Management of twin pregnancies discordant for anencephaly

Objective To examine options of management and outcome of twin pregnancies discordant for anencephaly.
Design Retrospective study.
Setting Research Centre for Fetal Medicine.
Population Twenty-four twin pregnancies discordant for anencephaly.
Methods A computer search was made of our database for twin pregnancies discordant for anencephaly. The data were reviewed for gestation at presentation, chorionicity, management and pregnancy outcome.
Main outcome measures Pregnancy outcome in relation to chorionicity and management.
Results There were 13 dichorionic and 11 monochorionic twin pregnancies discordant for anencephaly. In the dichorionic group five pregnancies had selective fetocide at 17 to 21 weeks; one pregnancy resulted in spontaneous abortion but in the others a healthy infant was born at a median gestation of 37 weeks. The other eight dichorionic pregnancies were managed expectantly, but three developed polyhydramios at 26 to 30 weeks; in one case amniodrainage was performed and in another selective fetocide was carried out. In this group the median gestation at delivery was 35 weeks. All 11 monochorionic pregnancies were managed expectantly and in three there was intrauterine death of both fetuses. In the other eight cases the normal twin was liveborn at a median gestation of 34 weeks; in four of these pregnancies polyhydramnios developed and two were managed by amniodrainage.
Conclusions In monochorionic pregnancies, expectant management is associated with a high rate of intrauterine lethality of the normal twin. In dichorionic pregnancies selective fetocide in the second trimester prevents the development of polyhydramnios and is associated with a lower risk of preterm delivery but can cause miscarriage.     

Screening for trisomy 21 in twin pregnancies by maternal age and fetal nuchal translucency thickness at 10–14 weeks of gestation

Objective To determine the prevalence of increased fetal nuchal translucency thickness in twin pregnancies and to evaluate screening for trisomy 21 by a combination of translucency thickness and maternal age.
Design Prospective screening study at 10 to 14 weeks of gestation.
Setting Fetal Medicine Centre.
Population 22,518 self-selected pregnant women at 10 to 14 weeks of gestation, including 21,477 singleton and 448 twin pregnancies with live fetuses.
Methods Fetal nuchal translucency thickness was measured by ultrasound examination at 10–14 weeks. Sensitivity and false positive rates of screening for trisomy 21 by a combination of fetal nuchal translucency thickness and maternal age were calculated.
Main outcome measures Prevalence of increased nuchal translucency thickness and detection of trisomy 21.
Results In the 448 twin pregnancies the nuchal translucency thickness was above the 95th centile of the normal range (for crown-rump length in singletons) in 65/896 fetuses (7.3%), including 7/8 (88%) with trisomy 21. Increased translucency was also present in four fetuses with other chromosomal abnormalities. In the chromosomally normal twin prebmancies the prevalence of increased nuchal translucency was higher in fetuses from monochorionic (8.4%; 16/190) than in those with dichori-onic pregnancies (5.4%; 37/688). The minimum estimated risk for trisomy 21, based on maternal age and fetal nuchal translucency thickness, was 1 in 300 in 19.5% (175/896) of the twins including all eight of those with trisomy 21.
Conclusions In twin pregnancies the sensitivity of fetal nuchal translucency thickness in screening for trisomy 21 is similar to that in singleton pregnancies, but the specificity is lower because translucency is also increased in chromosomally normal monochorionic twin pregnancies.     

Nonconventional approach to twin pregnancies complicated by extremely preterm premature rupture of membranes of one twin

The common management in most centers in cases of multiple pregnancies with preterm premature rupture of membranes (PPROM) before 22 weeks of gestation is termination of the pregnancy or the expectant approach. Expectant management of previable PPROM in twin pregnancies results in an increased rate of fetal and neonatal morbidity and mortality of both twins. Selective fetocide of the twin with early midtrimester rupture of membranes may improve the unfavorable pregnancy outcome of the remaining fetus. We report two successful cases of twin pregnancies complicated by extremely PPROM managed by selective fetocide of the affected twin, with an uneventful single pregnancy course and delivery of healthy newborns at 36 weeks of gestation.     

