scholarly journals An EPIC predictor of gestational age and its application to newborns conceived by assisted reproductive technologies

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Kristine L. Haftorn ◽  
Yunsung Lee ◽  
William R. P. Denault ◽  
Christian M. Page ◽  
Haakon E. Nustad ◽  
...  

Abstract Background Gestational age is a useful proxy for assessing developmental maturity, but correct estimation of gestational age is difficult using clinical measures. DNA methylation at birth has proven to be an accurate predictor of gestational age. Previous predictors of epigenetic gestational age were based on DNA methylation data from the Illumina HumanMethylation 27 K or 450 K array, which have subsequently been replaced by the Illumina MethylationEPIC 850 K array (EPIC). Our aims here were to build an epigenetic gestational age clock specific for the EPIC array and to evaluate its precision and accuracy using the embryo transfer date of newborns from the largest EPIC-derived dataset to date on assisted reproductive technologies (ART). Methods We built an epigenetic gestational age clock using Lasso regression trained on 755 randomly selected non-ART newborns from the Norwegian Study of Assisted Reproductive Technologies (START)—a substudy of the Norwegian Mother, Father, and Child Cohort Study (MoBa). For the ART-conceived newborns, the START dataset had detailed information on the embryo transfer date and the specific ART procedure used for conception. The predicted gestational age was compared to clinically estimated gestational age in 200 non-ART and 838 ART newborns using MM-type robust regression. The performance of the clock was compared to previously published gestational age clocks in an independent replication sample of 148 newborns from the Prediction and Prevention of Preeclampsia and Intrauterine Growth Restrictions (PREDO) study—a prospective pregnancy cohort of Finnish women. Results Our new epigenetic gestational age clock showed higher precision and accuracy in predicting gestational age than previous gestational age clocks (R2 = 0.724, median absolute deviation (MAD) = 3.14 days). Restricting the analysis to CpGs shared between 450 K and EPIC did not reduce the precision of the clock. Furthermore, validating the clock on ART newborns with known embryo transfer date confirmed that DNA methylation is an accurate predictor of gestational age (R2 = 0.767, MAD = 3.7 days). Conclusions We present the first EPIC-based predictor of gestational age and demonstrate its robustness and precision in ART and non-ART newborns. As more datasets are being generated on the EPIC platform, this clock will be valuable in studies using gestational age to assess neonatal development.

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M L Boutet ◽  
E Eixarch ◽  
P Ahumada-Droguett ◽  
F Crovetto ◽  
M S Cívico ◽  
...  

