy complications, preimplantation genetic diagnosis, donor oocytes. Multiple linear regression analysis was used.
Main Results:
- No significant difference in absolute birthweights between G1 v5 and G1-PLUS v5 media groups.
- Significantly higher birthweight Z scores (P=0.04) in the G1-PLUS v5 group.
- Higher proportion of large-for-gestational age (LGA) babies in the G1-PLUS v5 group (16.8% vs 12.1%, P=0.03).
- Culture media was identified as a significant factor affecting birthweight (P=0.04).
Conclusions:
- Embryo culture media composition, specifically the protein source/HSA, significantly affects birthweight Z scores and LGA rates.
- The study, though retrospective, suggests protein source is a critical factor in assisted reproduction outcomes.
- Further research may optimize culture media for improved neonatal outcomes.
Study Question:
Does protein source or human serum albumin (HSA) in embryo culture media influence the subsequent birthweight?
Summary Answer:
A significant difference was observed in gestational age- and gender-adjusted birthweight (Z scores) and the proportion of large-for-gestational age (LGA) babies between embryos cultured in G1 v5 and those cultured in G1-PLUS v5 media.
What Is Known Already:
It has been reported that the birthweights of singletons born from embryos cultured in Vitrolife are significantly higher than those cultured in the Cook group of media, and that G1-PLUS (Vitrolife, Gothenburg, Sweden) is associated with increased birth and placenta weights compared with Medicult ISMI.
Study Design, Size, And Duration:
This study was a retrospective analysis of neonatal birthweights, and included 1097 singletons born from fresh embryo transfer cycles at the Center for Reproductive Medicine of Peking University Third Hospital between January 2011 and August 2012. The number of singletons born from G1 v5 culture media was 489, and the number of singletons born from G1-PLUS v5 media was 608.
Participants/Materials, Setting, And Methods:
Patients <40 years of age with a BMI <30 kg/m² were analysed. Only data from newborns from singleton pregnancies and born alive after the 28th week of gestation were included. Patients with a vanishing twin or with pregnancy-related complications, such as diabetes and hypertension, were excluded, as were patients who received preimplantation genetic diagnosis or used donor oocytes. Multiple linear regression analysis was performed to determine the influence of individual factors on birthweights of singleton newborns. The birthweights and Z scores of singletons and LGA babies were compared between the G1 v5 and G1-PLUS v5 media groups.
Main Results And The Role Of Chance:
The absolute birthweights for singletons resulting from G1-PLUS v5 were not different from singletons resulting from G1 v5 (3375.9 ± 479.6 g versus 3333.2 ± 491.6 g, respectively; P = 0.14). However the Z scores for singletons from embryos cultured in G1-PLUS v5 were significantly higher than for singletons cultured in G1 v5 (0.28 ± 1.12 versus 0.09 ± 1.15, respectively; P = 0.04), and more LGA babies were born from G1-PLUS v5 culture compared with G1 v5 (16.8 versus 12.1%, respectively; P = 0.03) culture. Finally, multiple linear regression analysis suggested that female weight (P = 0.00), male height (P = 0.04), gestational age at birth (P = 0.00), infant gender (P = 0.00) and culture media (P = 0.04) all had significant effects on the birthweights of singleton newborns.
Limitations And Reasons For Caution:
This study was limited by its retrospective design.
Wider Implications Of These Findings:
Our study suggests that protein source/HSA has a significant effect on birthweights of singleton newborns.
Study Funding/Competing Interest(S):
This study was funded by the National Natural Science Foundation of China for Young Scholars (81300483). The authors have no conflicts of interest to declare.
Trial Registration Number:
Not applicable.
