Skip to main content

Table 1 Baseline characteristics of included pregnancies (N = 3027)

From: Should singleton birth weight standards be applied to identify small-for-gestational age twins?: analysis of a retrospective cohort study

Variables  
Maternal age 30.8 ± 4.6 (range: 17–52)
Nulliparity 2034 (67.2)
ART conceived pregnancies 1981 (65.4)
Monochorionic twins 542 (17.9)
Fetal sex  
Male-male 1053 (34.8)
Female-female 874 (28.9)
Male-female 1100 (36.3)
Preexisting diabetes mellitus 29 (1.0)
Preexisting hypertension 24 (0.8)
Syphilis 8 (0.3)
Hepatitis B 234 (7.7)
Hypertensive disorders of pregnancy 342 (11.3)
Gestational diabetes mellitus 615 (20.3)
Idiopathic jaundice of pregnancy 81 (2.7)
Caesarean section 2974 (98.3)
Gestational age at delivery 35.8 ± 1.8
Classification of twin birth weight  
Singleton standards  
Small for gestational age 2002 (33.1)
Appropriate for gestational age 4036 (66.7)
Large for gestational age 16 (0.3)
Twin standards  
Small for gestational age 443 (7.3)
Appropriate for gestational age 5322 (87.9)
Large for gestational age 289 (4.8)
  1. ART assisted reproductive technology