Abstract Study question Do in vitro fertilization (IVF) offspring present different neurodevelopment assessed by fetal neurosonography and infant neurobehavioral tests as compared to those spontaneously conceived (SC)? Summary answer IVF offspring, especially those obtained after fresh embryo-transfer (ET), showed subtle structural differences in fetal neurosonography and poorer neurobehavioral scores at twelve months of age. What is known already The number of pregnancies following assisted reproductive technologies (ART) is currently increasing worldwide. Concerns about the neurodevelopment of subjects conceived by IVF have been rising and mostly studied in children and adolescents with inconsistent results. Many of the identified risk associations were only observed in subgroups or disappeared after adjustment for covariates, mainly multiple pregnancy and gestational age at birth. It is unknown whether fetal brain development and cortical folding differ prenatally in IVF fetuses as compared to SC. Study design, size, duration This is the first study examining fetal neurodevelopment by neurosonography in IVF fetuses. A prospective cohort study of 210 singleton pregnancies recruited from 2017 to 2020, including 70 SC gestations, 70 conceived by IVF following frozen ET (FET) and 70 IVF after fresh ET. Fetal neurosonography was performed in all pregnancies. Additionally, Ages & Stages Questionnaires (ASQ) were obtained at 12 months of corrected age. Participants/materials, setting, methods IVF pregnancies were recruited from a single Assisted Reproduction Center, ensuring homogeneity in IVF stimulation protocols, endometrial preparation, laboratory procedures and embryo culture conditions. SC pregnancies were randomly selected from low-risk fertile couples and paired to IVF by maternal age. Fetal neurosonography including transvaginal approach was performed at 32±2 weeks of gestation, measured off-line by a single investigator and normalized by biparietal or occipitofrontal diameter. ASQ were obtained postnatally, at 12 months of corrected age. Main results and the role of chance Study groups were similar and comparable regarding maternal age, body mass index, study level and employment rate together with exposure to smoke, alcohol, aspirin and corticoids during pregnancy, gestational age (32±2 weeks) and estimated fetal weight (1700±400g) at neurosonography. As compared to SC pregnancies, both IVF populations showed differences in cortical development with reduced parieto-occipital (fresh ET 12.5mm [SD 2.5] vs FET 13.4 [2.6] vs SC 13.4 [2.6]), cingulate (fresh ET 5.8 [IQR 4.2–7.4] vs FET 5.8 [4.1–7.5] vs SC 6.5 [4.8–7.8]) and calcarine (fresh ET 13.5 [IQR 10.1–16.1] vs FET 14.5 [12.1–15.8] vs SC 16.4 [14.3–17.9]) sulci depth together with lower Sylvian fissure grading. Cortical development changes were more pronounced in the fresh ET group as compared to FET. Corpus callosum length and insula depth were lower in FET and fresh ET groups, respectively. Neurosonographic changes remained statistically significant after adjustment by ethnicity, gender, gestational age and weight centile at scan. IVF infants showed worse ASQ scores, especially in fresh ET for communication, personal-social, fine-motor and problem-solving skills. Gross-motor scores were significantly lower in FET as compared to SC and fresh ET. Differences were statistically significant after adjustment by maternal ethnicity, study level, employment status, breastfeeding, gender and corrected age. Limitations, reasons for caution The reported neurodevelopmental differences are subtle, with most neurosonographic findings lying within normal ranges. Infertility factors contribution to the outcome cannot be unraveled from the ART procedure itself. The milder features found in FET individuals cannot condition the techniqués choice and must be considered together with their global perinatal results. Wider implications of the findings: Neurosonography is an appropriate tool to identify subtle brain differences between fetuses exposed and not exposed to ART. Prenatal features were consistent with postnatal neurobehavioral findings. These results support the relevance of a neurodevelopmental follow-up in IVF patients. Further studies are warranted to assess the long-term performance in these subjects. Trial registration number Not applicable


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M L Boutet ◽  
E Eixarch ◽  
P Ahumada-Droguett ◽  
F Crovetto ◽  
M S Cívico ◽  
...  

