Zona Pellucida Thickness Variation Research Articles

Novel image analyser-assisted morphometric methodology offer unique opportunity for selection of embryos with potential for implantation

BackgroundPrevious studies looked into the connections between pregnancy and the Zona Pellucida (ZP) thickness and Zona Pellucida Thickness Variation (ZPTV), as well as the embryo’s radius, circumference, perimeter and global symmetry. However, no research has linked embryo implantation and pregnancy to the percentage of ZP thinning, the reduction in ooplasm volume, and the increase in perivitelline space (PVS) volume. Our objective is to correlate the percentage of ZP thinning, the percentage of ooplasm volume shrinkage and the percentage of PVS increase to the implantation. These data will be used for embryo selection as well as it can be put into a software that will assist embryo selection.Materials and methodsRetrospective study included 281 patients, all of them had 2 embryos transferred, 149 patients got pregnant with two gestation sacs and 132 patients did not get pregnant. All of the transferred embryos had the ZP thickness measured several times from time of ICSI till Embryo Transfer (ET), the ooplasm volume was calculated from time of ICSI till two Pronuclei (2PN) fading and the PVS was calculated from the ICSI time till the 2PN fading.ResultsThe first characteristic is the change in the average ZP thickness that decreased by 32.7% + 5.3% at 70 h for the implanted embryos (Group 1) versus 23.6% + 4.8% for non-implanted embryos (Group 2) p = 0.000. The second characteristic is the average reduction in the volume of the ooplasm which is 20.5% + 4.3% in Group 1 versus 15.1% + 5.2% in Group 2, p = 0.000. The third characteristic is the increase in the volume of the PVS which was 38.1% + 7.6% in Group 1 versus 31.6% + 9.7% in Group 2 p = 0.000.ConclusionThe implanted embryos showed higher percent of ZP thinning, higher percent of ooplasm reduction and higher percent of PVS increase.

The effect of zona pellucida thickness variation on fertilization and subsequent embryonic development: a large single center cohort study

The effect of zona pellucida thickness variation on fertilization and subsequent embryonic development: a large single center cohort study

Use of imaging software for assessment of the associations among zona pellucida thickness variation, assisted hatching, and implantation of day 3 embryos.

The aim of this study was to determine if zona pellucida thickness variation (ZPTV) is associated with implantation and if this relationship changes with use of assisted hatching (AH). Day 3 embryos from single or double embryo transfers (DETs) performed between 2014 and 2016 were included. ZPTV was assessed by examining photographs taken before transfer using an automated image processing platform to segment the zona pellucida (ZP) with an active contour technique. One hundred points were obtained of ZP thickness (ZPT) of each embryo to calculate ZPTV ([maximum ZPT-mean ZPT]/mean ZPT). Logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI) of implantation by tertile of ZPTV. Maternal age and AH were adjusted for a priori. Other cycle and embryo characteristics were adjusted for if they altered the continuous effect estimate by >10%. There was no statistically significant association between ZPTV and implantation across tertiles although embryos with greater ZPTV showed a trend of decreased implantation (Tertile 2 (T2) versus Tertile 1 (T1), OR=0.80, CI=0.50-1.28; Tertile 3 (T3) versus Tertile 1 (T3), OR=0.75, CI=0.47-1.20). While similar nonsignificant trends for the association between ZPTV and implantation were observed across tertiles after stratification of embryos hatched or not, embryos with the greatest ZPTV had slightly higher odds for implantation when AH was utilized (T3 vs. T1: with AH, OR = 0.89, CI = 0.49-1.62; without AH, OR = 0.61, 0.29-1.27). ZPTV was not associated with implantation after day 3 transfer. This finding did not vary by use of AH.

Investigation of zona pellucida thickness variation and implantation rate - with and without assisted hatching

Recent literature has proposed that zona pellucida thickness variation (ZPTV) in cleavage stage embryos is associated with implantation rate (IR), but studies have been small and have only used a crude ZPTV assessment. We utilized novel image processing software to assess ZPTV to evaluate the relation between ZPTV and IR. In addition, we investigated whether this relation was affected by assisted hatching (AH).

