**2.1 Incidence of urinary incontinence in pregnancy**

Urinary incontinence (UI) is common also among women who have not given birth (nulliparous women). A Norwegian study found prevalence of UI among nulliparous women aged 20 – 34 and 35 – 44 to be 8 % and 15 %, respectively (Rortveit et al., 2001). Other studies have found that 11 % (Brown et al., 2010, MacLennan et al., 2000) of nulliparous women had UI before pregnancy. Prevalence of UI increases considerably in pregnancy due to increased incidence of stress and mixed UI (Solans-Domenech et al., 2010).

Incidence of UI is low in 1. trimester, rising rapidly in 2. trimester and continues to rise, though more slowly, in 3. trimester (Marshall et al., 1998, Morkved & Bo, 1999, Solans-Domenech et al., 2010).

The nulliparous continent pelvis represents the best available clinical model of the unexposed pelvis, thereby the best study-population to assess incident UI in pregnancy.

Among published cross-sectional studies, Glazener et al published in 2006 data on incident UI in pregnancy among 3,405 nulliparous women with mean age of 25 years (Glazener et al., 2006). They found an incidence of UI in pregnancy of 11 %. A cross sectional study of 7,771 women from UK used questionnaire data collected postpartum (Marshall et al., 1998). They found an incidence of UI in pregnancy of 50 % and 45 % among nulliparous and parous women, respectively.

Several large population-based cohorts have been published during the recent years. A large Spanish cohort study from 2010 consisting of 1,128 nulliparous women who were continent before pregnancy had questionnaire data from each trimester. The article reported a cumulative incidence of UI in pregnancy of 39 % (Solans-Domenech et al., 2010). An Australian cohort study from 2009 consisting of 1,507 nulliparous women had interview data from early and late pregnancy. The authors found an incidence of any UI of 45 % in pregnancy (Brown et al., 2010). Results from 43,279 pregnant women in the Norwegian mother and child cohort study show a cumulative incidence of any UI in week 30 of pregnancy among nulliparous and parous women of 39 % and 49 %, respectively (Wesnes et al., 2007). Stress UI was the most common type of UI.

Several studies on incident UI in pregnancy are cross sectional. The lowest incidence estimates are reported in the cross sectional studies and in studies with focus on stress UI only. Some studies use questionnaire data while others use interview and objective testing. This might explain the diverging estimates.

No systematic review has presented pooled incidence of UI in pregnancy. Epidemiologic data are somewhat scarce and differ substantially for cumulative incidence of UI in pregnancy; from 8 – 57 % in different studies (Table 1). The majority of studies report incidence estimate of any UI in pregnancy between 28 – 45 % among primiparous, and 45 – 54 % among parous women.

understanding of incidence and prevalence estimates of urinary incontinence in association

Urinary incontinence (UI) is common also among women who have not given birth (nulliparous women). A Norwegian study found prevalence of UI among nulliparous women aged 20 – 34 and 35 – 44 to be 8 % and 15 %, respectively (Rortveit et al., 2001). Other studies have found that 11 % (Brown et al., 2010, MacLennan et al., 2000) of nulliparous women had UI before pregnancy. Prevalence of UI increases considerably in pregnancy due

Incidence of UI is low in 1. trimester, rising rapidly in 2. trimester and continues to rise, though more slowly, in 3. trimester (Marshall et al., 1998, Morkved & Bo, 1999, Solans-

The nulliparous continent pelvis represents the best available clinical model of the unexposed pelvis, thereby the best study-population to assess incident UI in pregnancy.

Among published cross-sectional studies, Glazener et al published in 2006 data on incident UI in pregnancy among 3,405 nulliparous women with mean age of 25 years (Glazener et al., 2006). They found an incidence of UI in pregnancy of 11 %. A cross sectional study of 7,771 women from UK used questionnaire data collected postpartum (Marshall et al., 1998). They found an incidence of UI in pregnancy of 50 % and 45 % among nulliparous and parous

Several large population-based cohorts have been published during the recent years. A large Spanish cohort study from 2010 consisting of 1,128 nulliparous women who were continent before pregnancy had questionnaire data from each trimester. The article reported a cumulative incidence of UI in pregnancy of 39 % (Solans-Domenech et al., 2010). An Australian cohort study from 2009 consisting of 1,507 nulliparous women had interview data from early and late pregnancy. The authors found an incidence of any UI of 45 % in pregnancy (Brown et al., 2010). Results from 43,279 pregnant women in the Norwegian mother and child cohort study show a cumulative incidence of any UI in week 30 of pregnancy among nulliparous and parous women of 39 % and 49 %, respectively (Wesnes

Several studies on incident UI in pregnancy are cross sectional. The lowest incidence estimates are reported in the cross sectional studies and in studies with focus on stress UI only. Some studies use questionnaire data while others use interview and objective testing.

