Connexin 43 is overexpressed in human fetal membrane defects after fetoscopic surgery

OBJECTIVE

We examined whether surgically induced membrane defects elevate connexin 43 (Cx43) expression in the wound edge of the amniotic membrane (AM) and drives structural changes in collagen that affects healing after fetoscopic surgery.

METHOD

Cell morphology and collagen microstructure was investigated by scanning electron microscopy and second harmonic generation in fetal membranes taken from women who underwent fetal surgery. Immunofluoresence and real-time quantitative polymerase chain reaction was used to examine Cx43 expression in control and wound edge AM.

RESULTS

Scanning electron microscopy showed dense, helical patterns of collagen fibrils in the wound edge of the fetal membrane. This arrangement changed in the fibroblast layer with evidence of collagen fibrils that were highly polarised along the wound edge but not in control membranes. Cx43 was increased by 112.9% in wound edge AM compared with controls (p < 0.001), with preferential distribution in the fibroblast layer compared with the epithelial layer (p < 0.01). In wound edge AM, mesenchymal cells had a flattened morphology, and there was evidence of poor epithelial migration across the defect. Cx43 and COX-2 expression was significantly increased in wound edge AM compared with controls (p < 0.001).

CONCLUSION

Overexpression of Cx43 in the AM after fetal surgery induces morphological and structural changes in the collagenous matrix that may interfere with normal healing mechanisms. © 2016 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd.

Antepartum amnioinfusion: a review

OBJECTIVE

Antepartum amnioinfusion is a relatively recent procedure introduced with fetal medicine techniques. It is usually indicated for severe oligohydramnios in order to avoid the related complications such as pulmonary hypoplasia, the deforming effects of oligohydramnios, variable fetal heart rate decelerations and intraventricular hemorrhage. Antepartum amnioinfusion is also employed to improve ultrasound visualization in cases with oligohydramnios. Our objective was to evaluate the benefits and complications related to this procedure which is still less commonly used compared to intrapartum amnioinfusion, and whose risks are therefore not well established.

STUDY DESIGN

Reports of study designs identified from searches of MEDLINE, PUBMED, the Cochrane Collaboration, specialized databases and bibliographies of review articles were identified. Studies in women who underwent amnioinfusion between 1987 and 2002 were included.

RESULTS AND CONCLUSIONS

Amnioinfusion seems to offer several benefits, in terms of both prenatal diagnosis and favorable perinatal outcome. Most clinical experiences report that amnioinfusion is safe, both for the mother and for the fetus. However, randomized control-group studies subdivided on the basis of the cause of oligohydramnios (e.g. premature rupture of membranes, fetal growth restriction, obstructive uropathy and renal agenesis) could help to determine the advantages and risks linked to this procedure. Prospective randomized studies should therefore be encouraged, to clarify any possible doubts regarding the procedure, before it can be introduced into routine practice in the management of oligohydramnios.

Transient Chorioamniotic Membrane Separation after Fetoscope Guide Laser Therapy for Twin–Twin Transfusion Syndrome: A Case Report

Chorioamniotic membrane separation (CMS) means that the close attachment of amniotic and chorionic membranes is disrupted, usually following the traumatic entry into the amniotic cavity including fetal therapy. We report a case of twin-twin transfusion syndrome receiving fetoscopic guide laser therapy at gestational age of 19 weeks with partial CMS detected at the fifth week (gestational age of 24 weeks) after surgery and resealed 1 week later. There was no more CMS noted till delivery at gestational age of 34 weeks 6 days. CMS after fetoscope surgery may reseal spontaneously.

Successful treatment of premature rupture of membranes after genetic amniocentesis by intra-amniotic injection of platelets and cryoprecipitate (amniopatch): a case report

BACKGROUND AND OBJECTIVES

Iatrogenic premature rupture of membranes (PROM) occurs in approximately 1% of patients after genetic amniocentesis. If membranes do not seal spontaneously, fluid leakage through the vagina may cause infection and pregnancy loss. Intra-amniotic infusion of a platelet concentrate followed by a cryoprecipitate (amniopatch) is a possible therapeutic approach to restore the amnio-corial link and to facilitate the amniotic repair process.

