Neonatal pulmonary hypertension after severe early-onset fetal growth restriction: post hoc reflections on the Dutch STRIDER study

The aim was to reflect on the unexpected finding of persistent pulmonary hypertension of the neonate (PPHN) and pulmonary hypertension in infants born within the Dutch STRIDER trial, its definition and possible pathophysiological mechanisms. The trial randomly assigned pregnant women with severe early-onset fetal growth restriction to sildenafil 25 mg three times a day versus placebo. Sildenafil use did not reduce perinatal mortality and morbidity, but did result in a higher rate of neonatal pulmonary hypertension (PH). The current paper reflects on the used definition, prevalence, and possible pathophysiology of the data on pulmonary hypertension. Twenty infants were diagnosed with pulmonary hypertension (12% of 163 live born infants). Of these, 16 infants had PPHN shortly after birth, and four had pulmonary hypertension associated with sepsis or bronchopulmonary dysplasia. Four infants with PPHN in the early neonatal period subsequently developed pulmonary hypertension associated with bronchopulmonary dysplasia in later life. Infants with pulmonary hypertension were at lower gestational age at delivery, had a lower birth weight and a higher rate of neonatal co-morbidity. The infants in the sildenafil group showed a significant increase in pulmonary hypertension compared to the placebo group (relative risk 3.67; 95% confidence interval 1.28 to 10.51, P = 0.02).Conclusion: Pulmonary hypertension occurred more frequent among infants of mothers allocated to antenatal sildenafil compared with placebo. A possible pathophysiological mechanism could be a “rebound” vasoconstriction after cessation of sildenafil. Additional studies and data are necessary to understand the mechanism of action. What is Known:• In the Dutch STRIDER trial, persistent pulmonary hypertension in the neonate (PPHN) was more frequent among infants after antenatal sildenafil exposure versus placebo. What is New:• The current analysis focuses on the distinction between PPHN and pulmonary hypertension associated with sepsis or bronchopulmonary dysplasia and on timing of diagnosis and aims to identify the infants at risk for developing pulmonary hypertension.• The diagnosis pulmonary hypertension is complex, especially in infants born after severe early-onset fetal growth restriction. The research field could benefit from an unambiguous consensus definition and standardized screening in infants at risk is proposed.

Maternal polymorphic loci of rs1979277 serine hydroxymethyl transferase and rs1805087 5-methylenetetrahydrofolate are correlated with the development of fetal growth restriction: A case-control study

Background: Key reactions in folate-mediated single-carbon metabolism are regulated by folate cycle enzymes. Violations of the folate cycle may be associated with the occurrence of fetal growth restriction (FGR) in pregnant women. Objective: To study the relationship between polymorphisms of folate cycle genes in the mother with the development of FGR. Materials and Methods: In this case-control study, 122 pregnant women with FGR and 243 pregnant women with normal newborn weight were enrolled. The polymorphic loci of folate cycle genes including rs1805087 5-methylenetetrahydrofolate (MTR) and rs1979277 serine hydroxymethyl transferase (SHMT1) were examined. The study of polymorphisms was carried out through the TaqMan probe detection method using polymerase chain reaction. Logistic regression was used to analyze the associations of the polymorphisms. Results: It was established that the T allele rs1979277 of the SHMT1 gene was correlated with the development of FGR within the framework of the allelic (OR = 1.67, 95% CI 1.20-2.33, pperm < 0.01), additive (OR = 1.69, 95% CI 1.20-2.37, pperm < 0.01), dominant (OR = 1.81, 95% CI 1.15-2.87, pperm = 0.01) and recessive (OR = 2.34, 95% CI 1.15-4.73, pperm = 0.01) models. The association of the G rs1805087 allele of the MTR gene with the occurrence of FGR was also identified following the recessive model (OR = 3.01, 95% CI 1.05-8.68, pperm = 0.04). Conclusion: Our results indicated that maternal polymorphic loci rs1979277 SHMT1 and rs1805087 MTR may be associated with the development of FGR. Key words: Polymorphism, Associations, Fetal growth restriction, Folic acid.