No systematic review has presented pooled incidence of UI in pregnancy. Epidemiologic data are somewhat scarce and differ substantially for cumulative incidence of UI in pregnancy; from 8 – 57 % in different studies (Table 1). The majority of studies report incidence estimate of any UI in pregnancy between 28 – 45 % among primiparous, and 45 –

to increased incidence of stress and mixed UI (Solans-Domenech et al., 2010).

with pregnancy.

Domenech et al., 2010).

women, respectively.

**2. Urinary incontinence in pregnancy** 

**2.1 Incidence of urinary incontinence in pregnancy** 

et al., 2007). Stress UI was the most common type of UI.

This might explain the diverging estimates.

54 % among parous women.


cross-s = cross sectional study, Quest. = Questionnaire, Interv. = interview, Ex. = examination, PP = postpartum, (s) = stress UI

Table 1. Incidence of urinary incontinence in pregnancy by parity.

Epidemiology of Urinary Incontinence in Pregnancy and Postpartum 25

**collection**

USA Cohort 523 Interv. 2 days PP 60 %

interv.

UK Cohort 549 Interv. 3. trimester 44 %

UK Cohort 492 Quest. 3. trimester 36 %

Israel Cross-s 300 Interv. 3 days PP 49 % 50 %

Denmark Cross-s 7,795 Quest. 2. trimestr 4 % 14–16%

Denmark Cross-s 376 Quest. 18 %

Denmark Cross-s 642 Quest. 20 % 24 %

Sweden Cohort 200 Quest. 3. trimester 26 % (s)

Irland Cross-s 7,771 Quest. 3 days PP 55 % 66 %

England Cohort 717 Quest. 3. trimester 32 % (s) 59 % (s)

interv.

interv.

Norway Cohort 43,279 Quest. 3. trimester 48 % 67 %

Netherland Cohort 515 Quest. 2. trimester 42 % (s)

Denmark Cohort 305 Interv. 1 week PP 32 % (s)

cross-s = cross sectional study, Ex. = examination, Quest. = questionnaire, Interv. = interview, PP =

USA Cohort 113 Quest. 3. trimester 70 % 75 %

Brasil Cross-s 340 Interv. 3. trimester 46 % (s) 55–64%

During pregn.

Germany Cross-s 350 Interv During

(Francis, 1960) England Cohort 400 Ex, interv. During pregn. 53 % 85 %

(Iosif, 1981) Sweden Cohort 1,411 Quest. 1-2 weeks PP 22 % (s)

Norway Cross-s 144 Ex.,

USA Cross-s 121 Ex.,

Table 2. Prevalence of urinary incontinence in pregnancy by parity.

**Time of UI Nulli-**

3. trimester 56 %

pregn.

**parous** 

8 weeks PP 35 % 37–70%

55 %

**Parous** 

55 %

**Author, year Origin Design N Data** 

Australia Cohort 1,507 Quest,

(Burgio et al.,

(Brown et al.,

(Chaliha et al.,

(Dimpfl et al.,

(Dolan et al., 2004)

(Groutz et al.,

(Hojberg et al.,

(Hvidman et al., 2003)

(Hvidman et al., 2002)

(Kristiansson et al., 2001)

(Marshall et al.,

(Mason et al.,

(Morkved & Bo, 1999)

(Raza-Khan et al., 2006)

(Scarpa et al.,

(Thomason et al., 2007)

(van Brummen et al., 2006)

(Viktrup et al.,

(Wesnes et al.,

postpartum, (s) = stress UI.

2003)

2010)

1999)

1992)

1999)

1999)

1998)

1999)

2006)

1992)

2007)

#### **2.2 Prevalence of urinary incontinence in pregnancy**

Data from a large number of cross-sectional studies and cohort studies indicate that UI in women is highly prevalent in pregnancy. More than 50 % of all pregnant women experience UI. UI when running, jumping, coughing or laughing (stress UI) is the most common symptom of UI in association with pregnancy.

