Level 2: Mid-level evidence
Pregnant women should be encouraged to give birth in the position they find most comfortable, as no clear benefits or risks of various delivery positions have been demonstrated in methodologically stringent trials. This conclusion is based on a systematic review of 19 trials of variable quality with 5,764 women (Cochrane Database Syst Rev. 2004;:CD002006).
Tentative findings suggest several possible benefits for upright posture, which must be weighed against the possibility of increased risk of blood loss >500 mL. Compared with supine or lithotomy positions, the use of any upright or lateral position was associated with reduced duration of second stage of labor (10 trials, mean 4.3 minutes), a small reduction in assisted deliveries (18 trials, NNT 59), a reduction in episiotomies (12 trials, NNT 16), less reporting of severe pain during second-stage labor (one trial, NNT 8), and fewer abnormal fetal heart-rate patterns (one trial, NNT 33). However, upright or lateral positioning was associated with an increase in second-degree perineal tears (11 trials, NNH 37) and an increased estimated risk of blood loss >500 mL (11 trials, NNH 34).
A recent study evaluated positioning in 271 primiparous women with normal pregnancy and a singleton fetus in the cephalic presentation (BJOG. 2006;113:165-170). Participants were in spontaneous labor at 37-42 weeks’ gestation and randomized to kneeling position (leaning toward head of delivery bed or cushion) vs. sitting position (head of bed raised at least 60°) in the second stage of labor until the child was crowning. Comparing the kneeling group vs. the sitting group, 77% vs. 84% completed the trial as randomized. There were no significant differences in duration of second-stage labor (48.5 vs. 41 minutes). Using a visual analog scale from 0-100, scores were 37 vs. 69 for “Did you experience the second stage as long?”(P = .002) and 17 vs. 33 for “How much pain did you experience in the assigned position?” (P = .01). The kneeling group had significantly reduced feelings of discomfort, vulnerability, exposure, difficulty, and postpartum perineal pain.