GYNECOLOGY
Temporal trends in obstetric trauma and inpatient surgery
for pelvic organ prolapse: an age-period-cohort analysis
Sarka Lisonkova, MD, PhD; Jessica A. Lavery, MS; Cande V. Ananth, PhD, MPH; Innie Chen, MD, MPH; Giulia Muraca, MPH; Geoffrey W. Cundiff, MD; K. S. Joseph, MD, PhDBACKGROUND:The rates of cesarean delivery have increased over time in industrialized countries, while the rates of instrumental vaginal delivery have declined. Instrumental vaginal delivery and obstetric trauma are risk factors for pelvic floor disorders.
OBJECTIVE:We carried out a population-based study to quantify the association between temporal changes in obstetric trauma during child-birth and temporal changes in surgery for pelvic organ prolapse. STUDY DESIGN:We designed a retrospective analysis to examine age-specific trends in vaginal and cesarean delivery, obstetric trauma, and surgery for pelvic organ prolapse among all women (pregnant and nonpregnant) in Washington State, from 1987 through 2009. Cases of obstetric trauma (including severe perineal tears and high vaginal lacer-ations) and inpatient surgery for pelvic organ prolapse were identified among all hospitalizations. Temporal trends and age-period-cohort regression analyses were used to quantify the time period, age, and birth cohort effects among women born from 1920 through 1980. RESULTS:From 1987 through 2009, cesarean delivery rates among women aged 15-44 years increased from 12.7-18.1 per 1000 women, vaginal delivery rates remained stable, and instrumental vaginal delivery
rates declined from 6.3-3.9 per 1000 women. Obstetric trauma decreased from 6.7 in 1987 to 2.5 per 1000 women aged 15-44 years in 2009. Surgery for pelvic organ prolapse decreased from 2.1 in 1987 to 1.4 per 1000 women aged 20-84 years in 2009. Obstetric trauma rates in 1987 through 1999 among women 15-44 years old were strongly correlated with the rates of surgery for pelvic organ prolapse among women 25-54 years of age 10 years later in 1997 through 2009 (correlation coefficient 0.87, P < .001). Similarly, rates of midpelvic forceps delivery in 1987 through 1999 were correlated with the rates of surgery for pelvic organ prolapse 10 years later (correlation coefficient 0.72, P < .01). Regression analyses showed a strong effect of age on surgery for prolapse, temporal decline in surgery, and an effect of birth cohort, as younger cohorts (women born in1965 vs 1940) had lower rates of surgery for pelvic organ prolapse.
CONCLUSION:Temporal decline in instrumental vaginal delivery and obstetric trauma may have contributed to the reduction in surgery for pelvic organ prolapse.
Key words:obstetric trauma, pelvic organ prolapse, temporal trend
Introduction
Pelvic floor disorders, including pelvic organ prolapse, urinary incontinence, and fecal incontinence, greatly impact the quality of life of a large number of women and represent a significant pub-lic health burden.1-3It is estimated that 25% of adult women in the United States have1 pelvic floor disorders, and that 1 in 4 women will undergo surgery for stress urinary incontinence or pelvic organ prolapse during their lifetime.1 Routine gynecologic examinations reveal evidence of pelvic organ prolapse in up to 50% of adult women.4,5
While the mechanical causes of pelvic floor disorders remain poorly
understood, age, obesity, and obstetric trauma increase the risk of these dis-orders.6,7 Studies have shown that par-ous women are 3 times more likely to have urinary and fecal incontinence8,9 and are twice as likely to experience pelvic organ prolapse compared with nulliparous women.10 Vaginal birth in particular has been implicated in the risk of pelvic organ prolapse and urinary incontinence later in life. One vaginal delivery is associated with a 2-fold increased risk of urinary incontinence and a 4-fold increased risk of pelvic organ prolapse, while 2 vaginal deliveries increase the risk 2.4-fold for urinary incontinence, and 8-fold for prolapse (as compared with women who have not had a vaginal delivery).11-13Long-term follow-up studies show a 40% increased risk of fecal incontinence among women with at least 1 vaginal delivery (as compared with 1 cesarean delivery), while a significant perineal tear (second-degree tear or higher) doubles the risk.14Conversely, cesarean delivery is associated with less need for
incontinence or prolapse surgery15and is protective against prolapse symp-toms.16 There is substantial epidemio-logical evidence showing a lower risk of pelvicfloor disorders following cesarean delivery without labor as compared with vaginal delivery.11,17-19
The last 2 decades have witnessed an unprecedented increase in the rate of cesarean delivery in high-income coun-tries.20-22In the United States, the per-centage of cesarean deliveries increased by 62.6% from 20.1% in 1996 to 32.7% in 2013. Cesarean delivery is the most common surgical procedure among US women, with close to 1.3 million cesar-ean deliveries performed annually.23,24 While rates of cesarean delivery have increased, the rates of instrumental vaginal delivery have declined in the United States (from 9.0% of live births in 1990 to 3.3% of live births in 2013).24,25 We hypothesized that the decrease in instrumental vaginal delivery, especially midpelvic forceps delivery, would have led to a decrease in pelvic floor injury requiring subsequent surgery for pelvic
Cite this article as: Lisonkova S, Lavery JA, Ananth CV, et al. Temporal trends in obstetric trauma and inpatient surgery for pelvic organ prolapse: an age-period-cohort analysis. Am J Obstet Gynecol 2016;215:208.e1-12. 0002-9378
ª 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).