MATERIALS AND METHODS

The autologeous platelet concentrate was produced by apheresis (MCS+, Haemonetics) and contained a total amount of 48 x 10(9) platelets in a volume of 30 ml. The concentration of fibrinogen in our cryoprecipitate (20 ml) was 680 mg/dl. An amniocentesis was performed to apply the amniopatch. The platelet concentrate was administered first followed by the cryoprecipitate.

RESULTS

We report the successful treatment of a 38-year-old woman with ruptured membranes after genetic amniocentesis in the 16th gestational week. Ten days after placement of the amniopatch we found a complete closure of the rupture, and in the 36th week of gestation the patient delivered a healthy infant by Caesarean section.

CONCLUSIONS

Intra-amniotic injection of platelets and cryoprecipitate was a successful and safe therapy for PROM in this patient. Knowledge of the site of rupture is not necessary for the amniopatch, as platelets seem to find their way to the defect and seal it. We consider that amniopatch therapy for iatrogenic PROM is a possible therapeutic alternative for prolonging and preserving pregnancy and improving the fetal outcome.

Only the nose knows: penile hemodynamic study of the perineum-saddle interface in men with erectile dysfunction utilizing bicycle saddles and seats with and without nose extensions

PURPOSE

To investigate the differential impact of straddles (A(ns) and B(ns)) and noseless two-cheek seats (A(ntcs) and B(ntcs)) on penile hemodynamics and perineal compressive forces in subjects who cycle in a stationary bicycle.

MATERIALS AND METHODS

Subjects underwent cavernosal artery peak systolic velocity (CAPSV) measurements after intracavernosal injection of vasoactive agents while supine, sitting upright on an examination table, straddling a saddle, sitting on a seat, and again supine. Mean perineal compression pressures recorded while straddling the saddles were compared with those while sitting upright.

RESULTS

No differences were found in right and left CAPSV values while supine, sitting upright on an examination table, sitting on a seat, and supine again. Right/left CAPSV (cm/second) values straddling A(ns) and saddle B(ns) (0.7 +/- 2.9/1.5 +/- 6.2 and 0/0, respectively) were significantly lower than values obtained while sitting on A(ntcs) and B(ntcs) (25.6 +/- 13.4/23.8 +/- 12.0 and 17.3 +/- 6.4/18.3 +/- 6.5, respectively) (P < 0.001). Mean perineal compression pressures (mm Hg) on A(ns) and saddle B(ns) (315.2 +/- 39 and 387.9 +/- 64.3, respectively) were significantly higher than values obtained while sitting upright on an examination table (47.6 +/- 5.2 and 46.0 +/- 8.1, respectively) (P < 0.001).

CONCLUSIONS

We have identified an objective test to assess if an individual bicycle rider, sitting on a certain shape of bicycle saddle or seat generates sufficient compressive forces at the perineal-saddle interface to obstruct cavernosal arterial inflow. This study also demonstrated that straddling bicycle saddles with nose extensions is associated with perineum-saddle interface compressive pressures that exceed systolic perfusion pressures, significantly diminishing penile hemodynamics.

A histological study of fetoscopic membrane defects to document membrane healing

OBJECTIVE

To evaluate the rate of spontaneous healing in human fetal membranes after fetoscopy.

STUDY DESIGN

Membranes from patients that had undergone fetoscopic interventions and delivered in one of the two treatment centers were included in the study. The membranes were examined macroscopically for any remaining defects and if present, the size of the defect in chorion and amnion was measured. Subsequently, the defect was excised and stained with HE for histological evaluation. Additional immunohistochemical staining was performed with Ki-67, cytokeratin and vimentin. The proliferation index (percentage of proliferating cells) was calculated in amnion and chorion.

