Prenatal diagnosis for multiple pregnancies

[Perinatal issues of biamniotic twin pregnancies depending on gestational ages of selective termination]

OBJECTIVES

A severe fetal abnormality is found in 1-2% of biamniotic twin gestations leading to the dilemma of expectative management or selective termination of the defective fetus. The primary objective of our study was to determinate the relationship between perinatal outcomes and gestational ages of selective termination.

METHODS

We conducted a single-center retrospective and observational study which reviewed 58 biamniotic twin pregnancies that underwent selective termination for discordant fetal anomalies between January 2006 and September 2017. Fetal anomalies, ages of diagnostic and selective termination, perinatal outcomes were noted.

RESULTS

Selective terminations realised before 20 weeks (group A) were complicated by 8,7% of fetal loss and 28,6% of prematurity, of which 14,3% before 32 GA. In group B (selective termination planned between 20 and 32 weeks), there was no fetal loss but 40% of prematurity of which 13,3% before 32 GA. In group C (selective termination planned after 32 weeks), there was no fetal loss, but 42,1% of prematurity, and one birth before 32 GA (5%).

CONCLUSIONS

Gestational age of a selective termination should be determined together with the parents, after informing them about the risks and technical difficulties at each gestational age.

Fetopathological investigations after induced abortions performed in mid-term gemini pregnancies

Multiple pregnancies present a special obstetric condition whose importance has increased due to the spread of assisted reproductive techniques. We have processed the fetopathological data of 43 abortions induced in mid-term gemini pregnancies, owing to malformations affecting one or both fetuses. 67.4% of the gemini pregnancies were conceived naturally and 32.6% by assisted reproduction techniques. The most commonly occurring malformations affected the fetuses' cardiovascular and central nervous systems. Positive histories could be detected in 23% of the cases. The male-to-female ratio was found to be 1.14. In the majority of the cases with central nervous system malformation, fetus "A" was affected (85.7%). In 29.4% of the cases, monochorionic placentation was established. Ultrasonography and fetopatological findings yielded perfectly matching results in 78.9% of the cases. The incidence of fetal malformations is probably not higher among fetuses conceived by assisted reproduction techniques compared to the ones conceived naturally. Fetal central nervous system malformations usually affect fetus "A". Based on the results of the fetopathological examinations, ultrasonography is a reliable method in the diagnostics of malformations affecting twin fetuses. Fetal echocardiography is indicated simply because of the pregnancy being a multiple one.

Cordocentesis in multifetal pregnancies

OBJECTIVE

To describe the experiences in diagnostic cordocentesis in twin pregnancies at midpregnancy

METHODS

The database and medical records of pregnant women attending Maternal Fetal Medicine Unit of the hospital for diagnostic cordocentesis at midpregnancy between January 1989 and September 2006 were retrospectively reviewed.

RESULTS

During 17 years of experience, 4,241 cordocenteses at midpregnancy were performed for prenatal diagnosis, including 59 procedures in 30 multiple pregnancies (29 twins and 1 triplet). The mean gestational age at the time of cordocentesis was 19.5 +/- 1.6 weeks. Success rate of the samplings was 98.3% with one sample was maternal blood contamination. Averaged-time used of the procedures was 8.2 minutes (range 1-45 minutes). The procedure-related complications included transient bleeding at puncture site (8.5%) and transient fetal bradycardia (22.0%). The total fetal loss rate was 10.5% but there was no cordocentesis-related fetal loss (0.0%), defined as a fetal loss within 2 weeks after the procedure.

CONCLUSION

This study may provide a new insight on the safety of cordocentesis in multifetal pregnancies at midpregnancy. The procedure-related fetal loss is not as high as reported in the past. This study suggests cordocentesis be a relatively safe and highly successful in obtaining fetal blood samples.

Diagnosis and management of obstetrical complications unique to multiple gestations

Obstetrical complications unique to multiple gestations pose a number of unique challenges. The presence of more than one fetus complicates the diagnosis and management of a pregnancy when one fetus has a structural or chromosomal abnormality, intrauterine demise, preterm premature rupture of the membranes, or delivers prematurely. Similarly, the diagnosis and management of monoamniotic twins and conjoined twins is challenging. These obstetrical complications that are unique to multiple gestations require thorough counseling of the expectant parents, as well as care by physicians with expertise in the management of multiple gestations.