First-trimester maternal serum PAPP-A,SP1 and M-CSF levels in normal and trisomic twin pregnancies

OBJECTIVE: To study PAPP-A and SP1 for biochemical trisomy screening in twin pregnancies and to investigate the role of maternal and placental compartments in marker production by comparing the levels of the decidual cytokine M-CSF with the PAPP-A and SP1 from the placenta. METHODS: Thirteen twin pregnancies with at least one chromosomally abnormal fetus were compared with 68 normal twin pregnancies. Sera were obtained between 11 + 3 and 13 + 6 weeks of gestation, and PAPP-A, SP1 and M-CSF levels were determined by immunoassay. These concentrations were also compared with gestation-matched groups of 18 singleton normal pregnancies and 18 singleton Down syndrome pregnancies. RESULTS: PAPP-A and SP1, but not M-CSF, levels were higher in normal twin pregnancy than in normal singleton pregnancy. SP1 levels, but not PAPP-A, correlated to M-CSF. PAPP-A, but not SP1, levels were reduced in abnormal twin pregnancies, with an increasing effect according to the number of affected fetuses, and were more pronounced in pregnancies with trisomy 18 or 13 than in trisomy 21 fetuses. M-CSF was inconsistent, with a trend towards increased levels in trisomy 21. CONCLUSION: PAPP-A remains the best biochemical screening marker for fetal trisomies 21, 18 or 13, in singleton as well as in twin pregnancy. In contrast to SP1, its site of production is not likely to be restricted to the placenta. The role of the (maternally produced) M-CSF remains to be further investigated.     

Histomorphological features of chorionic villi at 10-14 weeks of gestation in trisomic and chromosomally normal pregnancies

This study examines histomorphometric features in chorionic villi obtained by chorionic villus sampling (CVS) at 11-14 weeks of gestation from 124 ongoing pregnancies (38 with trisomy 21, 14 with trisomy 18, 11 with trisomy 13 and 61 chromosomally normal controls). In the trisomy 21 group there was an inverse relationship between fetal nuchal translucency thickness (NT) and villus diameter and number of capillaries per villus cross-section. In about half of the cases there was perivillous fibrinoid present, and the amount of this increased with gestation. Compared to the chromosomally normal group, in trisomy 18 the villus diameter was smaller and the number of capillaries per villus cross-section was reduced. In the trisomy 21 group, villi had an increased percentage of two layered trophoblast present and an increased proportion of villus capillaries with nucleated red blood cells present. In all three trisomies, but particularly in trisomies 18 and 13, both the amount of basophilic stippling of the basement membrane and the proportion of cases with stippling was increased. These results provide data on the possible mechanisms of increased fetal NT and on abnormal placental development in fetal trisomies.     

Growth hormone binding protein in normal and aneuploid pregnancy: a paradoxical decrease in trisomy 18

Objective To explore whether abnormalities in growth hormone binding protein (GHBP) may underlie the growth restriction associated with fetal aneuploidy.
Design A retrospective casecontrol study.
Setting Monash Medical Centre, Clayton, Victoria, Australia.
Population Twenty-one trisomy 18, and 30 trisomy 21 pregnancies, and 170 chromosomally normal pregnancies at 15–18 weeks of gestation representing three to five controls per case matched for source, gestation and duration of storage.
Methods GHBP was measured using a ligand immunofunctional assay
Results In the chromosomally normal pregnancies GHBP levels decreased slightly but significantly across the narrow gestational window studied. Compared with controls, levels of GHBP, expressed as median (95% CI) multiples of the median (MoM), in the trisomy 21 pregnancies were similar, 1.0 (0.92–1.39) MoM and 1.27 (1.04–1.50) MoM, respectively; P =0.061 (Mann-Whitney U test) but were significantly reduced in the trisomy 18 pregnancies, 0.68 (0.51–0.84) MoM; P =0.0014 (Mann-Whitney U test).
Conclusions These data suggest that decreased levels of maternal growth hormone binding protein, and by implication growth hormone receptor complement, may underlie the early severe growth restriction that is characteristic of trisomy 18.     

