The effect of polyhydramnios on cervical length in twins: a controlled intervention study in complicated monochorionic pregnancies

Management of short cervix in twin-to-twin transfusion syndrome: a role for pessary placement following fetoscopic laser surgery?

BACKGROUND

Preterm labor and delivery is a major concern for patients with twin-to-twin transfusion syndrome undergoing fetoscopic laser surgery. A preoperative short cervix is a risk factor for preterm labor. Pessary placement is a short-acting intervention that may be useful to reduce this adverse event.

OBJECTIVE

This study aimed to investigate the relationship between pessary placement and preterm delivery in monochorionic twin pregnancies with twin-to-twin transfusion syndrome and a short cervix before fetoscopic laser surgery.

STUDY DESIGN

This was a retrospective study in 2 centers, including all pregnancies affected by twin-to-twin transfusion syndrome that underwent fetoscopic laser surgery with the Solomon technique between 2013 and 2022 (center A) and 2014 and 2022 (center B) with a preoperative cervical length below 25 mm. This study explored the correlation between cervical length and fetoscopic laser surgery-to-delivery interval following active or expectant management and compared perinatal outcomes between patients managed expectantly and patients managed with pessary placement, using multivariate analysis to control for potential confounders. Patients with a cervical length below 5 mm were not included in the comparative analysis.

RESULTS

Of 685 patients, 134 met the inclusion criteria. Moreover, 21 patients were treated with a cervical cerclage and excluded from the analysis, leaving 113 patients for the final analysis. There was a significant negative correlation between cervical length at fetoscopic laser surgery and the risk of early delivery (adjusted odds ratio, 0.66; 95% confidence interval, 0.49-0.81; P<.001). The use of a pessary correlated with fewer patients delivering before 28 weeks of gestation (adjusted odds ratio, 0.28; 95% confidence interval, 0.09-0.75), fewer double neonatal demise (adjusted odds ratio, 0.2; 95% confidence interval, 0.05-0.75). Posthoc subgroup analysis suggested that these improvements were essentially noticeable for cervical lengths between 5 and 18 mm, where pessary placement was associated with an increased fetoscopic laser surgery-to-delivery interval (+24 days; 95% confidence interval, 0.86-42; P=.042) and later gestational age at delivery (+3.3 weeks; 95% confidence interval, 0.86-42; P=.035).

CONCLUSION

Patients with a moderately shortened cervix, between 5 and 18 mm, may benefit from pessary placement after fetoscopic surgery for twin-to-twin transfusion syndrome, resulting in a reduction of adverse neonatal outcomes, double neonatal demise, and severe preterm delivery.

Cx43 regulates mechanotransduction mechanisms in human preterm amniotic membrane defects

OBJECTIVE

The effects of mechanical stimulation in preterm amniotic membrane (AM) defects were explored.

METHODS

Preterm AM was collected from women undergoing planned preterm caesarean section (CS) due to fetal growth restriction or emergency CS after spontaneous preterm prelabour rupture of the membranes (sPPROM). AM explants near the cervix or placenta were subjected to trauma and/or mechanical stimulation with the Cx43 antisense. Markers for nuclear morphology (DAPI), myofibroblasts (αSMA), migration (Cx43), inflammation (PGE2 ) and repair (collagen, elastin and transforming growth factor β [TGFβ1 ]) were examined by confocal microscopy, second harmonic generation, qPCR and biochemical assays.

RESULTS

In preterm AM defects, myofibroblast nuclei were highly deformed and contractile and expressed αSMA and Cx43. Mechanical stimulation increased collagen fibre polarisation and the effects on matrix markers were dependent on tissue region, disease state, gestational age and the number of fetuses. PGE2 levels were broadly similar but reduced after co-treatment with Cx43 antisense in late sPPROM AM defects. TGFβ1 and Cx43 gene expression were significantly increased after trauma and mechanical stimulation but this response dependent on gestational age.

CONCLUSION

Mechanical stimulation affects Cx43 signalling and cell/collagen mechanics in preterm AM defects. Establishing how Cx43 regulates mechanosignalling could be an approach to repair tissue integrity after trauma.

Impact of Preoperative Cervical Length on Pregnancy Outcome in Twin-Twin Transfusion Syndrome

OBJECTIVE

To evaluate the impact of preoperative cervical length on pregnancy outcome in monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome that underwent laser surgery or cord occlusion.

MATERIALS AND METHODS

Retrospective study of 330 patients stratified by preoperative cervical length (≥25 mm, 16-24 mm,≤15 mm). Maternal characteristics, operative data, and pregnancy outcomes were compared between the cervical length groups as well as between the subgroups of patients with a cervical length≤15 mm according to management (expectant vs. cerclage).

RESULTS

A preoperative cervical length≥25 mm was observed in 82% (n=271) of cases, 16-24 mm in 9% (n=29), and≤15 mm in 9% (n=30). Patients with a preoperative cervical length≤15 mm showed shorter median procedure-to-delivery interval (5.5 weeks vs. 11.6 (16-24 mm) vs. 13.0 (≥25 mm); p<0.001); lower median gestational age at delivery (29.5 weeks vs. 34.3 (16-24 mm) vs. 33.4 (≥25 mm); p<0.001); higher rate of preterm delivery<32 weeks (78 vs. 20% (16-24 mm) vs. 31% (≥25 mm); p<0.001); and lower neonatal survival rate of at least one twin (70 vs. 88% (16-24 mm) vs. 93% (≥25 mm); p<0.001). Outcome of patients with a preoperative cervical length≤15 mm was similar regardless of management.

