Intrauterine death in multiple gestation

Intrauterine fetal death of a monochorionic twin with peripheral pulmonary infarcts: potential thromboembolic events following death of co-twin

In utero fetal lung infarction has rarely been reported. We present a case of intrauterine lung infarction in a 28-3/7 weeks' gestation monochorionic twin following intrauterine fetal demise of the co-twin at 20 weeks. This case highlights the potential for thromboembolic events (TBEs) associated with monochorionic gestations to include pulmonary TBE and infarction among the risks for fetal morbidity and mortality.

Genetics and developmental pathology of twinning

Twin pregnancy is associated with a high risk of congenital malformations. This review covers the risk of such anomalies in both dizygotic and monozygotic twin pregnancies, and discusses current insights into the associations relating to zygosity, chorionicity and genetic factors. The pathological basis of specific malformations unique to the monochorionic twinning process, including conjoined twinning and twin reversed arterial perfusion (TRAP) sequence, is discussed in more detail, and factors contributing to the higher perinatal mortality rate in multiple pregnancies are addressed.

Medicolegal issues in multiple pregnancy

Any discussion of multiple pregnancy figures prominently in the consideration of the medicolegal aspects of placental pathology. Multiple gestations are common and becoming more so with assisted reproductive techniques, and multiples are associated with a disproportionate share of complications that may result in disputes over quality of care. Higher rates of intrauterine growth retardation, prematurity, stillbirth, morbidity, mortality, cerebral palsy, anomalous development, and malformation as compared with singletons are well documented in multiple pregnancy and should be anticipated. Monochorionic placentation and complications of vascular anastomosis are important factors contributing to poor outcome. Other factors, although occurring in all gestations, are relevant because they are more common in multiple gestations.

Increased prevalence of fetal thrombi in monochorionic-twin placentas

OBJECTIVE

Fetal vessel thrombosis has been related to pregnancy complications and adverse neonatal outcomes in singleton pregnancies, but the clinical and pathologic characteristics of fetal thrombosis in twin pregnancy are still ill defined.

METHODS

To clarify the characteristics of fetal thrombosis in twins, we reviewed the histology slides and medical records of live-born infants of twin pregnancies involving the live birth of at least 1 fetus (monochorionic: 389 cases; dichorionic: 780 cases) and singleton pregnancies (1162 cases).

RESULTS

The incidence of fetal thrombosis in monochorionic-twin pregnancies was significantly higher than that of dichorionic-twin and singleton pregnancies (5.1% vs 3.0% and 2.8%, respectively). The incidence of velamentous umbilical cord insertion in monochorionic- and dichorionic-twin placentas was also higher than in singleton placentas (12% and 7% vs 2%, respectively). Fetal thrombosis in twin placentas was associated with intrauterine growth restriction. In monochorionic twins, fetal thrombosis was associated with co-twin fetal death, but in dichorionic twins no correlation was identified. Microscopically, fetal vessel thrombosis in twin placentas was associated with vascular cushions (fibrous hyperplasia of fetal vessel), as is the case occasionally in singletons.

CONCLUSIONS

The incidence of fetal vessel thrombosis in monochorionic placentas was higher than that seen in dichorionic-twin placentas and singleton gestations. Fetal vessel thrombosis in twin pregnancies showed a correlation with intrauterine growth restriction, peripheral cord insertions, and major vascular cushions.

Fatal fetal hemorrhage and placental pathology. Report of three cases and a new setting

We report three cases of late third trimester fetal death in utero consequent to fetal exsanguination from the chorionic vasculature. In general, fetal hemorrhage is unusual, exsanguination is rare and the location and basis of the hemorrhage varies widely. Intragestational and intrapartum hemorrhage is far more often of maternal rather than fetal origin. Even when severe, the former is almost always manageable whilst the latter may be clinically obscure, intractable, catastrophic and fatal. In this presentation, we review and characterize fetal hemorrhage by anatomical location and on the basis of its underlying origins. In our first two cases, the chorionic vascular failure is understood on the basis of mechanical factors, such as tearing by the presenting part or an amniotomy hook. Our third case demonstrates the first reported instance in which a severe chorionic vasculopathy has damaged a placental surface vessel sufficiently to permit spontaneous rupture and fetal exsanguination.

Haemoglobin differences at birth in monochorionic twins without chronic twin-to-twin transfusion syndrome

OBJECTIVES

To determine the haemoglobin (Hb) differences at birth in monochorionic (MC) twins without chronic twin-to-twin transfusion syndrome (TTTS) in relation to birth order and placental vascular anatomy.