In a cross-sectional study from Ireland 7,771 women received a questionnaire on UI 2-3 days postpartum (Marshall et al., 1998). Prevalence of UI was 55 % and 66 % among primiparous and parous women, respectively. The study has somewhat insufficient descriptive data which makes it difficult to evaluate the external validity. In 1999 Hojberg et al found a prevalence of UI of 4 % and 14 % among 7,794 Danish nulliparous and parous women, respectively (Hojberg et al., 1999). The low prevalence might be due to UI was reported in early in pregnancy (week 16).

Several cohorts have investigated prevalence of UI during pregnancy. One of the first studies to put focus on UI in pregnancy was done by Francis in 1960 (Francis, 1960). In this cohort he found the prevalence of UI to be 52 % and 85 % among nulliparous and parous women, respectively. Similar results were found in an Australian cohort study that used a validated questionnaire on UI on 1,507 nulliparous women (Brown et al., 2010). Prevalence of UI at least once a month was found to be 56 % in week 31 of pregnancy. New cases of stress UI accounted for more than two thirds of the reported UI prevalence in pregnancy. A study from USA found by structured questionnaire interview on 553 women a prevalence 60 % for UI during pregnancy (Burgio et al., 2003). In the large Norwegian mother and child cohort the prevalence of any UI in third trimester was 48 % among nulliparous and 67 % among parous women (Wesnes et al., 2007). Stress UI was the most common type of UI, affecting 31 % and 41 % of all nulliparous and parous women. The majority of women leaked only small amounts.

Lower prevalence estimates are reported in other cohorts; Dolan et al investigated prevalence of any UI in week 32 to term in a cohort of 492 nulliparous women in England (Dolan et al., 2004). Prevalence of UI was 36 % in pregnancy. However, prevalence of UI before pregnancy was only 2.6 %, which might explain a somewhat low UI prevalence in pregnancy. The majority of the women reported little impact on quality of life. The highest prevalence estimates were reported from a very small cohort recruiting 113 women from an American tertiary care hospital (Raza-Khan et al., 2006). A prevalence of 70 % and 75 % were found among nulliparous and parous women, respectively.

Prevalence estimates for UI in pregnancy among nulliparous women vary from 4 – 70 %, while estimates for parous women vary from 14 – 85 % (Table 2). However, the majority of studies appear to report prevalence estimates between 35 – 55 % among primiparous women, and somewhat higher figures for parous women. No systematic review on UI in pregnancy has been published. The International consultation on incontinence published in 2009 their latest report "Epidemiology of Urinary (UI) and Faecal (FI) Incontinence and Pelvic Organ Prolapse (POP)" (Milsom et al., 2009). It describes period prevalence of any UI in pregnancy of 32 – 64% among all women.

Data from a large number of cross-sectional studies and cohort studies indicate that UI in women is highly prevalent in pregnancy. More than 50 % of all pregnant women experience UI. UI when running, jumping, coughing or laughing (stress UI) is the most common

In a cross-sectional study from Ireland 7,771 women received a questionnaire on UI 2-3 days postpartum (Marshall et al., 1998). Prevalence of UI was 55 % and 66 % among primiparous and parous women, respectively. The study has somewhat insufficient descriptive data which makes it difficult to evaluate the external validity. In 1999 Hojberg et al found a prevalence of UI of 4 % and 14 % among 7,794 Danish nulliparous and parous women, respectively (Hojberg et al., 1999). The low prevalence might be due to UI was reported in

Several cohorts have investigated prevalence of UI during pregnancy. One of the first studies to put focus on UI in pregnancy was done by Francis in 1960 (Francis, 1960). In this cohort he found the prevalence of UI to be 52 % and 85 % among nulliparous and parous women, respectively. Similar results were found in an Australian cohort study that used a validated questionnaire on UI on 1,507 nulliparous women (Brown et al., 2010). Prevalence of UI at least once a month was found to be 56 % in week 31 of pregnancy. New cases of stress UI accounted for more than two thirds of the reported UI prevalence in pregnancy. A study from USA found by structured questionnaire interview on 553 women a prevalence 60 % for UI during pregnancy (Burgio et al., 2003). In the large Norwegian mother and child cohort the prevalence of any UI in third trimester was 48 % among nulliparous and 67 % among parous women (Wesnes et al., 2007). Stress UI was the most common type of UI, affecting 31 % and 41 % of all nulliparous and parous women. The majority of women

