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Does long in vitro culture promote large for gestational age babies?
S Mäkinen1, V Söderström-Anttila, J Vainio
1Family Federation of Finland, Fertility Clinic Helsinki, Helsinki, Finland.
Insights
Longer embryo culture in IVF increases the risk of delivering larger babies. This finding highlights the importance of embryo culture duration for infant birthweight in assisted reproductive technologies.
Area of Science:
- Reproductive Medicine
- Perinatal Outcomes
- Embryology
Background:
- In vitro fertilization (IVF) is associated with adverse perinatal outcomes, including preterm birth and low birthweight, compared to the general population.
- Understanding factors influencing IVF infant birthweight is crucial for improving outcomes.
Purpose of the Study:
- To investigate the impact of in vitro embryo culture duration on infant birthweight in IVF-treated children.
- To identify factors affecting birthweight and the proportion of small and large for gestational age (SGA/LGA) infants.
Main Methods:
- Retrospective cross-sectional cohort study of 1079 singleton IVF infants born between 2000-2010.
- Analysis included maternal age, BMI, parity, treatment type, infertility cause, and embryo culture period (Day 2 vs. Day 5-6).
- Multiple linear regression was used to determine the significance of each factor on birthweight.
Main Results:
- No overall deviation in SGA/LGA rates compared to the general population.
- A significant increase in the proportion of large for gestational age (LGA) infants was observed with longer embryo culture (Day 5-6 vs. Day 2).
- Maternal BMI, parity, and embryo culture duration were significant predictors of infant birthweight.
Conclusions:
- Embryo culture duration is a significant factor influencing infant birthweight after IVF.
- Further large-scale studies are needed to confirm these findings, especially concerning blastocyst (Day 5-6) culture.
- The study suggests that optimizing embryo culture length may play a role in managing birthweight outcomes in IVF.
Study Question:
Does the length of time during which embryos are cultured in vitro affect the birthweight of the infants?
Summary Answer:
The duration of the embryo culture period is a significant factor in determining the birthweight of the infants.
What Is Already Known:
IVF children show adverse perinatal outcome when compared with the general population and increased incidence of preterm birth and low birthweight is commonly observed.
Study Design, Size, Duration:
A retrospective cross-sectional cohort study including 1079 infants born after treatment at the Family Federation of Finland Fertility Clinic in Helsinki, between 2000 and 2010.
Participants, Setting, Methods:
All singleton IVF children were included. The gestation- and gender-adjusted birthweights of the babies were analyzed according to mother's age, BMI, and parity, type of treatment (IVF or ICSI), main cause of infertility and embryo culture period. Two outcomes were investigated: the birthweight and the proportion of small and large for gestational age (SGA and LGA) infants. Multiple linear regression analysis was performed to show the significance of each individual factor on determining the birthweight of the babies born.
Main Results And The Role Of Chance:
In the study group as a whole, the distribution of the SGA and LGA babies showed no deviation from the growth charts of the general population. However, when the birthweight of the children was analyzed according to the length of embryo culture from Day 2 to Days 5-6, an increase in the proportion of LGA babies was found (D2 9.4%, D3 11.5%, D5-6 18.8%; D2 n = 871, D3 n = 139, D5-6 n = 69). Multiple linear regression analysis showed that BMI (P < 0.001) and parity (P < 0.001) of the mother, as well as the embryo culture period (P = 0.007) had a significant effect on the birthweight. The value of the adjusted R(2) was 0.437.
Limitations, Reasons For Caution:
Small number of D5-6 infants and a lack of pregnancy-associated factors contributing to birthweight.
Wider Implications Of The Finding:
This study warrants larger studies to analyze the birthweight of the IVF children, particularly after blastocyst culture.
Study Funding/Competing Interest:
The study was funded by the Family Federation of Finland, Fertility Clinic Helsinki. No competing interests.