organ prolapse. We therefore carried out a population-based study to examine the temporal changes in instrumental vaginal delivery rates and obstetric trauma rates and their association with temporal trends in surgery for pelvic organ prolapse.
Materials and Methods
We carried out a population-based study to assess the association between ob-stetric events, including midpelvic for-ceps and obstetric trauma, and surgery for pelvic organ prolapse. We examined temporal trends in cesarean and vaginal delivery; instrumental vaginal delivery, including midpelvic forceps; and ob-stetric trauma among women who resided in Washington State during the period from 1987 through 2009. We also examined temporal trends in surgery for pelvic organ prolapse. All women (both pregnant and nonpreg-nant) in the appropriate age group were included in the analysis to assess the effect of childbirth and related events on population rates of pelvic organ prolapse.
Information on the mode of delivery was obtained from the Comprehensive Discharge Abstract Database, which included all hospitalizations in Wash-ington State from 1987 through 2009. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnostic and procedure codes were used to identify childbirth (Appendix Table 1); procedure codes 74.^^were used to identify cesarean de-livery and all other deliveries were considered vaginal. ICD-9-CM codes were used for identifying women who had an instrumental vaginal delivery and the subset with a midpelvic forceps de-livery (Appendix Table 1). Women with a diagnosis of pelvicfloor trauma during the delivery hospitalization, including third- and fourth-degree perineal lacer-ation, anal sphincter tear, obstetric laceration of cervix, and high vaginal laceration were also identified using ICD-9-CM diagnostic codes 664.2, 664.3, 664.6, 665.3, and 665.4, respec-tively. In addition, we examined tem-poral changes in the rates of prolonged labor, identified on hospital discharge
abstracts by ICD-9-CM diagnostic codes 662.20, 662.21, 662.22, and 662.23.
ICD-9-CM procedure and diagnostic codes were also used to identify inpatient surgery related to pelvic organ prolapse among all women in the Comprehensive Discharge Abstract Database (Appendix Table 2). This included prolapse sur-gery among all women 20-84 years of age. Among women with multiple sur-geries for the same indication, only the first surgery was used to calculate rates (identified though an internal linkage of hospital records). US census data for Washington State for the years 1990 through 2000 and yearly intercensal age-specific population estimates for women were used to calculate population rates of cesarean and vaginal delivery, instru-mental vaginal delivery, pelvic floor injury during childbirth, and surgery for pelvic organ prolapse. For calculation of the overall rates of childbirth-related events, the number of women aged 15-44 years residing in Washington State was used as the denominator, while for calculation of surgery for pelvic organ prolapse, the number of women aged 20-84 years was used.
We used age-period-cohort ana-lyses26,27to analyze temporal changes in the rates of childbirth-related events and pelvic organ prolapse surgery among various birth cohorts of women. Such analyses are important for describing the effects of age, period, and birth cohort simultaneously, as age effects can be confounded if period and/or cohort effects occur. Thus in our analyses, women aged 20 years in 1990 belonged to the cohort of women born in 1970. This cohort of women may have expe-rienced the events of interest as 25-year-old women during the period 1995, and as 30-year-old women during the year 2000.
Age-period-cohort effects on pelvic organ prolapse surgery were modeled for each year from 1990 through 2009. As age, period, and cohort are linearly dependent (cohort ¼ period-age), we used a regression model that first esti-mated an overall linear trend in surgery rates that reflected the sum of period and cohort effects (a drift parameter).28,29 Deviation from linearity uniquely
attributable to period and cohort effects was then modeled to estimate indepen-dent period and cohort effects. These estimates of curvature, or deviations from linearity, were interpreted as a measure of change in the linear trend for period and cohort.
