On the third trimester ultrasound, a very comprehensive article by Dr. Serena Simeone, gynecologist .
Article by Serena Simeone, gynecologist
In March 2017, the Ministry of Health published the new LEAs for physiological pregnancy, modifying the indications of the Ministerial Decree of 10 September 1998, which provided for the execution of an obstetric ultrasound between 28 and 32 weeks.
According to the new provisions, the obstetric ultrasound of the third trimester (28 – 32 weeks) is no longer foreseen for all women , but only in the case of fetal and / or adnexal or maternal pathology, indicating the diagnosis or diagnostic suspicion.
The change was introduced in order to rationalize health care costs, reserving the ultrasound examination only for cases where it is considered appropriate.
The scientific basis of the change lies in the evidence reported by papers published about a decade ago, which concluded that, statistically, there were no differences in terms of adverse perinatal outcomes between physiologically pregnant women who underwent the third ultrasound and those who, on the other hand, did not perform it.
According to these studies, the third protocol ultrasound can identify only 30% of fetuses with intrauterine growth retardation.
In these cases, fetal pathology is often accompanied by maternal hypertension, which would allow suspicion even in the absence of an ultrasound examination.
A first Cochrane review, dating back to 2007, already ruled out the usefulness of routine ultrasound beyond 24 weeks; however, this revision was later withdrawn and replaced by a more extensive revision published in 2009. In this latest version, 8 studies of sufficient quality for analysis were analyzed , which included approximately 27,000 cases. The authors concluded that, in low-risk pregnancies, ultrasound after 24 weeks had no statistically significant impact on the well-being of mother to fetus and that it could increase the rate of caesarean sections and reduce the rate of pregnancies reaching 42. Week.
The analysis of the results is very accurate and includes a complete list of variables .
The eight studies considered in the review are:
- 2 trials, performed in Scotland and New Zealand, dating back to 1984 and 1993, focusing on the diagnosis of small fetus by gestational age;
- A 1987 UK study, devoted to the evaluation of the placental aspect;
- The RADIUS study, US, which examined the diagnostic capacity of ultrasound on fetal anatomy, year 1993;
- Another Australian study from 1993 on the efficacy of fetal biometry and Doppler;
- 2 Norwegian studies, from 1999 and 1984;
- 1 Irish study from 2003
However, the perplexities shown by the scientific community with respect to this review are many.
The first undoubtedly resides in the inhomogeneity of the ultrasound protocols , since the studies taken into consideration are different from each other, conducted in different contexts and with different purposes from each other. The second perplexity is quite evident: studies dating back to an era in which obstetric ultrasound was not even remotely comparable to the current one were included in the analysis, both in terms of instrumentation, operator skills and knowledge of anomalies. recognizable ultrasonographically .
We can say that obstetric ultrasound as we know it today developed in the 2000s , if not later.
For example, the diagnosis of fetal anomalies in France went from 16.2% in the 1980s to 69% in 2000.
Even with respect to estimates of biometrics and fetal weight, the studies used in the Cochrane review refer to formulas that are now obsolete .
More recent studies have pointed out that up to 50% of fetal anomalies are diagnosed during the third trimester , because they are not recognized on the second trimester ultrasound (perhaps for visualization reasons) or because they are the result of an evolutionary pathology.
It has also been shown that the diagnosis of a fetal abnormality and the referral of the patient to a referral center can reduce the risk of perinatal mortality .
Even the diagnosis of apparently simple developmental pathologies, such as megaureter, can allow a dedicated postnatal follow-up, in which certainly the result to be evaluated is not perinatal mortality, as in the Cochrane review, but the onset of some forms of renal dysplasia.
As for cardiological pathologies, the studies cited by the meta-analysis were conducted in a period in which some of them were not even studied, such as transposition of the great vessels , the diagnosis of which is significantly more probable in the third trimester and, when performed before delivery, allows for a dramatic improvement in perinatal outcomes thanks to the referral of the patient to specialized centers.
Conversely, in the case of particularly serious pathologies, the termination of pregnancy abroad in the third trimester can be evaluated by the patient.
The studies considered in the meta-analysis concerning intrauterine growth retardation (IUGR) are prior to the 2000s, in which other data were presented that contradicted the previous statements on the possibility of diagnosing this pathology.
In one of the same studies cited by the meta-analysis, even if the intrauterine diagnosis of IUGR did not determine substantial differences in terms of perinatal outcomes, the diagnosis rate was still double in the screened patients compared to those who did not perform the ultrasound.
