Table 3 Outcomes reported in included records

Maternal outcomes

Labour pain

  - Pain score

35

(92.1)

5

(41.7)

0

(0.0)

40

(78.4)

Maternal assessment

  - Blood pressure

28

(73.7)

4

(33.3)

0

(0.0)

32

(62.7)

  - Maternal Heart Rate

19

(23.7)

4

(33.3)

0

(0.0)

23

(45.1)

  - Respiratory Rate

17

(44.7)

3

(25.0)

0

(0.0)

20

(39.2)

  - Motor block

15

(39.5)

1

(8.3)

0

(0.0)

16

(31.4)

  - SPO2

9

(23.7)

3

(25.0)

0

(0.0)

12

(23.5)

  - Sensory level

10

(26.3)

0

(0.0)

0

(0.0)

10

(19.6)

  - Vital signs

2

(5.3)

0

(0.0)

0

(0.0)

2

(3.9)

  - Fever

1

(2.6)

0

(0.0)

0

(0.0)

1

(2.0)

Delivery outcomes

  - Mode of delivery

20

(52.6)

9

(75.0)

0

(0.0)

29

(56.9)

  - Duration of labour

16

(42.1)

5

(41.7)

0

(0.0)

21

(41.2)

  - Induction of labour

7

(18.4)

8

(66.7)

0

(0.0)

15

(29.4)

  - Duration/Frequency of contraction

7

(18.4)

1

(8.3)

0

(0.0)

8

(15.7)

  - Duration of postpartum hospital stay

1

(2.6)

3

(25.0)

0

(0.0)

4

(7.8)

Analgesia

  - Duration of analgesia

19

(23.7)

4

(33.3)

0

(0.0)

23

(45.1)

  - Plasma/CSF fentanyl concentration

6

(15.8)

2

(16.7)

0

(0.0)

8

(15.7)

  - Request for additional analgesia

5

(13.2)

1

(8.3)

0

(0.0)

6

(11.8)

  - Time to request additional analgesia

4

(10.5)

0

(0.0)

0

(0.0)

4

(7.8)

Adverse effects

  - Nausea

25

(65.8)

3

(25.0)

0

(0.0)

28

(54.9)

  - Vomiting

25

(65.8)

3

(25.0)

0

(0.0)

28

(54.9)

  - Pruritus

25

(65.8)

1

(8.3)

0

(0.0)

26

(51.0)

  - Sedation

21

(55.3)

3

(25.0)

0

(0.0)

24

(47.1)

  - Headache

5

(13.2)

0

(0.0)

0

(0.0)

5

(9.8)

  - Shivering

4

(10.5)

0

(0.0)

0

(0.0)

4

(7.8)

  - Neurological symptoms (numbness, leg weakness)

4

(10.5)

0

(0.0)

0

(0.0)

4

(7.8)

  - Subjective maternal adverse effects

2

(5.3)

0

(0.0)

0

(0.0)

2

(3.9)

  - Nasal irritation

1

(2.6)

0

(0.0)

0

(0.0)

1

(2.0)

  - Post-partum haemorrhage

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)

  - Use of bag mask ventilation

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)

  - Maternal intubation

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)

  - Maternal naloxone

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)

  - Maternal SpO2 < 90

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)

Maternal stress

  - Norepinephrine and Epinephrine concentration in maternal blood

1

(2.6)

0

(0.0)

0

(0.0)

1

(2.0)

Breastfeeding status/problems

  - Breastfeeding status/problems

2

(5.3)

4

(33.3)

1

(100)

7

(13.7)

Satisfaction

  - Satisfaction on pain relief

7

(18.4)

1

(8.3)

1

(100)

9

(17.6)

Neonatal outcomes

  - Foetal Heart Rate

31

(81.6)

2

(16.7)

0

(0.0)

33

(64.7)

  - Apgar score

23

(60.5)

9

(75.0)

0

(0.0)

32

(62.7)

  - Cord blood gases

14

(36.8)

5

(41.7)

0

(0.0)

19

(37.3)

  - Birthweight

9

(23.7)

7

(58.3)

0

(0.0)

16

(31.4)

  - Naloxone requirement

9

(23.7)

5

(41.7)

0

(0.0)

14

(27.5)

  - Neurologic & Adaptive Capacity Score

10

(26.3)

0

(0.0)

0

(0.0)

10

(19.6)

  - Resuscitation efforts

4

(10.5)

4

(33.3)

0

(0.0)

8

(15.7)

  - NICU/Nursery admission

1

(2.6)

4

(33.3)

0

(0.0)

5

(9.8)

  - Neonatal fever

2

(5.3)

1

(8.3)

0

(0.0)

3

(5.9)

  - Neonatal SPO2

3

(7.9)

0

(0.0)

0

(0.0)

3

(5.9)

  - Time to establish breathing

1

(2.6)

2

(16.7)

0

(0.0)

3

(5.9)

  - Congenital anomalies

1

(2.6)

1

(8.3)

0

(0.0)

2

(3.9)

  - Fetal body movement

2

(5.3)

0

(0.0)

0

(0.0)

2

(3.9)

  - Requirement of CPAP

1

(2.6)

1

(8.3)

0

(0.0)

2

(3.9)

  - Skin cyanosis

1

(2.6)

0

(0.0)

0

(0.0)

1

(2.0)

  - Requirement of Epinephrine

0

(0.0)

1

(8.3)

0

(0.0)

1

(2.0)