Original Article

Cesarean Section for Suspected Fetal Distress, Continuous Fetal Heart Monitoring and Decision to Delivery Time K.K. Roy, Jinee Baruah, Sunesh Kumar, A.K. Deorari, J.B. Sharma and Debjyoti Karmakar Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences, New Delhi, India

ABSTRACT Objective. To find out the efficacy of continuous fetal heart monitoring by analyzing the cases of cesarean section for nonreassuring fetal heart in labor, detected by cardiotocography (CTG) and correlating these cases with perinatal outcome. To evaluate whether a 30 minute decision to delivery (D-D) interval for emergency cesarean section influences perinatal outcome. Methods. This was a prospective observational study of 217 patients who underwent cesarean section at ≥ 36 weeks for non-reassuring fetal heart in labor detected by CTG. The maternal demographic profile, specific types of abnormal fetal heart rate tracing and the decision to delivery time interval were noted. The adverse immediate neonatal outcomes in terms of Apgar score <7 at 5 minutes, umbilical cord þH <7.10, neonates requiring immediate ventilation and NICU admissions were recorded. The correlation between non-reassuring fetal heart, decision to delivery interval and neonatal outcome were analyzed. Results. Out of 3148 patients delivered at ≥ 36 weeks, 217 (6.8%) patients underwent cesarean section during labor primarily for non-reassuring fetal heart. The most common fetal heart abnormality was persistent bradycardia in 106 (48.8%) cases followed by late deceleration in 38 (17.5%) cases and decreased beat to beat variability in 17 (7.8%) cases. In 33 (15.2%) babies the 5 minutes Apgar score was <7 out of which 13 (5.9%) babies had cord þH <7.10. Thirty three (15.2%) babies required NICU admission for suspected birth asphyxia. Rest 184 (84.7%) neonates were born healthy and cared for by mother. Regarding decision to delivery interval of ≤30 minutes versus >30 minutes, there was no significant difference in the incidence of Apgar score <7 at 5 minutes, cord pH <7.10 and new born babies requiring immediate ventilation. But the need for admission to NICU in the group of D-D interval ≤ 30 minutes was significantly higher compared to the other group where D-D interval was >30 minutes. Conclusion. Non-reassuring fetal heart rate detected by CTG did not correlate well with adverse neonatal outcome. There was no significant difference in immediate adverse neonatal outcome whether the D-D time interval was ≤ 30 minutes or >30 minutes; contrary to this, NICU admission for suspected birth asphyxia in ≤ 30 minutes group was significantly higher. [Indian J Pediatr 2008; 75 (12) : 1249-1252] E-mail : [email protected] Key words: CEFM; Fetal distress; Cesarean section; Decision-delivery time; Perinatal outcome

Suspected fetal distress detected by cardiotocography (CTG) has been the most common indication for cesarean section (CS) for the past few decades. Many fetuses show heart rate changes without being adversely affected and CTG has been criticized to create an unnecessary high rate of operative deliveries. 1,2,3 Therefore there is a need to know which fetal heart abnormalities may lead to adverse neonatal outcome. Another important issue is the decision to delivery (D-

D) interval for emergency CS after fetal distress is diagnosed. American College of Obstricians and Gynecologists (ACOG) in 1988 recommended that this time interval should be ≤ 30 minutes.4 However developing countries are characterized by delays in handling of obstetric emergencies5 and most delays occur in transferring the patient to the operation theatre and achieving effective anaesthesia.6,7 Recent studies have doubted not only the practicability of this 30 minutes D-D interval but also the proposed beneficial effect on perinatal outcome.8,9,10

Correspondence and Reprint requests : Dr. K.K.Roy Addional Professor 3rd Floor, Room No. 385, Teaching Block Department of Obstetrics and Gynaicology All India Institute of Medical Science, New Delhi- 110 029, India [Received October 06, 200 7; Accepted April 28, 2008]

With these two issues in mind we carried out this study to evaluate the cases of emergency cesarean section for non-reassuring fetal heart and its correlation with perinatal outcome and to examine whether D-D interval of 30 minutes influences the perinatal outcome

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K.K. Roy et al MATERIAL AND METHODS

