Effects of levonorgestrel implant upon TSH and LH levels in male infants during lactation.
OBJECTIVE
The objective of the study is to evaluate the effects of levonorgestrel transferred through breast milk on thyroid stimulating hormone (TSH) and luteinizing hormone (LH) levels in full breast-fed infants.


METHODS
Forty healthy postpartum women and their male newborns were recruited for the study. Women were randomly allocated to two study groups: Group 1, IUD users and group 2, Norplant users. Blood and milk samples were collected on the day of IUD or Norplant insertion and 3 and 6 months later for TSH and levonorgestrel measurements.


RESULTS
The results disclosed a significant decrease in TSH levels, and a negative relationship between LNG levels and TSH concentration in breast feeding infants at 3 months after implant insertion. The lowest TSH levels were observed at 6 months in the women from group 2.


CONCLUSIONS
The overall data indicate that the LNG levels transferred to fully breast-fed infants through breast milk from Norplant users significantly modified their TSH levels.
Bassol
S
S
Department of Reproductive Biology, Biomedical Research Center, School of Medicine, University of Coahuila, Torreon, Coahuila, Mexico.
Nava-Hernandez
M P
MP
Hernandez-Morales
C
C
Trujillo-Macias
A M
AM
Lopez-Lozano
M R
MR
Recio
R
R
D001942:Breast Feeding; D003271:Contraceptive Agents, Female / Q000378:metabolism* / Q000494:pharmacology*; D004343:Drug Implants; D005260:Female; D006801:Humans; D007158:Immunologic Techniques; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation; D016912:Levonorgestrel / Q000378:metabolism* / Q000494:pharmacology*; D007986:Luteinizing Hormone / Q000652:urine*; D008297:Male; D008895:Milk, Human / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood*
D003271:Contraceptive Agents, Female; D004343:Drug Implants; D016912:Levonorgestrel; D007986:Luteinizing Hormone; D013972:Thyrotropin