Obstetric, neonatal and child development outcomes following assisted hatching treatment: a retrospective cohort study

Risk factors for placenta accreta spectrum in pregnancies conceived after frozen-thawed embryo transfer in a hormone replacement cycle

OBJECTIVE

Assisted reproductive technology (ART), especially frozen-thawed embryo transfer (FET) in a hormone replacement cycle (HRC), is a risk factor for placenta accreta spectrum (PAS). This study aimed to clarify the risk factors for PAS related to the maternal background and ART techniques in pregnancies achieved after FET in an HRC.

STUDY DESIGN

We performed a case-control study in two tertiary perinatal centres in Japan. Among 14,028 patients who delivered at ≥24 weeks of gestation or were transferred after delivery to two tertiary perinatal centres between 2010 and 2021, 972 conceived with ART and 13,056 conceived without ART. PAS was diagnosed on the basis of the FIGO classification for the clinical diagnosis of PAS or retained products of conception after delivery at ≥24 weeks of gestation. We excluded women with fresh embryo transfer, FET with a spontaneous ovulatory cycle, a donor oocyte cycle, and missing details of the ART treatment. Finally, among women who conceived after FET in an HRC, 62 with PAS and 340 without PAS were included in this study. Multivariate logistic regression models were used for case-control comparisons, with adjustment for maternal age at delivery, parity, endometriosis or adenomyosis, the number of previous uterine surgeries of caesarean section, myomectomy, endometrial polypectomy or endometrial curettage, placenta previa, the stage of transferred embryos, and endometrial thickness at the initiation of progestin administration.

RESULTS

PAS was associated with ≥2 previous uterine surgeries (adjusted odds ratio, 3.57; 95 % confidence interval, 1.60-7.97) and the stage of embryo transfer (blastocysts: adjusted odds ratio, 2.89; 95 % confidence interval, 1.15-7.26). In patients with <2 previous uterine surgeries, PAS was associated with an endometrial thickness of <7.0 mm (adjusted odds ratio, 5.18; 95 % confidence interval, 1.10-24.44).

CONCLUSION

Multiple uterine surgeries and the transfer of blastocysts are risk factors for PAS in pregnancies conceived after FET in an HRC. In women with <2 previous uterine surgeries, a thin endometrium before FET is also a risk factor for PAS in these pregnancies.

Clinical and neonatal outcomes of complete zona pellucida removal by laser-assisted hatching after single vitrified-warmed blastocyst transfer

Laser-assisted hatching (LAH) is a widely used and unavoidable technique in assisted reproductive technology after frozen embryo transfer (FET). We aimed to investigate the safety and efficacy of completely ZP (zona pellucida) removed by an assisted laser group compared to an intact group after FET. This retrospective study involved 320 SVBT  single vitrified-warmed blastocyst transfers of 213 patients who underwent clomiphene citrate (CC) based minimal stimulation protocol. This study compared 160 SVBT with ZP that were completely removed using laser-assisted (laser beams of 10-15, a wavelength of 1.48 μm, and duration of 1.8-2.2 ms) to 160 cases of intact SVBT. Fisher's exact test, chi-squared test, and logistic regression are used for statistical analysis. The women's age, cause of infertility, BMI, transferred embryo day, insemination methods, and blastocyst grade were not significantly different between two groups. The implantation rate (66.2% vs. 51.2%, P < 0.01), the clinical pregnancy rate (CPR, 52.5% vs. 39.3%, P = 0.01), and the live birth rate (LBR, 43.7% vs. 29.3%, P < 0.01) were significantly higher in the completely ZP removed than the intact group. In logistic regression analysis, the laser-assisted hatching group showed about 2 times higher implantation rate and CPR and LBR than the control group. But miscarriage, gestational weeks, gender, birth weight, and twin births were insignificant between two groups. Our study suggests ZP free embryo transfer by assisted laser is more effective and safer than intact embryo transfer.

Laser-assisted hatching improves pregnancy outcomes in frozen-thawed embryo transfer cycles of cleavage-stage embryos: a large retrospective cohort study with propensity score matching

INTRODUCTION

Laser-assisted hatching (LAH) is a commonly used adjunct technique; however, its effectiveness has not been fully established.

OBJECTIVE

We evaluated the effects of LAH on pregnancy outcomes in frozen-thawed embryo transfer (FET) cycles of cleavage-stage embryos.

MATERIALS AND METHODS

This retrospective study involved 5779 FET cycles performed at the Reproductive and Genetic Center in the Affiliated Hospital of Shandong University of Traditional Chinese Medicine between January 2016 and December 2020. After propensity score matching, 3535 FET cycles were included, out of which 1238 were subjected to LAH while the remaining 2297 cycles were non-LAH (NLAH). The primary outcomes were clinical pregnancy rate (CPR) and live birth rate (LBR) while secondary outcomes included implantation rate (IR), biochemical pregnancy rate (BPR), ectopic pregnancy rate (EPR), pregnancy loss rate (PLR), multiple pregnancy rate (MPL), and monozygotic twinning rate (MTR). Logistic regression analysis was conducted to adjust for possible confounders. Subgroup analysis was also performed based on the endometrial preparation regimen.

