In addition, other studies [2, 21] have
reported that the course of pregnancy also plays an important role in the pathophysiology of urinary incontinence and
especially SUI.
In our study, the prevalence of nocturia increased steadily
with gestational age inboth the multiparous and nulliparous
women, while (diurnal) frequency increased steadily with
gestational age only in the multiparous women. However,
two prospective studies [12, 14] found stable increases in
the prevalence rates of nocturia and frequency throughout
pregnancy in both nulliparous andmultiparous women.This
discrepancy may partly be due to differences in ethnicity
and study design. We found that the rates of nocturia and
frequency were most prevalent during the third trimester,
possibly due to the compression effect of gravid uterus and
more urine output [22, 23].
In this study, nocturia and frequency were the most
commonLUTSduringpregnancy inboth thenulliparous and
multiparous women. The multiparous pregnant women had
higher prevalence rates of frequency and nocturia compared
with the nulliparous women, which is comparable to the
report of Stanton et al. [14]. Long et al. reported increased
mRNA levels of the M3 receptor in the bladder after significant
birth trauma in an animal study [24]. This may partly
explain why urinary frequency, nocturia, and even urgency
incontinence occur more commonly in multiparous women.
Other LUTS explored in this study were less prevalent.
For example, we found that the prevalence of incomplete
emptying was 43.7% and the prevalence of urge incontinence
was 10.4%. These findings are similar to the study of Cutner