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ADMISSION TEST FOR SCREENING LABOUR

K R Chaudhari*, S S Pai**
Lecturer, *KEM, **Bhabha Hospital, Mumbai.

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Various antepartum conditions contribute to foetal morbidity/mortality. The admission test helps indicating foetal well being non invasively. Taking a short recording of foetal heart rate on admission helps us to determine the ability of foetus to withstand stress of labour.

We report below 50 normal as well as high risk patients.

Since time immemorial man has strewed to hear the healthy thimp of a baby in utero. We have come a long way from direct auscultation through the Pinnard’s foetoscope to the present day sophisticated continuous foetal monitoring.

There are various antepartum conditions and intrapartum events which contribute to foetal morbidity and mortality even in the so called low risk group.

Admission test today tries to indicate the foetal well being non invasively. Thus taking a short recording of foetal heart rate on admission helps us to determine the ability of the foetus to withstand the stress of labour.

50 normal as well as high risk patients were screened by admission test. Patients in second stage of labour were excluded from the study.

MATERIAL AND METHODS

A 20 minute cardiotocographic tracing was taken on corometrics at admission to labour ward. A repeat tracing was done after 1-2 hours for those patients who had an equivocal test and in those who were in labour for more than 6 hours.

The result of admission test were categorised into reactive, ominous and equivocal.

A reactive test is the one with normal baseline foetal heart rate and variability with two accelerations of 15 beats above baseline for 15 seconds and with no post contraction deceleration.

An equivocal test is a trace with no acceleration in addition to one abnormal feature such as reduced baseline variability or presence of a post contraction deceleration or baseline tachycardia or bradycardia.

Ominous trace refers to more than one abnormal feature, decreased beat to beat variability and repeated late decelerations.

Table 1
Primigravida	23
Multigravida	27

In our study out of 50 cases 23 were primi and 27 were multi-gravidas.

Table 2
	No.
Registered	36
Unregistered	14

36 had antenatal registration and 14 were unregistered.

37 of the patients had high risk factors like PIH, IUGR, PROM, Postdatism. A few of these patients had multiple high risk factors.

Out of 50 cases 37 had reactive admission test, 5 had ominous cases and 08 had an equivocal tracing. In the equivocal tracing repeat test was done after one/two hrs. which was reactive in all 8 cases. 5 patients of these had normal deliveries and 3 had instrumental deliveries.

Table 3
	No
PIH	12
PIH IUGR	07
PROM	06
Diabetes	01
Post datism	05
BOH	06

Table 4
Outcome of Admission test
Total No of cases 50
Reactive AT	Omnious AT	Equivocal AT
37	5 | Emergency LSCS	8 | Repeat AT after 2 hrs. | Reactive                  /                 \               Instrumental deliveries 3     Normal Deliveries 5

 

Table 5
Labour outcome in reactive AT
Total no of cases - 37
Within 6 hrs	After 6 hrs.
20        3          2 |         |          | Nor   Inst     LSCS Vag.  Deli.   Foetal                       Distress Del   veries  Nonprogress	Repeat CTG | 12 /                \ 9                       3 Reactive               Omnious normal deliveries              emergency LSCS

Ideally all of the 5 ominous cases would have to undergo a foetal scalp blood sampling. However due to lack of facilities these patients were taken up for emergency caesarean section.

Out of the 37 reactive admission tests 25 delivered within 6 hrs. Out of these 20 had normal vaginal deliveries, 3 had instrumental deliveries and 2 had to undergo emergency LSCS.

A repeat tracing was done in 12 cases in whom the duration of labour extended beyond 6 hrs. of these 9 were reactive and had normal vaginal deliveries. 3 patients had an ominous tracing and underwent emergency LSCS.

Table 6
Intrapartum Events :	Correlated to AT
	Reactive	Ominous	Equivocal
	37	05	08
Uneventful	28	—	—
Meconeum	03	—	05
Foetal distress	05	05	—
Prolonged II stage	03	—	02
Shoulder dystocia	—	—	01
	39	05	08

Table 7
Neonatal Outcome
AT	No. of Cases	Apgar at 5 min.
Reactive	19	9/10
< 6 hrs.	06	7/10
> 6 hrs. Repeat	10	9/10
Ominous	02	7/10
LSCS
Ominous
LSCS	04	9/10
	01	3/10
Equivocal
(No LSCS)	05	9/10
5 Normal	03	6/10
3 instrumentaldeliveries

Few patients had more than one event.

Correlating the intrapartum events with AT most of the patients with reactive tracing had an uneventful delivery. However despite a reactive AT. 03 patients developed meconium stained liquor and foetal distress of which 2 underwent LSCS.

Of the 8 equivocal cases 5 had meconium stained liquor 2 had prolonged second stage and all delivered normally. All 5 patients with ominous tracing had foetal distress and underwent LSCS.

With neonatal outcome in view most of the patients with reactive AT had neonates with a good apgar of 9/10 at 5 minutes.

6 cases however had an apgar of 7/10 at 5 minutes though the AT was reactive.

Out of the 5 ominous cases 4 had an apgar of 9/10 and one had 3/10 apgar at 5 minutes.

In the equivocal category more than 50% of the cases had an apgar of 9/10.

CONCLUSION

Table 8
AT	% AT	% Foetal distress
Reactive	74	13.5
Equivocal	16	3.4
Ominous	10	100
Sensitivity	31.3
Specificity	95.3

Admission Test is an extremely important screening test to predict neonatal outcome.

Ominous test - Severely compromised foetus, should never be ignored.

Positive predictive value - 31.3%

Negative predictive value - 95.3%

Thus all patients in labour should undergo the admission test.

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