Using the embryo-uterus statistical model to predict pregnancy chances by using cleavage stage morphokinetics and female age: two centre-specific prediction models and mutual validation.

BACKGROUND: The predictive capability of time-lapse monitoring (TLM) selection algorithms is influenced by patient characteristics, type and quality of data included in the analysis and the used statistical methods. Previous studies excluded DET cycles of which only one embryo implanted, introducing bias into the data. Therefore, we wanted to develop a TLM prediction model that is able to predict pregnancy chances after both single- and double embryo transfer (SET and DET). METHODS: This is a retrospective study of couples (n = 1770) undergoing an in vitro fertilization cycle at the Erasmus MC, University Medical Centre Rotterdam (clinic A) or the Reinier de Graaf Hospital (clinic B). This resulted in 2058 transferred embryos with time-lapse and pregnancy outcome information. For each dataset a prediction model was established by using the Embryo-Uterus statistical model with the number of gestational sacs as the outcome variable. This process was followed by cross-validation. RESULTS: Prediction model A (based on data of clinic A) included female age, t3-t2 and t5-t4, and model B (clinic B) included female age, t2, t3-t2 and t5-t4. Internal validation showed overfitting of model A (calibration slope 0.765 and area under the curve (AUC) 0.60), and minor overfitting of model B (slope 0.915 and AUC 0.65). External validation showed that model A was capable of predicting pregnancy in the dataset of clinic B with an AUC of 0.65 (95% CI: 0.61-0.69; slope 1.223, 95% CI: 0.903-1.561). Model B was less accurate in predicting pregnancy in the dataset of clinic A (AUC 0.60, 95% CI: 0.56-0.65; slope 0.671, 95% CI: 0.422-0.939). CONCLUSION: Our study demonstrates a novel approach to the development of a TLM prediction model by applying the EU statistical model. With further development and validation in clinical practice, our prediction model approach can aid in embryo selection and decision making for SET or DET.

Circulating maternal prorenin and oocyte and preimplantation embryo development: the Rotterdam Periconception Cohort.

STUDY QUESTION: Could circulating maternal prorenin serve as a proxy for oocyte and preimplantation embryo development, assessed by time-lapse parameters and clinical treatment outcomes? SUMMARY ANSWER: High circulating maternal prorenin concentrations after ovarian stimulation associate with a larger oocyte area, faster cleavage divisions from the five-cell stage onwards and increased chance of successful implantation. WHAT IS KNOWN ALREADY: After ovarian stimulation, circulating prorenin (renin's precursor), is largely ovary-derived. Prorenin may contribute to ovarian angiotensin synthesis, which is relevant in reproduction given its role in follicular development and oocyte maturation. STUDY DESIGN, SIZE, DURATION: Prospective observational cohort study including couples requiring fertility treatment from May 2017 as a subcohort of the ongoing Rotterdam Periconception Cohort conducted in a tertiary referral hospital. PARTICIPANTS/MATERIALS, SETTING, METHODS: Between May 2017 and July 2020, 309 couples with an indication for IVF treatment or ICSI were included. Resulting embryos (n = 1024) were submitted to time-lapse embryo culture. Time of fertilization (t0), pronuclear appearance (tPNa), and fading (tPNf) as well as the exact timing of reaching the two- to eight-cell stage (t2-t8), the start of blastulation (tSB), reaching the full (tB), and expanded blastocyst (tEB) were retrospectively recorded. Oocyte area was measured at t0, tPNa, and tPNf. Prorenin was determined at the day of embryo transfer. MAIN RESULTS AND THE ROLE OF CHANCE: After adjustment for patient- and treatment-related factors, linear mixed modeling showed that higher prorenin concentrations associate with a larger oocyte area at tPNa (ß 64.45 µm2, 95% CI 3.26; 125.64, P = 0.04), and faster progression from five-cell stage onwards (e.g. ß8-cell -1.37 h, 95% CI -2.48; -0.26, P = 0.02). Prorenin associated positively with pre-transfer outcomes (e.g. ßfertilized oocytes 2.09, 95% CI 1.43; 2.75, P < 0.001) and implantation (odds ratio+ß-hCG-test: 1.79, 95% CI 1.06; 3.08, P = 0.03), but not with live birth. LIMITATIONS, REASONS FOR CAUTION: This prospective observational study provides associations and therefore residual confounding cannot be excluded and causality has to be shown in intervention studies. WIDER IMPLICATIONS OF THE FINDINGS: Theca cell-derived factors, such as prorenin, may help to clarify the underlying endocrine mechanism of oocyte maturation and embryo development, with a special focus on the (patho)physiological reproductive role of prorenin and the identification of factors influencing its secretion and activity, which is of great added value for improving embryo selection and predicting implantation and pregnancy outcomes. This will bring us to investigate which determinants of oocyte quality and embryo development should take center stage in developing preconception care strategies. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by the Department of Obstetrics and Gynecology of the Erasmus MC, University Medical Center, Rotterdam, the Netherlands, and the Erasmus MC Medical Research Advisor Committee's 'Health Care Efficiency Research' program (OZBS72.16080). The authors have no competing interests to disclose. TRIAL REGISTRATION NUMBER: N/A.

