Concerns about Validity of Caesarian Section for Foetal Distress with No Risk in Mother – Baby

  

    
Method of diagnosing    foetal distress
    
No of Cases
    
%
    
Mean Apgar
      
At 1min
    
Mean Umbilical Cord    Blood pH
    
NICU Admissions
  
  

    
EFM/NST
    
Category –III
    
Early
    
29
    
11.5
    
8
    
7.14
    
5
  
  

    
Late
    
11
    
4.37
    
5.29
    
7.11
    
5
  
  

    
Variable
    
71
    
28.6
    
6.3
    
7.17
    
11
  
  

    
Loss of variability
    
68
    
27
    
8.26
    
7.13
    
12
  
  

    
Category – III    Non-Reassuring (Total)
    
179
    
71
    
-
    
-
    
-
  
  

    
Category – II    (Indeterminate)
    
17
    
6.74
    
8
    
7.22
    
-
  
  

    
Category – I    (Reassuring)
    
56
    
22.2
    
8
    
7.28
    
-
  
  

    
Total EFM/NST
    
252
    
100
    
-
    
-
    
-
  
  

    
Intermittent    Auscultation
    
Bradycardia
    
Mild (<110bpm)
    
9
    
3.57
    
6
    
7
    
-
  
  

    
Moderate    (<100bpm)
    
14
    
5.54
    
5
    
7
    
5
  
  

    
Severe (<80bpm)
    
1
    
0.39
    
2.75
    
6.9
    
1
  
  

    
Tachycardia
    
Mild (>160bpm)
    
14
    
5.55
    
6
    
7.18
    
-
  
  

    
Severe >180bpm)
    
21
    
8.33
    
6
    
7.18
    
2
  
  

    
Normal (110 –    160bpm)
    
193
    
76.6
    
8
    
7.28
    
-
  
  

    
Total Intermittent    Auscultation
    
252
    
100
    
-
    
-
    
-
  
  

    
Total Number of cases    diagnosed on FHR basis
    
153
    
60.7
    
-
    
-
    
-
  
  

    
Meconium staining of amniotic    fluid
    
99
    
39.3
    
7
    
7.15
    
-
  

Table 6: NST, IFHR Apgar score, NICU Admission.

Discussion

FD, term used in day to day clinical scenario, is deemed inappropriate by many, since it just means clinician’s interpretation of fetal status, and denotes that the clinician is not satisfied with the fetal status. Major drawback with the term FD is that it does not convey the cause or severity or implications on the outcome. Validity of interventions with this diagnosis is known only after the intervention has been done, too late. Women may be having some disorder/risk diagnosed during pregnancy which could affect the fetal cardio respiratory status and cause FD. But some women with no risk factor at all are diagnosed with FD and intervened by CS. Baby is vigorous at birth and beyond. So it was decided to look into some of the issues.

Substantial number, 252 (26.58% of all CS for FD, 948) were performed for FD without any obvious risk factors, in the mother or the baby during pregnancy or at the onset of labour. However of the 252 CS, in 30 (12%) abnormalities were detected intraoperatively, not known prior to CS. Additional 3 (1.20%) had concealed placental abruption detected during CS. Of the 252 cases, overall 56 (22.22%) had category I, 17 (6.75%) category II and 179 (71.03%) had category III NST. Most had variable deceleration [71 (28.57%)], loss of foetal heart rate variability was in 69 (26.99%) cases, early decelerations in 29 (11.51%) cases and late decelerations in 11 (4.37%) cases. In 27 (10.71%) cases there was cord around the neck of the baby & one (0.40%) baby had cardiac anomaly.

Of the 252 women in 167 (66.26%) cases, no abnormality was detected even during CS. Of these 167 cases, 140 (63%) babies were vigorous at birth, but 27 (16.17%) needed NICU management. So around 66% women who had CS for FD did not have any abnormality, even during CS. obviously over diagnosis of FD, through conventional modalities of diagnosis. Al-Abid [5] and Odongo [6] have also reported such findings. A study done by Low [7] of term pregnancies with diagnosis of foetal asphyxia revealed that in 63% cases no known risk factors for foetal asphyxia were present.

