About Us Apply Now What We Do Staffing Request Useful Links

Prenatal Diagnosis and Fetal Medicine

During the recent changes in the laws of bioethics has been added to Article L.2131-1 of the Public Health Code which defined prenatal diagnosis these words (in italics) “Prenatal diagnosis refers to medical practices, there including obstetric and fetal ultrasound , aiming to detect in utero in the embryo or fetus affection of particular gravity ( Code of Public Health, Article L.2131-1 Edited by ION from 2011-814 July 7, 2011 – art. 20 ). It is actually impossible in 2011 to disassociate prenatal diagnosis and ultrasound. In the last ten years we have seen major changes in our exercise: screening for trisomy 21 in the first trimester, non-invasive prenatal diagnosis and in utero treatments are just a few examples.

Combined first-trimester screening combining maternal age, nuchal translucency and PAPP-A and free ßHCG between 11 SA and 13 + 6 SA allows screening of up to 86% of the fetus carriers Trisomy 21 and other major aneuploids, with a low false-positive rate of 5% (1). This screening could be improved by the addition of echographic signs already described such as the absence of clean bones of the nose, an abnormal flow of the ductus venosus or a tricuspid leak. The inclusion of these markers in the first trimester screening would improve the aneuploid detection rate from 93% to 96%, with a false positive rate of 2.5% (2) (3). This screening has been implemented gradually since the decree of 23 June 2009 laying down the rules of good practice for prenatal screening and diagnosis using maternal trisomy 21 serum markers. Access to this technique is still Unequal in the different regions of France, but the majority of sonographers thanks to a very dynamic corporatism have bent to the regulation of the evaluation of professional practices and affiliation to a network. This result is important because it allows us to see a significant reduction in the number of amniocenteses performed for healthy fetuses and earlier sampling (trophoblast biopsy), which results in a reliable result before 14SA and To avoid, in the case of a fetus carrying T21, a late termination of pregnancy. Information on the risk of miscarriage, regardless of the levy and whatever the statements of some of our colleagues, should give a 1% risk . Even if 15 to 20% of the patients questioned said that they would keep their pregnancies if the child had T21, 96% of pregnancies with a fetus carrying T21 diagnosed in the prenatal period were interrupted in France. This screening, which is offered to patients, is obviously not mandatory. The duty to inform patients and signing a consent must be informed allows, in theory, do not turn this screening eugenic practice . This word irritates, irritates, irritates but if the doctor prescribes the examinations without understanding the functioning of the screening and the patient accepts that this screening is carried out without realizing that the stake can be the interruption of pregnancy and that this screening is prescribed by All, one might feel passing the specter of eugenics. This screening policy is, of course, implemented in the name of the well-being of individuals, but it is taken on collectively by the Health Insurance.

It is clear that in the coming years the first trimester will become the key period of prenatal diagnosis. The quality of ultrasound machines currently at our disposal allows us to make diagnoses reserved there is still little by ultrasonography 2 e quarter. There is a real benefit in diagnosing as early as 12 years some severe pathologies for which no treatment is possible, but earlier diagnosing curable anomalies but which can be associated with significant morbidity and mortality Is not without posing a number of questions and problems. Some of our colleagues sonographers prefer not to give all the information to the patients and wait for a later term to announce the diagnosis. Patients expect full information from us and it is our responsibility to give all the information and learn to manage an early announcement and to direct the patients as soon as possible to the CPDPN, which in turn will probably have to Adapt their mode of operation to these ads early in pregnancy if we do not want to witness an uncontrolled increase in pregnancy interruptions.

Many recent publications report a possible prediction of preeclampsia, preterm delivery , IUGR or of macrosomia. Some even go so far as to give results to patients. However, although these techniques are very likely to represent the future of our specialty, there are currently no preventive treatments that have proved to be effective either for pre-eclampsia or for premature delivery. Several points need to be analyzed before making these clinical research findings to patients: (i) What prevention strategy should be implemented when screening for at-risk patients ?, (ii) The cost of screening in the absence of treatment (Iii) How many patients will be alerted for nothing and what will be the impact on the pregnancy and the child?