RESULTS

This was a prospective, observational study conducted in our tertiary care centre. A total number of 217 patients underwent cesarean section in one unit for suspected fetal distress during labor. All these patients included were treated under one team of doctors in one unit. The inclusion criteria were gestational age ≥ 36 weeks, no fetal anomalies and non-reassuring fetal heart rate patterns detected by CTG not responding to conservative management. The conservative management included changing the maternal position, intravenous hydration and oxygen administration. Cases of abnormal presentation, multiple pregnancy, severe Intrauterine Growth Restriction (IUGR) and cesarean delivery for other primary indications were excluded from the study. The following outcome measures were documented in the maternal case sheets: maternal demographic profile, specific types of abnormal fetal heart rate tracing that prompted cesarean section, the precise decision to delivery interval, types of anaesthesia and intraoperative findings for any cause or effect of fetal distress. We also noted the following immediate neonatal outcome: the birth weight, Apgar score at 5 minutes, the umbilical cord þH in babies with low Apgar score, babies requiring immediate ventilation and admission to neonatal intensive care unit (NICU). The decision time was defined as when the senior resident on duty took the decision to perform the cesarean section. Informed consent was also taken at that time. The D-D interval was the time between the decision to perform the cesarean and the exact delivery time. Gestational age was estimated by a reliable last menstrual period and a first trimester sonographic examination. The data obtained was analyzed to correlate

From March 2002 to March 2007 in our unit, a total number of 3,148 patients were delivered ≥36 weeks period of gestation, out of which 217 (6.8%) patients

TABLE 1. Various Fetal Heart Abnormality Picked Up by CTG and Related Immediate Adverse Neonatal Outcome Abnormal Fetal heart abnormality

Number of Pateint

Adverse neonatal outcome AS<7 UA PH NICU at 5 Min <7.10 admission

Persistant bradycardia Recurrent late deceleration Variable deceleration Decreased beat to beat variability

106 (48.8%)

16

4

16

56 (25.8%)

10

5

10

38 (17.5%)

7

4

7

17 (7.8%)

Nil

Nil

Nil

AS - Apgar score UA - Umbilical artery NICU - Neonatal intensive care unit

the non-reassuring fetal heart and the D-D interval with adverse neonatal outcome. Statistical analysis was done with the help of student’s ‘t’ test and chi’ square test where appropriate and p<0.05 was considered significant. 1250

TABLE 2. Neonatal Outcome Among Parturient Who had Cesarean Section for Suspected Fetal Distress with D-D Interval ≤ 30 Minutes vs > 30 Minutes Neonatal outcome

D-D interval ≤ 30 min. (N-121)

D-D interval > 30 min. (N-96)

p-values

Means Birth 2850+340 2760+413 NS Weight (gms) Means birth 16/121(13.2%) 11/96(11.4%) NS Weight<2500 gms Apgar score 18/121(14.8%)* 15/96(15.6%)** NS <7 at 5 mins. Umbilical cord 8/121(6.6%) 5/96(5.2%) NS pH < 7.10 Neonatal requiring 4/121(3.3%) 2/96(2.08%) NS immediate ventilation Fresh still birth 1 nil Admission to 26(21.4%) 7(7.2%) <0.05(S) NICU NS - Not Significant S - Significant * 10 out of 18 pateints had AS < 4 at 5 mins. ** 3 out of 15 pateints had AS < 4 at 5 mins.

underwent cesarean section primarily for nonreassuring fetal heart during labor. The percentage of cesarean section for various indications among the total deliveries at 36 weeks or more was 16.2% (510/3,148). The various fetal heart abnormalities picked up by CTG for which cesarean section was done and associated immediate neonatal outcome are depicted in the table 1. The most common fetal heart abnormality for suspected fetal distress found was persistent bradycardia in 106 (48.8%) cases followed by late deceleration in 38 (17.5%) cases and decreased beat to beat variability in 17 (7.8%) cases. There were 34 (15.6%) patients who had more than one fetal heart abnormality. Out of 217 patients of cesarean section for suspected fetal distress, in 33 (15.2%) babies the 5 minute Apgar score was <7, TABLE 3. Indiactions of NICU Admissions Indications Severe birth asphyxia (apgar score <4 at 5 mins.) Moderate birth asphyxia (apgar score <7 at 5 mins.) TTN for observation

D-D interval ≤ 30 min.(n-26)

D-D interval >30 mins. (n-7)

10

3

8

2

8

2

TTN–Transient tachypnea of newborn

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Cesarean section for suspected fetal distress 13 (5.9%) babies had umbilical cord þH <7.10 and 33 (15.2%) babies required NICU admission. There were 184 (84.7%) neonates who did not show any adverse outcome.