Lower prevalence estimates are reported in other cohorts; Dolan et al investigated prevalence of any UI in week 32 to term in a cohort of 492 nulliparous women in England (Dolan et al., 2004). Prevalence of UI was 36 % in pregnancy. However, prevalence of UI before pregnancy was only 2.6 %, which might explain a somewhat low UI prevalence in pregnancy. The majority of the women reported little impact on quality of life. The highest prevalence estimates were reported from a very small cohort recruiting 113 women from an American tertiary care hospital (Raza-Khan et al., 2006). A prevalence of 70 % and 75 % were

Prevalence estimates for UI in pregnancy among nulliparous women vary from 4 – 70 %, while estimates for parous women vary from 14 – 85 % (Table 2). However, the majority of studies appear to report prevalence estimates between 35 – 55 % among primiparous women, and somewhat higher figures for parous women. No systematic review on UI in pregnancy has been published. The International consultation on incontinence published in 2009 their latest report "Epidemiology of Urinary (UI) and Faecal (FI) Incontinence and Pelvic Organ Prolapse (POP)" (Milsom et al., 2009). It describes period prevalence of any UI

found among nulliparous and parous women, respectively.

in pregnancy of 32 – 64% among all women.

**2.2 Prevalence of urinary incontinence in pregnancy** 

symptom of UI in association with pregnancy.

early in pregnancy (week 16).

leaked only small amounts.


cross-s = cross sectional study, Ex. = examination, Quest. = questionnaire, Interv. = interview, PP = postpartum, (s) = stress UI.

Table 2. Prevalence of urinary incontinence in pregnancy by parity.

Epidemiology of Urinary Incontinence in Pregnancy and Postpartum 27

(Arya et al., 2001) USA Cohort 315 Interv. 3 mth. 10 % (s) (Boyles et al., 2009) USA Cross-s 5,599 Quest. 6 mth 10 %

(Francis, 1960) England Cohort 400 Ex., interv. 3 mth 0 %

**collection**

USA Cohort 523 Interv. 3 mth 10 %

Germany Cross-s 350 Interv. 3 mth 4 % (s) 4 %

Denmark cross-s 1,232 Quest. > 12 mth 14 %

Denmark Cross-S 642 Quest. 3 mth 8 %

England Cohort 717 Quest. 3 mth 15 %

Norway Cross-S 144 Ex., interv. 2 mth 19 %

USA Cohort 113 Quest. Postpartum 4 %

England Cohort 549 Interv. 3 mth 6 %

Sweden Cohort 665 Quest. 12 mth 21 %

Canada Cohort 595 Quest. 6 mth 26 %

UK, N.Z. Cross-S 3,405 Quest. 3 mth 15 %

UK Cohort 103 Ex, interv. 3 mth 4 %

Spain Cohort 1,128 Quest. 2 mth 5 %

USA Cross-S 121 Ex., interv. 6 mth 16 %

UK Cohort 189 Interv. Postpartum 6% (s),

Denmark Cohort 305 Interv. 3 mth 7% (s),

Norway Cohort 12,679 Quest. 6 mth 21 %

Cross-s = cross sectional study, Ex. = examination, Quest. = questionnaire, Interv. = interview, PP =

Cross-S 1,505 Quest. 3 mth 12 % 21 %

(Iosif, 1981) Sweden Cohort 1,411 Quest. 6-12 mth 19 % (s)

**Time of UI PP** 

**Primiparous** 

9% (u)

4% (u)

11% (s), 7% (u)

**Parous** 

**Author, year Origin Design N Data** 

(Burgio et al.,

(Chaliha et al.,

(Dimpfl et al.,

(Eliasson et al.,

(Farrell et al.,

(Foldspang et al.,

(Glazener et al.,

(Hvidman et al.,

(King & Freeman,

(Mason et al.,

(Morkved & Bo,

(Raza-Khan et al.,

Domenech et al.,

(Thomason et al.,

(Stanton et al.,

(Viktrup et al.,

(Wesnes et al.,

(Wilson et al.,

New Zealand

postpartum, (s) = stress UI, (u) = urgency UI, mth = month.

Table 3. Incidence of urinary incontinence postpartum by parity.

2003)

1999)

1992)

2005)

2001)

2004)

2006)

2003)

1998)

1999)

1999)

2006)

2010)

2007)

1980)

1992)

2009)

1996)

(Solans-