Abstract Study question Do in vitro fertilization (IVF) offspring present different neurodevelopment assessed by fetal neurosonography and infant neurobehavioral tests as compared to those spontaneously conceived (SC)? Summary answer IVF offspring, especially those obtained after fresh embryo-transfer (ET), showed subtle structural differences in fetal neurosonography and poorer neurobehavioral scores at twelve months of age. What is known already The number of pregnancies following assisted reproductive technologies (ART) is currently increasing worldwide. Concerns about the neurodevelopment of subjects conceived by IVF have been rising and mostly studied in children and adolescents with inconsistent results. Many of the identified risk associations were only observed in subgroups or disappeared after adjustment for covariates, mainly multiple pregnancy and gestational age at birth. It is unknown whether fetal brain development and cortical folding differ prenatally in IVF fetuses as compared to SC. Study design, size, duration This is the first study examining fetal neurodevelopment by neurosonography in IVF fetuses. A prospective cohort study of 210 singleton pregnancies recruited from 2017 to 2020, including 70 SC gestations, 70 conceived by IVF following frozen ET (FET) and 70 IVF after fresh ET. Fetal neurosonography was performed in all pregnancies. Additionally, Ages & Stages Questionnaires (ASQ) were obtained at 12 months of corrected age. Participants/materials, setting, methods IVF pregnancies were recruited from a single Assisted Reproduction Center, ensuring homogeneity in IVF stimulation protocols, endometrial preparation, laboratory procedures and embryo culture conditions. SC pregnancies were randomly selected from low-risk fertile couples and paired to IVF by maternal age. Fetal neurosonography including transvaginal approach was performed at 32±2 weeks of gestation, measured off-line by a single investigator and normalized by biparietal or occipitofrontal diameter. ASQ were obtained postnatally, at 12 months of corrected age. Main results and the role of chance Study groups were similar and comparable regarding maternal age, body mass index, study level and employment rate together with exposure to smoke, alcohol, aspirin and corticoids during pregnancy, gestational age (32±2 weeks) and estimated fetal weight (1700±400g) at neurosonography. As compared to SC pregnancies, both IVF populations showed differences in cortical development with reduced parieto-occipital (fresh ET 12.5mm [SD 2.5] vs FET 13.4 [2.6] vs SC 13.4 [2.6]), cingulate (fresh ET 5.8 [IQR 4.2-7.4] vs FET 5.8 [4.1-7.5] vs SC 6.5 [4.8-7.8]) and calcarine (fresh ET 13.5 [IQR 10.1-16.1] vs FET 14.5 [12.1-15.8] vs SC 16.4 [14.3-17.9]) sulci depth together with lower Sylvian fissure grading. Cortical development changes were more pronounced in the fresh ET group as compared to FET. Corpus callosum length and insula depth were lower in FET and fresh ET groups, respectively. Neurosonographic changes remained statistically significant after adjustment by ethnicity, gender, gestational age and weight centile at scan. IVF infants showed worse ASQ scores, especially in fresh ET for communication, personal-social, fine-motor and problem-solving skills. Gross-motor scores were significantly lower in FET as compared to SC and fresh ET. Differences were statistically significant after adjustment by maternal ethnicity, study level, employment status, breastfeeding, gender and corrected age. Limitations, reasons for caution The reported neurodevelopmental differences are subtle, with most neurosonographic findings lying within normal ranges. Infertility factors contribution to the outcome cannot be unraveled from the ART procedure itself. The milder features found in FET individuals cannot condition the techniqués choice and must be considered together with their global perinatal results. Wider implications of the findings Neurosonography is an appropriate tool to identify subtle brain differences between fetuses exposed and not exposed to ART. Prenatal features were consistent with postnatal neurobehavioral findings. These results support the relevance of a neurodevelopmental follow-up in IVF patients. Further studies are warranted to assess the long-term performance in these subjects. Trial registration number not applicable


2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Adhwaa Khudhari ◽  
Ali Mourad ◽  
Simon Phillips ◽  
Mohammad Zubair Alam ◽  
Robert Hemmings ◽  
...  

Abstract Background Obstetrical outcomes in assisted reproduction techniques (ART) were compared with naturally conceived pregnancies and among each other in multiple reports. However, many important changes in the practice of in vitro fertilization (IVF) over the years, including single embryo transfers (sET) and the introduction of modified natural IVF (mnIVF), and the advances in the frozen embryo transfer (FET) might have impacted the outcomes. Our study is the first to our knowledge to assess four different groups, including spontaneous pregnancies, mnIVF, stimulated IVF (sIVF), and FET altogether in a head-to-head comparison. This is a retrospective study on perinatal outcomes of singleton babies conceived naturally or using three different ART protocols between 2011 and 2014. The primary objective was the comparison of gestational age and birth weight between spontaneously conceived pregnancies (NAT, n= 15,770), mnIVF (n=235), sIVF (n=389), and FET (n=222). Results Our results show a significant difference in favor of naturally conceived pregnancies over ART in term of gestational age. In fact, the gestational age of babies in the NAT group was statistically higher compared to each one of the ART groups alone. Regarding the birth weight, the mean was significantly higher in the FET group compared to the other categories. Conclusion Differences in perinatal outcomes are still found among babies born after different modes of conception. However, there is still need for well-designed high-quality trials assessing perinatal outcomes between naturally conceived pregnancies and different ART protocols based on different maternal and treatment characteristics.


2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M L Boutet ◽  
L Youssef ◽  
L Erlandsson ◽  
E Hansson ◽  
D Manau ◽  
...  