The discovery of the presence of fetal DNA in maternal blood in 1997 by D Lo marked the beginning of the non-invasive prenatal diagnosis . Fifteen years later, the diagnosis of fetal sex is proposed with a 100% reliability in the management of patients at risk of transmitting X-linked pathology or congenital adrenal hyperplasia and determination of fetal RhD from A simple blood test from 11SA can reassure alloimmunized patients and alleviate the monitoring of unimmunized negative RhD patients and thus avoid systematic injection of blood products if the fetus is RhD negative. The diagnosis of certain genetic diseases (cystic fibrosis, spinal muscular atrophy) on fetal cells is also possible, but this research has not yet reached the stage of clinical trials. It is the same for the diagnosis of trisomy 21. Some papers are promising T21 diagnostic status on maternal blood and some tests are already commercialized but their price and reliability not possible at present to generalize these techniques (4 ).

Non-invasive diagnostic tests are regulated in the same way as other biological examinations of prenatal diagnosis by HAS and the Agency of Biomedicine. It would be necessary for the various professionals, obstetricians, geneticists, psychiatrists, philosophers, lawyers … to quickly reflect on the way in which we will have to supervise the arrival of these new tests, particularly that of the T21. The stakes of implementing these tests are numerous because they will replace probabilistic tests (screening) and tests involving risks of miscarriage (amniocentesis, trophoblast biopsy) by easy, reliable, early, rapid diagnostic tests And without risk.

Fetal medicine makes it possible to oppose the natural history of certain pathologies. We currently know how to place drains of pleuro-amniotic or kysto-amniotic derivations, treat transfuse-transfused syndrome, or place a balloon under endoscopy in fetuses with a diaphragmatic dome hernia. Of course, these techniques are not routinely performed by all teams, but the results obtained are encouraging and encourage us to develop them in the framework of, in particular, Rare Disease Referral Centers. Two new techniques could modify the management of children with diaphragmatic dome hernia and myelomeningocele.

As a result of animal studies showing the potential preservation of neurological functions in utero surgery, the first in utero surgery of human myelomeningocele occurred in 1997. Since then, 200 fetuses have been operated in utero. Monitoring of these fetuses showed an improvement in post-natal neurological signs but associated with significant maternal and fetal morbidity and mortality. The MOMS (Management Of Myelomeningocele Study) study recently compared randomized prenatal treatment to postnatal myelomeningocele treatment (5). The primary endpoint was a composite criterion combining the risk of fetal or neonatal death and the need for a cerebro-peritoneal shunt before 12 months of life. Another composite criterion was the neurobehavioral assessment at 30 months of life between the 2 groups. The study was discontinued prior to the inclusion of the 200 patients expected for the proven efficacy of prenatal surgical treatment: the primary endpoint was found in 68% of cases in the prenatal treatment group versus 98% in the post- Natal (RR = 0.7 p <0.001). A shunt was set up in 40% of cases in the prenatal treatment group, compared with 82% of cases in the postnatal group (RR = 0.48 p <0.001). Prenatal surgery also showed improvement in the psycho-motor development score at 30 months of life (p = 0.007). Prenatal surgery, however, is associated with an increase in the risk of prematurity (average duration of delivery: 34 SA vs 37 SA and 13% of fetuses born before 30 SA) and dehiscence of the uterine scar. Despite these encouraging results, the practical application of this study remains limited due to the need for specialized teams for this type of management, and the significant morbidity associated with it (In the prenatal surgery group, the sequelae remain important). Moreover, this study was carried out in a country where the IMG is not authorized after 24-28 SA according to the states, which is not the case in France.

Prenatal assessment of the postnatal prognosis of children with diaphragmatic dome hernia (HCD) has improved over the last 5 years. Although the prognostic factors used are not unanimous, it seems important that all teams use the same measures in order to compare and improve our practices. The prognosis will be assessed using the Lung over Head Ratio (LHR) between 22 and 28 SA or the observed / expected LHR (LHRo / a) irrespective of the term, liver position and volume measurement Pulmonary artery by MRI. These factors make it possible to define a group of fetuses carrying HCD with poor prognosis. When LHR is <1 or LHRo / a <25% and the liver in the chest, the chances of survival in the neonatal period are less than 20%. For this group, in utero treatment may be proposed. A balloon is placed, between 28 and 30 SA, endoscopically in the fetal trachea. It is withdrawn towards 34 SA. The first results show that the survival rate of these children goes from less than 20% to about 50%. This technique does not appear to lead to an increase in morbidity, but this is currently being evaluated (6).

Hopefully, recent progress allows us to quickly contradict D Sicard, who wrote, “Most of the prenatal screening activity is aimed at suppression and not treatment.” It is true that technical advances in terms of diagnosis have progressed more rapidly than the development of treatment and the management of disability. Read more here Rosh Maternal.

The first quarter will become the key period for risk prevention and the discovery of fetal anomalies. To us “prenatalist” doctors to adapt us to this new medicine.