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Table 2 Pregnancy and fetal/neonatal characteristics by mode of conception

From: Complications and adverse outcomes in pregnancy and childbirth among women who conceived by assisted reproductive technologies: a nationwide birth cohort study of Japan environment and children’s study

  Natural conception OI without ART Conventional IVT-ET ICSI
N % N % N % N %
Pregnancies N = 90,506 N = 3939 N = 1476 N = 1671
 Singleton pregnancy 88,873 99.3 3702 95.1 1407 95.7 1586 96.0
 Multiple pregnancies 625 0.7 189 4.9 63 4.3 66 4.0
 (Missing) 1008   48   6   19  
Fetus/Neonate born ≥22 weeks N = 89,576 N = 4067 N = 1518 N = 1699
Number of fetuses
 Singletons 88,337 98.6 3682 90.6 1393 91.8 1570 92.4
 Multiples 1209 1.4 383 9.4 125 8.2 129 7.6
 (Missing) 30   2   0   0  
Fetal presentation
 Cephalic 85,331 96.4 3726 93.2 1345 90.7 1516 90.8
 Non-cephalic 3179 3.6 273 6.8 138 9.3 153 9.2
 (Missing) 1066   68   35   30  
Sex of neonate
 Male 45,942 51.3 2062 50.7 805 53.0 850 50.0
 Female 43,608 48.7 2003 49.3 713 47.0 849 50.0
 (Missing) 26   2   0   0  
  1. ART assisted reproductive technology, ICSI intracytoplasmic sperm injection, ICU intensive care unit, IVF-ET in vitro fertilization and embryo transfer, OI ovulation induction
  2. Proportions were calculated excluding cases with missing data