Table 2

Univariate analysis of maternal and infant characteristics

p Values
CharacteristicSingletons (n=3717)Twins (n=1394)Triplets (n=483)1 v 21 v 32 v 3
Values are either percentage or mean (SD). Maternal hypertension = pregnancy induced or chronic hypertension.
*p>0.05; **p<0.05; ***p<0.01; ****p<0.001.
    Week at start of prenatal care
        >20 or none9.4%4.3%0
    Maternal age (years)29.3 (6.3)29.2 (5.5)29.0 (5.1)***
    Ethnic origin (Jewish)70.6%80.6%78.3%********
    Fertility treatment10.3%56.2%91.3%************
    Maternal hypertension26.4%9.7%14.3%***********
    Antenatal steroids
    Caesarean saection62.1%64.8%89%*********
    Birth weight (g)1096 (269)1062 (271)1049 (259)*****
    Gestational age (weeks)28.9 (2.6)28.4 (2.3)28.5 (2.4)*****
    Sex (male)53.1%52.2%50.1%***
    Apgar ≤3 at 5 minutes4.1%4.1%3.9%***
    Small for gestational age22.8%15.5%16.4%*****
    Resuscitation in delivery room82.2%86.1%83.6%****