METHODS

All consecutive cases of MC twins without chronic TTTS and dichorionic (DC) twins delivered at our centre and admitted to our neonatal nursery between June 2002 and December 2004 were included in our study. We analysed Hb differences at birth and on day 2, in relation to birth order and placental vascular anatomy.

RESULTS

Forty-five pairs of MC twins and 71 pairs of DC twins were included. Mean Hb differences at birth in MC and DC twins were similar, respectively 1.5 and 1.4 g/dL. Hb differences >5 g/dL at birth were found in 2% (1/45) of MC twins compared to 8% (6/71) in DC twins. On day 2, mean Hb differences in MC twins increased to 3.8 g/dL, and the rate of MC twins with Hb differences >5 g/dL increased to 27% (12/45) (p < 0.001). Mean Hb differences and the percentage of twins with Hb differences >5 g/dL in DC twins did not change on day 2. In MC twins, Hb levels measured on day 2 were significantly higher in second-born twins than in first-born twins, respectively 17.7 and 15.5 g/dL (p = 0.002). Hb differences on day 2 were significantly higher in MC twins with superficial vascular anastomoses than those without superficial anastomoses, respectively 4.0 g/dL and 1.5 g/dL (p = 0.036).

CONCLUSIONS

Hb differences occur more frequently in MC twins without chronic TTTS than in DC twins, but only when measured on the second day of life. Hb differences in MC twins are associated with birth order and superficial vascular anastomoses.

Fetal or infant death in twin pregnancy: neurodevelopmental consequence for the survivor

AIM

To determine the neurodevelopmental morbidity in the surviving twin after fetal or infant death of the co-twin.

METHODS

Twin pregnancies with an antepartum or infant death delivered between 1981 and 1992 were identified from the Northern Perinatal Mortality Survey. Information on the neurodevelopmental morbidity of infant survivors of a deceased co-twin was obtained by a questionnaire sent to the community paediatrician or general practitioner.

RESULTS

A total of 111 children who survived infancy after the fetal death of the co-twin (group 1) and 142 from liveborn twin pairs in which one twin died in infancy (group 2) were traced. Responses were received from 97 (87%) and 130 (92%) respectively. In group 1, the cerebral palsy prevalence was 93 (95% confidence interval (CI) 43 to 169) per 1000 infant survivors; it was more common in like-sex pairs (8/70) with a prevalence of 114 (95% CI 51 to 213) compared with 45 (95% CI 1 to 228) per 1000 infant survivors in unlike-sex pairs (1/22). The overall prevalence of neurodevelopmental morbidity (including developmental delay) was 175 (95% CI 106 to 266) per 1000. In group 2, the cerebral palsy prevalence was 154 (95% CI 84 to 223) per 1000 infant survivors in like-sex (16/104) and 77 (95% CI 9 to 251) in unlike-sex (2/26) survivors; the overall prevalence of neurodevelopmental morbidity was 246 (95% CI 172 to 320) per 1000.

CONCLUSIONS

The risk of cerebral palsy is increased in the surviving twin after a fetal or infant co-twin death compared with the general twin population. Like-sex twins are at greater risk than unlike-sex. The probable cause, in addition to the consequences of prematurity, is twin-twin transfusion problems associated with monochorionicity.

Fetal blood sampling immediately before and within 24 hours of death in monochorionic twin pregnancies complicated by single intrauterine death

OBJECTIVE

Our goal was to investigate the mechanisms that play a role in intrauterine death in monochorionic twins and that contribute to the high perinatal mortality and morbidity in the survivors.

STUDY DESIGN

In 8 monochorionic twin pregnancies complicated by the intrauterine death of a single twin, we took samples from 5 twin fetuses immediately before death and from 4 of their cotwins and also from 4 surviving fetuses within 24 hours after death of the cotwin.

RESULTS

Four of the 5 fetuses sampled who subsequently died were acidemic and 3 were hypoxemic. None of these fetuses or their cotwins were anemic at that time. All 4 survivors sampled within 24 hours of the death of each cotwin had low hematocrits.

CONCLUSION

Fetal anemia, probably the consequence of acute blood loss just before the time of death of the cotwin, may play a role in the high mortality and morbidity found in the surviving twin. It is unlikely that immediate delivery of the surviving twin after death could affect the outcome.

Endoscopic laser coagulation in the management of severe twin-to-twin transfusion syndrome

OBJECTIVE

To assess the clinical effectiveness of endoscopic laser coagulation of placental vessels in the treatment of severe transfusion syndrome.

DESIGN

Prospective study.

SETTING

Three referral centres for the management of twin-to-twin transfusion syndrome.