Automatic Dissection Position Selection for Cleavage-Stage Embryo Biopsy.

Embryo biopsies are routinely performed for preimplantation genetic diagnosis (PGD). In order to avoid blastomere membrane rupture and cell lysis, correct selection of a suitable dissection position on the zona pellucida (ZP) is necessary. Although, the technology for automated cell manipulation has advanced greatly over the past decade, fully automated embryo biopsy in PGD has not been realized yet. Automated PGD may ultimately set a new clinical standard that improves the consistency of outcomes, increases cell survival rates, flattens the learning curve of the manual procedure, and reduces the effects of human fatigue. In this paper, we present the first approach to automatically select a suitable ZP dissection position prior to embryo biopsy from a single focused embryo image based on edge detection. The proposed method consists of a technique that estimates the elliptical ZP boundaries and another two techniques that select the suitable position for ZP dissection. These techniques achieved success rates of 96%, 94%, and 94% respectively. In addition, the proposed ZP boundary estimation technique has the potential to perform ZP thickness variation (ZPTV) test and other ZP morphology measurements with further improvement in the future. Our methods provide a starting point for fast position selection prior to automatic embryo biopsy.

Automatic segmentation of zona pellucida and its application in cleavage-stage embryo biopsy position selection.

A very important step of Pre-implantation genetic diagnosis (PGD) is embryo biopsy, in which process the zona pellucida (ZP) is cut open partially and a part of cellular material is extracted from the embryo. Recognition of the ZP is necessary not only for embryo biopsy, but also for other applications such as zona pellucida thickness variation (ZPTV), embryo dissection, etc. The ZP opening position is closely related to the cell survival rate after the biopsy. Selection of an unsuitable position may cause blastomere lysis after the ZP opening. Normal procedures of ZP recognition and biopsy position selection involve a skilled human embryologist. In order to make the process automatic, we introduce an automatic segmentation method for ZP recognition by using edge detection and ellipse fitting with a value adjustment algorithm in this paper. An application of ZP recognition in embryo biopsy position selection is also introduced. Our ZP recognition algorithm was able to correctly segment 43 out of 45 sample embryo images, achieving a success rate of 96%. Its application in embryo biopsy position selection achieved a success rate of 93%.

Compared relationship between the degree of zona pellucida thickness variation of transferred embryos and clinical outcomes between fresh IVF-ET cycles and freezing-thawed ET cycles

Objective: Recently, much interest has been generated in ZP thickness or variation in the ZP thickness of the transferred embryo as a potentially reliable parameter for embryo selection.The purpose of this study was to examine whether freezing embryo transfer (F-ET) is as correlation well between the degree of zona pellucida thickness variation (ZPTV) of transferred embryos and clinical outcomes as fresh embryos transfer cycles (IVF-ET).

Relationship between the degree of zona pellucida thickness variation of transferred embryos and clinical outcomes in IVF-ET cycles

Relationship between the degree of zona pellucida thickness variation of transferred embryos and clinical outcomes in IVF-ET cycles

Apoptosis in human cumulus cells in relation to zona pellucida thickness variation, maturation stage, and cleavage of the corresponding oocyte after intracytoplasmic sperm injection

Objective: To assess the degree of apoptosis in the cumulus cells and the variation of the zona pellucida and the maturity and fertilization of the corresponding oocyte. Design: Retrospective study. Setting: Private fertility clinic. Patient(s): Fifty couples undergoing ICSI. Intervention(s): ICSI. Main Outcome Measure(s): Correlation between apoptosis in the cumulus cells and the zona pellucida thickness variation, maturation stage, fertilization rate, and embryo score. Result(s): This study demonstrated no correlation between apoptosis in cumulus cells and the thickness and variation of the zona pellucida in oocytes and embryos. The incidence of apoptosis was significantly higher in cumulus cells from empty zona pellucidas and germinal vesicle stage and metaphase I oocytes compared with metaphase II oocytes. Nonfertilized metaphase II oocytes showed significantly higher incidence of apoptosis compared with fertilized metaphase II oocytes. There was a correlation between embryo score and the zona pellucida thickness variation. Conclusion(s): Apoptosis in cumulus cells had no impact on the zona pellucida thickness and variation in oocytes and embryos. The zona pellucida thickness variation was positively correlated to good embryo score. A higher degree of apoptosis was seen in cumulus cells from immature oocytes compared with mature oocytes. Furthermore, apoptosis in cumulus cells impaired the fertilization rate of metaphase II oocytes after ICSI.

