Objective:To investigate the influencing factors and perinatal outcomes associated with monozygotic twins (MZT) following elective single embryo transfer (eSET) via in vitro fertilization or intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET). Methods:A retrospective cohort study was conducted on 12 079 patients who achieved pregnancy after undergoing IVF/ICSI-eSET at Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University between January 2015 and September 2023. Patients were stratified into two groups based on ultrasound findings 30 d post-transfer: singleton pregnancy group and MZT pregnancy group. Finally, 300 MZT and 1 500 single pregnancies, which were randomly matched according to 1∶5 were included by study period. General patients' characteristics, embryo-related factors, and perinatal outcomes were compared between the two groups. A multivariate logistic regression model was employed to identify risk factors for MZT after single embryo transfer, adjusting for potential confounding variables.Results:The incidence of twin pregnancy following single embryo transfer was 2.48% (300/12 079), which was higher than that of naturally conceived monozygotic twin pregnancy. No significant difference was found in baseline characteristics between the two groups (all P>0.05). The blastocyst transfer rate was higher in the MZT pregnancy group [93.3% (280/300)] than in the singleton pregnancy group [88.8% (1 332/1 500), P=0.022]. Multivariate logistic regression analysis also showed that blastocyst transfer was associated with an increased risk of MZT ( OR=0.552, P=0.016, 95% CI: 0.341-0.894). Analysis of blastocyst cycles showed that the risk of MZT was higher when transferring high-quality blastocysts [79.6% (223/280) vs. 67.8% (903/1 332), P<0.001], where as a trophectoderm (TE) grading of C [20.4% (57/280) vs. 32.2% (429/1 332), P<0.001] had a lower risk of MZT. After adjusting for confounding factors, the risk of MZT was found to increase with the transfer of blastocysts with a B-grade inner cell mass (ICM) ( OR=0.601, P=0.001, 95% CI: 0.442-0.819) and A/B grade TE (grade A: OR=2.951, P<0.001, 95% CI: 1.980-4.399; grade B: OR=1.840, P<0.001, 95% CI: 1.315-2.576). The risk of complications during pregnancy [47.7% (143/300) vs. 19.3% (289/1 500), P<0.001], preterm labor [55.1% (140/254) vs. 7.4% (101/1 368), P<0.001], and the risk of stillbirth [3.7% (11/300) vs. 1.5% (22/1 500), P=0.016] were significantly higher in the MZT pregnancy group than in the singleton pregnancy group. Conclusion:Assisted reproductive technology may contribute to the risk of MZT. Transfer of blastocysts, particularly those with loose ICM arrangement and dense TE arrangement, appears to increase the risk of MZT in patients undergoing eSET.

Objective:To investigate the influencing factors and perinatal outcomes associated with monozygotic twins (MZT) following elective single embryo transfer (eSET) via in vitro fertilization or intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET). Methods:A retrospective cohort study was conducted on 12 079 patients who achieved pregnancy after undergoing IVF/ICSI-eSET at Reproductive Health Hospital of the Third Affiliated Hospital of Zhengzhou University between January 2015 and September 2023. Patients were stratified into two groups based on ultrasound findings 30 d post-transfer: singleton pregnancy group and MZT pregnancy group. Finally, 300 MZT and 1 500 single pregnancies, which were randomly matched according to 1∶5 were included by study period. General patients' characteristics, embryo-related factors, and perinatal outcomes were compared between the two groups. A multivariate logistic regression model was employed to identify risk factors for MZT after single embryo transfer, adjusting for potential confounding variables.Results:The incidence of twin pregnancy following single embryo transfer was 2.48% (300/12 079), which was higher than that of naturally conceived monozygotic twin pregnancy. No significant difference was found in baseline characteristics between the two groups (all P>0.05). The blastocyst transfer rate was higher in the MZT pregnancy group [93.3% (280/300)] than in the singleton pregnancy group [88.8% (1 332/1 500), P=0.022]. Multivariate logistic regression analysis also showed that blastocyst transfer was associated with an increased risk of MZT ( OR=0.552, P=0.016, 95% CI: 0.341-0.894). Analysis of blastocyst cycles showed that the risk of MZT was higher when transferring high-quality blastocysts [79.6% (223/280) vs. 67.8% (903/1 332), P<0.001], where as a trophectoderm (TE) grading of C [20.4% (57/280) vs. 32.2% (429/1 332), P<0.001] had a lower risk of MZT. After adjusting for confounding factors, the risk of MZT was found to increase with the transfer of blastocysts with a B-grade inner cell mass (ICM) ( OR=0.601, P=0.001, 95% CI: 0.442-0.819) and A/B grade TE (grade A: OR=2.951, P<0.001, 95% CI: 1.980-4.399; grade B: OR=1.840, P<0.001, 95% CI: 1.315-2.576). The risk of complications during pregnancy [47.7% (143/300) vs. 19.3% (289/1 500), P<0.001], preterm labor [55.1% (140/254) vs. 7.4% (101/1 368), P<0.001], and the risk of stillbirth [3.7% (11/300) vs. 1.5% (22/1 500), P=0.016] were significantly higher in the MZT pregnancy group than in the singleton pregnancy group. Conclusion:Assisted reproductive technology may contribute to the risk of MZT. Transfer of blastocysts, particularly those with loose ICM arrangement and dense TE arrangement, appears to increase the risk of MZT in patients undergoing eSET.

Objective To explore the changes of placental growth factor (PLGF) in patients with acute coronary syndrome (ACS).Methods One hundred and twelve patients were divided into four groups according to clinical data and coronary angiography:non-coronary artery disease (non-CAD) group (27 cases),stable angina (SA) group (28 cases ),unstable angina (UA) group (29 cases) and acute myocardial infarction (AMI) group (28 cases).Fifty-seven patients with ACS were divided into single lesion group (19 cases),twice lesion group ( 16 cases) and triple lesion group (22 cases) by coronary angiography,and 0-7 scores group (23 cases),8-15 scores group (27 cases) and 16-32 scores group (7 cases) by Jenkins scores.The serum PLGF levels of all the cases were determined on admission.The serum PLGF levels of 40 cases receiving percutaneous coronary intervention (PCI) were determined at 30 min before operation,the first and second day after operation.Results The serum PLGF levels of AMI group and UA group were (38.33 ±10.14) ng/L and (37.44 ± 13.32) ng/L respectively,which were significant higher than that of SA group [(20.90 ± 3.88) ng/L] and non-CAD group [(20.34 ±4.53) ng/L](P＜ 0.01),and there was no significant difference between AMI group and UA group,SA group and non-CAD group (P ＞0.05).There was no significant difference in the serum PLGF level among triple lesion group,twice lesion group and single lesion group (P ＞ 0.05 ).There was no significant difference in the serum PLGF level among 0-7 scores group,8-15scores group and 16-32 scores group (P ＞ 0.05).The serum PLGF level of patients receiving PCI on the first day after operation [ (32.03 ± 7.41 ) ng/L] was significantly higher than that before operation [ (23.86 ± 6.91 ) ng/L](P＜ 0.05 ),and on the second day after operation the serum PLGF level [ (29.37 ± 6.99) ng/L] was less than that on the first day after operation,showing a fall tendency(P＞ 0.05).Pearson correlation analysis showed that the serum PLGF levels in patients with ACS were not related with cardiac troponin T and creatine kinase isozyme-MB (r =-0.158,P=0.421;r =0.302,P=0.118).Conclusion The serum PLGF level of ACS patients is an inflammatory marker reflecting coronary atherosclerotic plaque destabilizing or plaque ruptured,and may also play an important role in early diagnosis of the borderline case of ACS.