Abstract
Objective. To elucidate whether there is a distention of the symphysis pubis intra partum and whether a history of pelvic pain during pregnancy is associated with increased distention during delivery. Methods. Using ultrasonography, the width of the symphysis pubis was measured on two occasions during delivery; firstly, upon engagement of the fetal head in the pelvic inlet, secondly, when the largest diameter of the fetal head was at the level of the ischiadic spines. The first measurement was conducted in 24 patients, the second measurement was obtained in 16 of these patients. Results. The average width of the symphysis pubis at onset of labor was 5.8 mm. The average distention of the symphysis during labor was 1.1 mm for those without pelvic pain and 0.2 mm for those with a history of pelvic pain during pregnancy (p = 0.02). Parity and ensuing birth weight had no statistically significant influence on degree of distention. Conclusion. The symphyseal distention during labor is minimal regardless of parity and size of the child. No added symphyseal distensibility was found in patients with a history of pelvic pain.