Role of pathological cardiotocography in evaluating fetal well-being.

OBJECTIVE

To determine the frequency of pathological pattern of cardiotocography (C.T.G) in antepartum and intrapartum period and to evaluate the significance of those patterns in determining fetal well-being.

DESIGN

Analytical study.

PLACE AND DURATION OF STUDY

The study was conducted at Lady Dufferin Hospital, Karachi from February 2000 to January 2001.

PATIENTS AND METHODS

All women with singleton pregnancies of >35 weeks gestation and cephalic presentations were electronically monitored in antepartum and intrapartum period and those with pathological trace were identified according to International Federation of Obstetricians and Gynaecologists (FIGO) classification. After delivery, Apgar score, fetal cord, blood gas values and neonatal intensive care unit admission duration were examined as the main outcome measures.

RESULTS

Among the 3701 patients who qualified for the study, 60 (1.62%) had tracing, classified as pathological, of which 44 (73%) were in the intrapartum and 16 (27%) in the antepartum period. Out of these 60 patients, 53 (88.33%) were delivered alive while neonatal death (NNDs) occurred in 9 (16.9%) of the live born babies. There were 07 (11.6%) still births. In 53 of live born babies, Apgar score was <7 at 1 minute in 34 (64.15 %), while it was >7 at 1 minute in 19 (35.84%). Low Apgar score persisted at 5 minutes in 10 (18.86%) cases of pathological CTG. Out of these 10, there were 3(30%) NNDs, while 6 (13.95%) NNDs occurred in those whose apgar had improved to >7 at 5 minute (P=0.9). Cord pH results were available in 31 (58.49 %) cases and were acidotic (<7.20) in 16 (51.61%), pre-acidotic (7.20-7.25) in 9 (29.03%) and normal (7.25-7.35) in 6 (19.35 %). All alive born babies with a pathological CTG tracing were admitted in NICU as per hospital policy. The duration of admission was less than 24 hours in 15 (28.30 %), 2-4 days in 26 (49%) and more than 4 days in 12 (22.64%).

CONCLUSION

In this series, an increased frequency of detectable hypoxia on CTG was observed during the intrapartum period as compared to the antepartum period, however, no significant association was found between a pathological CTG recording, fetal APGAR score and acidemia, if a pathological trace is used alone to assess fetal well-being. An increased cesarean section rate in babies with a pathological CTG stresses on the need for additional tests to differentiate hypoxic from non-hypoxic fetuses thus avoiding unnecessary intervention.