Temporal trends were assessed using the Cochran-Armitage test for a linear trend in proportions. Pearson correla-tion coefficients were used to assess the correlation between the rates of obstetric events among women 15-44 years old in the years from 1987 through 1999 and the rates of prolapse surgery 10 years later (from 1997 through 2009) among women aged 25-54 years. In addition, temporal trends in the number of births to primiparous women were examined to assess the potential effect of changes in parity. Data on the number of births by birth order and maternal age were obtained for years 1990 through 2009 from the Washington State Department of Health. Information on the total number offirst births per year from 1987 through 2009 was also avail-able from public vital statistics files (through the Washington State Depart-ment of Health).
Sensitivity analyses were carried out to examine the potential impact of changes in insurance status among women with surgery for pelvic organ prolapse. The distribution and types of primary payers were evaluated to assess if changes in medical insurance contributed to temporal changes in the number of procedures performed.
Since all analyses were performed on publicly accessible deidentified data, an exemption from ethics approval was granted by the Department of Social and Health Services, State of Washington. Analyses were carried out using software (SAS, Version 9.3; SAS Institute Inc, Cary, NC). Age-period-cohort models were fitted using the apc.fit function in the Epi package of the R program (Version 2.14.2).
Results
The number of women aged 15-84 years in Washington State increased from 1,769,357 in 1987 to 2,634,461 in 2009. The number of women aged 15-44 years
also increased from 1,093,389 in 1987 to 1,352,302 in 2009.
Obstetric events
While population rates of vaginal de-livery remained relatively stable during this period (approximately 45 per 1000 women aged 15-44 years), the rate of cesarean delivery increased from 12.7 per 1000 women aged 15-44 years in 1987 to 18.1 per 1000 women in 2009. During this period, the rate of instru-mental vaginal delivery decreased from 6.3 in 1987 to 3.9 per 1000 women aged 15-44 years in 2009, midpelvic forceps use declined sharply from 4.1-0.1 per 10000 women aged 15-44 years, while the rate of obstetric trauma declined from 6.7-2.5 per 1000 women aged 15-44 years (P value for linear trend <.001 for all trends). These proportions were calculated using all women (preg-nant and nonpreg(preg-nant) in the denomi-nator to allow comparisons with rates of prolapse surgery and differ from rates calculated using a denominator of preg-nant women only (which would produce more commonly reported rates). In fact rates calculated using pregnant women in the denominator yielded cesarean delivery rates that increased from 22.1% in 1987 to 29.8% in 2009, instrumental vaginal delivery rates that decreased from 10.9-6.4%, and midpelvic forceps delivery rates that declined sharply from 0.7-0.1%. The rate of perineal trauma declined from 27.5% in 1987 to 15.0% in 2009 among women with instrumental vaginal delivery, and from 12.9 to 4.9% among women with noninstrumental vaginal delivery. The rate remained relatively stable among those with mid-pelvic forceps delivery (average 35.5%). There was a strong correlation between temporal declines in rates of instru-mental vaginal delivery and temporal declines in obstetric trauma (correlation coefficient 0.93, P < .001).
Analysis by birth cohort (Figure 1) showed that each cohort experienced similar rates of vaginal delivery, while the younger cohorts (born from 1970 through 1985) were more likely to experience a cesarean delivery at ages 25 years. Successive cohorts of women had lower rates of instrumental delivery,
especially midpelvic forceps delivery, and lower rates of obstetric trauma compared with older cohorts. The rate of midpelvic forceps delivery and obstetric trauma declined for each successive cohort, particularly those born in 1970, and a similar decline was observed for prolonged labor among women born in1975.
Surgery for pelvic organ prolapse
The rate of surgery for pelvic organ prolapse remained relatively stable from 1987 through 1998 and then decreased from 2.1 in 1998 to 1.4 per 1000 women aged 20-84 years in 2009 (Figure 2, A). Age-specific incidence rates of surgery for pelvic organ prolapse showed a bimodal distribution, with a smaller peak at age 45-54 years, especially from 1990 through 1994, and a larger peak at age 70-74 years; this peak shifted to 65-69 years in later years (2005 through 2009). A temporal decline in surgery for pelvic organ prolapse was observed for all age groups (Figure 2, B).
