Calcitonin Gene Related Peptide, Adrenomedullin, and Adrenomedullin 2 Function in Uterine Artery During Human Pregnancy

RATIONALE

Calcitonin gene-related peptide (CGRP) and its family members adrenomedullin (ADM) and adrenomedullin 2 (ADM2; also known as intermedin) support vascular adaptions in rat pregnancy.

OBJECTIVE

This study aimed to assess the relaxation response of uterine artery (UA) for CGRP, ADM, and ADM2 in nonpregnant and pregnant women and identify the involved mechanisms.

FINDINGS

(1) Segments of UA from nonpregnant women that were precontracted with U46619 (1μM) in vitro are insensitive to the hypotensive effects of CGRP, ADM, and ADM2; (2) CGRP, ADM, and ADM2 (0.1-100nM) dose dependently relax UA segments from pregnant women with efficacy for CGRP > ADM = ADM2; (3) the relaxation responses to CGRP, ADM, and ADM2 are differentially affected by the inhibitors of nitric oxide (NO) synthase (L-NAME), adenylyl cyclase (SQ22536), apamin, and charybdotoxin; (4) UA smooth muscle cells (UASMC) express mRNA for calcitonin receptor-like receptor (CRLR) and receptor activity modifying protein (RAMP)1 and RAMP2 but not RAMP3; (5) receptor heterodimer comprising CRLR/RAMP1 and CRLR/RAMP2 but not CRLR/RAMP3 is present in UA; (6) soluble fms-like tyrosine kinase (sFLT-1) and TNF-α treatment decrease the expression of RAMP1 mRNA (P < 0.05) in UASMC; and (7) sFLT-1 treatment impairs the association of CRLR with all 3 peptides while TNF-α inhibits the interaction of CGRP but not ADM or ADM2 with CRLR in UASMC (P < 0.05).

CONCLUSIONS

Relaxation sensitivity of UA for CGRP, ADM, and ADM2 is increased during pregnancy via peptide-specific involvement of NO system and endothelium-derived hyperpolarizing factors; vascular disruptors such as sFLT-1 and TNFα adversely impact their receptor system in UASMC.

Society for Maternal-Fetal Medicine Special Statement: Beyond the scalpel: in utero fetal gene therapy and curative medicine

With the recent advances in gene editing with systems such as CRISPR-Cas9, precise genome editing in utero is on the horizon. Sickle cell disease is an excellent candidate for in utero fetal gene therapy, because the disease is monogenic, causes irreversible harm, and has life-limiting morbidity. Gene therapy has recently been proven to be effective in an adolescent patient. Several hurdles still impede the progress for fetal gene therapy in humans, including an incomplete understanding of the fetal immune system, unclear maternal immune responses to in utero gene therapy, risks of off-target effects from gene editing, gestational age constraints, and ethical questions surrounding fetal genetic intervention. However, none of these barriers appears insurmountable, and the journey to in utero gene therapy for sickle cell disease and other conditions should be well underway.

Society for Maternal-Fetal Medicine Special Statement: COVID-19 research in pregnancy: progress and potential

The COVID-19 global pandemic has broad implications for obstetrical care and perinatal outcomes. As we approach the 2-year mark into an unprecedented international pandemic, this review presents the progress and opportunities for research related to COVID-19 and pregnancy. Research is the basis for evidence-based clinical guidelines, and we aim to provide the structure and guidance for framing COVID-19-related obstetrical research. This structure will pertain not only to this pandemic but future ones as well.

Complex gastroschisis: a new indication for fetal surgery?

