Oral Presentation The Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2014

Sildenafil – a first ever therapy of IUGR? (#71)

Katie Groom 1
  1. Senior Lecturer and Maternal Fetal Medicine Subspecialist , Department of Obstetrics and Gynaecology, University of Auckland and National Women’s Health, Auckland City Hospital, Auckland, New Zealand

There is no treatment available for intrauterine growth restriction (IUGR); the only management option obstetricians can currently offer is delivery. When IUGR occurs early there is high risk of in-utero hypoxia and death and many require extreme preterm birth, leading to further risk of morbidity and mortality through infancy, childhood and beyond.  

In IUGR pregnancies, abnormal placental invasion and spiral artery remodelling may leave nitric oxide responsive layers of the utero-placental vasculature intact and so susceptible to the effect of sildenafil, phosphodiesterase inhibitor and arterial vasodilator. Therefore in these compromised pregnancies, sildenafil may have the potential to improve gaseous and nutrient exchange and fetal growth. Animal studies have demonstrated sildenafil normalises pup growth measures and umbilical artery Doppler waveforms in models of IUGR. In human ex vivo myometrial studies, it significantly reduces vasoconstriction and improves relaxation of small arteries from IUGR pregnancies.

STRIDER NZAus is a randomised placebo controlled trial recruiting women with severe early onset IUGR <30 weeks. Participants will receive sildenafil or an identical placebo tablet up to delivery (or 32 weeks). The trial will demonstrate if sildenafil improves fetal growth velocity measured by mean daily increase in abdominal circumference. The results will also be used in an international IPD collaboration to demonstrate if sildenafil improves rates of neonatal survival free of major morbidity.