The hypothalamus-pituitary-ovary and hypothalamus-pituitary-thyroid axes in spinal cord-injured women

Sixteen women with spinal cord injury (SCI) underwent studies of the hypothalamus-pituitary-ovary (HPO) and hypothalamus-pituitary-thyroid (HPT) axes with luteinizing hormone (LH) releasing hormone (LHRH) and thyrotropin (TSH) releasing hormone (TRH) stimulation tests during the early follicular phase. The mean interval from injury to participation in this study was 7.5 years (range, 1.5 to 13.1). All subjects were menstruating regularly. Five (35.7%) SCI subjects who were menstruating before injury had postinjury amenorrhea for 1 to 12 months, and the other nine (64.3%) SCI subjects had no interruption of menstruation after injury. Two SCI subjects whose injury occurred in preadolescence proceeded to menarche without any delay. The amount of menstrual flow was noted to be reduced in nine (64.3%) SCI subjects. Two and three SCI subjects had elevated follicle-stimulating hormone (FSH) and prolactin (PRL) levels, respectively. LH responses to LHRH were significantly higher in the SCI group (P < .001). Ten (62.6%) SCI subjects had enhanced LH responses to LHRH. The mean TSH, PRL, and FSH responses to TRH and LHRH of the SCI group were not significantly different from those of age-matched controls. However, five (31.2%), four (25.0%), and five (31.2%) SCI subjects had enhanced TSH, PRL, and FSH responses to TRH and LHRH, respectively. Six (37.5%) SCI subjects had a delayed FSH response to LHRH. In total, 13 (81.2%) SCI subjects had at least one axis abnormality. These findings are consistent with the hypothesis that changes of central neurotransmitters may occur after SCI.