In 2015, the POP study, published in the Lancet, showed that the universal use of the third trimester ultrasound not only allowed to identify a greater number of small fetuses by gestational age, but also to distinguish 30% of real cases. growth restriction, on which it was possible to concentrate care.
However, it is confirmed that the ultrasound of the III trimester, as proposed, does not allow adequate accuracy for the diagnosis of late IUGR, which represents, if not recognized, the cause of about 50% of stillbirths .
In 2015, the meta-analysis was updated with a more rigorous study selection criterion, reaffirming previous results, but always including pre-2000 studies to support the results presented. Even with regard to the diagnosis of fetal abnormalities amenable to surgical correction in utero, the authors refer to a 1997 RCOG paper, when fetal surgery was just in its infancy.
However, the authors agree that some variables, such as preterm birth and the psychological impact of the absence of the third trimester ultrasound (also in terms of impact on the possible consequences of non-execution) have not been considered and require further studies . .
The absence of ultrasound screening of the III trimester will require that the clinical attention on low-risk pregnant women be even higher, since there will be no other tools for detecting pathological conditions.
The medical history and careful clinical examination will have to search for specific risk factors to identify the pregnancies to be addressed to the execution of the ultrasound, even if, at the moment, the specific factors that would allow the patient to access the ultrasound evaluation are not indicated. .
It will always be necessary to measure the symphysis-fundus distance, which will be the only tool available to personnel dedicated to the management of low-risk pregnancy, to suspect a growth failure. However, this instrument also has important limitations, ranging from intra and inter-operator variability, to technical difficulties in measuring in overweight women, to the absence of satisfactory evidence of efficacy. It is also evident that this tool is in no way useful for the suspicion of fetal anomalies, the diagnosis of which will be postponed at birth or in the first years of the child’s life .
It remains unproven that such a healthcare approach is applicable to the Italian context.
In fact, all the evidence considered comes from situations where perinatal mortality is at least double that recorded in Italy (5-6 per thousand against 2-3 per thousand). A very critical editorial, published in 2018 on BJOG, “beats” the UK model of care, underlining how obstetric practice has not changed adequately for the prevention of stillbirth between 1921 and 2016.
Currently, a prospective cost-benefit analysis is underway in the Netherlands to determine the advantage of performing the 3rd trimester ultrasound in the general population (the IRIS study), finally with criteria and instruments comparable to contemporary routine.
In conclusion, the data provided against universal ultrasound screening in the third trimester appear to be inhomogeneous, not adequate for current ultrasound practice and not tested on the Italian reality.
The alternative would have been to re-discuss the opportunity to define ways and times for performing ultrasound (30-34 weeks or 34-36 , for example), to improve the ability and relevance to the guidelines of the operators and to study a model useful for the diagnosis also of pathologies, such as late IUGR, for which today the ultrasound of the III trimester is not effective enough.
- Bricker L, Neilson JP, Dowswell T. Routine ultrasound in late pregnancy (after 24 weeks’ gestation). Cochrane Database Syst Rev. 2008 Oct 8; (4): CD001451. doi: 10.1002 / 14651858.CD001451.pub3. Review.
- Bricker L , Medley N , Pratt JJ . Ultrasound routine in late pregnancy (after 24 weeks’ gestation). Cochrane Database Syst Rev. 2015 Jun 29; (6): CD001451. doi: 10.1002 / 14651858.CD001451.pub4.
- Henrichs J, Verfaille V, Viester L, Westerneng M, Molewijk B, Franx A, van der Horst H, Bosmans JE, de Jonge A, Jellema P; IRIS Study Group. Effectiveness and cost-effectiveness of routine third trimester ultrasound screening for intrauterine growth restriction: study protocol of a nationwide stepped wedge cluster-randomized trial in The Netherlands (The IRIS Study). BMC Pregnancy Childbirth. 2016 Oct 13; 16 (1): 310.
- Trudell AS, Cahill AG, Tuuli MG, Macones GA, Odibo AO Risk of stillbirth after 37 weeks in pregnancies complicated by small-for-gestational-age fetuses. Am J Obstet Gynecol. 2013 May; 208 (5): 376.e1-7. doi: 10.1016 / j.ajog.2013.02.030. Epub 2013 Mar 21.
