Placental transfer and decay of varicella-zoster virus antibodies in preterm infants.

OBJECTIVES: To compare the placental transfer of maternal varicella-zoster (VZV) antibodies to preterm and term infants and to investigate antibody decay during the first 6 months of life in the preterm infants. STUDY DESIGN: Maternal and umbilical cord blood samples were taken from 113 healthy mother-newborn pairs: 64 term (gestational age > or =37 weeks) and 49 preterm (gestational age < or =35 weeks). Premature infants were further tested at 1, 2, and 6 months. Anti-VZV antibody to membrane antigen was measured with the immunofluorescent technique. RESULTS: Preterm infants of gestational age < or =28 weeks had positive cord antibody and a geometric mean titer significantly lower than those in preterm infants of gestational age 29 to 35 weeks and term infants (25% vs 95% and 95%, respectively, P <.001 for each, and 2.5 +/- 2.2 vs 10.5 +/- 2.4 and 12.6 +/- 2.4, respectively, P <.001 for each). There was no difference between the preterm 29 to 35 weeks of gestation and term groups. Fetal-maternal ratios for both preterm groups were <1 and were significantly less than the fetal-maternal ratio in the term infants. The transfer of maternal antibodies to term infants was significantly greater than to the 29- to 35-week preterm infants (P =.01). At 2 months of age, 25% of 29- to 35-week preterm infants and no preterm infant < or =28 weeks had a positive titer. At 6 months of age, all preterm infants were seronegative, and the geometric mean titer in both groups declined to undetectable levels. CONCLUSION: Transplacental transfer of maternal VZV antibodies is diminished in preterm infants. VZV antibody levels are significantly lower in preterm infants born at < or =28 weeks' gestational age compared with those in preterm infants 29 to 35 weeks' gestational age and term infants. Anti-VZV titers decrease to undetectable levels in preterm infants by 6 months of age or earlier; thus these infants appear to be susceptible to chickenpox before the scheduled 12-month vaccination.

Topical iodine-containing antiseptics and subclinical hypothyroidism in preterm infants.

The influence of topical iodine-containing antiseptics on thyroid function test results of premature infants was determined in two separate studies. Thyroxine and thyrotropin levels were measured on blood-spotted filter paper. Samples were obtained from 128 premature infants on their tenth day of life; the infants were treated in two neonatal intensive care units. Both units used similar treatment protocols; however, one routinely used topical iodinated antiseptic agents (n = 73), whereas the other used chlorhexidine-containing antiseptics (n = 55). There was no difference in the mean T4 levels between the two groups. The mean thyrotropin levels were elevated in preterm babies exposed to iodine (15.4 vs 7.8 mIU/L, p < 0.01). Among the iodine-exposed infants, elevated thyrotropin levels (> 30 mIU/L) were found in 13.7% of infants, compared with none in the chlorhexidine-treated group (p < 0.01). We then studied an additional 46 premature infants who were treated in one neonatal intensive care unit. Iodine-containing solutions were used in 24 infants and chlorhexidine was used in 22 infants. T4 and thyrotropin levels were measured weekly during the first 28 days, one every 2 weeks until the age of 60 days, and at the age of 90 days. Among iodine-exposed infants, 20.8% had thyrotropin values > 30 mIU/L, whereas none of the infants in the chlorhexidine group had elevated thyrotropin values (p < 0.05). The elevated thyrotropin levels correlated positively with the area of disinfection. Elevated urine iodine levels were present reflecting an abnormally high iodine absorption. This study suggests that iodine absorption from topical iodine-containing antiseptics may cause disturbances in thyroid function test results in premature infants. We recommend that caution be exercised in the use of iodine-containing antiseptics in premature infants.

Hypertrophy of the tongue associated with inhaled corticosteroid therapy in premature infants.

We describe three infants in whom hypertrophy of the tongue developed while they were receiving beclomethasone inhalation therapy. The condition resolved after cessation of treatment, an outcome suggesting that tongue hypertrophy is a possible side effect of this therapy.

Early immunization with inactivated poliovirus vaccine in premature infants.

The antibody titers of 41 premature infants receiving inactivated poliovirus vaccine at 2 months of age (control group) were compared with titers of 39 infants receiving an additional dose at 5 to 10 days of age (study group). At 1 month of age 97.4% of the study group but only 70.8% of the control group had protective antibodies against poliovirus 3 (p < 0.001).

Need for endotracheal intubation and suction in meconium-stained neonates.

In a prospective study, we determined whether routine immediate tracheal aspiration at birth is necessary in meconium-stained but otherwise normal infants delivered vaginally and having a 1-minute Apgar score greater than 8. A total of 572 newborn infants who met these criteria were randomly allocated to one of two groups. All infants underwent oropharyngeal suctioning with a DeLee catheter while the head was still on the perineum. In group I (n = 308) suctioning of the trachea under direct vision was performed instantly at birth; in group II (n = 264) this procedure was not done. There was no mortality among infants in the study, but morbidity, mainly pulmonary and laryngeal disorders, occurred in six of 308 group I infants and in none of the group II infants (P less than 0.025). Immediate tracheal suction is not a harmless intervention, and should be considered superfluous in a vigorous term neonate born with meconium-stained amniotic fluid.