POPULATION

One hundred and thirty-two pregnancies complicated by severe twin-to-twin transfusion syndrome, reflected by polyhydramnios and enlarged bladder of one twin and oligoanhydramnios and collapsed bladder of the other twin, presenting before 28 weeks of gestation.

METHODS

Prospective collection of data on pre-procedure assessment, the procedure and the follow up were collected prospectively. Laser coagulation of placental vessels crossing the intertwin membrane on the chorionic surface under sono-endoscopic guidance, followed by amniodrainage.

MAIN OUTCOME MEASURES

Maternal and pregnancy complications, perinatal death and morbidity were assessed over the last five years with follow up of survivors.

RESULTS

Endoscopic laser was carried out at a median gestation of 21 weeks. The total number of surviving infants was 144 (55%) and there was at least one survivor in 97 cases (73%). At a minimum age of one year neurological handicap was suspected in six survivors (4.2%).

CONCLUSIONS

The results of this multicentre study are similar to those in our original report on the first 45 cases. In comparison with serial amniodrainage, the survival rate may be similar, but the handicap rate in survivors appears much lower. This study stresses the need for a prospective study comparing these two techniques.

Cerebral palsy and thrombi in placental vessels of the fetus: insights from litigation

Fetal vessels in the placentas of 11 of 15 infants with cerebral palsy contained thrombi. An alternate basis for the injury was identified in the four placentas without thrombi. Autopsy findings in one infant who died at age 1 month confirmed the presence of cerebral thrombi and infarcts. It is concluded that thrombotic events in utero may explain the pathogenesis of many instances of cerebral palsy and that identification of a coagulopathy in parents could potentially identify those at risk and provide a basis for preventive treatment during pregnancy.

Cortical visual impairment caused by twin pregnancy

PURPOSE

To report a possible relationship between twin pregnancy and cortical visual impairment.

METHODS

Three children who had been the products of twin pregnancies were identified as having cortical visual impairment. One child (Patient 2), a dizygotic twin, developed cortical visual impairment after a preterm birth. Two children (Patients 1 and 3), the products of monochorionic pregnancies, developed cortical visual impairment. All children were examined ophthalmologically and neurologically.

RESULTS

An evaluation of the gestations of these children indicates that twin pregnancy per se was probably etiologic in the development of cortical visual impairment. In Patient 2, twin pregnancy probably caused preterm birth and resulting cortical visual impairment. In Patients 1 and 3, twin-to-twin transfusion syndrome was the cause of cortical visual impairment. In Patient 1, fetal demise precipitated an acute twin-to-twin transfusion syndrome.

CONCLUSIONS

Children who show cortical visual impairment at or shortly after birth should be evaluated for the possibility of twin pregnancy. Twin pregnancy increases the risk of neurologic damage, including damage to the visual cortex, to optic radiations, or both.

The sequential in utero death of heterokaryotic monozygotic twins. A case report and literature review

A case of monozygotic twins in a 19-year-old primigravida is presented. Ultrasound examination at 15 weeks' gestation showed one twin to have a cystic hygroma and hydrops fetalis. The other twin appeared normal. The twins appeared to occupy the same amniotic cavity. Fluid was taken from the cystic hygroma under ultrasound guidance for karyotyping and this showed 45,XO chromosomes. Conservative management was adopted. Serial ultrasound examination showed deteriorating hydrops and at 26 weeks the first twin died. Intensive monitoring of the remaining twin was undertaken with weekly ultrasound, cardiotocography (CTG), and clotting screens. At 29 weeks' gestation the CTG and clotting were normal, but ultrasound revealed that multicystic encephalomalacia had developed in the second twin. A very thin dividing membrane was seen for the first time between the twins. The parents decided to terminate the pregnancy. Prior to an intracardiac potassium chloride injection, a fetal blood sample was taken which revealed 46,XX chromosomes and a normal clotting screen including natural anticoagulant levels. Labour was then induced. Delivery took place 5 h later and the woman made an uneventful recovery. The mechanism for genetic differences between monozygotic twins is discussed and the literature reviewed. A non-disjunction event around the time of splitting of the twins is proposed as the cause. The prognosis for the remaining twin is also discussed, as is the pathogenesis of the cerebral damage.