Abstract Study question Does the presence of corpus luteum (CL) in in vitro fertilization (IVF) treatments affect maternal and fetal concentrations of hemopexin and α1-microglobulin in preeclampsia? Summary answer Decreased hemopexin and increased α1-microglobulin levels in maternal and fetal blood in IVF pregnancies with absence of CL particularly in pregnancies complicated by preeclampsia. What is known already: Pregnancies after frozen embryo transfer (FET) in programmed cycles have higher rates of hypertensive disorders of pregnancy, suggesting a link between the absence of CL in programmed cycles and adverse maternal outcomes.Cardiovascular function is impaired early in pregnancy in women conceiving by IVF treatments in the absence of CL.Plasma relaxin–2, a potent vasodilator and stimulus of decidualization, has been reported to be undetectable in a non-CL cohort, but markedly elevated in a multiple-CL cohort through pregnancy.Hemopexin and α1-microglobulin act as scavengers that eliminate free heme-groups responsible for hemoglobin-induced oxidative stress known to contribute to preeclampsia development. Study design, size, duration A case-control study of 160 singleton pregnancies recruited from 2016 to 2020, including 54 spontaneous pregnancies from fertile couples, 50 conceived by IVF following fresh embryo transfer (ET) and FET in natural cycle (presence of CL) and 56 IVF after fresh oocyte-donation or FET in programmed cycles (absence of CL). Pregnancies were subclassified according to the presence of preeclampsia in uncomplicated, preeclampsia and severe preeclampsia cases. Participants/materials, setting, methods IVF pregnancies were recruited from a single Assisted Reproduction Center, ensuring homogeneity in IVF stimulation protocols, endometrial preparation, laboratory procedures and embryo culture conditions. Spontaneous pregnancies from fertile couples were randomly selected from our general population and matched to IVF by gestational age at birth. Hemopexin and α1-microglobulin concentrations were measured by ELISA in maternal and cord plasma collected at delivery. All comparisons were adjusted for age, ethnicity, prematurity, birthweight centile, oocyte-donation and FET cycles. Main results and the role of chance Parental ethnicity, body mass index, exposure to aspirin and corticoids during pregnancy, mean gestational age at birth and birthweight were similar in all study groups. While maternal hemopexin levels were lower in treatments without CL, the IVF group with one or several CL showed significantly increased hemopexin concentrations, both in uncomplicated and preeclampsia cases (uncomplicated: spontaneous conceptions median 1520 ug/ml [interquartile range 1054–1746], IVF with CL 1554 [1315–1778], IVF without CL 1401 [1130–1750]; Preeclampsia: spontaneous conceptions 1362 [1121–1667], IVF with CL 1372 [403–2558], IVF without CL 1215 [971–1498]). Maternal α1-microglobulin was significantly higher in the absence of CL in severe preeclamptic cases as compared to spontaneous pregnancies and IVF with CL (spontaneous conceptions median 23 ug/ml [interquantile range 20–24], IVF with CL 24 [24–26], IVF without CL 26 [25–28]). The cord blood profiles were identical to the maternal for both biomarkers. Overall, and in line with previous studies, preeclamptic pregnancies independently of the mode of conception, showed decreased concentrations of hemopexin and increased concentrations of α1-microglobulin both in maternal and fetal plasma, with more pronounced changes in severe preeclampsia cases. Limitations, reasons for caution Infertility factors contribution to the outcome cannot be unraveled from the assisted reproductive technologies procedure itself as we have only included spontaneous pregnancies from fertile couples. Adjustments for oocyte-donation and FET modalities were performed due to the higher proportion of these features in the ET in programmed cycles group. Wider implications of the findings: These findings acknowledge physiological differences between pregnancies following ET in stimulated and natural versus programmed cycles, supporting the hypothesis that the CL activity could influence perinatal results. This approach to perinatal outcomes in IVF patients could lead to changes in ET protocols in order to develop a CL if possible. Trial registration number Not applicable


GYNECOLOGY ◽  
2021 ◽  
Vol 23 (3) ◽  
pp. 270-274
Author(s):  
Gunai R. Asfarova ◽  
Veronika I. Smol'nikova ◽  
Natalia P. Makarova ◽  
Iuliia S. Drapkina ◽  
Anastasiia P. Sysoeva ◽  
...  