RESULTS

Nineteen membrane defects were included in the study. The median time interval between invasive procedures and delivery was 60 days (range 3-112). All fetoscopic defects (n=19) could be identified in the gestational sac and in none spontaneous closure had occurred. Proliferation indices as measured by inmunohistochemistry were very low (median 2.8%, range 0-7%) in the chorion and 0% in the amnion.

CONCLUSION

No evidence of spontaneous membrane healing was found after fetoscopic procedures, suggesting that the membrane defect normally persists until delivery. Absence of amniotic fluid leakage after invasive procedures may be based on mechanisms other than histologic membrane repair.

The Effect on Pregnancy Rate of Progesterone Administration after Manual Reduction of Twin Embryos in Dairy Cattle

Twin pregnancies are undesirable in dairy cattle as they increase the risk of abortion and have many negative effects on the profitability of the herd. The purpose of this study was to evaluate manual reduction of a twin embryo in dairy cows bearing unilateral twins. On day 34 of gestation, 33 cows were assigned to one of three treatment groups (n = 11 for each group): untreated cows (group control), amnion rupture (group AR), and amnion rupture plus treatment (intravaginal progesterone for 28 days) (group ART). A significantly higher (P = 0.0001) pregnancy loss rate was recorded in the AR group (100%, 11/11), than in the ART (54.5%, 6/11) and control (27.3%, 3/11) groups. In the ART group, one embryo survived amnion rupture and the cow bearing it had twins at parturition, while the remaining four cows delivered singletons. Our results suggest that the procedure of rupturing the amnion with progesterone supplementation may provide a satisfactory way for twin reduction in dairy cattle.

In vitro lesion repair by human amnion epithelial and mesenchymal cells

OBJECTIVE

The purpose of this study was to compare wound healing by human amnion epithelial and mesenchymal cells from preterm and term placenta with the use of an in vitro lesion repair assay.

STUDY DESIGN

Lesions were created in confluent monolayers of amnion epithelial and mesenchymal cells from preterm and term placentas. The repair was monitored by the measurement of the lesion area and the response to potential stimulants (platelet-derived growth factor, tumor necrosis factor-alpha, fibrinogen, and phorbol myristate acetate). Cell proliferation was detected with 5-bromodeoxyuridine staining.

RESULTS

Lesion repair was complete within 40 hours in control epithelial cultures from preterm and term placenta but incomplete in mesenchymal cultures (preterm cells, 80%; term cells, 40%). Platelet-derived growth factor, tumor necrosis factor-alpha, fibrinogen, and phorbol myristate acetate did not accelerate repair in either cell type.

CONCLUSION

An in vitro lesion repair assay revealed the differences in lesion repair capacity between amnion epithelial and mesenchymal cells and between mesenchymal cells from preterm and term placenta.

Chorioamniotic membrane separation following open fetal surgery: pregnancy outcome

OBJECTIVE

To review the incidence of posthysterotomy chorioamniotic membrane separation and delivery outcome following open fetal surgery [myelomeningocele (MMC); cystic adenomatoid malformation (CCAM); congenital diaphragmatic hernia (CDH); sacrococcygeal teratoma (SCT)].

STUDY DESIGN

Retrospective review of a maternal population undergoing open fetal surgery at a single tertiary level program (1998-2001) following the initiation of close postoperative ultrasound follow-up for membrane separation. Onset of membrane separation was coded as not present (NP), immediate (<2 weeks) or delayed (>2 weeks) from day of surgery.