Discordant lower urinary tract obstruction in early twin gestations: management and outcome

OBJECTIVE: To report our experience with the management of twin pregnancies discordant for lower urinary tract obstruction. METHODS: Cases of twin pregnancies discordant for lower urinary tract obstruction were identified from our fetal medicine database. Information on ultrasonographic findings, antenatal course, pregnancy complications, and perinatal outcome was obtained by reviewing medical records or contacting the referring obstetricians. RESULTS: Five twin pregnancies discordant for lower urinary tract obstruction were diagnosed between 11 and 15 weeks of gestation. There were 3 dichorionic and 2 monochorionic pregnancies (1 diamniotic and 1 monoamniotic). The dichorionic pregnancies were managed conservatively, resulting in a pregnancy loss of both twins in 1 case, a single fetal death at 29 weeks in 1 case, and an early neonatal death due to lung hypoplasia of the affected twin in 1 case. On the other hand, both monochorionic twin pregnancies were managed with serial vesicocenteses. In both cases, the prenatal course was complicated, 1 by premature rupture of the membranes and the other by cord entanglement, requiring delivery at 29 and 31 weeks, respectively. Among the 4 continuing pregnancies with complete perinatal outcome, none of the affected twins survived, and the structurally normal twins were delivered between 29 and 36 weeks and discharged from the hospital in good condition. CONCLUSION: Twin pregnancies discordant for lower urinary tract obstruction are at high risk of perinatal death and premature delivery. Prenatal intervention seems not to be associated with an improved perinatal outcome of the affected twin, but it may be beneficial in selected cases to attain viability of the unaffected twin.     

Fetal blood chromosome analysis: some new indications for prenatal karyotyping

Prenatal karyotyping using stimulated fetal blood lymphocytes was undertaken in 170 pregnancies between 16 and 36 weeks gestation for the following reasons--mosaicism or marker chromosomes found in amniotic fluid culture; a family history of X-linked mental retardation with fragile Xq28; fetal abnormalities detected ultrasonographically; late booking or amniotic fluid culture failure in patients with advanced age or balanced translocations; and twin pregnancies discordant for a chromosomal anomaly. Forty-one karyotypic abnormalities were detected (24%). These were: 45,X (7 cases), trisomy 13 (5 cases), trisomy 18 (6 cases), trisomy 21 (4 cases), twin pregnancy where one twin had trisomy 21 (1 case), supernumerary marker chromosome (3 cases, one of which occurred in a twin pregnancy), triploidy (3 cases), X-linked mental retardation with fragile site at Xq28 in males (6 cases), fetal erythroleukaemia (3 cases including 2 cases with Turner's), Fanconi's anaemia (1 case), unbalanced chromosome translocation 47,XY+der22,t(11;22) mat (1 case), mos 46,XX18p-/46,XX,-18+i(18q) (1 case), 46,XXdel(2q) (1 case), and 46,XYt(5;17) de novo (1 case). In fetuses at high risk of a chromosome aberration, a rapidly obtained karyotype is helpful and fetoscopy and fetal blood sampling are justified in the second or third trimester.     

Serum parameters and nuchal translucency in first trimester screening for fetal chromosomal abnormalities