Women in each subsequent birth cohort were less likely to experience surgery for pelvic organ prolapse compared with earlier cohorts (Figure 2, C). This was apparent mainly among women born from 1920 through 1934, to a lesser extent in the cohort born in 1935 through 1939, and from 1940 through 1969. In general, each successive cohort had a lower rate of surgery compared with earlier cohorts, with the exception of women aged 70-75 years born in 1920 through 1924, women aged 60-64 years born in 1930 through 1934, and women aged 50-54 years old born in 1935 through 1939, who did not expe-rience lower rates of surgery compared to the previous cohort of women of the same age.
Age-period-cohort analysis
Regression models revealed a large age effect, with a steep increase in the rate of prolapse surgery between 20-45 years of age from <0.05% to approximately 0.4%. This was followed by a plateau in surgery rates, another increase from age 60-71 years, and then a decline in rates of prolapse surgery (Figure 3). The birth cohort effect was less pronounced,
although a progressively lower rate of prolapse surgery was evident among younger cohorts (born in 1965) as compared with those born in 1945. The period effect (ie, rate ratio of prolapse surgery by calendar year) showed that there was a gradual decline in prolapse surgery rates from 1990 through 2009 (Figure 3).
Correlation between obstetric
trauma and surgery for pelvic
organ prolapse
The rates of obstetric trauma and the rates of midpelvic forceps delivery in each year from 1987 through 1999 were highly correlated with the rates of pro-lapse surgery 10 years later (from 1997 through 2009) among women aged 25-54 years: correlation coefficients (r) were 0.87 and 0.72, respectively, both P values<.01 (Figure 4).
Potential effects of temporal
changes in insurance and parity
Sensitivity analysis showed that the dis-tribution and types of primary payers for surgery hospitalization did not change appreciably during the study period. The largest proportion of hospitaliza-tions for pelvic organ prolapse was covered through commercial insurance (21-32%), health care service contrac-tors (22-30%), and Medicare (24-30%). Thefirst-birth rates per 100 women aged 15-44 years were essentially stable from 1987 through 2009, changing only slightly from 2.6 per 100 women in 1987 to 2.8 per 100 women in 2009. This represents an increase in the proportion offirst births from 44.4% of all births in 1987 to 45.5% of all births in 2009. The first-birth rate declined among women aged 15-24 years and increased in women 25-44 years old (Appendix Figure 1 and Appendix Table 3). The rates of birth to grand-multiparas (fourth or subsequent birth) were also stable, within the range from 0.69 per 100 women in 1990 to 0.74 per 100 women in 2009.
Comment
This study showed a temporal increase in the population rates of cesarean delivery and a concurrent decline in the
FIGURE 1
Birth cohort effects associated with obstetric events
Rates of vaginal delivery, cesarean delivery, instrumental vaginal delivery, midpelvic forceps delivery, obstetric trauma, and prolonged labor by birth cohort, Washington State, 1990 through 2009. Birth cohorts include women born at specific time periods from 1960-64 to 1980-84.
population rate of instrumental vaginal delivery and obstetric trauma in Wash-ington State from 1987 through 2009. Rates of cesarean delivery increased, and rates of instrumental vaginal delivery, including midpelvic forceps delivery,
prolonged labor and obstetric trauma declined for each subsequent birth cohort, particularly for women born in 1970 or later. Age-period-cohort regression analysis showed that younger cohorts of women born >1965 had
lower rates of surgery for pelvic organ prolapse and rates of prolapse surgery declined from 1990 through 2009. Pop-ulation rates of obstetric trauma in 1987 through 1999 were strongly correlated with population rates of surgery for pelvic organ prolapse in 1997 through 2009 (correlation coefficient 0.87, P< .01).
The rates of surgery for pelvic organ prolapse in our study are consistent withfindings based on the US National Hospital Discharge Survey, which showed that age-adjusted rates of inpa-tient prolapse procedures (including all hysterectomies irrespective of indica-tion) declined significantly from 2.9 in 1997 to 1.5 per 1000 women in 2006.30 The temporal trends in the rates of vaginal delivery, cesarean delivery, and instrumental vaginal delivery observed in our study were comparable with those observed in other studies.31
There is substantial epidemiological evidence for the association between vaginal delivery and pelvic floor disor-ders, including evidence from case-control and cohort studies.6-19,32,33 A recent population-based study showed a 70% reduced lifetime risk of pelvicfloor surgery among women who delivered exclusively by cesarean in 1970 or later compared with women who had vaginal deliveries. Similarly, women who had at least 1 perineal laceration or forceps delivery had an increased risk of pelvic floor surgery.33
A cohort study including >1000 women followed for 5-10 years after their first delivery found a 5-fold increased risk of prolapse among women who delivered vaginally as compared with those who delivered by cesarean without labor.18In this study, instrumental vaginal delivery increased the risk of prolapse 7-fold.18 In our study, the age-period-cohort model showed that age had the largest effect on pelvic organ prolapse surgery; rates peaked at 45 years of age with a second, higher peak around 70 years of age. The analysis also revealed that more recent birth cohorts of women were at lower risk of surgery as compared with those born in 1945, suggesting that lower rates of midpelvic forceps delivery and ob-stetric trauma in these cohorts may have
FIGURE 2
Trends in surgery for pelvic organ prolapse
Washington State rates of surgery for pelvic organ prolapse by A, calendar year; B, age; and C, birth cohort. A, 1987 through 2009. B and C, 1990 through 2009.