Influence of zona pellucida thickness of human embryos on clinical pregnancy outcome following in vitro fertilization treatment.

To evaluate the correlation between the degree of zona pellucida thickness variation (ZPTV) of transferred embryos with identical morphologies and subsequent clinical pregnancy rates during 141 intracytoplasmic sperm injection (ICSI) treatment cycles. A total of 141 women participating in the study group comprising mostly male factor infertilities and some repeat in vitro fertilization (IVF) failures were transferred, 2 days after ovum pickup, with two to three embryos with identical grades created by fertilization with ICSI. All selected embryos were subjected to zona pellucida thickness measurements immediately prior to transfer using a computerized embryo measurement program from videocinematography recordings. A total of 326 identical-grade transferred pre-embryos resulted in 70 clinical pregnancies with live-born implantation rate of 27.6%. A highly significant correlation was observed between ZPTV of transferred embryos and the IVF outcome with 77.1% and 83.64% of the clinical pregnancies resulting from transferred embryos with ZPTV values greater than 20 and 25, respectively. The mean ZPTV values for 70 conceptual cycles and 62 nonconceptual cycles were 28 +/- 6.43 and 17.85 +/- 8.11, respectively. No significant correlation between ZP thickness and number of blastomeres in the transferred embryos was evident, though embryos with better scores had significantly thinner zonae and higher ZPTV values. Though average zona thickness of embryos declined with age, the mean ZPTV value for women less than 30 years old was significantly higher (25.84 +/- 8.57) as compared with those from women older than 35 years (20.72 +/- 8.45). The degree of ZPTV of the transferred embryos exhibits a strong correlation with clinical pregnancy outcome following IVF treatment. This potentially reliable indicator of IVF success rate could be used as a criteria for embryo selection during clinical transfers.

P-142. Is there a relationship between human embryo zona pellucida thickness variation, assisted hatching results, diagnosis and pre-ovulatory hormonal environment?

P-142. Is there a relationship between human embryo zona pellucida thickness variation, assisted hatching results, diagnosis and pre-ovulatory hormonal environment?

Zona pellucida thickness variation and occurrence of visible mononucleated blastomers in preembryos are associated with a high pregnancy rate in IVF treatment.

The ability of six morphological criteria (embryo development rate, fragmentation, regularity of blastomere shape, equality of blastomere size, zona pellucida thickness variation [ZPTV], and visible mononucleated blastomeres [VMBs]) to predict pregnancy in IVF treatment cycles was evaluated. In order to select a homogeneous study group, 85 consecutive nulliparous couples with single tubal infertility undergoing their first IVF treatment and receiving three preembryos at embryo replacement 2 days after ovum pickup were included. A total of 255 preembryos was replaced two days after ovum pickup and resulted in 34 clinical pregnancies (40%). By logistic regression analysis, ZPTV and VMBs showed highly significant and strong predictive values, whereas none of the other parameters was a significant predictor of pregnancy. In the treatments in which all replaced preembryos had a ZPTV of less than 15%, the pregnancy rate was extremely low (1/22). If the maximum ZPTV of any of the replaced preembryos was in the interval between 15 and 20%, the pregnancy rate was 24.1% (7129). In the treatments in which at least one preembryo had a ZPTV of more than 20%, the pregnancy rate was 76.5% (26/34). When VMBs were added to the results of the ZPTV analysis, the pregnancy rate was as high as 92.3% (24/26). ZPTV and VMBs seem to be strong predictors of pregnancy in IVF treatment and thus important indicators of good embryo quality.