RESULTS

Fifty-three charts were reviewed: MMC 43, CCAM 7, CDH 1, and SCT 2. In the MMC group there were 26 NP, 8 immediate, and 9 delayed. Preterm labor occurred in 4 patients with only 2 having had membrane separation. Risk of membrane separation is increased for surgery done at less than 23 weeks gestation (p < 0.005). Delay from MMC surgery to delivery was 11.0, 9.8, 12.0 weeks for NP, immediate, and delay, respectively. In the MMC group, there were 3 neonatal deaths (NND) at 9, 9, and 21 days post surgery (PROM/PTL; chorioamnionitis, PROM/PTL, respectively). No membrane separation was present in the CCAM, CDH, and SCT cases.

CONCLUSIONS

(1) Membrane separation was significantly more likely to occur if surgery was performed prior to 23 weeks. (2) Membrane separation post hysterotomy (17/50 = 34%) may be associated with an increased risk of PROM but not delivery before 30 weeks gestation. (3) Delivery prior to 33 weeks gestation for MMC groups was 12/43 (28%) with 3 NND (7%). (4) Elective delivery at 36-37 weeks gestation was possible for 43% of the fetal surgery population.

Chorioamniotic membrane separation following fetal surgery

OBJECTIVE

As the volume of fetal surgery cases has steadily increased, an increasing incidence of chorioamniotic membrane separation (CMS) has been noted. Due to the potential adverse consequences from this abnormality, we reviewed the last decade of experience with fetal intervention at our institution and examined the incidence and outcomes of fetuses given this diagnosis.

STUDY DESIGN

A retrospective chart review of 75 fetal surgery cases at our institution was performed. Variables analyzed included preoperative, operative, and outcome data. Postoperative ultrasounds were evaluated for the presence of CMS.

RESULTS

Excluding operative deaths, the incidence of CMS was 47%. There were significant differences (p<0.05) in time to delivery (7 vs 5 weeks), cases using a perfusion pump (80% vs 60%), and number of trocars (2.13 vs 1.54) in cases of CMS versus those without. Ultrasounds showed normal to high levels of amniotic fluid in 97% of cases. There was an increased incidence of premature rupture of membranes (63% vs 45%), preterm labor (57% vs 38%), and chorioamnionitis (29% vs 15%) with CMS, but no difference in mortality rate.

CONCLUSION

CMS is a frequent finding following fetal surgery. It is associated with significant morbidity but is manageable with close follow-up in a hospital setting. Following fetal surgery, the finding of CMS can be a life-threatening complication that warrants further study to understand its etiology and prevention.

Effect of amniotic sac puncture on parturition in rat

Pregnant Charles Foster rats were subjected to amniotic sac puncture on day 15 of gestation and the effect was observed on parturition. All the control rats as expected delivered on day 22 of gestation. In the group where all the sacs were punctured, only 12.5% rats delivered on day 22 while rest either failed to deliver (62.5%) or died (25%). In the group with unpunctured sacs at vaginal ends, 75% rats delivered on day 21 while 25% on day 22. In the group with unpunctured sacs at ovarian ends, 75% rats delivered on day 23 and rest 25% failed to deliver. The resorption rates ranged between 61 to 94% in different groups. Malformations were observed only in one pup. The results suggest that amniotic sac puncture interferes with parturition in the form of either failure or delayed parturition. Nonpatency of the birth canal due to puncture induced fetal deaths and tissue adhesions were presumed to be the contributing factors.

Studies of the mechanism of amniotic sac puncture-induced limb abnormalities in mice

The principal advantage of chorionic villus sampling (cvs) over amniocentesis for the determination of the genetic constitution of the embryo is that it may be undertaken earlier in pregnancy. If carried out too early in pregnancy, it has the risk of inducing craniofacial and limb abnormalities, a condition termed the oromandibulofacial limb hypogenesis (OMFL) syndrome in genetically normal infants. It is believed that the defects observed have a vascular origin, possibly due to anoxia of tissues due to fetal blood loss or thrombus formation at the site of biopsy with distal embolization. We believe that this does not adequately explain the findings from the experimental animal literature involving amniotic sac puncture (ASP). Based on these experimental findings, we have hypothesised that (i) the defects observed following cvs may result from the consequences of oligohydramnios following the inadvertent puncturing of the amniotic sac during this procedure, and (ii) that cleft palate and the postural limb defects observed (e.g., clubfoot and clubhand) are secondary to embryonic/fetal compression. Our experimental studies shed new light on the mechanism of induction of the limb defects seen, but particularly syndactyly. Evidence of hypoperfusion of the peripheral part of the developing limb bud is observed, which interferes with apoptosis that occurs in the digital interzones, or induces an abnormal degree of cellular proliferation and/or tissue regeneration in these sites, possibly because of over-expression of critical genes involved in limb pattern specification. Cleft palate, tail abnormalities and abnormalities of sternal ossification are also observed in our model.