Prenatal diagnosis of fetal growth restriction with polyhydramnios, etiology and impact on postnatal outcome

To assess the spectrum of different etiologies, the intrauterine course, outcome and possible prognostic markers in prenatally detected fetal growth restriction (FGR) combined with polyhydramnios. Retrospective study of 153 cases with FGR combined with Polyhydramnios diagnosed by prenatal ultrasound over a period of 17 years. Charts were reviewed for ultrasound findings, prenatal and postnatal outcome. All cases were categorized into etiological groups and examined for differences. Five etiological groups were identified: chromosomal anomalies (n = 64, 41.8%), complex malformation syndromes (n = 37, 24.1%), isolated malformations (n = 24, 15.7%), musculoskeletal disorders (n = 14, 9.2%) and prenatal non-anomalous fetuses (n = 14, 9.2%). Subgroups showed significant disparities in initial diagnosis of combination of both pathologies, Ratio AFI/ gestational weeks and Doppler ultrasound examinations. Overall mortality rate was 64.7%. Fetuses prenatally assigned to be non-anomalous, showed further complications in 42.9% (n = 6). Fetuses prenatally diagnosed with FGR combined with polyhydramnios are affected by a high morbidity and mortality. Five etiologic groups can be differentiated, showing significant disparities in prenatal and postnatal outcome. Even without recognizable patterns prenatally, long-term-follow up is necessary, as neurodevelopmental or growth delay may occur.

Comparison of pregnancy outcomes and placental characteristics between selective fetal growth restriction with and without thick arterio-arterial anastomosis in monochorionic diamniotic twins

Background Unequal placental territory in monochorionic diamniotic twins is a primary cause of selective fetal growth restriction (sFGR), and vascular anastomoses play important role in determining sFGR prognosis. This study investigated differences in placental characteristics and pregnancy outcomes in cases of sFGR with and without thick arterio-arterial anastomosis (AAA). Methods A total of 253 patients diagnosed with sFGR between April 2013 and April 2020 were retrospectively analyzed. An AAA greater than 2 mm in diameter was defined as a thick AAA. We compared placental characteristics and pregnancy outcomes between cases of sFGR with and without thick AAA. Results Prevalence of AAA, thick arterio-venous anastomosis (AVA), veno-venous anastomosis (VVA), and thick VVA were significantly higher in the thick AAA group relative to the non-thick AAA group (100.0 vs. 78.5%, P < 0.001; 44.3 vs. 15.4%, P < 0.001; 27.1 vs. 10.8%, P = 0.017, and 24.3 vs. 6.2%, P = 0.004, respectively). The total numbers of AVA and total anastomoses were significantly higher in thick AAA group relative to the non-thick AAA group (5 [1, 14] vs. 3 [1, 15, P = 0.016; and 6 [1, 15] vs. 5 [1, 16], P = 0.022, respectively). The total diameter of AAA, AVA, VVA, and all anastomoses in the thick AAA group was larger than in the non-thick AAA group (3.4 [2.0,7.1] vs. 1.4 [0.0, 3.3], P < 0.001; 6.3 [0.3, 12.0] vs. 2.5 [0.3, 17.8], P < 0.001; 4.2±1.8 vs. 1.9±1.2, P =0.004; and 10.7 [3.2,22.4] vs. 4.4 [0.5, 19.3], P < 0.001, respectively). Growth-restricted fetuses in the thick AAA group exhibited significantly increased birthweight relative to those in thenon-thick AAA group (1570 (530, 2460)g vs. 1230 (610, 2480)g, p = 0.002). Conclusions In the placentas associated with sFGR, thick AAA can co-occur with thick AVA and VVA, and placental angiogenesis may differ significantly based upon whether or not thick AAA is present. The birth weights of growth-restricted fetuses in cases of sFGR with thick AAA are larger than in cases without thick AAA.

Hepatitis E, Schistosomiasis and Echinococcosis–Prevalence in a Cohort of Pregnant Migrants in Germany and Their Influence on Fetal Growth Restriction

Background: Infections, as well as adverse birth outcomes, may be more frequent in migrant women. Schistosomiasis, echinococcosis, and hepatitis E virus (HEV) seropositivity are associated with the adverse pregnancy outcomes of fetal growth restriction and premature delivery. Methods: A cohort study of 82 pregnant women with a history of migration and corresponding delivery of newborns in Germany was conducted. Results: Overall, 9% of sera tested positive for anti-HEV IgG. None of the patients tested positive for anti-HEV IgM, schistosomiasis, or echinococcus serology. Birth weights were below the 10th percentile for gestational age in 8.5% of the neonates. No association between HEV serology and fetal growth restriction (FGR) frequency was found. Conclusions: In comparison to German baseline data, no increased risk for HEV exposure or serological signs of exposure against schistosomiasis or echinococcosis could be observed in pregnant migrants. An influence of the anti-HEV serology status on fetal growth restriction could not be found.