Evidence-based care of women with a multiple pregnancy

Women with a multiple pregnancy face greater risks for themselves and their infants than women pregnant with one child. Pre-pregnancy care should focus on avoiding multiple pregnancy. Early prenatal care centres on determining chorionicity and screening for fetal anomalies, with later care focusing on the presentation, prediction and management of preterm birth, and intrauterine growth restriction. The optimal timing and mode of birth are the focus of current multicentre, randomised, controlled trials. However, the data from such trials on care for women with a multiple pregnancy are limited. Many areas of care require better-quality information, including when using assisted reproductive techniques, the optimal number of embryos to be transferred, care after the diagnosis of chorionicity, and the benefits of specialised multiple pregnancy clinics. Better-quality information is required to inform clinical practice for women with complications of multiple pregnancy, including monoamniotic twin pregnancy, treatment of twin-to-twin transfusion syndrome, and care following single intrauterine fetal death.

First-trimester fetal reduction to a singleton infant or twins: outcome in relation to the final number and karyotyping before reduction by transabdominal chorionic villus sampling

OBJECTIVE

The purpose of this study was to evaluate fetal outcome and maternal complications of multifetal pregnancy reduction to a single fetus or twins. To evaluate safety and efficacy of transabdominal chorionic villus sampling for karyotyping before fetal reduction.

STUDY DESIGN

Four hundred twenty-four consecutive multiple pregnancies were reduced to twins (255 pregnancies) or a single fetus (169 pregnancies) at 8 to 13 weeks of gestation after transabdominal chorionic villus sampling for fetal karyotyping. Fetal and maternal outcome were observed prospectively and compared with control series of twin (147) and singleton (885) pregnancies in which reduction procedures were not performed.

RESULTS

Transabdominal chorionic villus sampling was performed successfully in 100% of the cases. The accuracy of karyotyping was 99.2%. The overall pregnancy loss rate after reduction was 3.3%. No differences were observed between study and control series for severe prematurity, low birth weight, and neonatal deaths. Mean gestational age at delivery (35.2% vs 38.1%) and mean birth weight (2180 g vs 2873 g) were significantly lower; preterm delivery (64% vs 11%), neonatal death (3.4% vs 0.6%), and maternal complications (42.8% vs 9.5%) were significantly higher when the reduction was to twins rather than in reduction to a single fetus. Pregnancy loss rate did not differ between study series. The overall rate of chromosomal abnormalities in the study series was higher (relative risk, 2.0) than in singleton control series.

CONCLUSION

The outcome of multiple pregnancies that were reduced to a single fetus or twins was similar to that of nonreduced pregnancies; fetal and maternal complications were significantly lower in the series of pregnancies that were reduced to a single fetus. The safety and efficacy of transabdominal chorionic villus sampling and the higher pregnancy rate of chromosomal abnormalities in multiple pregnancies imply that fetal karyotyping should be advised before fetal reduction.

Recent advances in fetal surgery

Fetal surgery is now an accepted modality for treatment of a variety of lethal and non-lethal congenital conditions. It represents a new, fast-moving frontier of medicine in which cooperative mulitdisciplinary effort and input are required to assure both fetal and maternal welfare. A wide range of therapeutic strategies from percutaneous to open invasive techniques has led to a complex list of different procedures for different diseases. This review identifies the most common disease entities managed by fetal intervention, examines the evolution in development of techniques to those currently used, and describes the prospective, randomized trials presently underway that are designed to establish the safety and determine true efficacy of treatment. Fetal surgery as a (multi)discipline continues to strive to minimize maternal and fetal risk. Undoubtedly, as tocolytic therapy and neonatal intensive efforts improve, fetal therapy will expand.