The midgestational rabbit as a model for the creation of membrane defects after needle fetoscopy

OBJECTIVES

The aim of the study was to determine whether the pregnant rabbit at mid gestation could be used as a suitable in vivo model for the study of membrane defects after invasive procedures.

STUDY DESIGN

Pregnant rabbits at gestational ages of 22 and 18 days (term is 32 days' gestation) underwent needle insertion with different instrument diameters (1.1 mm, 1.35 mm, 2.0 mm, and 2.7 mm). Two different insertion techniques were evaluated, blind amniotic puncture and puncture through surgically exposed amnion. Membrane integrity, presence of amniotic fluid, and fetal lung/body weight ratio were evaluated at 31 days' gestation.

RESULTS

Among rabbits operated on at 22 days' gestation the amniotic integrity restoration at 31 days' gestation ranged from 46% to 76% in the different diameter and access technique groups, as compared with 98% in untreated sacs (P <.05 for all groups). Fetuses from sacs with persisting membrane defects had oligohydramnios and significantly lower fetal lung/body weight ratios. Survival rates among fetuses operated on at 18 days' gestation were so poor that appropriate statistical analysis was not possible in this group.

CONCLUSIONS

The rabbit at mid gestation can be used as a model to reproduce permanent membrane defects after fetoscopy, reproducing oligohydramnios and pulmonary hypoplasia. This may provide a suitable in vivo model for the study of iatrogenic membrane defects.

Efficacy of fibrin glue for in vitro sealing of human chorioamniotic membranes

OBJECTIVE

To assess the changes in tensile strength properties of artificially punctured chorioamniotic membranes after sealing the defect with fibrin glue, a tissue sealant.

STUDY DESIGN

Chorioamniotic membranes were obtained from 30 term, uncomplicated pregnancies immediately after delivery. Adjacent, same-sized strips were cut from each membrane sample. After baseline tensile strength properties were obtained, identical size holes were made on each strip, and fibrin glue was applied onto half the specimens. Following adequate stabilization of fibrin, tensile strength properties--rupture tension, strain to rupture and work to rupture--were measured.

RESULTS

Membrane puncture decreased the tensile strength characteristics, indicating weakening of the chorioamniotic membranes: Rupture tension (g/cm) dropped from 153.1 +/- 12.3 to 76.8 +/- 15.7; strain to rupture (%) from 193.9 +/- 29.9 to 152.6 +/- 36.8; and work to rupture (g x cm) from 560.8 +/- 51.8 to 239.0 +/- 65.5 (P < .05). Significant increases were noted in rupture tension (116.0 +/- 19.6), strain to rupture (173.5 +/- 30.8) and work to rupture (394.3 +/- 91.3) after application of fibrin glue; however, all three measurements remained less than prepuncture values (P < .05).

CONCLUSION

Fibrin glue effectively improved the structural integrity of artificially punctured chorioamniotic membranes.

Chorioamniotic separation after second-trimester genetic amniocentesis: importance and frequency

PURPOSE

To determine the frequency and importance of chorioamniotic separation (CAS) after second-trimester genetic amniocentesis.

