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Table 2 Pregnancy outcomes following transferring embryos with or without blastomere loss

From: Outcomes of neonates born following transfers of frozen-thawed cleavage-stage embryos with blastomere loss: a prospective, multicenter, cohort study

  Intact embryo group (n = 9846) Blastomere loss group (n = 2259) p value
Total no. of embryo transferred 21,136 5036  
Embryo implantation rate (n, %)a 4615 (21.8) 641 (12.7) < 0.001
Chemical pregnancies (n, %)b 4134 (42.0) 575 (25.5) < 0.001
Clinical pregnancies (n, %)c 3610 (36.7) 499 (22.1) < 0.001
Ongoing pregnancies (n, %)d 3108 (31.6) 423 (18.7) < 0.001
Live births (n, % per embryo transfer cycle)e 2962 (30.1) 407 (18.0) < 0.001
Live births (n, % per clinical pregnancy)f 2962 (82.1) 407 (81.6) 0.791
 Singleton (% per live birth) 2187 (73.8) 332 (81.6) 0.003
 Twins (% per live birth) 76 (25.9) 74 (18.2)
 Triplets (% per live birth) 9 (0.3) 1 (0.3)
Ectopic pregnancies (n, %) 101 (1.0) 19 (0.8) 0.424
Early miscarriages (n, % per clinical pregnancy) 501 (13.9) 76 (15.2) 0.415
Stillbirths (n, % per clinical pregnancy) 13 (0.4) 2 (0.4) 0.703
Pregnancy termination due to fetal anomaly (n, % per clinical pregnancy)g 11 (0.3) 2 (0.4) 0.666
  1. aThe implantation was defined as an observation of gestational sacs by ultrasound. The implantation rate was defined as the number of gestational sacs divided by the number of embryos transferred
  2. bChemical pregnancy was defined as an elevated serum β-hCG level of more than 10 mIU/mL. Chemical pregnancy rate was defined as the number of chemical pregnancies divided by the number of embryo transfer cycles for each group
  3. cClinical pregnancy was defined as a pregnancy documented by ultrasound at 6–8 gestational weeks that showed a gestational sac inside the uterus. Clinical pregnancy rate was defined as the number of clinical pregnancies divided by the number of embryo transfer cycles for each group
  4. dOngoing pregnancy was defined as a pregnancy documented by ultrasound at 12 gestational weeks that showed the presence of fetal heartbeat. Ongoing pregnancy rate was defined as the number of ongoing pregnancies divided by the number of embryo transfer cycles for each group
  5. eLive birth was defined as the delivery of one or more infants with any signs of life after 28 gestational weeks. Live birth rate (% per embryo transfer cycle) was defined as the number of live birth divided by the number of embryo transfer cycle for each group
  6. fLive birth rate (% per clinical pregnancy) was defined as the number of live birth divided by the number of clinical pregnancy for each group
  7. gOf the 11 patients who terminated the pregnancy in the intact embryo group, three were diagnosed as chromosome anomalies, two were never system development disorder, two were multiple malformation, the rest were congenital heart disease, umbilical hernia, bilateral renal agenesis, and achondroplasia. Both patients in the blastomere loss group terminated pregnancy due to limb deformity