Endocrinology: Low dose transdermal oestradiol suppresses gonadotrophin secretion in breast-feeding women

Abstract

The object of the study was to investigate the effect on gonadotrophin secretion of a small increase in oestradiol concentration. A total of 13 fully breast-feeding women (12 weeks post-partum) underwent serial blood sampling at 10 min intervals for 12 h on 2 different days; day 1 untreated and day 5 after 3 days of treatment with transcutaneous oestradiol (100 micrograms/day). On both days bolus gonadotrophin-releasing hormone (GnRH; 10 micrograms i.v.) was given after a 10 h baseline period. In six of the subjects, a naloxone infusion was administered during the second study day. Application of transdermal oestradiol raised the oestradiol concentration within the normal follicular phase range. The mean luteinizing hormone (LH) concentration on day 5 was found to be significantly lower than that on day 1 (P < 0.05). The LH response to GnRH was, however, significantly higher on day 5 than day 1 (P < 0.001). The mean follicle stimulating hormone (FSH) concentration on day 5 was also significantly lower than that on day 1 (P < 0.01), while the peak concentration after GnRH was unchanged. When the opioid antagonist naloxone was infused after oestradiol treatment, the subjects with low pre-study oestradiol concentrations exhibited no effect on LH concentration, while in the subjects with higher oestradiol concentrations the LH concentration was increased. It was concluded that the administration of small doses of oestradiol caused a significant fall in gonadotrophin concentration in breast-feeding women.(ABSTRACT TRUNCATED AT 250 WORDS)

Exploring the potential for a set of UK hormone replacement therapy eligibility guidelines: A suggested proposal on the topic of venous thromboembolism

“…6 Although not directly relevant to the topic of VTE, the allocation of HRT to an eligibility category should take into consideration any effect on infant health or breast feeding. There is limited data on this; however, in general, no negative impact has been found with initiation of the combined contraceptive pill containing ethinylestradiol from 6 weeks onwards 6,77 and comparable results have been reported in small studies using estradiol patches [78][79][80][81] and MP. 82 Similarly most studies indicate that progestogens are not detrimental to milk production or infant health outcomes 83 and this includes data for women using the 52 mg LNG-IUS with insertion either immediately post-partum or after 4 weeks.…”

Transdermal estradiol treatment during breastfeeding: maternal and infant serum concentrations

“…Vaginal E2 treatment significantly increases maternal plasma and breastmilk E2 concentrations (Nilsson et al 1978), but transdermal E2 doses up to 100 mcg/d did not significantly increase E2 concentrations in plasma (Illingworth et al 1995; Perheentupa et al 2000), serum (Perheentupa et al 2004), or breastmilk (Perheentupa et al 2004). None of the studies on E2 treatment for breastfeeding mothers included infant serum or plasma concentrations.…”