The impact of IVF culture medium on post-implantation embryonic growth and development with emphasis on sex specificity: the Rotterdam Periconceptional Cohort.

RESEARCH QUESTION: Are there (sex-specific) differences in first-trimester embryonic growth and morphological development between two culture media used for IVF and intracytoplasmic sperm injection (ICSI) treatment? DESIGN: A total of 835 singleton pregnancies from a prospective hospital-based cohort study were included, of which 153 conceived after IVF/ICSI treatment with Vitrolife G-1™ PLUS culture medium, 252 after culture in SAGE 1-Step™ and 430 were naturally conceived. Longitudinal three-dimensional ultrasound examinations were performed at 7, 9 and 11 weeks of gestation for offline biometric (crown rump length, CRL), volumetric (embryonic volume) and morphological (Carnegie stage) measurements. RESULTS: Embryos cultured in SAGE 1-Step grew faster than those cultured in Vitrolife G-1 PLUS (betaEV 0.030 3√ml [95% CI 0.008-0.052], P = 0.007). After stratification for fetal sex, male embryos cultured in SAGE 1-Step demonstrated faster growth than those cultured in Vitrolife G-1 PLUS (betaEV 0.048 3√ml [95% CI 0.015-0.081], P = 0.005). When compared with naturally conceived embryos, those cultured in SAGE 1-Step grew faster (betaEV 0.040 3√ml [95% CI 0.012-0.069], P = 0.005). This association was most pronounced in male embryos (betaEV 0.078 3√ml [95% CI 0.035-0.120], P < 0.001). CONCLUSIONS: This study shows that SAGE 1-Step culture medium accelerates embryonic growth trajectories compared with Vitrolife G-1 PLUS and naturally conceived pregnancies, especially in male embryos. Further research should focus on the impact of culture media on postnatal development and the susceptibility to non-communicable diseases.

The Impact of Culture Medium on Morphokinetics of Cleavage Stage Embryos: An Observational Study.

To study the impact of culture media on preimplantation morphokinetics used for predicting clinical outcomes. All IVF and ICSI cycles performed between 2012 and 2017 with time-lapse information available were included. In November 2014, culture medium was changed from Vitrolife G-1 PLUS to SAGE 1-Step. Each embryo was retrospectively assigned a morphokinetic-based KIDScore for prediction of implantation. Clinical outcomes were retrieved from medical records. Linear mixed models were used to study differences in morphokinetic parameters, a proportional odds model for KIDScore ranking and logistic regression for differences in clinical outcomes. All analyses were adjusted for patient and treatment characteristics. In 253 (63.1%) cycles, embryos (n = 671) were cultured in Vitrolife, and in 148 (36.9%) cycles, embryos (n = 517) were cultured in SAGE. All cleavage divisions occurred earlier for SAGE embryos than for Vitrolife embryos (2-cell: -2.28 (95%CI: -3.66, -0.89), 3-cell: -2.34 (95%CI: -4.00, -0.64), 4-cell: -2.41 (95%CI: -4.11, -0.71), 5-cell: -2.54 (95%CI: -4.90, -0.18), 6-cell: -3.58 (95%CI: -6.08, -1.08), 7-cell: -5.62 (95%CI: -8.80, -2.45) and 8-cell: -5.32 (95%CI: -9.21, -1.42) hours, respectively). Significantly more embryos cultured in SAGE classified for the highest KIDScore compared to embryos cultured in Vitrolife (p < 0.001). No differences were observed in clinical outcomes. Our results demonstrate an impact of culture medium on preimplantation embryo developmental kinetics, which affects classification within the KIDScore algorithm, while pregnancy outcomes were comparable between the groups. This study underscores the need to include the type of culture medium in the development of morphokinetic-based embryo selection tools.

