Main Findings
The cardiotocograph was developed in the 1960s to improve fetal
surveillance. But its generalization has led to an increase in the rate
of cesarean section and extractions for FHR abnormalities and without
significant reduction in neonatal risk (16,17). A recent Cochrane review
also found no differences in cerebral palsy, infant mortality, or other
standard measures of neonatal well-being between intermittent or
continuous FHR auscultation (17). The only difference found is the
reduction of neonatal convulsion rates during continuous auscultation.
These findings, including the increase in caesarean section rate, are
related to the high sensitivity of the FHR and its low specificity, but
not only. Misinterpretations or erroneous decisions are involved with a
failure to take into account a pathological pattern in 20% of cases in
newborns with metabolic acidosis (18). It therefore appears essential to
improve our analysis of FHR and we wanted to evaluate the interest of
training on fetal physiology in obstetric gynecology residents
regardless of their initial level. We find a better global knowledge in
fetal physiology with a reduction of ”extreme” classification during the
analysis of FHR, resulting in a decrease in the number of FBS, a better
estimation of these and a homogenization of practices in clinical cases
performed.
The FHR interpretation training starts at the residency but the training
time is variable and generally limited. The training is not systematic
in France and varies according to the enrollments in workshops during
congresses and the courses planned in the university. Conversely, in
other countries such as England, the regulation has imposed the need for
continuing education on the interpretation of the FHR every 6 months for
midwives (19). Therefore, the formation of residents on the FHR and
fetal physiology is insufficient in France and all of our residents
interviewed were applicants for such training.
The FHR analysis makes it possible to detect situations at risk of fetal
acidosis when its interpretation is correctly performed and thus to
provide indications of second-line examinations or fetal extraction.
Metabolic acidosis and associated neonatal morbidity could potentially
be prevented in 40-50% of cases (18). Indeed, the most found errors are
a misinterpretation of the RCF, an imprudent use of oxytocin and a
failure to recognize at-risk pregnancies (20–22). Training development
could reduce the consequences of inadequate monitoring. Indeed, Draycott
and al conducted a retrospective study evaluating the value of training
in obstetric emergencies. They were interested in the Apgar scores at 5
minutes of all the liveborn singletons with vaginal deliveries at term,
between 1998 and 2003. They also identified hypoxic and ischemic
encephalopathies. All the medical staff (midwife, gynecologist,
anesthesiologist …) benefited from a training day during the year
2000. Draycott and al did not analyze the year 2000 and compared two
periods: a pre-training period (from 1998 to 1999) and a post-training
period (from 2001 to 2003). They found a significant reduction in low
Apgar scores (<6) and in the incidence of hypoxic and ischemic
encephalopathy (23). Thellesen and al, for their part, found a 14%
decrease in fetal extraction, without increased risk of fetal hypoxia,
after a training program for midwives and gynecologists from a Danish
maternity hospital (24). Their training consisted of e-learning sessions
and a day of theoretical courses.
The interpretation of the FHR is subject to intra- and inter-observer
variability well studied now (25–27). This variability persists despite
the existence of classification and this is more important when it comes
to FHR classified as intermediate or pathological according to the FIGO
classification (28). Regular training on FHR could reduce this
inter-observer variability. Pehrson and al interviewed the Medline
database to study and evaluate FHR training programs (29). Of the 409
citations they found, 20 studies included and analyzed. They report a
better inter-observer agreement after training on the physiology and
interpretation of FHR. We had the same findings by studying the
reproducibility of the responses and therefore the inter-observer
variability via the Krippendorff’s alpha index (0.60 before training vs.
0.72 after). Therefore, training in fetal physiology promotes the
homogenization of answers. Thus, an education in the interpretation of
the FHR would allow a reduction of its variability inter and intra
observer and therefore standardize our practices.
Finally, we wanted to evaluate the impact on the use of a second-line
examination. Indeed, when the FHR analysis is considered non-reassuring,
there are different second-line exams to better characterize the fetal
state such as the FBS with pH measurement to study the acidobasic state
of the fetus (3,4,30). The interest of FBS is currently debated. It may
not be representative of fetal acid-base status as it is derived from
peripheral tissue or because of the compression of the fetal scalp
during labor for example. This could lead to unnecessary interventions
in fetuses that are not really hypoxic, which means that the debate on
this subject persists (9,31). The purpose of this study was not to
discuss the interest of FBS but to evaluate the decision to perform this
second-line exam in our residents. We note a decrease in the number of
FBS requested so second-line examination, currently being discussed,
through a better interpretation.