Objective To assess the relation between serum parameters and nuchal translucency in pregnancies affected by fetal aneuploidy in the first trimester.
Design Retrospective study of different serum parameters collected prior to chorionic villus sampling and measurement of nuchal translucency in relation to fetal aneuploidy.
Setting Switzerland (German and Italian sector) and Bregenz, Austria.
Population One thousand one hundred and fifty-one women aged 25 to 44 years at 10 to 13 weeks of gestation undergoing chorionic villus sampling, mostly for advanced maternal age. Fetal aneuploidy was found in 23 pregnancies including four cases of trisomy 21, five of trisomy 18 and one case of trisomy 13.
Main outcome measure Fetal karyotype, serum levels of free β-hCG, pregnancy-associated plasma protein A (PAPP-A) and alpha-fetoprotein and the measurement of nuchal translucency.
Results Serum PAPP-A was decreased in all common chromosomal abnormalities. Free β-hCG levels were increased in trisomy 21 but decreased in trisomy 18, whereas alpha-fetoprotein was low in trisomy 21, 18 and other chromosomal abnormalities. Nine of twenty-three abnormal embryos had evidence of an increased nuchal translucency. Nuchal translucency, however, did not seem to be associated with any alteration in the levels of the biochemical parameters in either chromosomally normal or abnormal embryos. A low serum PAPP-A or an increased nuchal translucency was seen in two-thirds of all pregnancies with chromosomal abnormalities.
Conclusion A nuchal translucency 3 mm and depressed serum PAPP-A levels have a good predictive value in the detection of fetal aneuploidy at 10 to 13 weeks of pregnancy. Serum free 0-hCG and alpha-fetoprotein levels may give additional information. An increased nuchal translucency was not-associated with altered serum parameters. This would allow these different markers to be used in combination.     

Fetal karyotyping in twin pregnancies: selection of technique by measurement of fetal nuchal translucency

Objective To examine the usefulness of selecting the appropriate techque for fetal karyotyping in twin pregnancies by using maternal age and fetal nuchal translucency thickness to determine risk for chromosomal defects in each fetus.
Setting Fetal Medicine Centre, London, United Kingdom.
Subjects Sixty-seven twin pregnancies identified at the time of an ultrasound scan for determination of fetal nuchal translucency thickness, where the parents requested karyotyping.
Intervention The risk for chromosomal defects in each fetus was calculated from the maternal age and fetal nuchal translucency thickness at 10 to 14 weeks of gestation. If the estimated risk for either fetus was 1 in 50 or greater, chorion villus sampling was the method of choice, whereas if the risk was less than 1 in 50 second trimester amniocentesis was performed.
Results The estimated risk for trisomies was more than 1 in 50 in 34 pregnancies and 23.5% of these fetuses were found to be chromosomally abnormal. In contrast, in the 33 low risk pregnancies chromosomal abnormalities were found in only 1.5% of the fetuses.
Conclusions In twin pregnancies the technique for fetal karyotyping may be selected by calculating the risk for chromosomal abnormality based on maternal age and fetal nuchal translucency thickness.     

Absence of fetal nasal bone and aneuploidies at first-trimester nuchal translucency screening in unselected pregnancies

OBJECTIVES: The absence of nasal bone (NB) has been noted in trisomy 21 fetuses at first-trimester ultrasound, in high-risk pregnancies. In this study, the nasal bone was evaluated in relation to fetal karyotype, in unselected pregnancies. METHODS: From September 2001 to September 2002, the fetal facial profile was examined at the 11 to 14 weeks' scan for screening by nuchal translucency (NT). Risks for trisomy 21 were calculated using the Fetal Medicine Foundation's software, and the presence or absence of NB was noted. Prenatal karyotype and pregnancy outcomes were recorded. RESULTS: NT screening was performed in 5532 fetuses from 5425 pregnancies (85 twins, 8 triplets, 2 quadruplets). The visualization of fetal profile was obtained in 5525 fetuses (99.8%), and in 5491 fetuses (99.4%) the NB was present and in 34 cases (0.6%) it was absent. Fetal karyotype and pregnancy outcome were available in 3503 pregnancies, and 40 chromosomal abnormalities were diagnosed (27 trisomies 21, 5 trisomies 18, 2 trisomies 13, 3 Turner syndromes, 1 partial trisomy 9 and 2 others). The NB was absent in 19 (70%) trisomies 21, 4 trisomies 18 (80%), 2 Turner syndromes (66%), in the partial trisomy 9, in 7 normal karyotype fetuses (0.2%), and in a case with spontaneous first-trimester abortion before prenatal diagnosis. A significant difference was found between NT thickness, expressed as a multiple of the median, in trisomy 21 fetuses with present and absent nasal bone. CONCLUSIONS: The absence of NB at 11 to 14 weeks is more frequent in fetuses with trisomy 21 and other aneuploidies than in normal karyotype fetuses.     