When electronic fetal heart monitoring by cardiotocography was introduced 30 years ago, the aim was to identify fetuses affected by hypoxia during labor better. But no benefit in long term neonatal outcome has been shown and cesarean section rates have been reported to be increased by four folds.3,11 Various studies12,13 implicate that CTG interpretation is inconsistent, is at times inaccurate, may fail to predict early neonatal outcome and is subject of influence by the medicolegal climate. In the present study there was high incidence (6.8%) of cesarean delivery at ≥ 36 weeks primarily for non-reassuring fetal heart in labor. This was similar to other reported studies.12,13,14 The present study also showed that in 171 (78.8%) cases there was no detectable cause or effect of fetal distress found during cesarean section. This

demonstrated the limitation of CTG in the present study. But in this medicologal era ‘play safe’ attitude was also adopted by us and resulted in high incidence of cesarean section at ≥36 weeks for non-reassuring fetal heart. To improve this situation the concept of detecting fetal acidosis using fetal scalp blood sampling appeared attractive, but practical difficulties in carrying it out have restricted its use.15,16 These limitations of fetal heart monitoring and fetal blood sampling have led to the introduction of fetal electrocardiogram (ECG) which has been subjected to more investigation recently. Various randomized controlled trials17,18 showed that addition of ST analysis to conventional CTG improved the specificity of intrapartum monitoring and thereby reducing the rate of operative deliveries for fetal distress. Recently Vayssiere et al19 in 2007 reported that, in a population with abnormal fetal heart rate in labor ST-segment analysis (STAN) sensitivity is moderate (almost 40%) for predicting pH = 7.15 and better (almost 60%) for severe acidosis (þH <7.05). Therefore we strongly feel, fetal ECG system needs to be introduced in addition to conventional CTG wherever possible including our centre to reduce the rate of unnecessary cesarean section at term for nonreassuring fetal heart. Since the rate of cesarean section done for suspected fetal distress is increasing, it is important to monitor the D-D interval in evaluating the quality of maternity care and to find out the ideal D-D interval time for better neonatal outcome. The ACOG Committee’s recommendation4 of 30 minutes D-D interval time for cesarean section for fetal distress is arbitrary. Moreover, this recommendation does not appear to be an evidence based rule9,10, but has the approval of respected authorities including medicolegal bodies.20 Chauhan et al9 in his study of 117 patients of cesarean section for fetal distress concluded that, although a cesarean section with a D-D interval ≤ 30 minutes is a desirable goal, failure to achieve this goal is not associated with a measurable negative impact on the newborn. Bloom et al21 in his large study of 2808 patients of emergency cesarean section showed that when the D-D interval was more than 30 minutes, 95% of these neonate did not experience adverse outcome. Similar evidence that “achieving the 30 minute standard does not benefit the infant” has been reported in other studies.22,23 In the present study we have found that there was no significant difference in Apgar score <7 at 5 minutes, umbilical cord þH <7.10 and newborn requiring immediate ventilation in both the groups, but the admission to NICU was significantly higher in the group where D-D interval ≤ 30 minutes. Though the mean DD time interval for the whole group was 38 minutes and the real difference between two groups with regard to time was marginal, we found majority of cases (22/26), where NICU admission in <30 minutes group was required, the D-D interval was actually ≤24 minutes. The incidence of asphyxia was higher in these patients where a crash attitude was followed to perform CS early. One possible explanation for increased NICU admission in this group is that a crash attitude to shorten the D-D interval may in fact provoke