A higher preconceptional paternal body mass index influences fertilization rate and preimplantation embryo development.

BACKGROUND: Obesity is a worldwide problem affecting the health of millions of people throughout the life course. Studies reveal that obesity impairs sperm parameters and epigenetics, potentially influencing embryonic development. OBJECTIVE: To investigate the association between preconceptional paternal body mass index (BMI) and embryo morphokinetics using a time-lapse incubator and in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) outcomes. MATERIALS AND METHODS: Participants were recruited from a tertiary hospital in this prospective periconceptional cohort study. A total of 211 men were included: 86 with normal weight (BMI < 25.0), 94 overweight (BMI 25-29.9), and 41 obese (BMI ≥ 30). These men were part of a couple that underwent IVF/ICSI treatment with ejaculated sperm after which 757 embryos were cultured in a time-lapse incubator. The main outcome parameters consisted of fertilization rate, embryo developmental morphokinetics, embryo quality assessed by a time-lapse prediction algorithm (KIDScore), and live birth rate. RESULTS: A higher paternal BMI was associated with faster development of the preimplantation embryo, especially during the first cleavage divisions (t2: -0.11 h (p = 0.05) and t3: -0.19 h (p = 0.01)). Embryo quality using the KIDScore was not altered. The linear regression analysis, after adjustment for confounders (paternal age, ethnicity, smoking, alcohol use, education, total motile sperm count, and maternal age and BMI), showed an inverse association between paternal BMI and fertilization rate (effect estimate: -0.01 (p = 0.002)), but not with the live birth rate. DISCUSSION AND CONCLUSION: Our data demonstrate that a higher preconceptional paternal BMI is associated with a reduced fertilization rate in IVF/ICSI treatment. Our findings underline the importance of a healthy paternal weight during the preconception period.

Higher preconceptional maternal body mass index is associated with faster early preimplantation embryonic development: the Rotterdam periconception cohort.

BACKGROUND: Overweight and obesity affect millions of people globally, which has also serious implications for reproduction. For example, treatment outcomes after in vitro fertilisation (IVF) are worse in women with a high body mass index (BMI). However, the impact of maternal BMI on embryo quality is inconclusive. Our main aim is to study associations between preconceptional maternal BMI and morphokinetic parameters of preimplantation embryos and predicted implantation potential. In addition, associations with clinical IVF outcomes are investigated. METHODS: From a tertiary hospital, 268 women undergoing IVF or IVF with intracytoplasmic sperm injection (ICSI) were included; 143 normal weight, 79 overweight and 46 obese women. The embryos of these women were cultured in the EmbryoScope, a time-lapse incubator. The morphokinetic parameters of preimplantation embryos and predicted implantation potential, assessed by the KIDScore algorithm were longitudinally evaluated as primary and secondary outcomes, respectively. The tertiary outcomes included clinical outcomes, i.e., fertilization, implantation and live birth rate. RESULTS: After adjustment for patient- and treatment-related factors, we demonstrated in 938 embryos that maternal BMI is negatively associated with the moment of pronuclear appearance (ßtPNa -0.070 h (95%CI -0.139, -0.001), p = 0.048), pronuclear fading (ßtPNf -0.091 h (95%CI -0.180, -0.003), p = 0.043 and the first cell cleavage (ßt2 -0.111 h (95%CI -0.205, -0.016), p = 0.022). Maternal BMI was not significantly associated with the KIDScore and tertiary clinical treatment outcomes. In embryos from couples with female or combined factor subfertility, the impact of maternal BMI was even larger (ßtPNf -0.170 h (95%CI -0.293, -0.047), p = 0.007; ßt2 -0.199 h (95%CI -0.330, -0.067), p = 0.003). Additionally, a detrimental impact of BMI per point increase was observed on the KIDScore (ß -0.073 (se 0.028), p = 0.010). CONCLUSIONS: Higher maternal BMI is associated with faster early preimplantation development. In couples with female or combined factor subfertility, a higher BMI is associated with a lower implantation potential as predicted by the KIDScore. Likely due to power issues, we did not observe an impact on clinical treatment outcomes. However, an effect of faster preimplantation development on post-implantation development is conceivable, especially since the impact of maternal BMI on pregnancy outcomes has been widely demonstrated.

