title: Effects of levonorgestrel implant upon TSH and LH levels in male infants during lactation.
abstract: 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.
authors.affiliation: Department of Reproductive Biology, Biomedical Research Center, School of Medicine, University of Coahuila, Torreon, Coahuila, Mexico.
authors.forename: S
authors.initials: S
authors.lastname: Bassol
authors.forename: M P
authors.initials: MP
authors.lastname: Nava-Hernandez
authors.forename: C
authors.initials: C
authors.lastname: Hernandez-Morales
authors.forename: A M
authors.initials: AM
authors.lastname: Trujillo-Macias
authors.forename: M R
authors.initials: MR
authors.lastname: Lopez-Lozano
authors.forename: R
authors.initials: R
authors.lastname: Recio
mesh_terms: 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*
chemical_list: D003271:Contraceptive Agents, Female; D004343:Drug Implants; D016912:Levonorgestrel; D007986:Luteinizing Hormone; D013972:Thyrotropin