Cumulus cells are essential during oocytes growth and development, as well as during their maturation and fertilization. Research results have shown that embryo co-cultivation with autologous cumulus cells increases the frequency of blastocyst formation, and also improves the effectiveness of ART programs. Embryo transfer in such programs is recommended to be carried out using the CAT technology (Cumulus-Aided embryo Transfer), which includes embryo cultivation on a layer of cumulus cells and embryo transfer with a certain amount of diluted cumulus cells. Patient G., 38 years old, came to the department with infertility for 15 years and recurrent implantation failure in history. The patient had ART program with autologous co-cultivation of embryos with cumulus cells and a new CAT transfer technology. The patient fell pregnant and gave birth to a healthy child. Autologous cumulus cells can be a source of biologically active substances and improve embryological parameters and implantation rate in ART programs. Embryo co-cultivation with cumulus cells is especially important for patients with recurrent implantation failure. This technique can become an alternative for optimizing human embryos culturing.


2021 ◽  
pp. 70-76
Author(s):  
Abuduwaili Ruziguli ◽  
Nikolai Nikolaevich Rukhliada ◽  
Anna Nikolaevna Taits ◽  
Tatyana Ivanovna Prohorovich ◽  
Tatyana Aleksandrovna Libova

This article is devoted to the assessment of the role of ALK5 in the profile of early reproductive losses in the use of assisted reproductive technologies, in particular, by using immunohistochemical study in the group of patients with early spontaneous abortion after the procedure of embryo transfer, a lower level of ALK5 expression in the decidual tissue was revealed (in comparison with control), which may be related to the occurrence of early reproductive losses caused by the imbalance in Th1 / Th2 and its effect on the increase in the concentration of natural killer cells.


2020 ◽  
Vol 2020 (2) ◽  
Author(s):  
V Bacal ◽  
D B Fell ◽  
H Shapiro ◽  
A Lanes ◽  
A E Sprague ◽  
...  

Abstract STUDY QUESTION Are data accurately documented in the Canadian Assisted Reproductive Technologies Register (CARTR) Plus database? SUMMARY ANSWER Measures of validity were strong for the majority of variables evaluated while those with moderate agreement were FSH levels, oocyte origin and elective single embryo transfer. WHAT IS KNOWN ALREADY Health databases and registries are excellent sources of data. However, as these databases are typically not established for the primary purpose of performing research, they should be evaluated prior to utilization for research both to inform the study design and to determine the extent to which key study variables, such as patient characteristics or therapies provided, are accurately documented in the database. CARTR Plus is Canada’s national register for collecting extensive information on IVF and corresponding pregnancy outcomes, and it has yet to be validated. STUDY DESIGN, SIZE, DURATION This study evaluating the data translation CARTR Plus database examined IVF cycles performed in 2015 using data directly from patient charts. Six clinics across Canada were recruited to participate, using a purposive sampling strategy. Fixed random sampling was employed to select 146 patient cycles at each clinic, representing unique patients. Only a single treatment cycle record from a unique patient at each clinic was considered during chart selection. PARTICIPANTS/MATERIALS, SETTING, METHODS Twenty-five data elements (patient characteristics, treatments and outcomes) were reabstracted from patient charts, which were declared the reference standard. Data were reabstracted by two independent auditors with relevant clinical knowledge after confirming inter-rater reliability. These data elements from the chart were then compared to those in CARTR Plus. To determine the validity of these variables, we calculated kappa coefficients, sensitivity, specificity, positive predictive value and negative predictive value with 95% CI for categorical variables and calculated median differences and intraclass correlation coefficients (ICC) for continuous variables. MAIN RESULTS AND THE ROLE OF CHANCE Six clinics agreed to participate in this study representing five Canadian provinces. The mean age of patients was 35.5 years, which was similar between the two data sources, resulting in a near perfect level of agreement (ICC = 0.99; 95% CI: 0.99, 0.99). The agreement for FSH was moderate, ICC = 0.68 (95% CI: 0.64, 0.72). There was nearly perfect agreement for cycle type, kappa = 0.99 (95% CI: 0.98, 1.00). Over 90% of the cycles in the reabstracted charts used autologous oocytes; however, data on oocyte source were missing for 13% of cycles in CARTR Plus, resulting in a moderate degree of agreement, kappa = 0.45 (95% CI, 0.37, 0.52). Embryo transfer and number of embryos transferred had nearly perfect agreement, with kappa coefficients greater than 0.90, whereas that for elective single or double embryo transfer was much lower (kappa = 0.55; 95% CI: 0.49, 0.61). Agreement was nearly perfect for pregnancy type, and number of fetal sacs and fetal hearts on ultrasound, all with kappa coefficients greater than 0.90. LARGE-SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION CARTR Plus contains over 200 variables, of which only 25 were assessed in this study. This foundational validation work should be extended to other CARTR Plus database variables in future studies. WIDER IMPLICATIONS OF THE FINDINGS This study provides the first assessment of the quality of the data translation process of the CARTR Plus database, and we found very high quality for the majority of the variables that were analyzed. We identified key data points that are either too often lacking or inconsistent with chart data, indicating that changes in the data entry process may be required. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by Canadian Institutes of Health Research (CIHR) (Grant Number FDN-148438) and by the Canadian Fertility and Andrology Society Research Seed Grant (Grant Number: N/A). The authors report no conflict of interest. TRIAL REGISTRATION NUMBER Not applicable.