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Regional anaesthesia was given in 198 (91.2%) cases and the remaining 19 (8.7%) patients required general anaesthesia. The mean D-D interval time in 217 patients who underwent cesarean section for fetal distress was 38.2 ± 12.5 minutes. For 121 (55.7%) of these patients the decision to delivery time interval was ≤ 30 minutes and in rest 96 (44.9%) patients, this D-D interval was > 30 minutes. The comparison of neonatal outcome between these two groups of patients is given in table 2. The birth weights of babies <2500 gms were similar between the two groups (13.4% in ≤ 30 minutes group vs 11.4% in >30 minutes group). There was no significant difference in the incidence of Apgar score <7 at 5 minutes, umbilical cord þH <7.10 and newborn babies requiring immediate ventilation in both the groups. The indications of NICU admission in two groups are given in table 3. There were 10 cases of severe birth asphyxia (AS<4 at, 5 minutes) and 8 cases of moderate birth asphyxia (AS<7 at 5 minutes) in ≤ 30 min group compared to 3 cases and 2 cases of severe asphyxia and moderate asphyxia respectively in the other group. We found admission to NICU in the group of D-D time ≤30 minutes was significantly higher compared to the other group of D-D time >30 minutes (21.4% vs 7.2%, p<0.05). This was due to higher incidence of birth asphyxia in the former group. There was one fresh still birth where D-D interval was <30 minutes and the still birth was due to placental abruption. When we analyzed the intraoperative findings of all these cesarean section cases, we found that 18(8.2%) patients had thick meconium stained liquor in the hind waters, 17(7.8%) babies had two or more tight loops of cord around the neck, and in 11(5.1%) patients there was retroplacental clot with blood stained liquor. In the remaining 171(78.8%) patients there was no detectable cause or effect of fetal distress. DISCUSSION

K.K. Roy et al increased maternal catecholamine release which may cause reduced perfusion of the placental bed leading to fetal acidosis.24 On the other hand the fetuses in the group of D-D interval >30 minutes were exposed more to intrauterine resuscitation in the form of left lateral position of mother, intravenous hydration and oxygen administration. These may have facilitated the distressed fetuses to recover from hypoxia to some extent. However this should not be concluded that in cesarean section for fetal distress the D-D interval of >30 minutes is desirable. But all cases of nonreassuring fetal heart during labor should attain thorough intrauterine resuscitation and a crash attitude to shorten D-D interval should be avoided. It is also important to note that, similar to other reports, in the present study there were neonates who required immediate ventilation and there was one fresh still birth in the ≤ 30 minutes D-D interval group. It is therefore more important to differentiate between the fetus who requires prompt delivery and the fetus not in acute distress, who could be reflecting recent or remote insults, the after effects of which would be unaffected by speedy delivery. Therefore in addition to CTG, other technologies for intrapartum fetal monitoring e.g., fetal ECG may be helpful to detect actual fetal distress. CONCLUSION In our observation we found that non-reassuring fetal heart detected by CTG did not correlate well with adverse neonatal outcome and this resulted in high incidence of unnecessary cesarean section rate at ≥36 weeks during labor. There was significantly higher NICU admission rate due to asphyxia in the ≤30 minutes group. The crash attitude to shorten the D-D interval to ≤ 30 minutes may not be beneficial to improve neonatal outcome. Fetal ECG along with CTG may be helpful to pick up actual fetal distress and thereby may reduce the incidence of operative delivery. REFERENCES 1. Hornbuckle J, Vail A, Abrans KR, Thornton JG. Bayesian interpretation of trials: the example of intrapartum electronic fetal heart rate monitoring. Br J Obstet Gynaecol 2000; 107: 3-10. 2. Olofsson P. Current status of intrapartum fetal monitoring: cardiotocography versus cardiotocography + ST analysis of the fetal ECG. Eur J Obstet Gynaecol Rep Biol 2003; 110: S113-S118. 3. Nielson JP, Grant AM. The randomized trails of intrapartum electronic fetal monitoring. In Spencer JA, Ward RH, eds. Intrapartum fetal surveillance. London; RCOG Press, 1993. 4. American college of Obstetricians and Gynecologists: Guidelines for Vaginal Delivery after a Previous Cesarean Birth, ACOG Committee Opinion No. 64. Washington; DC, ACOG, 1988. 5. Onah EE, Ibeziako N, Umezulike AC, Effetie ER, Ogboukiri CM. Decision – delivery interval and perinatal outcome in emergency caesarean sections. J Obstet Gynaecol 2005; 25: 342-346.

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