Gastroschisis (GS) is a congenital abdominal wall defect, in which the bowel eviscerates from the abdominal cavity. It is a non-lethal isolated anomaly and its pathogenesis is hypothesized to occur as a result of two hits: primary rupture of the 'physiological' umbilical hernia (congenital anomaly) followed by progressive damage of the eviscerated bowel (secondary injury). The second hit is thought to be caused by a combination of mesenteric ischemia from constriction in the abdominal wall defect and prolonged amniotic fluid exposure with resultant inflammatory damage, which eventually leads to bowel dysfunction and complications. GS can be classified as either simple or complex, with the latter being complicated by a combination of intestinal atresia, stenosis, perforation, volvulus and/or necrosis. Complex GS requires multiple neonatal surgeries and is associated with significantly greater postnatal morbidity and mortality than is simple GS. The intrauterine reduction of the eviscerated bowel before irreversible damage occurs and subsequent defect closure may diminish or potentially prevent the bowel damage and other fetal and neonatal complications associated with this condition. Serial prenatal amnioexchange has been studied in cases with GS as a potential intervention but never adopted because of its unproven benefit in terms of survival and bowel and lung function. We believe that recent advances in prenatal diagnosis and fetoscopic surgery justify reconsideration of the antenatal management of complex GS under the rubric of the criteria for fetal surgery established by the International Fetal Medicine and Surgery Society (IFMSS). Herein, we discuss how conditions for fetoscopic repair of complex GS might be favorable according to the IFMSS criteria, including an established natural history, an accurate prenatal diagnosis, absence of fully effective perinatal treatment due to prolonged need for neonatal intensive care, experimental evidence for fetoscopic repair and maternal and fetal safety of fetoscopy in expert fetal centers. Finally, we propose a research agenda that will help overcome barriers to progress and provide a pathway toward clinical implementation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Intertwin differences in umbilical artery pulsatility index are associated with infant survival in twin-to-twin transfusion syndrome

OBJECTIVES

To evaluate the association of intertwin differences in umbilical artery pulsatility index (DUAPI) and infant survival in twin-to-twin transfusion syndrome (TTTS).

METHODS

Absolute DUAPI was calculated prior to laser surgery. Receiver-operating characteristics (ROC) curve analysis provided an intertwin DUAPI cutoff of 0.4 for the prediction of double twin survival to 30 days of life. Infant survival was compared between women with an intertwin DUAPI <0.4 and ≥0.4 in the whole cohort, in TTTS cases with Quintero stages I/II and in those with Quintero stages III/IV. Regression analyses were performed to evaluate the association of intertwin DUAPI <0.4 and infant survival adjusted for confounders.

RESULTS

In total, 349 TTTS cases were included. Double twin survival to 30 days was observed in 67% (234/349) of cases. Significant differences in double twin survival was seen between intertwin DUAPI groups in the whole cohort (76.8 vs. 52.2%; p<0.001), in women with TTTS Quintero stage I or II (77.8 vs. 58.5%; p=0.015) as well as in women with TTTS Quintero stage III or IV (75 vs. 49.5%; p=0.001). Intertwin DUAPI <0.4 conferred a threefold increased chance for double twin survival.

CONCLUSIONS

Small intertwin DUAPI is associated with increased double infant survival in early and advanced TTTS stages.

Efficacy of long-term indomethacin therapy in prolonging pregnancy after fetoscopic laser surgery for twin-to-twin transfusion syndrome: a collaborative cohort study

OBJECTIVE

To evaluate the efficacy of long-term indomethacin therapy (LIT) in prolonging pregnancy and reducing spontaneous preterm birth (PTB) in patients undergoing fetoscopic laser surgery (FLS) for the management of twin-to-twin transfusion syndrome (TTTS).

DESIGN

Retrospective cohort study of prospectively collected data.

SETTING

Collaborative multicentre study.

POPULATION

Five hundred and fifty-seven consecutive TTTS cases that underwent FLS.

METHODS

Long-term indomethacin therapy was defined as indomethacin use for at least 48 hours. Log-binomial regression was used to estimate the relative risk of PTB in the LIT group compared with a non-LIT group. Cox regression was used to evaluate the association between LIT use and FLS-to-delivery survival.

MAIN OUTCOME MEASURES

Gestational age (GA) at delivery.

RESULTS

Among the 411 pregnancies included, a total of 180 patients (43.8%) received LIT after FLS and 231 patients (56.2%) did not. Median GA at fetal intervention did not differ between groups (20.4 weeks). Median GA at delivery was significantly higher in the LIT group (33.6 weeks) compared with the non-LIT group (31.1 weeks; P < 0.001). FLS-to-delivery interval was significantly longer in the LIT group (P < 0.001). The risks of PTB before 34, 32, 28 and 26 weeks of gestation were all significantly lower in the LIT group compared with the non-LIT group (relative risks 0.69, 0.51, 0.37 and 0.18, respectively). The number needed to treat with LIT to prevent one PTB before 32 weeks of gestation was four, and to prevent one PTB before 34 weeks was five.