Fetal blood chromosome analysis: some new indications for prenatal karyotyping

Summary. Prenatal karyotyping using stimulated fetal blood lymphocytes was undertaken in 170 pregnancies between 16 and 36 weeks gestation for the following reasons-(1) mosaicism or marker chromo somes found in amniotic fluid culture; (2) a family history of X-linked mental retardation with fragile Xq28; (3) fetal abnormalities detected ultrasonographically; (4) late booking or amniotic fluid culture failure in patients with advanced age or balanced translocations; and ( 5 ) twin pregnancies discordant for a chromosomal anomaly. Forty-one karyotypic abnormalities were detected (24%). These were: 45,X (7 cases). trisomy 13 ( 5 cases), trisomy 18 (6 cases), trisomy 21 (4 cases), twin pregnancy where one twin had trisomy 21 (1 case), supernumerary marker chromosome (3 cases, one of which occurred in a twin pregnancy). triploidy (3 cases), X-linked mental retardation with fragile site at Xq28 in males (6 cases), fetal erythroleukaemia (3 cases including 2 cases with Turner's), Fanconi's anaemia (1 case), unbalanced chromosome translocation 47,XY+der22,t(l1;22) mat (1 case), mos 46,XXI8p-/46,XX.-18,+i(l8q) (1 case), 46,XXde1(2q) (1 case), and 46,XYt(5;17) de novo (1 case). In fetuses at high risk of a chromosome aberration. a rapidly obtaincd karyotype is helpful and fetoscopy and fetal blood sampling are justified in the second or third trimester.     

Interphase FISH--assisted second-trimester termination of a trisomy 21 fetus in an IVF-ET twin pregnancy. A case report.

BACKGROUND: When confronting a dizygotic pregnancy with one fetus affected with chromosomal aberrations, most couples would opt for selective termination of the affected twin. CASE: Routine genetic amniocentesis was performed for an in vitro fertilization-embryo transfer twin pregnancy at 18 weeks' gestation due to advanced maternal age. After two weeks, cytogenetic analysis revealed that both twins were male and one was affected with trisomy 21. At that time, ultrasound examination could not tell them apart with certainty. With the aid of interphase fluorescence in situ hybridization (FISH), we had no trouble locating the affected twin and performed feticide successfully with an intracardiac potassium chloride injection. At 37 weeks of gestation, a normal male was delivered along with a macerated trisomy 21 fetus. CONCLUSION: In a dizygotic twin pregnancy discordant for chromosome aberrations, when ultrasound cannot distinguish the affected twin, performing interphase FISH with an appropriate chromosome probe proves very useful in quickly and accurately locating the chromosomally abnormal twin for selective termination.     

Screening for chromosomal abnormalities in the first trimester using ultrasound and maternal serum biochemistry in a one-stop clinic: a review of three years prospective experience

Objective To evaluate the performance of a one-stop multidisciplinary clinic of screening for fetal chromosomal anomalies in the first trimester of pregnancy by a combination of maternal serum biochemistry and ultrasonography.
Design Retrospective review of screening performance.
Setting District General Hospital maternity unit.
Population All women booked for routine antenatal care at Harold Wood Hospital between 1 June 1998 and 31 May 2001. The population included 12,339 women with singleton pregnancies presenting at 10–14 weeks of gestation.
Methods Women were offered screening using a combination of maternal serum free β-hCG and pregnancy associated plasma protein-A (PAPP-A) and fetal nuchal translucency thickness. Those with an estimated risk of  ≥1 in 300  of carrying a fetus with trisomy 21 or trisomy 18 or trisomy 13 were offered the option of an invasive diagnostic test. Follow up of the outcome of all pregnancies was carried out.
Main outcome measures Uptake of screening and invasive testing, detection rate for fetal chromosomal abnormalities and false positive rate.
Results The uptake of first trimester screening was 97.5% and the uptake of invasive testing in the increased risk group was 77%. The rate of detection of trisomy 21 was 92% (23 of 25), of trisomy 13 or 18 was 100% (all 15) and of all aneuploidies was 96% (49 of 51). The false positive rate was 5.2%.
Conclusion First trimester screening for trisomy 21 and other aneuploidies can be delivered in an efficient manner in a one-stop multidisciplinary clinic. The detection rates are far better than can be achieved by second trimester serum screening.     