CONCLUSION

Monochorionic diamniotic twin pregnancies complicated by twin-twin transfusion syndrome with a preoperative cervical length≤15 mm showed a higher rate of preterm delivery<32 weeks and lower neonatal survival. The role of a cervical cerclage remains unclear.

Preoperative Cervical Length Predicts the Risk of Delivery within One Week after Pleuroamniotic Shunt in Fetuses with Severe Hydrothorax

OBJECTIVE

The objective of this study was to assess the predictive performance of preoperative cervical length (CL) for delivery within 1 week after pleuroamniotic shunting (PAS) in fetuses with severe hydrothorax.

METHODS

A prospective cohort of fetuses with severe hydrothorax referred to our fetal surgery center in Querétaro, Mexico from January 2012 to July 2020. Severe fetal hydrothorax was diagnosed as an accumulation of fluid within the fetal pleural space accompanied with severe bilateral lung compression, mediastinal shift, polyhydramnios, and/or hydrops. Transvaginal CL was measured immediately before PAS, and a short cervix was defined as that <25 mm. The interval from fetal intervention to delivery, prevalence of preterm prelabor rupture of membranes (PPROMs), and associations with delivery within the first week after PAS according to a short or a normal CL, were evaluated.

RESULTS

Thirty-five pregnancies with severe fetal hydrothorax treated with PAS were evaluated. Median gestational age at PAS was (weeks + days) 31+2 (range, 26+0-36+1). Two (5.7%) and 7 (20.0%) cases delivered within the first 24 h and 1 week after PAS, respectively. Ten (28.6%) women had a short cervix before PAS, while 25 (71.4%) had normal preoperative CL. Women with a short cervix showed lower mean interval between fetal intervention and delivery (2.4 vs. 5.5 weeks, p = 0.01), and higher prevalence of PPROM (50 vs. 12%, p = 0.01), as compared to women with a nonshort cervix. Preoperative short cervix was associated with significantly higher risk of delivery within the first 24 h (20.0 vs. 0%, respectively, p < 0.05) and 1 week after PAS (50.0 vs. 8.0%, respectively, p < 0.01) compared with pregnancies with normal preoperative CL.

CONCLUSION

In pregnancies with severe fetal hydrothorax candidates for pleuroamniotic shunt, identification of a short cervix before fetal intervention can predict delivery within 1 week after the surgical procedure.

Effect of intra-amniotic fluid pressure from polyhydramnios on cervical length in patients with twin-twin transfusion syndrome undergoing fetoscopic laser surgery

OBJECTIVES

To determine the relationship between intra-amniotic pressure and cervical length (CL) in patients with twin-twin transfusion syndrome (TTTS) undergoing fetoscopic laser photocoagulation (FLP), and to identify pre- or intraoperative factors associated with increased intra-amniotic pressure in this population.

METHODS

This was a prospective cohort study of patients undergoing FLP for TTTS. Exclusion criteria were triplet or higher-order gestation and prior cervical cerclage, amnioreduction or FLP procedure. CL was assessed using preprocedure transvaginal ultrasound. Intra-amniotic pressure measurements were obtained on initial placement of the trocar into the amniotic cavity, using a direct hydrostatic pressure gauge. The relationship between intra-amniotic pressure and CL was assessed using multivariate linear regression analysis, including relevant preoperative and intraoperative variables.

RESULTS

In total, 283 pregnancies met the inclusion criteria. Quintero stage of TTTS was I in 33 pregnancies, II in 88, III in 150 and IV in 12. Mean gestational age (GA) at FLP was 20.7 ± 3 weeks. Mean intra-amniotic pressure was 23.1 ± 9 mmHg. On unadjusted linear regression analysis, there was no significant association between intra-amniotic pressure and preoperative CL (P = 0.24) or GA at delivery (P = 0.22). On multivariate analysis, the factors associated significantly with intra-amniotic pressure were: number of prior term deliveries (P = 0.03), recipient maximum vertical pocket (P < 0.0001), Quintero stage IV (P = 0.01) and type of anesthesia (sedation vs general anesthesia; P = 0.01).

CONCLUSION

In pregnancies with TTTS, intra-amniotic pressure is not associated with CL or GA at delivery. This novel finding suggests that cervical shortening in this population is not mechanically driven. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Effect of Cervical Length Recovery after Laser Surgery for Twin-Twin Transfusion Syndrome

Objective To evaluate the impact of polyhydramnios on preoperative cervical length and whether cervical length recovery after amnioreduction during selective fetoscopic laser photocoagulation (SFLP) is associated with a greater gestational age at delivery in pregnancies complicated by twin-twin transfusion syndrome (TTTS). Methods Retrospective study of 50 pregnancies complicated by TTTS treated with SFLP between March 2010 and July 2014 at a single center. Preoperative maximum vertical pocket (MVP) was measured along with pre- and postoperative cervical length. A cervical length difference was calculated, with a difference of ± 3 mm considered no change. Results Only 12 (34%) patients showed an increased cervical length after amnioreduction during laser surgery. There was no statistical difference between either negative or positive change in cervical length groups and mean gestational age at delivery (p = 0.82). There also was no correlation between preoperative MVP and preoperative cervical length (p = 0.36) or gestational age at delivery (p = 0.77). However, there was a statistically shorter mean preoperative cervical length in patients who delivered <32 weeks of gestation (3.62 ± 0.66 vs. 4.20 ± 0.85 cm; p = 0.03). Conclusion Severity of polyhydramnios does not correlate with preoperative cervical length, and variability of the cervix postoperatively does not appear to affect gestational age at delivery.