RESULTS

The LAH group exhibited a higher LBR, compared to the NLAH group (34.9% vs. 31.4%, OR = 1.185, 95% CI = 1.023, 1.374, P = 0.024). Additionally, the LAH group showed a decreasing trend in PLR and EPR; however, differences were insignificant (P = 0.078, P = 0.063 respectively). Differences in IR (24.6% vs. 24.3%), BPR (41.8% vs. 40.4%), CPR (40.7% vs. 38.3%), MPR (14.1% vs. 17.3%), and MTR (1.4% vs. 1.1%) were insignificant. Subgroup analysis revealed that LAH may be more conducive for pregnancy outcomes in hormone replacement cycles.

CONCLUSIONS

In summary, LAH has an increased chance of achieving live births. However, further prospective studies should be performed to confirm our findings.

Placental histology following assisted hatching in fresh transfer cycles

PURPOSE

To assess placental histological findings following assisted hatching in fresh transfer in vitro fertilization cycles.

METHODS

Evaluation of a historic cohort of live singleton deliveries after fresh embryo transfer (ET) at a single university medical center between 2009 and 2017. We compared perinatal outcomes and placental histology in cases where assisted hatching was performed prior to ET (AH group) and cases with no AH (no AH group).

RESULTS

Overall, 166 deliveries following AH were compared to 494 deliveries with no AH. Patients' demographics were similar between the groups. Median antral follicle count was significantly lower in the AH group, median 11 (range 1-50) vs. 16 (range 1-80), p < 0.001, and the primary indication for infertility treatment significantly more often diminished ovarian reserve (p < 0.001). Cycle characteristics in the AH group included a higher gonadotropin dose employed, and a lower rate of single and blastocyte transfer. Pregnancies following AH were associated with less low-lying placentas, 0.6% vs. 6.2%, p = 0.001, and comparable for other perinatal outcomes. After adjusting for confounders, the rate of bilobated placentas was higher following AH, aOR 7.10, 95% CI 1.50-33.51. The rate of perivillous depositions was higher with AH, aOR, 95% CI 3.18, 1.46-6.93, and the rate of chorangiosis lower in this group, aOR, 95% CI 0.32, 0.11-0.93. The overall rate of vascular lesions was similar between the groups.

CONCLUSION

Pregnancies following AH are notable for a lower rate of placenta previa, yet a higher rate of bilobated placentas and perivillous depositions and less chorangiosis, warranting further investigation.

Obstetric and neonatal outcomes after frozen-thawed embryos transfer with laser-assisted hatching: a retrospective cohort study

PURPOSE

To ascertain if assisted hatching (AH) increases the risk of placenta-associated diseases and perinatal outcomes after frozen-thawed cleavage-stage embryo transfer.

METHODS

We retrospectively evaluated 924 women who conceived with frozen-thawed cleavage-stage embryos transfer with (n = 390) or without (n = 534) laser-AH between 2013 and 2015. Data were obtained from the database on in vitro fertilization (IVF) patients in Shanghai First Maternity and Infant Hospital. We assessed neonatal (preterm birth, low birthweight, fetal macrosomia, stillbirth) and obstetric (miscarriage, ectopic pregnancy, post-term pregnancy, gestational diabetes (GDM), preeclampsia, intrahepatic cholestasis (ICP), placenta previa, placental abruption, premature rupture of membranes) outcomes.

RESULTS

In twins, the median birthweight was lower in the AH group than that in the control group, and the prevalence of low birthweight (< 2500 g) was significantly higher in the AH group; after adjusting for maternal age, body mass index, mode of fertilization, and parity, no significant difference was found. In twins, no significant difference was detected in the prevalence of stillbirth or preterm pregnancy. In singleton births, there was no significant difference in the prevalence of low birthweight, macrosomia, preterm pregnancy or post-term pregnancy between the two groups. In singletons and twins, there were no significant differences in the prevalence of miscarriage, ectopic pregnancy, preeclampsia, GDM, ICP, or placenta abruption between the two groups.

CONCLUSIONS

AH is a relatively safe method and our study provides important information for using this method in carefully selected patients.

Laser-assisted hatching on clinical and neonatal outcomes in patients undergoing single vitrified Blastocyst transfer: A propensity score-matched study

PURPOSE

This study determined the effect of laser-assisted hatching on the clinical and neonatal outcomes of single vitrified blastocyst transfer.

METHODS

From June 2014 to March 2018, 289 matched pairs after propensity score matching were analyzed. During the blastocyst warming procedure, a small section of the zona pellucida area in the empty perivitelline space was sliced off using multiple laser beams. The clinical and neonatal outcomes of the laser-treated group and non-treatment control were analyzed.

RESULTS

In the laser-assisted hatching group, significantly higher rates of clinical pregnancy (40.8% vs 29.4%, P < .01) and live delivery (34.3% vs 22.5%, P < .01) were observed compared to the control group. Other variables such as the average gestational weeks, the sex of the baby, birthweight, or congenital malformations were found to have no significant differences in neonatal outcomes. Moreover, all babies were singleton live births.

CONCLUSIONS

Single vitrified blastocyst transfer treated with laser-assisted hatching increases the live birth rate and has no adverse effects on neonatal outcomes.