CONCLUSION

Long-term indomethacin after FLS for TTTS was found to be associated with prolongation of pregnancy and reduced risk for PTB.

TWEETABLE ABSTRACT

Long-term indomethacin used after fetoscopic laser surgery for twin-to-twin transfusion syndrome is effective in prolonging pregnancy and reducing the risk for preterm birth; especially extreme preterm birth.

Prediction of post-laser fetal death in selective growth restriction complicating twin-twin transfusion syndrome using standardized definitions

OBJECTIVE

Selective fetal growth restriction (sFGR) complicating twin-twin transfusion syndrome (TTTS) is associated with a 3-6-fold increased risk of fetal demise after fetoscopic laser surgery (FLS). Identifying these patients is challenging due to varying definitions of sFGR used in the literature. The objective of this study was to determine the association of three currently used definitions for sFGR with demise of the smaller twin, typically the donor, following FLS for TTTS.

METHODS

This was a retrospective cohort study of monochorionic diamniotic twin pregnancies undergoing FLS for TTTS between January 2015 and December 2018. Classification of the cohort as sFGR or non-sFGR was performed using three different definitions: (1) estimated fetal weight (EFW) of one twin < 10^th centile and intertwin EFW discordance > 25%, according to the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) (Definition A); (2) EFW of one twin < 3^rd centile, according to the solitary criterion for sFGR reported in a Delphi consensus (Definition B); and (3) presence of at least two of four of the following criteria: EFW of one twin < 10^th centile, abdominal circumference of one twin < 10^th centile, intertwin EFW discordance of ≥ 25% and umbilical artery pulsatility index of the smaller twin > 95^th centile, according to the contributory criteria for sFGR in monochorionic diamniotic twin pregnancies reported in the Delphi consensus (Definition C). Pearson's χ² and univariate and multivariate logistic regression analyses were performed to assess the association of classification as sFGR according to the different definitions with fetal demise within 48 h after FLS.

RESULTS

A total of 124 pregnancies underwent FLS for TTTS during the study period. Of these, 46/124 (37.1%) were identified as having sFGR according to the ISUOG criteria (Definition A), 57/124 (46.0%) based on EFW < 3^rd centile (Definition B) and 70/124 (56.5%) according to the Delphi contributory criteria (Definition C). There were no differences in maternal body mass index, recipient twin amniotic fluid volume, gestational age (GA) at intervention or GA at delivery between sFGR and non-sFGR cases for any of the three definitions. There were also no differences in the rates of postprocedure recipient demise or Doppler abnormalities in the recipient. Regardless of the definition used, sFGR cases showed a significantly higher rate of postprocedure donor twin demise compared with that in non-sFGR cases (Definition A: 28.3% vs 3.8%, P < 0.01; Definition B: 22.8% vs 4.5%, P = 0.02; Definition C: 22.9% vs 0%, P < 0.01). For all of the sFGR definitions, the rate of Stage-III TTTS was increased in sFGR compared to non-sFGR cases (Definition A: 65.2% vs 35.9%, P ≤ 0.01; Definition B: 59.6% vs 35.8%, P = 0.04; Definition C: 62.9% vs 25.9%, P < 0.01). All cases of donor demise met the criteria for sFGR according to Definition C. Classification as sFGR according to Definition C was associated with a significantly higher rate of post-FLS donor demise compared to Definitions A and B (χ² , 15.32; P < 0.01). Logistic regression analysis demonstrated that sFGR cases had an increased risk of donor demise (Definition A: odds ratio (OR), 4.97 (95% CI, 1.77-13.94), P < 0.01; Definition B: OR, 4.39 (95% CI, 1.36-14.15), P = 0.01) and that staging of TTTS was also predictive of demise (OR, 2.26 (95% CI, 1.14-4.47), P = 0.02). After adjusting for GA at intervention and stage of TTTS, the results were similar (Definition A: OR, 6.48 (95% CI, 2.11-24.56), P = 0.002; Definition B: OR, 4.16 (95% CI, 1.35-15.74), P = 0.02).