contributed to lower rates of pelvic or-gan prolapse surgery. The earlier cohorts (born in 1905 through 1925) showed lower rates of surgery as compared to those born in 1945; this may have been due to a lesser tendency to seek surgical treatment among the oldest generation of women. Our findings, however, do not indicate that the population preva-lence of pelvic floor disorders will necessarily decline in the future. With a demographic shift toward a higher pro-portion of older women in the popula-tion, the demand for such surgery may actually increase, as older women have the highest prevalence of this disorder.34
Limitations of the study
Before the findings can be interpreted within the context of other studies, a few limitations of the data merit some discussion. Importantly, we included women with pelvic organ prolapse who required inpatient surgery only. Studies show that the burden of this disorder is
larger, as an estimated 3% of women experience symptoms of pelvic organ prolapse.6,35A recent study showed that approximately 16% of procedures for pelvic organ prolapse were performed in ambulatory settings in California in 2008.36Extreme assumptions regarding outpatient surgery (ie, no surgery vs 16% of prolapse surgery performed outside hospital in 1987 and in 2009, respec-tively) show that a shift to outpatient procedures could potentially account for approximately 32% of the observed decline in surgery for pelvic organ pro-lapse in our study. As mentioned, this is an extreme estimate as the number of women undergoing ambulatory pro-cedures in the United States has been relatively stable from 1996 through 2006.37Second, we did not have infor-mation on the number of repeat vaginal and cesarean deliveries and only limited information on parity. The population changes in parity (first-time births, births to grand-multiparas) provide little
evidence to suggest that temporal changes in this factor were critical in influencing rates of pelvic organ pro-lapse. Data on temporal trends in the first-birth rate showed a decline among young women and an increase among older women. This corresponds with the trend toward delayed childbearing,38-40 increased cesarean delivery rates,25,41 and decline in total fertility rates.25 These temporal changes may (or may not) have contributed to the decline in surgery for pelvic organ prolapse. We were unable to include data on women who delivered at home or out of state. This proportion, however, is likely to be small and unlikely to substantially in-fluence our findings. In addition, the childbearing experience of women who immigrated to Washington State with children was not accounted for in this study. Finally, the accuracy of the data was dependent on the quality of the coding, although coding errors for major procedures have been reportedly small.42
FIGURE 3
Age-period-cohort analysis of pelvic organ prolapse surgery
Age-period-cohort analysis of pelvic organ prolapse surgery among women 20-84 years old, Washington State, 1990 through 2009. The first panel (left) shows the effect of age expressed as increasing rate of prolapse surgery; the second panel (middle) shows the birth cohort effect expressed as rate ratio compared with the reference cohort of women born in 1945; and the third panel (right) shows the period effect (time trend) expressed as rate ratio compared with the reference year 1990.
Since we utilized aggregate-level data in our analyses, ourfindings are poten-tially subject to the ecological fallacy, a bias that can occur when inferences based on group-level associations are applied to individuals. However, a sub-stantial body of previous research dem-onstrates individual-level associations between obstetric trauma and pelvic floor disorders, and our results merely
quantify thesefindings on a population level.
Strengths of the study
The strengths of our study include its population-based nature, with outcomes obtained from hospital admissions collected in a consistent manner over an extended period of time using ICD-9-CM. In contrast to similar
population-based studies, we were able to exclude all rehospitalizations for the same sur-gery or indication (pelvic organ pro-lapse); the reoperation rate for pelvic organ prolapse is estimated to be be-tween 17-30%,6,43 and this can artifi-cially inflate the population rate of such surgery if repeat surgeries are counted. We were also able to show that the temporal trends in pelvic organ prolapse surgery were likely not influenced by temporal changes in medical insurance.