2014 ◽  
Vol 102 (3) ◽  
pp. e42-e43
Author(s):  
R.S. Weinerman ◽  
J. Ghosh ◽  
S. Song ◽  
M. Truongcao ◽  
C. Sapienza ◽  
...  

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sebastian Canovas ◽  
Elena Ivanova ◽  
Raquel Romar ◽  
Soledad García-Martínez ◽  
Cristina Soriano-Úbeda ◽  
...  

The number of children born since the origin of Assisted Reproductive Technologies (ART) exceeds 5 million. The majority seem healthy, but a higher frequency of defects has been reported among ART-conceived infants, suggesting an epigenetic cost. We report the first whole-genome DNA methylation datasets from single pig blastocysts showing differences between in vivo and in vitro produced embryos. Blastocysts were produced in vitro either without (C-IVF) or in the presence of natural reproductive fluids (Natur-IVF). Natur-IVF embryos were of higher quality than C-IVF in terms of cell number and hatching ability. RNA-Seq and DNA methylation analyses showed that Natur-IVF embryos have expression and methylation patterns closer to in vivo blastocysts. Genes involved in reprogramming, imprinting and development were affected by culture, with fewer aberrations in Natur-IVF embryos. Methylation analysis detected methylated changes in C-IVF, but not in Natur-IVF, at genes whose methylation could be critical, such as IGF2R and NNAT.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Congru Li ◽  
Yang Yu

Abstract Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of childbearing age and is the main cause of anovulatory infertility. To increase the number of oocytes obtained, controlled ovarian stimulation (COS) has become a routine choice for in vitro fertilization-embryo transfer (IVF-ET), which is one of the common assisted reproductive technologies for PCOS patients. However, for these patients, there is a high risk of ovarian hyperstimulation syndrome (OHSS). Obtaining in vitro maturation (IVM) of immature oocytes, and then in vitro fertilization and embryo transfer of mature oocytes provides a possible way for people to solve the above problems. Since the IVM technology will expose oocytes to in vitro conditions for a longer period of time, theoretically increasing the risk of the oocytes being affected by the culture environment, further research and explorations are needed for study in gene programming, epigenetics, etc. Therefore, to explore the impact of IVM operation on embryonic development is of great significance for further clarifying assisted reproductive safety and improving IVM operation conditions. Here we focused on DNA methylation reprogramming process which was essential for embryonic development. We tested the DNA methylation of sperm, IVM oocytes and IVM generated early stage embryos including pronucleus, 4cell, 8cell, morula, inner cell mass, trophoectoderm (TE) as well as six-week embryos by Nimble Gen Human DNA Methylation 3x729K CpG Island Plus RefSeq Promoter Array and compared the data with our published genome-wide DNA methylomes of human gametes and early embryos generated from in vivo maturation oocytes. We showed that IVM embryos show abnormal DNA methylation reprogramming pattern. By analyzing the abnormally reprogrammed promoters, we further found that IVM may affect the functions of demethylation related genes. Oocytes from IVM manipulation were tested with higher DNA methylation levels, and their abnormal methylated promoters mainly enriched in immune and metabolism pathways. Furthermore, we investigated the DNA methylation of TE, which was directly related with implantation process and revealed the abnormal methylated promoters were related with metabolism pathway too. Our data support that IVM may influence the DNA methylome of oocytes, which in turn affects the methylome of their embryos. However, due to the limited number of samples and the inability of the chip to cover all CpG sites, the results of this study require further research and validation.


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