REF-576 · Ackerman, Singhal, Baskaran, Misra et al., 2019 · British Journal of Sports Medicine, · Paper · PubMed
In oligo-amenorrhoeic athletes, a transdermal 17β-estradiol patch improved bone density over 12 months
The ethinyl-estradiol pill did NOT
Participants
n=121 normal-weight oligo-amenorrhoeic athletes (OAA) aged 14–25 years engaged in weight-bearing activity; randomised groups did not differ in age, BMI or baseline BMD Z-scores.
Protocol
Arms: (1) transdermal 17β-estradiol patch continuously + cyclic oral micronised progesterone (PATCH), (2) combined ethinyl estradiol + desogestrel pill (PILL), (3) no oestrogen/progesterone (NONE); all received calcium + vitamin D. Areal BMD (spine, femoral neck, total hip, total body less head) by DXA at baseline, 6 and 12 months.
Key Findings
ITT: spine and femoral-neck BMD Z-scores increased in PATCH vs PILL (p=0.011 / 0.021) and PATCH vs NONE (p=0.021 / 0.033); hip BMD Z-scores increased PATCH vs PILL (p=0.018). Completers analysis showed similar findings.
The oral EE pill did not outperform no treatment for bone. Mechanism proposed by the authors — oral ethinyl estradiol suppressing hepatic IGF-1 — is from the paper's discussion (full text, checked 2026-09-28: author manuscript PMC6686188, Discussion; IGF-1 fell more on the pill than with the patch or no treatment over 12 months).
Practical Application
RCT, 121 oligo-amenorrhoeic athletes aged 14–25, 12 months: a transdermal estradiol patch (with cyclic progesterone) raised spine and femoral-neck BMD Z-scores versus both the ethinyl-estradiol pill and no hormones; the pill did no better than nothing for bone.
When bone health is the concern in an athlete with menstrual dysfunction, the combined pill is not first-line — this is a physician referral, and the transdermal route is what the evidence supports.
Don't let "she's on the pill, so her bones are covered" enter your reasoning — the pill can normalise bleeding while leaving low BMD unaddressed.
Coach what you control: energy availability, calcium/vitamin D, weight-bearing loading; escalate the hormonal/bone decision to a sports physician/endocrinologist.
Limitations
Oligo/amenorrhoeic, weight-bearing athletes aged 14–25 (minors included) — doesn't speak to bone effects in eumenorrhoeic bone-healthy athletes; BMD (surrogate) not fractures; 12 months.
How this entry was checked and changed
Why this level
(RCT)
Content correction 2026-09-27
Entry described the population as "with low BMD / low-EA"; the abstract says normal-weight oligo-amenorrhoeic athletes "at risk for low BMD" — corrected. IGF-1 mechanism labelled as full text. Participants section and lead added; Sport line set to "general".
2026-09-28: lines labelled "full text; not checked" read against the open-access full text (author manuscript PMC6686188): 1 confirmed, 0 corrected, 0 removed.