Conclusions
The temporal decline in operative vaginal delivery and obstetric trauma in previous decades was associated with subsequent reductions in surgical inpa-tient procedures for pelvic organ pro-lapse. This adds to the epidemiological evidence of an association between instrumental vaginal delivery and ob-stetric trauma and subsequent pelvic
organ prolapse. n
References
1.Wu JM, Vaughan CP, Goode PS, et al. Prevalence and trends of symptomatic pelvic floor disorders in US women. Obstet Gynecol 2014;123:141-8.
2.Doshi AM, Van Den Eeden SK, Morrill MY, Schembri M, Thom DH, Brown JS; Reproduc-tive risks for incontinence study at Kaiser Research Group. Women with diabetes: understanding urinary incontinence and help seeking behavior. J Urol 2010;184:1402-7. 3.Kiyosaki K, Ackerman AL, Histed S, et al. Patients’ understanding of pelvic floor disorders: what women want to know. Female Pelvic Med Reconstr Surg 2012;18:137-42.
4.Nygaard I, Bradley C, Brandt D. Pelvic organ prolapse in older women: prevalence and risk factors. Obstet Gynecol 2004;104:489-97. 5.Swift SE. The distribution of pelvic organ support in a population of female subjects seen for routine gynecologic health care. Am J Obstet Gynecol 2000;183:277-85.
6.Memon HU, Handa VL. Vaginal childbirth and pelvic floor disorders. Womens Health (Lond Engl) 2013;9:265-77.
7.Handa VL, Blomquist JL, McDermott KC, Friedman S, Munoz A. Pelvicfloor disorders after vaginal birth: effect of episiotomy, perineal laceration, and operative birth. Obstet Gynecol 2012;119:233-9.
8.Hansen BB, Svare J, Viktrup L, Jørgensen T, Lose G. Urinary incontinence during pregnancy and 1 year after delivery in primiparous women compared with a control group of nulliparous women. Neurourol Urodyn 2012;31:475-80. 9.Abramov Y, Sand PK, Botros SM, et al. Risk factors for female anal incontinence: new insight
FIGURE 4
Correlation between the rates of obstetric trauma, mid-pelvic forceps, and the rates of pelvic organ prolapse surgery
Correlation between A, rates of obstetric trauma among women age 15-44 years in 1987 through 1999 and rates of surgical procedure for pelvic organ prolapse among women age 25-54 years in 1997 through 2009, and between B, rates of midpelvic forceps delivery in 1987 through 1999 and rates of surgical procedure for pelvic organ prolapse in 1997 through 2009. Dots represent years. Washington State, 1987-2009.
through the EvanstoneNorthwestern twin sis-ter’s study. Obstet Gynecol 2005;106:726-32. 10.Kudish BI, Iglesia CB, Gutman RE, Sokol AI, Rodgers AK, Gass M. Risk factors for prolapse development in white, black, and Hispanic women. Female Pelvic Med Reconstr Surg 2011;17:80-90.
11.Rortveit G, Daltveit AK, Hannestad YS, Hunskaar S; Norwegian EPINCONT Study. Uri-nary incontinence after vaginal delivery or ce-sarean section. N Engl J Med 2003;348:900-7. 12.Mant J, Painter R, Vessey M. Epidemiology of genital prolapse: observations from the Ox-ford Family Planning Association Study. Br J Obstet Gynaecol 1997;104:579-85.
13.Tegerstedt G, Miedel A, Maehle-Schmidt M, et al. Obstetric risk factors for symptomatic prolapse: a population-based approach. Am J Obstet Gynecol 2006;194:75-81.
14.Gyhaden M, Bullarbo M, Nielsen TF, Milsom I. Fecal incontinence 20 years after one birth: as comparison between vaginal delivery and cesarean section. Int Urogynecol J 2014;25:1411-8.
15.MacLennan AH, Taylor AW, Wilson DH, Wilson PD. The prevalence of pelvicfloor disor-ders and their relationship to gender, age, parity and mode of delivery. Br J Obstet Gynaecol 2000;107:1460-70.
16.DeLancey J. The hidden epidemic of pelvic floor dysfunction: achievable goals for improved prevention and treatment. Am J Obstet Gynecol 2005;192:1488-95.
17.MacArthur C, Glazener C, Lancashire R, et al. Fecal incontinence and mode offirst and subsequent delivery: a five year longitudinal study. BJOG 2005;112:1075-82.
18.Handa VL, Blomquist JL, Knoepp LR, Hoskey KA, McDermott KC, Munoz A. Pelvic floor disorders 5-10 years after vaginal or cesarean childbirth. Obstet Gynecol 2011;118: 777-84.
19.Dietz HP. Pelvic floor trauma following vaginal delivery. Curr Opin Obstet Gynecol 2006;18:528-37.