Periconceptional maternal body mass index and the impact on post-implantation (sex-specific) embryonic growth and morphological development.

OBJECTIVE: Women with obesity have an increased risk of pregnancy complications. Although complications generally present in the second and third trimester of pregnancy, most of them develop in the periconception period. Moreover, fetal sex also impacts pregnancy course and outcome. Therefore, our aim is to study (sex-specific) associations between periconceptional maternal body mass index (BMI) and embryonic growth and morphological development. METHODS: A total of 884 women with singleton pregnancies were selected from the Rotterdam Periconception Cohort, comprising 15 women with underweight, 483 with normal weight, 231 with overweight and 155 with obesity. Longitudinal three-dimensional ultrasound examinations were performed at 7, 9, and 11 weeks of gestation for offline measurements of crown-rump length (CRL), embryonic volume (EV), and Carnegie stages. Analyses were adjusted for maternal age, parity, ethnicity, education, and periconceptional lifestyle. RESULTS: A negative trend was observed for embryos of women with obesity (ßEV -0.03, p = 0.086), whereas embryonic growth and developmental trajectories in women with overweight were comparable to those with normal weight. Maternal underweight was associated with faster morphological development (ßCarnegie 0.78, p = 0.004). After stratification for fetal sex, it was demonstrated that female embryos of underweight women grow and morphologically develop faster than those of normal weight women (ßEV 0.13, p = 0.008; ßCarnegie 1.39, p < 0.001), whereas female embryos of women with obesity grow slower (ßEV -0.05, p = 0.027). CONCLUSION: We found that periconceptional maternal underweight is associated with faster embryonic growth, especially in females. In contrast, female embryos of women with obesity grow slower than female embryos of women with normal weight. This may be the result of altered female adaptation to the postnatal environment. Future research should focus on strategies for optimizing preconceptional maternal weight, to reduce BMI-related pregnancy complications and improve the health of future generations.

Prenatal growth trajectories and birth outcomes after frozen-thawed extended culture embryo transfer and fresh embryo transfer: the Rotterdam Periconception Cohort.

RESEARCH QUESTION: Are there differences in prenatal growth trajectories and birth outcomes between singleton pregnancies conceived after IVF treatment with frozen-thawed extended culture embryo transfer at day 5, fresh embryo transfer at day 3 or naturally conceived pregnancies? DESIGN: From a prospective hospital-based cohort, 859 singleton pregnancies were selected, including 133 conceived after IVF with frozen-thawed embryo transfer, 276 after fresh embryo transfer, and 450 naturally conceived pregnancies. Longitudinal 3D ultrasound scans were performed at 7, 9 and 11 weeks of gestation for offline crown-rump length (CRL) and embryonic volume measurements. Second trimester estimated fetal weight was based on growth parameters obtained during the routine fetal anomaly scan at 20 weeks of gestation. Birth outcome data were collected from medical records. RESULTS: No differences regarding embryonic growth trajectories were observed between frozen-thawed and fresh embryo transfer. Birthweight percentiles after fresh embryo transfer were lower than after frozen-thawed embryo transfer (38.0 versus 48.0; P = 0.046, respectively). The prevalence of non-iatrogenic preterm birth (PTB) was significantly lower in pregnancies resulting from fresh embryo transfer compared with frozen-thawed embryo transfer (4.7% versus 10.9%; P = 0.026, respectively). Compared with naturally conceived pregnancies, birthweight percentiles and percentage of non-iatrogenic PTB were significantly lower in pregnancies after fresh embryo transfer and gestational age at birth was significantly higher. CONCLUSIONS: This study shows that embryonic growth is comparable between singleton pregnancies conceived after fresh and frozen-thawed embryo transfer. The lower relative birthweight and PTB rate in pregnancies after fresh embryo transfer than after frozen-thawed embryo transfer and naturally conceived pregnancies warrants further investigation.