Stratégies de diagnostic prénatal et prise en charge des pathologies liées aux grossesses multiples

In the first trimester, ultrasound is crucial to screen for aneuploidies based on nuchal translucency, to diagnose major birth defects, and to establish chorionicity. Indeed prenatal diagnosis strategies as well as obstetrical management options are largely based on placental type. In the second trimester, maternal serum screening is not as effective, and ultrasound screening is more difficult in twins than in singletons. When a severe abnormality in found in one twin, selective termination of pregnancy may be considered. This technique is safe in dichorionic twins, but hazardous in monochorionic pregnancies. Selective termination in dichorionic twins is safer in the first trimester, underscoring the need for early prenatal diagnosis in twins. Monochorionic twin pregnancies carry specific risks, such as the twin-to-twin transfusion syndrome, which can be treated by endoscopic photo-coagulation of intertwin anastomoses in the severe early onset cases, or by amnioreduction in milder cases.

Monochorionic Triplets following Intracytoplasmic Sperm Injection: A Report of Two Consecutive Cases

Monochorionic triplet pregnancies are very rare. Here we report 2 cases of multiple pregnancies with monochorionic triplets following intracytoplasmic sperm injection (ICSI) and day 3 embryo transfer. The 2 women concomitantly underwent controlled ovarian hyperstimulation due to male factor infertility. Following oocyte retrieval, ICSI and assisted hatching (AH) were performed, and the 2 women conceived consecutively. One patient had a quadruplet pregnancy, which included monochorionic triplets, while the other had monochorionic triplets. Selective embryo reduction by intracardiac KCl injection targeted at 2 of the triplets was performed on the patient with the quadruplet pregnancy, but the third triplet also died. The gestation continued as a singleton pregnancy, and the patient gave birth to a healthy female baby at 38 weeks. The other patient gave birth to 3 healthy female babies at 34 weeks. Possible etiologic factors for the formation of monozygotic splitting among women undergoing assisted reproduction treatment are discussed.

Invasive procedures in multiple gestations

PURPOSE OF REVIEW

The incidence of multiple gestations has increased significantly with advances in assisted reproductive techniques resulting in a concomitant increase in invasive procedures in these pregnancies. Commonly performed invasive procedures include amniocentesis, chorionic villus sampling, multifetal pregnancy reduction, and selective termination. Amniocentesis and chorionic villus sampling are also performed in singleton pregnancies, while multifetal pregnancy reduction and selective termination are procedures that are unique to multiple gestations.

RECENT FINDINGS

With increased operator experience, pregnancy loss rates after chorionic villus sampling, multifetal pregnancy reduction, and selective termination have decreased to acceptably low levels. Amniocentesis and chorionic villus sampling continue to have similar loss rates in experienced hands. A recent study suggests that amniocentesis in twins may have a higher post-procedural loss rate than in singletons; this may be due to the higher background loss rate of twins. There has been a recent increase in multifetal pregnancy reduction to a singleton with a trend towards improved outcomes over reduction to twins; future studies should focus on whether this confers a definitive advantage. Newer data suggests that selective termination after 20 weeks gestation in experienced hands does not increase loss rates over those procedures performed before 20 weeks. Newer techniques, such as cord coagulation, continue to be developed for selective termination in monochorionic pregnancies, though still with considerable morbidity and mortality.

SUMMARY

In summary, invasive procedures in multiple gestations are now commonly performed with. It is our hope that primary prevention of high order multiple pregnancies by optimization of assisted reproductive techniques will decrease the need for these procedures.

Chorionic villus sampling and amniocentesis: what are the risks in current practice?

PURPOSE OF REVIEW

Public demand for genetic counselling and prenatal diagnosis has increased during the past decade. As invasive diagnostic methods, such as chorionic villus sampling and amniocentesis, still have an important role to play in evaluating the fetus, one of the most important questions to address during genetic counselling is the procedure-related risk of these techniques.

RECENT FINDINGS

The possible factors modifying the specific risk of the actual fetus are discussed, together with factors that have an impact on procedure-related fetal loss and other complications. Risk factors regarding twin pregnancies, first and second-trimester chorionic villus sampling, early and mid-trimester amniocentesis are discussed separately. New developments have recently occurred in the laboratory techniques used in prenatal diagnosis. Their impact on genetic counselling and the employment of invasive techniques are also addressed.

SUMMARY

During genetic counselling, an individually tailored risk assessment needs to be established before any invasive procedure. This should take into account all the factors modifying the specific risk for aneuploidy or other disorders of the fetus, as well as the actual procedure-related risks.