Changes in maternal androgens and oestrogens in mares with experimentally-induced ascending placentitis.
Authors: Canisso I F, Ball B A, Esteller-Vico A, Williams N M, Squires E L, Troedsson M H
Journal: Equine veterinary journal
Summary
# Editorial Summary: Placental Health Assessment via Maternal Steroid Profiles Ascending placentitis remains diagnostically challenging in its early stages, limiting therapeutic intervention before clinical deterioration occurs. Canisso and colleagues characterised peripheral steroid hormone concentrations in healthy pregnancies and compared four key hormones—DHEA-S, testosterone, oestradiol and oestrone sulphate—between mares with experimentally-induced *Streptococcus equi* ssp. *zooepidemicus* placentitis and uninfected controls from days 260–280 of gestation onwards. Whilst androgen concentrations (DHEA-S and testosterone) showed no significant differences between infected and control mares, oestrogen profiles diverged markedly: oestradiol declined substantially in placentitis cases during the final week before abortion, and oestrone sulphate dropped significantly in the 24 hours preceding pregnancy loss. These findings suggest that oestrogen measurement—particularly in the peripartum window—may serve as a complementary diagnostic tool alongside transrectal ultrasound, potentially identifying subclinical placental compromise when intervention remains possible. For practitioners managing high-risk pregnancies, establishing oestrogen baseline values and monitoring their trajectory could enhance early detection of ascending placentitis and improve pregnancy outcomes.
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Practical Takeaways
- •Measurement of circulating oestrogen concentrations (particularly oestradiol and oestrone sulphate) may help identify early placentitis before clinical signs or ultrasonographic changes become apparent
- •Declining oestrogen levels in late pregnancy warrant investigation for ascending placentitis, particularly within 6 days of expected parturition
- •Androgen measurements alone are insufficient as biomarkers for placentitis; focus diagnostic efforts on oestrogen monitoring in at-risk pregnancies
Key Findings
- •In normal pregnancies, DHEA-S peaked by 180 days gestation while testosterone increased progressively from days 100-180 then plateaued until ~240 days before declining
- •Experimentally-induced placentitis caused significant reductions in oestradiol at -6, -2, -1 and 0 days from abortion (DFA)
- •Oestrone sulphate (OES) concentrations were significantly reduced on the day before abortion in placentitis mares
- •Androgens (DHEA-S and testosterone) were not significantly different between control and placentitis groups, whereas oestrogens showed significant time-by-group interactions