Determinants of stillbirth mortality in Greece

A population-based case-control study of the determinants of stillbirths was conducted in Greece from 1989 to 1991. All reported stillbirths after 28 weeks of pregnancy (N = 2,006) during the three year study period comprised the case group. The control group derived from random sampling of 10% of all livebirths in Greece, during the same period (N = 30,705). The data were analysed by modelling through multiple logistic regression. The adjusted relative risk of stillbirth was significantly higher for males compared to females. A statistically significant monotonic increase in relative risk was observed with shorter gestational age, low maternal education, and older maternal age. Birthweight and parity showed a statistically significant U-shaped association with stillbirth risk, with a higher risk being observed among both low and high birthweight deliveries, as well as among primiparous or multiparous (4+) mothers. Positive associations of stillbirth with multiple births, out-of-wedlock marriage and non-Greek-orthodox maternal religion were noted in crude analyses, but these associations almost disappeared in logistic regression model. Maternal urban or rural residence showed no relation to risk. Overall, the prospective risk of stillbirth after the 24th week of gestation in Greece has been estimated to be higher than that in Japan (a more developed country) with more than 40% of stillbirths occurring after the 36th week of pregnancy.

The assessment of the umbilical blood flow of the surviving twin after the intrauterine death of the other twin

This paper summarizes our experience with Doppler velocimetry in survivors of intrauterine co-twin demise. In the first trimester, ten dichorionic deaths occurred; none of the survivors developed flow disorders. During the second trimester, there were three intrauterine demises, two of them were monochorionic and the survivors developed flow disorders: one presented transitory venous flow aberration, the other one an impaired development of diastolic flow. In the third trimester, two intrauterine deaths occurred. One case of twin to twin transfusion syndrome (TTTS) was complicated by the donor's death and the recipient showed a loss of diastolic flow. The second one happened during a dichorionic twin pregnancy. The survivor presented high systolic/diastolic daily ratio (S/D = 7.8).

The biology of the twinning process: how placentation influences outcome

Placentation of twins has important bearing on the fetal development and neonatal outcome. Because of limitation in space of the endometrial cavity, twin placentas frequently collide during their expansion. This may restrict their growth and also lead to a somewhat increased rate of placenta previa. Moreover, abnormal cord insertions such as marginal and velamentous cords are much more frequent in multiple gestation. Absence of one umbilical artery is also much more frequent in twins. The best prognosis is had when two independent placentas develop, the dichorionic separate organs. Fusion of two separate placentas does not lead to vascular anastomoses in human twins, whereas it often does in other species (marmoset, cattle). Blood vessel fusion occurs only in monochorionic twins, all of which are "identical" (monozygotic). Large anastomoses (usually artery-to-artery) allow blood to shift rapidly from one to the other. Thus, when one twins dies, the survivor may quickly exsanguinate into the dead twin, leading to hypotension and occasionally to cerebral palsy. Arteriovenous anastomoses are the basis for the twin transfusion syndrome. This results in severe prematurity and gross discordance of all sorts of physical parameters. Knowing this type of vascular shunts helped develop the prenatal laser obliteration with salvage of the twins. The worst prognosis occurs with the rarest type of placentation in twin, in which both reside in the same cavity. This is the monoamnionic-monochorionic twin placentation. By moving about, the twins often entangle their umbilical cords and some 40% to 50% may die in utero.

Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome

OBJECTIVE

We undertook a pilot study to determine the feasibility and efficacy of fetoscopic laser occlusion of chorioangiopagous vessels in severe previable twin-twin transfusion syndrome.

STUDY DESIGN

A total of 35 patients were referred to the investigators with ultrasonographic findings consistent with twin-twin transfusion syndrome, posterior placental implantation, gestational age < 25 weeks, and clinical hydramnios. Placental vessel occlusion was performed with a rigid 2.9 x 3.85 mm dual-channel fetoscope and neodymium:yttrium-aluminum-garnet laser light.

RESULTS

Of the original 35 patients, 5 were eliminated preoperatively and 4 intraoperatively for various factors. The 26 treated patients had a mean gestational age of 20.8 weeks (range 18 to 24) and a mean fundal height of 36.1 cm (range 29 to 44). One patient has surviving triplets, 8 have surviving twins, 9 have a single survivor (2 neonatal and 7 fetal deaths occurred in this group), and 8 have no survivors (all had pregnancy loss within 3 weeks of treatment). The cases with survivors were delivered for obstetric indications at a mean of 32.2 weeks (range 26 to 37), having gained a mean of 11.7 weeks (range 6 to 17) in utero. Fifty-three percent (28/53) of the fetuses survived with 96% (27/28) developing normally at a mean age of 35.8 months (range 1 to 68). Thirty-three of 35 placentas were monochorionic with chorioangiopagous vessels on gross and microscopic evaluation.

CONCLUSIONS

Fetoscopic laser occlusion of chorioangiopagous vessels is technically feasible and improves the course and outcome of severe twin-twin transfusion syndrome in previable fetuses.