The Dutch STRIDER (Sildenafil TheRapy In Dismal Prognosis Early-onset Fetal Growth Restriction) (STRIDER)

Rationale: Severe, early-onset fetal growth restriction (FGR) due to placental insufficiency is associated with a high risk of perinatal morbidity with long-lasting sequelae and mortality. Placental insufficiency is the result of abnormal formation and function of the placenta (placentation) with inadequate remodelling of the maternal spiral (uteroplacental) arteries. There is currently no therapy available with demonstrated effectiveness. Evidence suggests Sildenafil citrate improves uteroplacental blood flow, growth, and meaningful outcomes. Objective: To evaluate the effectiveness of sildenafil (versus placebo) in achieving healthy perinatal survival. Study design: Multicenter nationwide randomized placebo-controlled clinical trial. Study population: Women with a singleton pregnancy between 20 and 30 weeks with severe fetal growth restriction of likely placental origin, and with estimated significant likelihood of perinatal death. Intervention: Sildenafil 25mg or placebo tablet orally three times daily. Main study parameters/endpoints: Perinatal healthy survival, i.e. survival without severe neonatal morbidity at term age. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Taking tablets three times daily. No additional ultrasounds, other than standard clinical protocol, one extra blood sample at inclusion. No risks anticipated, unexpected medication-associated risks can't be excluded on beforehand.

Age-adequate performance on the two-year Bayley scales of infant development (BSID)-III (composite cognitive score and composite motor score)

Co-incidence and severity of the maternal syndrome of pre-eclampsia / HELLP-syndrome (Hemolysis Elevated Liver enzymes Low Platelets)

Fetal ultrasound and Doppler studies: estimated fetal weight, abdominal circumference and Doppler of umbilical artery

Umbilical artery, middle cerebral artery, ductus venosus and aortic isthmus Doppler indices; fetal biometry; amniotic fluid index; deepest vertical amniotic fluid pocket.

Inclusion Criteria: Inclusion criteria ((I OR II) AND III): At 20+0-27+6 weeks: an ultrasound measurement of the fetal abdominal circumference (AC) <3rd percentile for gestational age or an ultrasound estimate of fetal weight (EFW) <5th percentile OR At 28+0-29+6 weeks: an ultrasound estimate of fetal weight (EFW) <700 grams using Hadlock C formula AND Likely placental origin defined by (a AND/OR b AND/OR c AND/OR d) The presence of uterine artery notching Abnormal flow velocity patterns of the umbilical artery or middle cerebral artery Maternal hypertensive disorders Low PlGF in point-of-care assessment Exclusion Criteria: Plan to terminate pregnancy for maternal or fetal indication within days Known multiple pregnancy Identified congenital anomalies or congenital infection Maternal age at eligibility <18 years Cocaine use Current use of sildenafil Current use of cyp3A5 inhibitors: amiodaron, azitromycine, ciclosporine, claritromycine, diltiazem, erytromycine, fluconazol, itraconazol, ketoconazol, verapamil, voriconazol. Recent myocardial infarction or stroke

Pels A, Derks J, Elvan-Taspinar A, van Drongelen J, de Boer M, Duvekot H, van Laar J, van Eyck J, Al-Nasiry S, Sueters M, Post M, Onland W, van Wassenaer-Leemhuis A, Naaktgeboren C, Jakobsen JC, Gluud C, Duijnhoven RG, Lely T, Gordijn S, Ganzevoort W; Dutch STRIDER Trial Group. Maternal Sildenafil vs Placebo in Pregnant Women With Severe Early-Onset Fetal Growth Restriction: A Randomized Clinical Trial. JAMA Netw Open. 2020 Jun 1;3(6):e205323. doi: 10.1001/jamanetworkopen.2020.5323.

Pels A, Jakobsen JC, Ganzevoort W, Naaktgeboren CA, Onland W, van Wassenaer-Leemhuis AG, Gluud C. Detailed statistical analysis plan for the Dutch STRIDER (Sildenafil TheRapy In Dismal prognosis Early-onset fetal growth Restriction) randomised clinical trial on sildenafil versus placebo for pregnant women with severe early onset fetal growth restriction. Trials. 2019 Jan 11;20(1):42. doi: 10.1186/s13063-018-3136-z.

Pels A, Kenny LC, Alfirevic Z, Baker PN, von Dadelszen P, Gluud C, Kariya CT, Mol BW, Papageorghiou AT, van Wassenaer-Leemhuis AG, Ganzevoort W, Groom KM; international STRIDER Consortium. STRIDER (Sildenafil TheRapy in dismal prognosis early onset fetal growth restriction): an international consortium of randomised placebo-controlled trials. BMC Pregnancy Childbirth. 2017 Dec 28;17(1):440. doi: 10.1186/s12884-017-1594-z.