CONCLUSIONS

The rate of fetal demise following FLS for TTTS is increased in the presence of sFGR. Improving diagnosis of sFGR should improve counseling and may affect management. The Delphi method of defining sFGR based on the presence of at least two of four contributory criteria had the highest predictive value for donor demise following FLS for TTTS. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

The effect of phosphodiesterase-5 inhibitors on uteroplacental and fetal cerebral perfusion in pregnancies with fetal growth restriction: A systematic review and meta-analysis

OBJECTIVES

To evaluate the effect of phosphodiesterase-5 (PDE-5) inhibitors on uteroplacental and fetal cerebral perfusion in pregnancies complicated with fetal growth restriction (FGR).

MATERIAL AND METHODS

Relevant databases were searched from inception up to June 2021. The random-effects model was used to pool the weighted mean differences (WMDs) and the corresponding 95% confidence intervals (CIs). The primary outcomes were the effect of PDE-5 inhibitors on uterine (UtA-PI), umbilical (UA-PI) and middle cerebral artery (MCA-PI) pulsatility indices. Subgroup analyses were also performed based on the type of PDE-5 inhibitor medication, the dosage of medication, duration of treatment, sample size and onset of FGR.

RESULTS

Seven clinical trials were eligible, 6 trials using sildenafil, and one using tadalafil. The random-effects models indicated PDE-5 inhibitors significantly decrease UtA-PI (WMD = -0.28, 95% CI = -0.46,-0.11) and UA-PI (WMD = -0.07, 95% CI = -0.13, -0.01); however it failed to show a significant effect on MCA-PI (WMD = 0.24, 95% CI = -0.63, 1.11). Subgroup analyses showed similar significant effects of sildenafil on UtA-PI and UA-PI; however, no significant effect was observed after treatment with tadalafil.

CONCLUSION

PDE-5 inhibitors administration, especially sildenafil, may improve uteroplacental, but not fetal cerebral blood perfusion in pregnancies complicated by FGR.

Perinatal risk factors of neurodevelopmental impairment after fetoscopic laser photocoagulation for twin-twin transfusion syndrome: systematic review and meta-analysis

OBJECTIVE

Monochorionic twins with twin-twin transfusion syndrome (TTTS) treated with fetoscopic laser photocoagulation (FLP) are at increased risk of neurodevelopmental impairment (NDI). This meta-analysis aimed to identify the prevalence of and perinatal risk factors for NDI in TTTS survivors treated with FLP.

METHODS

We performed a search in PubMed, EMBASE, Scopus and Web of Science, from inception to 13 February 2021, for studies evaluating perinatal risk factors for NDI in children diagnosed prenatally with TTTS managed by FLP. Data on severity of TTTS at the time of diagnosis, defined according to the Quintero staging system, FLP-related complications and perinatal outcomes were compared between children with a history of TTTS treated with FLP with and those without NDI, which was defined as performance on a cognitive or developmental assessment tool ≥ 2 SD below the mean or a defined motor or sensory disability. A random-effects model was used to pool the mean differences or odds ratios (OR) with the corresponding 95% CIs. Heterogeneity was assessed using the I² statistic.

RESULTS

Nine studies with a total of 1499 TTTS survivors were included. The overall incidence of NDI was 14.0% (95% CI, 9.0-18.0%). The occurrence of NDI in TTTS survivors was associated with later gestational age (GA) at FLP (mean difference, 0.94 weeks (95% CI, 0.50-1.38 weeks); P < 0.0001, I²  = 0%), earlier GA at delivery (mean difference, -1.44 weeks (95% CI, -2.28 to -0.61 weeks); P = 0.0007, I²  = 49%) and lower birth weight (mean difference, -343.26 g (95% CI, -470.59 to -215.92 g); P < 0.00001, I²  = 27%). Evaluation of different GA cut-offs showed that preterm birth before 32 weeks was associated with higher risk for NDI later in childhood (OR, 2.25 (95% CI, 1.02-4.94); P = 0.04, I²  = 35%). No statistically significant difference was found between cases with and those without NDI with respect to Quintero stage of TTTS, recipient or donor status, development of postlaser twin anemia-polycythemia sequence, recurrence of TTTS and incidence of small- for-gestational age or cotwin fetal demise.