The influence of frozen-thawed and fresh embryo transfer on utero-placental (vascular) development: the Rotterdam Periconception cohort.

STUDY QUESTION: Does frozen-thawed or fresh embryo transfer (ET) influence utero-placental (vascular) development, when studied using three-dimensional (3D) ultrasound and virtual reality imaging techniques? SUMMARY ANSWER: In the first trimester, placental developmental parameters, that is, placental volume (PV) and utero-placental vascular volume (uPVV), were comparable between pregnancies resulting from frozen-thawed ET, fresh ET and natural conception; and in the second and the third trimester, uterine artery Doppler indices were lower in pregnancies after frozen-thawed ET compared to pregnancies after fresh ET and natural conception. WHAT IS KNOWN ALREADY: Pregnancies after frozen-thawed ET are at risk of developing placenta-related pregnancy complications. There is strong evidence that impaired first-trimester spiral artery remodelling is involved in the pathophysiology of these complications. Studies on longitudinal placental development in pregnancies with different modes of conception, that is, after frozen-thawed ET, fresh ET or natural conception, are lacking. STUDY, DESIGN, SIZE, DURATION: Women with singleton pregnancies were included before 10 weeks of gestation, between January 2017 and July 2018, as a subcohort of the ongoing Rotterdam Periconception cohort. Results were partially validated in 722 women from the total cohort, which was conducted from November 2010 onwards. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 214 women, of whom 32 conceived after frozen-thawed ET, 56 conceived after fresh ET and 126 conceived naturally, were selected. PV and uPVV measurements were obtained at 7, 9 and 11 weeks of gestation by transvaginal 3D (power Doppler) ultrasound. The uterine artery pulsatility index (UtA-PI) and resistance index (UtA-RI) were measured transvaginally at 7, 9, 11 and 13 weeks and abdominally at 22 and 32 weeks of gestation by pulsed wave Doppler ultrasound. In the validation cohort, the PV was measured in 722 women. Associations between mode of conception and placental development were studied using linear mixed models. MAIN RESULTS AND THE ROLE OF CHANCE: First-trimester parameters of placental development, that is, PV, uPVV, UtA-PI and UtA-RI, were comparable between pregnancies after frozen-thawed and fresh ET and naturally conceived pregnancies. In our validation cohort, comparable results were found for PV. However, the second- and third-trimester UtA-PI and UtA-RI in pregnancies after frozen-thawed ET were significantly lower than in pregnancies after fresh ET (ßUtA-PI -0.158 (95% CI: -0.268, -0.048), P = 0.005; ßUtA-RI -0.052 (95% CI: -0.089, -0.015), P = 0.006). The second- and third-trimester uterine artery indices in pregnancies after fresh ET were comparable to those in pregnancies after natural conception. LIMITATIONS, REASONS FOR CAUTION: The main limitation of this study is the lack of power to optimally detect differences in placental development and placenta-related pregnancy outcomes between pregnancies after different modes of conception. Moreover, our population was selected from a tertiary hospital and included a relatively limited number of pregnancies. Therefore, external validity of the results should be confirmed in a larger sample size. WIDER IMPLICATIONS OF THE FINDINGS: These findings indicate no significant impact of conception mode on early placental development and a beneficial impact for frozen-thawed ET on the second- and third-trimester Doppler indices. This suggests that frozen-thawed ET may not be as detrimental for placental perfusion as previous research has demonstrated. As the number of clinics applying the 'freeze-all strategy' increases, future research should focus on establishing the optimal uterine environment, with regards to hormonal preparation, prior to ET to reduce placental-related pregnancy complications after frozen-thawed ET. STUDY FUNDING/COMPETING INTEREST(S): This research was funded by the Erasmus MC Medical Research Advisor Committee's 'Health Care Efficiency Research' program and the department of Obstetrics and Gynaecology of the Erasmus MC, University Medical Center, Rotterdam, The Netherlands. JSEL reports grants and personal fees from Ferring, personal fees from Titus Healthcare, grants and personal fees from Ansh Labs, grants from NIH, grants from Dutch Heart Association and grants from ZonMW outside the submitted work. None of the other authors have a conflict of interest. TRIAL REGISTRATION NUMBER: Registered at the Dutch Trial Register (NTR6684).