MATERIALS AND METHODS

In part 1 of the study, ultrasonography (US) databases were reviewed for cases of CAS. In part 2, a study population of 388 women undergoing amniocentesis underwent directed US examination for assessment of CAS 15 minutes and/or 2 weeks after amniocentesis. CAS, when present, was graded. A control population consisted of 363 women undergoing amniocentesis in whom the membranes were not assessed.

RESULTS

In part 1, a review of 23,883 records revealed seven cases of complete CAS, with three deaths, two preterm deliveries, and one emergency cesarean section delivery due to fetal distress. In two of these cases, there were extremity deformities at birth. In part 2, CAS was present in 98 (25%) of 388 women at some point. There was no association between CAS and procedural variables. There was no substantial difference in morbidity between patients with and those without CAS, between patients with different grades of CAS, or between the study and control populations.

CONCLUSION

Small degrees of CAS are frequently present after amniocentesis but are not detected because the membranes are not specifically evaluated. Complete CAS is less frequent.

Iatrogenic monoamniotic twins as a complication of therapeutic amniocentesis

BACKGROUND

Therapeutic amniocentesis has been accepted widely as a safe and efficacious way to treat the polyhydramnios-oligohydramnios sequence associated with twin-twin transfusion syndrome.

CASE

A 28-year-old woman, gravida 2, para 1, diagnosed with twin-twin transfusion syndrome at 28 weeks' gestation was treated with serial amniocenteses. The dividing membrane was ruptured inadvertently during therapeutic amniocentesis, with subsequent complete disruption of the amniotic membrane. Iatrogenic monoamniotic twins with cord entanglement and knotting resulted.

CONCLUSION

Creation of monoamniotic twins by disruption of the dividing membrane can be a complication of therapeutic amniocentesis for twin-twin transfusion syndrome. Such disruption may result in the same morbidity and mortality that are seen in naturally occurring monoamniotic twins.

Limb and other postcranial skeletal defects induced by amniotic sac puncture in the mouse

A mouse model for studying the teratogenic effects of amniotic sac puncture has recently been established (MacIntyre et al. 1995), and the anomalies encountered included cleft palate, limb and tail abnormalities, and postural deformities. In order to investigate the underlying mechanism(s) involved, mouse embryos subjected to amniotic sac puncture on day 13 of gestation were examined externally on day 19, then 'cleared' and bulk stained with alizarin red S and Alcian blue to reveal, respectively, their bony and cartilaginous elements. This procedure allowed a comparison to be made between the incidence of soft tissue anomalies of the distal parts of the limbs and the appearance of the underlying skeletal elements. Despite a high incidence of soft tissue (principally digital) anomalies, relatively few skeletal anomalies were encountered. Measurements of intact long bones, and regions of ossification, were made in the major long bones of 'nonexperimental' and 'internal' controls and 'experimental' fetuses that displayed external morphological malformations to establish whether the experimental procedure had a greater effect on the proximal or distal components of the limb skeleton. No significant difference was observed when the ratios of proximal: distal length were compared with those obtained from the control series. The degree of severity of 'clubhand' and 'clubfoot' deformity was determined, and a comparison made between the severity observed on the right and left sides. This analysis revealed that for 'clubhand', the left forelimb was more severely affected than the right forelimb. The incidence of 'clubfoot' deformity was similar between the 2 sides. A possible explanation for this asymmetric effect is provided. An unexpected finding was the abnormal pattern of ossification seen in the sternum of two thirds of the 'experimental' fetuses that displayed external morphological malformations. This abnormal pattern was seen in none of the controls nor in fetuses in the 'experimental' series that displayed no external morphological malformations.