20.Barber EL, Lundsberg L, Belanger K, Pettker CM, Funay EF, Illuzzi JL. Contributing indications to the rising cesarean delivery rate. Obstet Gynecol 2011;118:29-38.
21.Blanchette H. The rising cesarean delivery rate in America: what are the consequences? Obstet Gynecol 2011;118:687-90.
22.Liu S, Rusen ID, Joseph KS, et al. Recent trends in cesarean delivery rates and indications for cesarean delivery in Canada. J Obstet Gynaecol Can 2004;26:735-42.
23.Declercq E, Young R, Cabral H, Ecker J. Is rising cesarean delivery rate inevitable? Trends in industrialized countries, 1987 to 2007. Birth 2011;38:99-104.
24.MacDorman MF, Menacker F, Declercq E. Cesarean birth in the United States: epidemi-ology, trends, and outcomes. Clin Perinatol 2008;35:293-300.
25.Martin JA, Hamilton BE, Osterman MJK, Curtin SC. Births:final data for 2013. Natl Vital Stat Rep 2015;64:1-65.
26.Czklo M, Nieto FJ. Epidemiology: beyond the basics, 2nd ed. Sudbury, MA: Jones and Bartlett Publishers; 2007:4-14.
27.Carstensen B. Age-period-cohort models for the Lexis diagram. Stat Med 2007;26: 3018-45.
28.Clayton D, Schifflers E. Models for temporal variation in cancer rates, II: age-period-cohort models. Stat Med 1987;6:469-81.
29.Holford TR. Analyzing the temporal effects of age, period and cohort. Stat Methods Med Res 1992;1:317-37.
30.Jones KA, Shepherd JP, Oliphant SS, et al. Trends in inpatient prolapse procedures in the United States, 1979-2006. Am J Obstet Gyne-col 2010;200:501.e1-7.
31.Oliphant SS, Jones KA, Wang L, Bunker CH, Lowder JL. Obstetric and gynecologic inpatient procedures. Obstet Gynecol 2010;116:926-31. 32.Leijonhufvud A, Lundholm C, Cnattingius S, Granath F, Andolf E, Altman D. Risks of stress urinary incontinence and pelvic organ prolapse surgery in relation to mode of childbirth. Am J Obstet Gynecol 2011;204:e1-6.
33.Abdel-Fattah M, Familusi A, Fielding S, Ford J, Bhattacharyia S. Primary and repeat surgical treatment for female pelvic organ pro-lapse and incontinence in parous women in the UK: a register linkage study. BMJ Open 2011;1: e000206.
34.Wu JM, Hundley AF, Fulton RG, Myers ER. Forecasting the prevalence of pelvicfloor disor-ders in US women: 2010 to 2050. Obstet Gynecol 2009;114:1278-83.
35.Nygaard I, Barber MD, Burgio KL, et al. Pelvic Floor Disorders Network. Prevalence of symptomatic pelvic floor disorders in US women. JAMA 2008;300:1311-6.
36.Elliott CS, Rhoads KF, Comiter CV, Chen B, Sokol ER. Improving the accuracy of prolapse and incontinence procedure epidemiology by utilizing both inpatient and outpatient data. Int Urogynecol J 2013;24:1939-46.
37.Erekson EA, Lopes V V, Raker CA, et al. Ambulatory procedures for female pelvicfloor
disorders in the United States. Am J Obstet Gynecol 2010;203:497.e1-5.
38.Ventura SJ, Hamilton BE, Mathews TJ. National and state patterns of teen births in the United States, 1940-2013. Natl Vital Stat Rep 2014;63:1-34.
39.Mathews TJ, Hamilton BE. Mean age of mothers in on the rise: United States, 2000-2014. NCHS Data Brief no. 232, 2016. 40.Mathews TJ, Hamilton BE. Delayed childbearing: more women are having their first child later in life. NCHS Data Brief 2009;21:1-8.
41.Luke B, Brown MB. Elevated risks of preg-nancy complications and adverse outcomes with increasing maternal age. Hum Reprod 2007;22:1264-72.
42.Lydon-Rochelle MT, Holt VL, Nelson JC, et al. Accuracy of reporting maternal in-hospital diagnoses and intrapartum procedures in Washington State linked records. Paediatr Perinat Epidemiol 2005;19:460-71.
43.Denman MA, Gregory WT, Boyles SH, Smith V, Edwards SR, Clark AL. Reoperation 10 years after surgically managed pelvic organ prolapse and urinary incontinence. Am J Obstet Gynecol 2008;198:555.e1-5.