Foetal asphyxia/FD can occur in cases without any obvious risk factor, making it essential to conduct studies regarding the causes of fetal asphyxia and also authenticity of diagnosis of FD. This is essential because women with disorders which predispose to foetal asphyxia should be managed appropriately and timely and those without such disorders should be managed in such a way that unnecessary interventions are not done. ACOG [2] and Rosser [8] also reported that an important aspect of foetal monitoring is the high or false positive rate of FD associated with most IPFHR monitoring methods, coupled with the poor ability to interpret monitoring results that may both contribute to unnecessary interventions. Nelson et al [9] reported that despite the rise in CS rate to excess of 25%,neither the rate of Cerebral Palsy (CP), nor that of any other childhood neurologic problems have been affected in the slightest, weighing against the inappropriate & alarming rise in CS rate due to false-positive rate of 99.8% in EFM. Unfortunately, precise information about the frequency of false-positive results is lacking, and this lack is due in large part to the absence of accepted definition of FD [10]. IFHA criticized in all low risk cases with advent of EFM long back was reanalyzed and has been advised as standard of care by joint committee of American Association of Paediatricians [4]. The suggested duration & frequency of IA is minimum of 60 seconds, at least every 30 minutes after a contraction in the active stage and every 5 minutes in the second stage of labour [3]. In the presence of increased risk of perinatal death, CP or neonatal encephalopathy or with oxytocin for induction or augmentation, continuous EFM has been suggested [11].

From time to time several hospital based studies have proved that various antepartum, intrapartum maternal & fetal or postnatal risk factors are responsible for perinatal asphyxia. Chauhan et al [12] conducted a meta-analysis comprising of 169 articles, and 37 reports and concluded that the overall risk of prompt CB for foetal concern was 3.1%. In the present study it was 2.74%. Any mother, if screened and found to be with no risk factor has chance of being diagnosed as FD either due to intrapartum decreased oxygenation of foetus because of suboptimal uterine perfusion, placental dysfunction, and other intrapartum events or with false alarm. The research needs to continue.

Present study revealed better sensitivity (75.43%), but low specificity (21.67%) with NST in predicting perinatal asphyxia, high false positivity in detecting foetal status diagnosed as FD in women without risk factors, thus increasing the risk of CS without actual need. After Cochrane Database Systematic review Devane et al [13] reported that women who were low risk at admission for labour, should have been informed that admission EFM/ NST was likely to be associated with an increase in the incidence of CS without evidence of clear benefits.

Overall 100(39.68%) women had meconium in liquor amnii, Wong [14] reported 20%, 43 (17.06%) women had FD with thick meconium, while 35 (13.88%) had thin meconium in liquor with abnormalities, in IFHA or NST though, 11 (4.36%) women with normal FHR also had thick meconium. Presence of meconium in liquor amnii, especially thick meconium, carries more risk of fetus being asphyxiated [12]. Also suspicious and pathologic tracings on EFM/NST were often found in the cases with meconium in liquor, though there was no significant difference in the Apgar scores (6.3 without meconium & 7.15 with meconium). Use of IFHA in conjunction with EFM/NST could give better interpretation of foetal status.

Neilson [9] after Cochrane review advocated use of Foetal Electrocardiogram (ECG) for foetal monitoring during labour. His findings provided modest support to the use of fetal ST waveform analysis when a decision has been made to undertake continuous electronic FHR monitoring during labour.

Simple assessment techniques need to be widely available for diagnosis of non reassuring foetal status or FD. The clinician should reconsider the diagnosis made by FHR changes alone i.e. IFHA & electronic foetal heart monitoring, and should interprete findings with some reservations due to limited accuracy in diagnosing foetal hypoxia, asphyxia and subsequent neonatal outcome.

The CS for FD with doubtful authenticity continue, due to defensive practices by clinicians worldwide, fear of litigation associated with poor labour outcome. More accurate techniques of foetal assessment, need to be available for wide use. So research must continue. Further research is also needed for non-conventional or unknown risk factors, which might be responsible for fetal asphyxia, there by leading to diagnosis of FD, also for establishing the authenticity of the diagnosis of non-reassuring fetal status, as well as appropriateness of the interventions done for the same.

Acknowledgement

We thank the patients for their consent and cooperation.

References

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