Frequency and nocturia are the commonest and the earliest symptoms to develop in pregnancy [3]. These occur as early as the first trimester because of an increase in renal glomerular filtration rate and urine output, and with the fatigue of pregnancy more time is spent in bed at night. Pressure from an enlarged uterus or the descent of the presenting part with fetal engagement during late pregnancy would lead to a decrease in bladder capacity and an increase in urinary frequency. Eighty percent of pregnant women will experience urinary frequency at some stage during the pregnancy [31]. Increase in sodium excretion as well as the mobilization of dependent oedema at night is the major reasons for increased night-time voiding. Urinary hesitancy may occur in up to 27% of patients in the first two trimesters [3]. Cutner et al. assessed flow rates in pregnancy, adjusted for voided volume, and found no difference in women complaining of hesitancy or incomplete emptying compared with women with normal voiding [32].
Urinary retention can occur in pregnancy, associated with the enlargement of a retroverted uterus, enlarging fibroid, or a pelvic mass. This retention usually resolves by 16 weeks’ gestation as the uterus grows out of the pelvis, but can be managed meanwhile with either bladder drainage or intermittent self-catheterization. A Smith Hodge pessary may be inserted to maintain anteversion of the uterus and relieve the obstruction of the bladder neck.
Postpartum urinary retention (PUR) is commonly defined as the lack of spontaneous micturition 6 h after vaginal delivery or removal of indwelling catheter; with a reported incidence of 0.45–17.9% [33]. The risk factors for this include a first labour, instrumental vaginal delivery, epidural analgesia, longer duration of labour (>800 min), perineal laceration and caesarean section [34], [35] and [36]. Because of this, women with these risk factors should be watched carefully to ensure that voiding is adequate, and if necessary catheterized to avoid overdistention. It is important to rule out urinary tract infection.
Management involves bladder drainage; this could be continuous or by intermittent self-catheterization as there is no evidence of one being more effective than the other [37]. The role of prophylactic antibiotics during treatment is debatable. Though a distressing condition, the prognosis is normally good with few published data on long-term sequelae. Overstretching of the bladder wall can result in severe detrusor damage followed by voiding dysfunction and rarely bladder rupture but no increase prevalence of urinary stress incontinence [36]. Pregnant women should be encouraged to pass urine regularly in labour with early use of catheterization when they fail on multiple attempts.
Silent PUR is defined as a postvoid residual >150 ml after delivery or removal of urethral catheter. It affects a significant proportion of women after delivery but the significance of this is not known [38]. Most women are willing to put up with their lower urinary tract symptoms when they are reassured that they are likely to resolve soon after delivery