Umbilical artery pulsatility index in early pregnancies with chromosome anomalies

Objective The aim of our study was to obtain measurements of the umbilical artery pulsatility index in pregnancies before invasive procedures for prenatal diagnosis, to investigate its potential prognostic value in predicting chromosomal abnormalities.
Design A prospective study.
Participants Nine hundred and twenty-four consecutive women with singleton pregnancies between 10 and 18 weeks of gestation who underwent chorionic villus sampling (   n = 385  ) or genetic amniocentesis (   n = 539  ). All Doppler measurements were obtained by a single investigator before the invasive procedure. Pregnancies where structural malformations were detected by ultrasound were excluded.
Results Twenty-six fetuses with chromosomal anomaly, including 12 with trisomy 21, were diagnosed. Using the 90th centile in umbilical artery pulsatility index values as a cut-off for trisomy 21 the detection rate was 66.6%, with a specificity of 90.4% and a positive predictive value (defined as the proportion of unaffected individuals with positive results, 1-specificity) of 8.8%. However, with this cut-off the false positive rate was 9.6%. All 19 chromosomally normal pregnancies in which a fetal loss occurred after the procedure had a normal umbilical artery pulsatility index before it was carried out.
Conclusions These preliminary data suggest that trisomic fetuses have an abnormally increased umbilical artery pulsatility index in early pregnancy. Because the number of cases is too small to draw any firm conclusions, the use of a single measurement for screening purposes needs to be confirmed by further investigation and the clinical significance of reference curves of normal values in the detection of pathological conditions has still to be determined. The potential of umbilical artery pulsatility index as an additional parameter along with others previously established for Down's syndrome screening, such as nuchal oedema, needs to be explored further.     

The use of lidocaine for fetocide in late termination of pregnancy

Objective To assess the use of lidocaine (1%) to induce permanent fetal cardiac asystole for fetocide in late termination of pregnancy.
Design Prospective observational study.
Setting One tertiary referral fetal medicine unit in France.
Sample Fifty patients undergoing termination of pregnancy between 20 and 36 weeks of gestation for severe abnormalities or severe maternal conditions.
Methods Fetocide was performed by umbilical vein puncture under ultrasound guidance with injection of sufentanil (5 μg) followed by 7 to 30 mL of lidocaine (1%).
Main outcome measures Percentage of successful procedures to obtain permanent fetal cardiac asystole and maternal side effects.
Results The procedure was successful in 92% of cases (46/50) with complete cessation of heart activity. The mean amount of lidocaine was 15.3 (6.5) mL. In three cases, fetocide was performed by cardiocentesis and in one case lidocaine was unsuccessful and fetocide was performed with KCl. There were no maternal side effects.
Conclusion Lidocaine is an effective drug to perform fetocide with doses below the toxic dose for the mother.     

Complicated monochorionic twin pregnancies: experience with bipolar cord coagulation

OBJECTIVE: The purpose of the study was to evaluate our experience with ultrasound-guided bipolar diathermy forceps for cord occlusion in complicated monochorionic twin pregnancies. STUDY DESIGN: Seventeen consecutive cases were included: 9 cases were twin-to-twin transfusion syndrome; 2 cases were twin reversed arterial perfusion syndrome, and 6 cases were discordant for fetal abnormality. Bipolar diathermy was performed under local anesthetic with the use of 3-mm forceps with ultrasound guidance. RESULTS: Cord occlusion was successfully accomplished in all cases between 18 and 27 weeks' gestation. There were 2 deaths of the co-twin within 12 hours; 1 death was due to cord hemorrhage, and 1 death was unexplained. One neonatal death occurred after delivery at 27 weeks, and 1 woman with twin-to-twin transfusion syndrome elected termination of pregnancy when hydrocephaly was diagnosed 7 days after the procedure (probably related to the underlying pathologic condition). All other co-twins are alive and well, although 2 pregnancies were complicated by preterm delivery and premature rupture of membranes before 30 weeks' gestation. CONCLUSION: Bipolar diathermy is an effective procedure for cord occlusion, although it still has significant morbidity and mortality rates.     

