Menopausal estrogen therapy predicts better nocturnal oxyhemoglobin saturation

Maturitas. 2006 Oct 20;55(3):255-63. doi: 10.1016/j.maturitas.2006.03.007. Epub 2006 May 3.


Objectives: The respiratory responses in the few previous studies evaluating the effects of short-term unopposed estrogen therapy on breathing in postmenopausal women have been inconsistent. We performed a study to investigate whether long-term estrogen therapy would prevent age-related decline in nocturnal arterial oxyhemoglobin saturation and whether higher serum estradiol concentration is associated with better arterial oxyhemoglobin saturation.

Methods: Sixty-four healthy postmenopausal women were followed-up for 5 years in a 5-year prospective open follow-up study. The women were users or non-users of estrogen therapy according to their personal preference.

Results: Mean overnight arterial oxyhemoglobin saturation was similar at baseline (94.3 +/- 1.1%) and after follow-up (94.5 +/- 1.6%). Present estrogen users had higher mean arterial oxyhemoglobin saturation (95.2 +/- 1.4%) than present non-users (94.0 +/- 1.5%), when adjusted for age and body mass index (p = 0.042). The change in mean arterial oxyhemoglobin saturation during follow-up was not associated with serum estradiol concentration at baseline but associated with estradiol at follow-up (p = 0.042), when adjusted for age and body mass index. At follow-up, women with higher serum estradiol concentration had also higher mean nocturnal arterial oxyhemoglobin saturation (Pearson r = 0.29, p = 0.019) and lower apnea-hypopnea index (Spearman r = -0.28, p = 0.031). The pooled current estrogen users spent proportionally less time with SaO(2) below 90% than non-users (ANCOVA adjusted for age and BMI, p = 0.017).

Conclusions: Estrogen use and especially high serum estradiol concentration predict higher mean overnight arterial oxyhemoglobin saturation. The present data suggest that estrogen therapy has favorable respiratory effects.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Body Mass Index
  • Circadian Rhythm
  • Estradiol / blood
  • Estradiol / pharmacology*
  • Estrogen Replacement Therapy*
  • Female
  • Follow-Up Studies
  • Humans
  • Menopause / drug effects*
  • Menopause / physiology
  • Middle Aged
  • Oximetry
  • Oxyhemoglobins / drug effects*
  • Polysomnography
  • Prospective Studies


  • Oxyhemoglobins
  • Estradiol