Changes of serum gonadotropin concentrations in premature babies submitted to phototherapy.

In order to determine if phototherapy was influencing any change in plasma gonadotropin levels, we have compared a group of 8 premature infants (4 males and 4 females) who have been treated with phototherapy because of jaundice, to a control group of 6 premature infants who did not require phototherapy. During the third and fourth week of life, luteinizing hormone (LH) and folicule stimulating hormone (FSH), increased simultaneously in a significant range in phototherapy treated females. In the group of treated males, LH but not FSH increased significantly. Constant phototherapy and/or the sudden stopping of the treatment in the jaundiced premature newborn female is responsible for a marked and transient elevation of gonadotropins. A clear mechanism of the observed phenomenon with pathways including the retina, pineal gland and hypothalamus, is not apparent.