Amniotic fluid levels of human chorionic gonadotropin and its alpha and beta subunits in second-trimester chromosomally abnormal pregnancies.

Amniotic fluid from 135 pregnancies was assayed for human chorionic gonadotropin (hCG) and its free alpha (ahCG) and free beta (bhCG) subunits. Forty-six chromosomally abnormal pregnancies between 14 and 20 weeks' gestation were matched with 89 chromosomally normal samples. Compared with controls, trisomy 21 pregnancies exhibited significantly elevated levels of all three peptides, whereas trisomy 18 gestations gave rise only to significant elevation of ahCG. Female fetuses in both the trisomy 21 and trisomy 18 pregnancies provided significantly elevated levels of hCG and bhCG compared to their male counterparts. On converting the values to multiples of the median, it was determined that 6 of 7 trisomy 18 samples had abnormally elevated alpha/beta ratios, as did 6 of 21 Down's syndrome pregnancies. Further, 11 of 21 trisomy 21 gestations had abnormal amniotic fluid hCG levels. Using only ahCG, bhCG and their ratio, a 61 per cent sensitivity was found for these trisomies, with a 96 per cent specificity.     

Maternal serum free β-hCG at 10 to 14 weeks of gestation in trisomic twin pregnancies

Maternal serum free β-hCG was measured at 10 to 14 weeks of gestation in 136 normal twin pregnancies and in 12 twin pregnancies where one or both fetuses had trisomy 21. The values were compared with a normal range from 4181 singleton pregnancies. In the normal twins the median free β-hCG (65 ng/mL) was about twice as high as in singletons (34 ng/mL z =−12.1,   P < 0.0001  ). In the trisomy 21 group the median free β-hCG (95 ng/mL) was significantly higher than in normal twins ( z = 2.1,   P < 0.05  ). However, only one of the trisomic pregnancies had a level above the 95th centile. In twin pregnancies maternal serum free β-hCG at 10 to 14 weeks of gestation is unlikely to be useful in the prediction of fetal trisomy 21.     

Outcome of anaemic monochorionic single survivors following early intrauterine rescue transfusion in cases of feto-fetal transfusion syndrome

Objective  To evaluate the outcome of severely anaemic monochorionic (MC) twins surviving the death of their co-twin following early intrauterine rescue transfusion in cases of feto-fetal transfusion syndrome (FFTS).
Study design  We reviewed all MC pregnancies complicated with FFTS following primary management, in which a single intrauterine fetal death (IUFD) was diagnosed with certainty within 24 hours between January 1999 and December 2006. We included MC survivors who presented ultrasound or Doppler features of fetal anaemia following the death of their co-twin. Intrauterine transfusion (IUT) was given to all survivors who were anaemic.
Results  Nineteen MC twin pregnancies presented a single intrauterine death (IUD) associated with an anaemic co-twin. Median gestational age at IUD was 23 [20–28] weeks. The median interval between IUD and IUT was 12 [8–24] hours. There were 58% (11/19) healthy survivors. Perinatal death rate was 26% (5/19) including 16% (3/19) intrauterine and 10% (2/19) neonatal deaths. Abnormal prenatal cerebral findings developed in 21% (4/19) cases, always within 1 month after the death of the co-twin. Considering occlusive techniques and other management separately, there were 64% (7/11) and 50% (4/8) healthy survivors, respectively, and perinatal death occurred in 36% (4/11) and 12.5% (1/8) of fetuses, respectively. Prenatal fetal cerebral lesions developed in 9% (1/11) of cases following occlusive techniques and in 37.5% (3/8) of fetuses when managed differently. The median gestational age at delivery in the survivors was 31 [25–38] weeks.
Conclusion  In cases of FFTS with single anaemic survivors, early IUT could be offered following extensive counselling and close follow up.