Teratogenic effects of amniotic sac puncture: a mouse model

The possibility of an association between chorionic villus sampling (cvs) and limb abnormalities has prompted a review of the relevant experimental data. Although a vascular aetiology is favoured by many at present, the possibility exists that a proportion of cases may be caused by oligohydramnios secondary to inadvertent amniotic sac puncture. A mouse model of amniotic puncture syndrome has been developed to study the craniofacial and limb abnormalities produced by this procedure. Pregnant mice were anaesthetised and a laparotomy performed. One uterine horn was exteriorised, and the amniotic sacs punctured through the wall of the uterus with either a 21 gauge or a 25 gauge needle. The conceptuses in the contralateral uterine horn acted as controls. The mice were all killed on d 19 of pregnancy (day of finding a vaginal plug = d 1 of pregnancy) by cervical dislocation, and the morphological features of the embryos examined in detail. In a preliminary study, amniotic sac puncture was carried out on d 12, 13, 14, 15 or 16 of pregnancy, with either a 21 or a 25 gauge needle. Since the highest rates of palatal defects and limb deformities were observed following amniotic sac puncture using a 21 gauge needle, when this procedure was carried out on either d 13 or 14 of pregnancy, the main study was undertaken using a 21 gauge needle on these two days of pregnancy. Of 102 embryos in which amniotic sac puncture was carried out on d 13, 53% survived to d 19. Of the latter, 35% had a cleft palate, 61% had one or more morphologically abnormal limbs, and 43% had an abnormal tail. When amniotic sac puncture was carried out on d 14 of pregnancy, of 83 embryos subjected to this procedure, 81% survived to d 19. Of the latter, 27% had a cleft palate, 39% had one or more morphologically abnormal limbs, and 19% had an abnormal tail. In the controls, of 86 and 61 embryos isolated respectively from the d 13 and 14 mice, the survival rates were 97 and 90%, respectively. Palatal, limb and tail abnormalities were not observed in the control series. Tentative relationships are drawn between cvs and amniocentesis-associated abnormalities, the Robin sequence and their rodent phenocopies.

[Extra-amniotic pregnancy. Diagnosis with transvaginal color Doppler]

We report on the early diagnosis of two cases of extraamniotic pregnancy in the first trimester using transvaginal colour Doppler. The flow alterations in trophoblastic and corpus luteum vessels were of low diagnostic significance.

Brief communication: sliding displacement of amnion and chorion following controlled laser wounding suggests a mechanism for short-term sealing of ruptured membranes

The Erbium-YAG laser was used to produce narrow wounds of defined depth in term amniochorion. The charring effect of the laser meant that sites could be readily localized in histological sections. During brief post-wounding incubations, sliding displacement of the amnion relative to the chorion occurred through the plane of the spongy layer. This suggests a possible short-term mechanism whereby a spontaneous rupture could be sealed in vivo.

Pseudomonoamniotic twins with cord entanglement following genetic funipuncture

Amniocentesis was performed twice on a twin gestation, and twice there was cell growth failure in one of the twins. Therefore, funipuncture was attempted at 24 weeks. The anatomical relationship and position of the fetuses, placental cord insertion, and membranous septum dictated needle entry into the cord of the lower left fetus through the sac of the upper right fetus and the septum. The procedure was uneventful and the pregnancy was carried to 39 weeks. However, the septum between the twins had been disrupted, creating a pseudomonoamniotic pregnancy. This was noticed only after delivery of the first fetus, when it was found that the two umbilical cords were entangled. We believe that, whenever possible, puncture of the membrane between twins should be avoided. Should puncture be necessary, the possibility of pseudomonoamniotic twins must be considered.

Amniochorionic bands and adhesions with fetal deformities

The amniochorionic bands and adhesions in 2 malformed human fetuses are described. The anencephaly, left harelip with grossly distorted face, and rudimentary right upper limb of case 1, and multiple pits and cavities in the liver of case 2, are directly attributable to membranous adhesions. The toughness of the bands is indicative of their mesoblastic (chorionic) origin. The histolytic effect on the liver of case 2 may suggest a contact with the trophoblastic cells. The exomphalos of case 1, and extroversion of cloaca with other caudal defects of case 2, are possibly due to vascular and mesodermal deficits imposed by single umbilical artery.