Author and article information
From the Department of Obstetrics and Gynecology (Drs Lisonkova, Cundiff, and Joseph) and School of Population and Public Health (Ms Muraca and Dr Joseph), University of British Columbia, and the Children’s and Women’s Hospital and Health Center of British Columbia (Drs Lisonkova, Cundiff, and Joseph), Vancouver, British Columbia, Canada; Department of Obstetrics and Gyne-cology, College of Physicians and Surgeons (Dr Ananth) and Department of Epidemiology, Mailman School of Public Health (Ms Lavery and Dr Ananth), Columbia University, New York, NY; and Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, Ontario, Canada (Dr Chen).
Received Sept. 23, 2015; revised Jan. 29, 2016; accepted Feb. 9, 2016.
This study was supported by a Canadian Institutes of Health Research (CIHR) Team grant in severe maternal morbidity (MAH-115445). G.M. is supported by a Vanier Canada Graduate Scholarship from CIHR. K.S.J. holds a CIHR Chair in maternal, fetal, and infant health services research and his work is also supported by the Child and Family Research Institute.
The authors report no conflict of interest.
Corresponding author: Sarka Lisonkova, MD, PhD.
APPENDIX FIGURE 1
Birth cohort effect on first-birth rates
First-birth rates per 1000 women aged 15-44 years by birth cohort, Washington State, 1990 through 2009. Birth cohorts include women born at specific time periods from 1960-64 to 1980-84.
APPENDIX TABLE 1
Diagnostic and procedure codes to identify childbirth hospitalization
Diagnosis ICD-9-CM code
Outcome of delivery V27
Normal delivery 65
Complication mainly related to pregnancya 64
Normal delivery and other indications for care in pregnancy, labor, and deliverya
65
Complications occurring mainly in course of labor and deliverya 66
Procedure ICD-9-CM code
Forceps, vacuum, and breech delivery 72
Other procedures assisting or inducing delivery 73
Cesarean delivery and removal of fetus 74
Repair of current obstetrics laceration of uterus 75.5
Repair of current obstetric laceration 75.6
Obstetric tamponade of uterus or vagina 75.8
Other obstetric operations 75.9
ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification.
aOnly with fifth digit 1 or 2 (delivered with or without mention of antepartum or postpartum condition).
APPENDIX TABLE 2
Surgical procedures for pelvic organ prolapse
Surgical procedure for pelvic organ prolapse ICD-9-CM code
Anterior and posterior colporrhaphy 70.5
Anterior colporrhaphy 70.51
Posterior colporrhaphy 70.52
Repair of cystocele and rectocele with graft or prosthesis 70.53
Repair of cystocele with graft or prosthesis 70.54
Repair of rectocele with graft or prosthesis 70.55
Other operations on vaginaa 70.91
Other repair of vaginaa 70.79
Other uterine suspension 69.22
Other repair of uterus/supporting structuresa 69.29
Vaginal suspension/fixation of vagina 70.77
Vaginal suspension and fixation with graft or prosthesis 70.78 Other operations on cul-de-sac (includes enterocele
repair and cul-de-sac obliteration)
70.92
Vaginal hysterectomya 68.5
Subtotal hysterectomya 68.3
Total abdominal hysterectomya 68.4
Laparoscopically assisted vaginal hysterectomya 68.51
LeFort operation 70.8
Obliteration and total excision of vaginaa 70.4
Other and unspecified hysterectomya 68.9
Other vaginal hysterectomya 68.59
Watkins procedure 69.21
Vaginal repair of chronic inversion of uterus 69.23
ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification.
a
Included only with concomitant International Classification of Diseases, Ninth Revision diagnosis for pelvic organ prolapse (618.0e618.6, 618.8, 618.9).
APPENDIX TABLE 3
Temporal trends in age-specific rates of first birth to women 15e44 years old, Washington State, 1990 through 2009
Age, y
Year
Rate ratio (95% CI)
1990 through 1994 1995 through 1999 2000 through 2004 2005 through 2009
15e19 42.6 28.8 28.0 26.4 0.62 (0.61e0.63) 20e24 58.1 52.4 50.7 49.0 0.84 (0.83e0.85) 25e29 41.6 41.6 39.8 47.7 1.15 (1.13e1.16) 30e34 23.2 22.3 28.6 31.4 1.35 (1.33e1.38) 35e39 8.2 8.3 10.3 13.2 1.62 (1.58e1.66) 40e44 1.4 1.7 2.0 2.4 1.65 (1.54e1.76)
