"The effect of presentation and mode of delivery on neonatal outcome in the second twin"--is this study biased?
Mittendorf
R
R
D001946:Breech Presentation; D002585:Cesarean Section; D036861:Delivery, Obstetric; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011272:Pregnancy, Multiple; D015983:Selection Bias; D014427:Twins