A randomized prospective study comparing delivery with metal and silicone rubber vacuum extractor cups.

OBJECTIVE

To determine the relative benefits and complications of assisted vaginal delivery with metal and silicone rubber vacuum extractor cups.

DESIGN

Prospective randomized controlled study.

SETTING

A busy referral maternity hospital in Kathmandu, Nepal.

SUBJECTS

101 women were assigned to delivery with the Silc-cup and 98 to delivery with the metal cup.

MAIN OUTCOME MEASURES

Success rate at achieving delivery with the assigned instrument and incidence of neonatal trauma. Analysis was by 'intention to deliver' with women remaining in their original group regardless of the eventual mode of delivery.

RESULTS

Randomization resulted in two groups of women similar in respect of age, parity, gestation and indication for delivery. The overall success rate was similar for the two instruments (Silc-cup 85% and metal cup 87%). The Silc-cup was more likely to fail if there was excessive caput (seven failures compared with one in the metal cup group). The frequency of clinically significant maternal trauma was low in both groups. There were fewer babies with clinically significant scalp trauma in the Silc-cup group (22%), compared with the metal cup group (37%).

CONCLUSIONS

The data indicate a greater tendency for the Silc-cup to fail when excessive caput is present but that metal cups are associated with increased scalp injuries.