- Chauhan SP, Rouse DJ, Ananth CV, Magann EF, Chang E, Dahlke JD, Abuhamad AZ. Screening for intrauterine growth restriction in uncomplicated pregnancies: time for action. Am J Perinatol. 2013 Jan; 30 (1): 33-9. doi: 10.1055 / s-0032-1321497. Epub 2012 Jul 13
- Ray CL , Lacerte M , Iglesias MH , Audibert F , Morin L. Ultrasound third trimester routine: what is the evidence? J Obstet Gynaecol Can. 2008 Feb; 30 (2): 118-122. doi: 10.1016 / S1701-2163 (16) 32734-7.
- Gardosi J, Francis A. Controlled trial of fundal height measurement plotted on customized antenatal growth charts. Br J Obstet Gynaecol. 1999 Apr; 106 (4): 309-17.
- Sovio U , White IR , Dacey A , Pasupathy D , Smith GCS . Screening for fetal growth restriction with universal third trimester ultrasonography in nulliparous women in the Pregnancy Outcome Prediction (POP) study: a prospective cohort study. 2015 Nov 21; 386 (10008): 2089-2097. doi: 10.1016 / S0140-6736 (15) 00131-2. Epub 2015 Sep 7.
- Kaiser JE. Stillbirth prevention 1921 and 2016: the call for ‘adequate antenatal supervision’. 2018 Jan; 125 (2): 130. doi: 10.1111 / 1471-0528.14378
Comment by Claudia Ravaldi, psychiatrist, CiaoLapo Onlus
Dr. Simeone has been dealing for some time with high-risk pregnancies and pregnancies following perinatal bereavement, at the Careggi AUOC, and has given us this interesting article on a discussion that is dividing healthcare workers (some of them now divided into two historical factions: the pro-ultrasound always and in any case and the anti-ultrasound always and in any case, often regardless of the literature, unfortunately): all this it is confusing pregnant women, not only those in their first pregnancy, but above all those they know, because they have experienced them directly on their skin or because they have seen them face the shadow areas of birth by friends or relatives.
We sincerely thank Serena for the clarity of presentation, for the bibliographic synthesis, and for having indicated all the problems connected with this decision of the Ministry.
In my opinion, problems are not negligible: the consequences risk falling not on those who actually DO NOT need a third ultrasound, but on those who can’t afford a private ultrasound (the poverty rate in our country is growing) in a center suitable for the purpose (because as we have already said, it is not true that an ultrasound, an ultrasound machine or an ultrasound specialist are all the same, the ultrasound is done for a purpose precise, not so much to say that it was done). Furthermore, this decision will fall on those mothers who, having language problems, will not be able to tell the doctor about the presence of hereditary family pathologies. They will also fall on those who, pursuing the myth of “physiology” at all costs , often promoted to exorcise the ancestral fears inherent in the mind of pregnant women, albeit on an unconscious level, risk receiving a bad diagnosis only after birth.
An Italian study would be needed.
A shared reflection would be needed between obstetricians and gynecologists and parents’ representatives.
It would be necessary to reflect on why and for whom field choices like this are made.
Because, I can guarantee you, “winning “the third ultrasound after stillbirth or late diagnosed heart disease can only make things worse, making parents feel left on their own, unprotected, not so important as citizens. Citizens of that country that launched the”fertility day “ to increase the birth rate (!) and is unable to think of the needs of the weakest citizens, of those who do not fall into the diagnostic categories or who have a pathology that cannot otherwise be diagnosed except with that service that has been removed.
Perhaps it would take less celebratory days and more respect for the townspeople who become pregnant in our country. Perhaps the resources available should be better used.
Perhaps we should think of women who cannot / do not want to go to a private gynecologist and find themselves more disadvantaged than those who can afford it and therefore can make an early diagnosis (absurd, thinking of a public health that boasts centers of excellence and very capable operators who cannot exercise the preventive part of their profession, which is so important to world organizations).
Because if we go from 3 stillbirths out of a thousand to 4 out of a thousand, it will not be a “negligible” increase, it will not be just “a few hundred cases” in the face of “huge savings”: we also consider that we have been asked by the WHO to reach 2 in 1000 by 2020.
We were asked to lower the stillbirth rate , not to lower spending .
Behind those numbers, behind the appropriateness of an intervention, are the saved lives of future generations.
This should be the ultimate goal of any discussion, any faction, any public health intervention. This should be the first point of any health policy discussion.
Save the mothers and save the children.
Can you save on a child’s life?