CONCLUSIONS

TTTS survivors with later GA at the time of FLP, earlier GA at delivery and lower birth weight are at higher risk of developing NDI. No significant association was found between Quintero stage of TTTS and risk of NDI. Our findings may be helpful for parental counseling and highlight the need for future studies to understand better the risk factors for NDI in TTTS survivors. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Outcomes of laparoscopy-assisted fetoscopic laser photocoagulation for twin-twin transfusion syndrome: An established alternative for inaccessible anterior placenta

OBJECTIVE

To evaluate laparoscopy-assisted fetoscopic laser photocoagulation (FLPC) of placental anastomoses in the treatment of twin-to-twin-transfusion syndrome (TTTS).

STUDY DESIGN

We performed a retrospective cohort study analyzing pregnancies complicated by TTTS who underwent FLPC in a single university-affiliated tertiary medical-center. Outcomes were compared between patients who received laparoscopy-assisted FLPC (study group) and patients who underwent the conventional FLPC technique (control group). Baseline characteristics, sonographic findings, procedure details, and neonatal outcomes were compared between groups.

RESULTS

The cohort included 278 women with 31 in the study group and 247 in the control group. Sonographic parameters, including fetal biometry and TTTS stage, were comparable between study groups. Gestational age at delivery did not differ between the groups (29.22 ± 4.55 weeks in the study group vs. 30.62 ± 4.3 weeks in the control group, p = 0.09). There were no differences in neonatal survival rates at birth and at 30 days between both groups. A subanalysis comparing the laparoscopy-assisted group to only those patients with anterior placenta in the control group, showed a lower rate of incomplete Solomonization in the laparoscopy-assisted study group (3.4% vs. 33%, p = 0.01).

CONCLUSION

Laparoscopy-assisted FLPC is a reasonable and safe option that may be offered in cases of FLPC where an anterior placenta restricts adequate surgical access.

Geographic variation in management of patients with placenta accreta spectrum: An international survey of experts (GPASS)

OBJECTIVE

To describe global geographic variations in the diagnosis and management of placenta accreta spectrum (PAS).

METHODS

An international cross-sectional study was conducted among PAS experts practicing at medical institutions in member states of the United Nations. Survey questions focused on diagnostic evaluation and management strategies for PAS.

RESULTS

A total of 134 centers participated. Participating centers represented each of the United Nations' designated regions. Of those, 118 (88%) reported practicing in a medium-volume or high-volume center. First-trimester PAS screen was reported in 35 (26.1%) centers. Respondents consistently implement guideline-supported care practices, including utilization of ultrasound as the primary diagnostic modality (134, 100%) and implementation of multidisciplinary care teams (115, 85.8%). Less than 10% of respondents reported routinely managing PAS without hysterectomy; these centers were predominantly located in Europe and Africa. Antepartum management and availability of mental health support for PAS patients varied widely.

CONCLUSION

Worldwide, there is a strong adherence to PAS care guidelines; however, regional variations do exist. Comparing variations in care to outcomes will provide insight into the clinically significant practice variability.

Twin twin transfusion syndrome with and without selective fetal growth restriction: Predictors of donor demise

OBJECTIVE

Evaluate survival in twin twin transfusion syndrome (TTTS) with and without selective fetal growth restriction (sFGR) after fetoscopic laser surgery (FLS).

METHODS

Retrospective study of monochorionic diamniotic twins undergoing FLS. The cohort was classified as TTTS and TTTS with sFGR. Baseline, intra-operative and postoperative variables were analyzed. Mann-Whitney U, Pearson chi-square, Fisher's exact, t-test and receiver operating characteristic (ROC) curve analysis were performed.

RESULTS

Four hundred and ninety-two pregnancies were included, 304 (61.78%) TTTS and 188 (38.22%) TTTS with sFGR. No difference in donor outcomes. TTTS group had higher donor estimated fetal weight (EFW%) percentile (19.7 ± 18.8 vs. 2.2 ± 2.1, p < 0.001). Significant predictors for demise at 30 days were 37% intertwin weight discordance (IWD) with donor EFW% < first (area under ROC curve [AUC] = 0.85, p = 0.001) or IWD >25% and intertwin umbilical artery pulsatility index discordance (DUAPI) ≥0.4 (AUC = 0.71, p = 0.001).

CONCLUSION

Combination of IWD of 37% and donor EFW% <first was most predictive for demise 30 days after birth. DUAPI ≥0.4 was also associated with increased risk for demise.