Persistent occiput posterior position: predictive factors of spontaneous rotation of the fetal head

Figures & data

Figure 1. Flowchart.

OPP: Occiput Posterior Position; NRFC: Non-Reassuring Fetal Condition.

Table 1. Demographic and obstetrical outcomes.

	Spontaneous rotation n = 78	No spontaneous rotation n = 410	p
Maternal weight (kg)	64.7 (13.5)	64.6 (14.2)	.73
Maternal height (cm)	165.7 (6.9)	163.9 (5.7)	.02
Maternal BMI (kg/m²)	23.5 (4.4)	24.1 (5.2)	.57
Maternal Age (years)	30.2 (5.5)	29.8 (5.2)	.54
Parity, n (%)
Nulliparous	33 (42%)	230 (56%)	.03
Parous	45 (58%)	180 (44%)
Unscarred uterus, n (%)	74 (95 %)	380 (93%)	.65
No gestational diabetes, n (%)	67 (86%)	365 (89%)	.55
Epidural analgesia, n (%)	71 (91.0%)	391 (95%)	.16
Term (WG)	39.6 (1.6)	39.5 (2.0)	.83
Male fetus, n (%)	44 (56%)	215 (52%)	.60

Continuus data are shown in mean (standard deviation).

Abbreviations: WG: Weeks of Gestation; BMI: Body Mass Index.

Table 2. Duration of the different stages of labor (means, in hours and in minutes).

Durations (mean, standard deviation)	Spontaneous rotation n = 78	No spontaneous rotation n = 410	p
First stage duration (minutes)	236.7 (138.3)	334.2 (210.6)	<.01
First stage duration (hours)	3.9 (2.3)	5.5 (3.5)	<.01
Delay FD – start of EE (minutes)	76.9 (55.3)	91.6 (53.1)	.02
Delay FD – start of EE (hours)	1.3 (0.92)	1.5 (0.88)	.02
Duration of EE (minutes)	11.8 (9.4)	17.0 (10.6)	<.01
Total duration of second stage (minutes)	88.8 (61.4)	108.0 (58.1)	<.01

Abbreviations: FD: Full Dilation; EE: Expulsive Efforts.

Table 3. Maternal and fetal outcomes.

	Spontaneous rotation n = 78	No spontaneous rotation n = 410	p
Episiotomy, n (%)	20/78 (25.6 %)	203/388^a (52.3%)	<.01
Post-partum hemorrhage, n (%)	2/78 (2.6%)	36/410 (8.8%)	.1
Instrumental delivery, n (%)	7/78 (8.9%)	194/388^a (50.0%)	<.01
Cesarean section, n (%)	0/78 (0%)	22/410 (5.4%)	.03
Apgar score <7 at 5 min, n (%)	1/78 (0,01%)	3/410 (0.0%)	.5
Umbilical arterial pH <7.0, n (%)	1/78 (0.01%)	2/410 (0.0%)	.41
Shoulder dystocia, n (%)	1/78 (1.3%)	4/410 (1%)	.58
Cephalic trauma, n (%)	0/78 (0%)	5/410 (0.1%)	1
Transfer in neonatal care unit, n (%)	2/78 (2.6%)	23/410 (5.6%)	.40

Continuous data are shown in mean (standard deviation).

^a388 vaginal deliveries.

Figure 2. Probability of spontaneous rotation at full dilation, depending on the duration of the first stage of labor.

Table 4. Univariable analysis by simple logistic regressions for the probability of spontaneous rotation; then multivariable analysis by multiple logistic regression (step-by-step descending selection).

