Number of samples tested, geometric mean concentration (GMCs) and transplacental transport ratios of antibodies to measles, mumps, rubella and varicella zoster in preterm and term infants.

NOTE. Maternal serum samples were obtained from mothers between 2 days before and after delivery and cord serum samples were obtained from umbilical cords. CI, confidence intervals; IU, international unit; RU, RIVM unit; IgG, immunoglobulin G; *p<0.01, †p<0.05.