Pelvic floor biometry during a first singleton pregnancy and the relationship with symptoms of pelvic floor disorders: a prospective observational study

Objective To assess pelvic floor biometry during pregnancy and the correlation with symptoms of pelvic floor disorders in women. Design A prospective observational study. Setting Antenatal clinic between A ugust 2009 and M ay 2011. Population Nulliparous women in their first pregnancy. Methods Pelvic floor was assessed by translabial ultrasound and symptoms of pelvic floor disorders were explored with a standardised questionnaire at each trimester. Main outcome measures Pelvic floor biometry during pregnancy. Results A total of 405 (91.6%) women completed the study. As the pregnancy advanced, there was significant descent of the bladder neck ( BN ), cervix, and anorectal junction. The hiatal area ( HA ) was significantly enlarged, with a mean increase of 15.1 ± 24.8% at rest, and 24.7 ± 28.5% at Valsalva, at third trimester when compared with first trimester. Risk factors for stress urinary incontinence ( SUI ) were: descent of BN at V alsalva ( OR  3.2, 95%  CI 1.2–8.5), increase in HA at pelvic floor contraction ( PFMC ; OR  1.3, 95%  CI 1.0–1.6), and increase in maternal age ( OR  1.1, 95%  CI 1.0–1.2), at first trimester; increase in HA at PFMC ( OR  1.3, 95%  CI 1.1–1.5) at second trimester; and descent of BN at rest ( OR  2.3, 95%  CI 1.1–4.9) and increase in maternal age ( OR  1.1, 95%  CI 1.02–1.2) at third trimester. Descent of anorectal junction ( OR  1.5, 95%  CI 1.1–1.9) and increase in HA at rest ( OR  1.2, 95%  CI 1.0–1.3) were factors for prolapse symptoms at second and third trimester, respectively. Conclusions Pelvic floor changes begin during pregnancy. There was significant descent of the BN , cervix, and anorectal junction, and enlargement of the hiatal area, as the pregnancy advanced. SUI was associated with descent of the BN , and prolapse symptoms were associated with an increase in the hiatal area.