Variables analyzed	OR [CI 95%]	Adjusted OR [CI 95%]
Maternal weight (kg) in quartiles
[38; 55[	1	NS
[55; 62[	1.30 [0.65; 2.65]
[62; 71[	1.21 [0.59; 2.51]
[71; 149]	1.04 [0.51; 2.17]
Maternal height (cm) in quartiles
[140; 160[	1	NS
[160; 164.5[	0.77 [0.35; 1.69]
[164.5; 168[	1.11 [0.50; 2.52]
[168; 178]	1.76 [0.89; 3.66]
Maternal BMI (kg/m²) in quartiles
[15.9; 18.5[	1	NS
[18.5; 25[	1.08 [0.45; 3.30]
[25; 30[	1.56 [0.58; 4.98]
[30; 48.7]	0.56 [0.14; 2.16]
Maternal age (years) in quartiles
[16; 26)	1	NS
[26; 29)	1.45 [0.70; 3.15]
[30.; 33)	1.47 [0.69; 3.27]
[33; 44]	1.27 [0.60; 2.81]
Parity
Nulliparous	1	NS
Parous	1.74 [1.07; 2.86]
Unscarred uterus
No	1	NS
Yes	0.68 [0.20; 1.80]
Gestational diabetes
No	1	NS
Yes	1.33 [0.63; 2.62]
Epidural analgesia
No	1	NS
Yes	0.49 [0.21; 1.30]
Term (WA)
< 37	1	NS
[37; 40]	1.58 [0.53; 6.83]
> 40	1.29 [0.40; 5.76]
Fetal sex
Male	1	NS
Female	0.85 [0.52; 1.39]
Birth weight (g) in quartiles
[805,3028)	1	NS
[3028,3340)	0.86 [0.44; 1.69]
[3340,3650)	0.78 [0.39 ; 1.54]
[3650,4700]	0.83 [0.42 ; 1.63]
Birth size (cm) in quartiles
[42.5 ; 48)	1	NS
[48 ; 49)	1.06 [0.49 ; 2.23]
[49 ; 50)	0.68 [0.30 ; 1.48]
[50 ; 54]	0.89 [0.48 ; 1.66]
Cephalic perimeter (cm) in quartiles
[24 ; 33)	1
[33 ; 34)	0.73 [0.31 ; 1.77]
[34 ; 35)	0.68 [0.30 ; 1.57]
[35 ; 39]	0.90 [0.43 ; 1.99]	NS
Duration of first stage (hours)
[0; 3[	1	1
[3; 5[	1.19 [0.65; 2.23]	1.19 [0.65; 2.23]
[5; 7[	0.47 [0.20; 1.02]	0.47 [0.20; 1.02]
[7; 18]	0.39 [0.19; 0.77]	0.39 [0.19; 0.77]
Duration of first stage (hours)
< 7	1	1
≥ 7	0.43 [0.23; 0.76]	0.43 [0.23; 0.76]

Abbreviations: NS: not significant. BMI: Body Mass Index; WG: Weeks of Gestation.

This model included every factor statistically associated with spontaneous rotation. Our model was based on a descending stepwise multivariate analysis which retained no other adjustment variable than the duration of the 2nd stage in the final analysis. This explains why the OR and adjusted OR are identical.

Table 5. Posthoc analysis: comparison of maternal and neonatal outcomes, between “spontaneous rotation” and “manual rotation.”

	Spontaneous rotation n = 78	Manual rotation n = 219	p
Episiotomy, n (%)	20/78 (25.6 %)	100/219 (45.7%)	<.01
Post-partum hemorrhage, n (%)	2/78 (2.6%)	18/219 (8.2%)	.15
Instrumental delivery, n (%)	7/78 (8.9%)	83/219 (37.9%)	<.01
Cesarean section, n (%)	0/78 (0%)	0/219 (0%)	1
Apgar score at 5 min < 7, n (%)	1/78 (0,01%)	0/219 (0 %)	.26
Umbilical arterial pH <7.0, n (%)	1/78 (0.01%)	0/219 (0 %)	.26
Shoulder dystocia, n (%)	1/78 (1.3%)	0/219 (0%)	.26
Cephalic trauma, n (%)	0/78 (0%)	1/219 (0.5%)	1
Transfer in neonatal care unit, n (%)	2/78 (2.6%)	13/219 (5.9%)	.37
Birth weight (grams)	3284.5 (480.7)	3375.6 (550.9)	.20
Birth size (cm)	48.7 (2.1)	49.2 (1.99)	.07
Cephalic perimeter at birth (cm)	34.2 (1.5)	34.2 (0.7)	.97

Abbreviations: NS: not significant.

Continuous data are shown in mean (standard deviation).