Abstract
Severe perineal injury (third and fourth degree laceration) at the time of vaginal delivery increases the risk of fecal incontinence, chronic perineal pain, and dyspareunia.1–5 Studies suggest the prevalence of severe perineal injury may vary by racial group.6 The purpose of the current study was to examine rates of severe perineal injury in different Asian and Pacific Islander subgroups. A retrospective cohort study was performed among all patients who had a vaginal delivery at Queens Medical Center in Honolulu, Hawai‘i between January 1, 2002 and December 31, 2003. Demographic and health related variables were obtained for each participant. Maternal race/ethnicity (Japanese, Filipino, Chinese, other Asian, Part-Hawaiian/Hawaiian, Micronesian, other Pacific Islander, Caucasian, multiracial [non-Hawaiian], and other) was self-reported by the patient at the time admission. The significance of associations between racial/ethnic groups and demographic and health related variables was determined using chi-square tests for categorical variables and analysis of variance for continuous factors. Multiple logistic regression was performed to adjust for potential confounders when examining severe laceration rates. A total of 1842 subjects met inclusion criteria. The proportion of severe perineal lacerations did not differ significantly between racial groups. In the multiple logistic regression analysis, operative vaginal delivery was related to both race and severe perineal laceration. However, despite adjusting for this variable, race was not associated with an increased risk of having a severe laceration (P = .70). The results of this study indicate the risk of severe perineal laceration does not differ based on maternal race/ethnicity.
Introduction
Severe perineal lacerations (third and fourth degree) as a consequence of vaginal delivery have both short- and long-term consequences including fistula formation, fecal incontinence, fecal urgency, chronic perineal pain, and dyspareunia.1–5 An estimated 20 to 50 percent of women who require repair of anal sphincter lacerations after delivery will experience symptoms of anal incontinence.7 Maternal age, nulliparity, operative vaginal delivery, episiotomy, persistent occiput posterior position, and increasing birth weight have been associated with an increased risk of these types of lacerations.8–11 Recent studies suggest race may play a role in the risk of severe lacerations.6,11 In a retrospective cohort study, nulliparous Filipino and Chinese women were found to be at increased risk of third- and fourth-degree laceration compared to other racial groups.6 Other retrospective studies have identified Asian race as a risk factor for severe lacerations. Specifically, Indian and Filipino women were found to be at increased risk of sustaining anal sphincter lacerations.11 It is unclear whether an increased risk of severe perineal laceration is present among all Asian and Pacific Islander subgroups. Clinical practice would suggest that there are many physical differences between the subgroups. The purpose of this study was to examine the impact of maternal race on the risk of developing third and fourth degree perineal lacerations at the time of vaginal delivery. In particular, the risk of severe perineal laceration among the various Asian (Chinese, Japanese, Filipino, other Asian) and Pacific Islander (Micronesian, Hawaiian/Part-Hawaiian, other Pacific Islander) subgroups was explored.
Study Design
A retrospective cohort study was performed at the Queens Medical Center (QMC) in Honolulu, Hawai‘i in 2004. This study was approved by the QMC Institutional Review Board. All women who had a vaginal delivery between January 1, 2002 and December 31, 2003 were reviewed. Women were excluded if there was malpresentation of the fetus (breech or transverse position) or if there was a multiple gestation such as a twin pregnancy. Demographic variables including age and race as well as health related variables, such as gestational age, parity, and the presence of diabetes mellitus (diet controlled or insulin dependent) were collected by reviewing hospital and prenatal records. Diabetics were sub-classified as either diet controlled or insulin dependent due to the higher rates of complications that insulin dependent diabetics experience in pregnancy. Physicians were required by this facility to include the patient's prenatal record in the medical record. Labor and delivery events were recorded in the medical record using standardized forms. If the prenatal record was not included in the medical record or if portions of the labor and delivery record were incomplete, physicians were required to complete these deficiencies resulting in complete records for data collection for this study.
Maternal race was extracted from the medical record. Patients self-reported race at the time of admission. If it was inappropriate to collect admission information when the patient arrived at the hospital (eg, if a patient was in active labor), hospital staff returned to the bedside sometime after delivery to collect admission information. In the medical record, patients could select as many races as they thought appropriate. For this analysis, if an individual identified with more than one race, they were either; (1) considered to be part-Hawaiian/Hawaiian if one of those races was Hawaiian or part-Hawaiian, or (2) were categorized as multiracial. Patients were thus grouped into one the following 10 categories: Japanese, Filipino, Chinese, other Asian, part-Hawaiian/Hawaiian, Micronesian, other Pacific Islander, Caucasian, multiracial (non-Hawaiian), and other. Maternal height was self-reported by the patient on the day of admission. Maternal weight was measured on the day of admission. Information was collected regarding mode of delivery, in particular whether the patient had an operative delivery (forceps or vacuum assisted delivery), whether the patient had an episiotomy, birth weight, fetal position (occiput anterior, non-occiput anterior), and degree of perineal laceration if present.
Descriptive statistics, including frequency measures were calculated. Association between racial/ethnic groups and demographic and health related variables were determined using chi-square tests for categorical variables and analysis of variance for continuous factors. A Bonferroni adjustment was used when making pair-wise comparisons between racial groups. A multiple logistic regression model was created to adjust for potential confounders that were associated with severe lacerations using a P<.05 cutoff for initial inclusion in the model. All analyses were performed using Statistical Package for the Social Sciences version 16.0 for Windows (SPSS Inc., Chicago, IL).
Results
A total of 1842 subjects met inclusion criteria. Demographic characteristics are presented in Table 1. The most commonly reported maternal races were Japanese (24.6%), part-Hawaiian/Hawaiian (18.3%), and Filipino (15.0%). Chinese women had the greatest mean age (30.6 [SD 5.7] years), and the “Other” category had the youngest mean age (28.6 [SD 6.8] years) at the time of delivery. Mean maternal body mass index (BMI) at the time of delivery for the study population was 28.2 (SD 7.0) kg/m2 and there was no difference between groups (P=.80). Mean birth weight for the study population was 3262.2 (SD 467.5) grams and there was also no significant difference between groups (P=.46). No differences by race emerged in the proportion of women who reported that this was their first child; approximately 40% of the study population reported a parity of one following delivery (P=.79). The only variable that differed significantly was the proportion of women who had an operative vaginal delivery (P<.05). Caucasian (18.4%) and Micronesian (23.2%) women had the highest proportion of operative vaginal deliveries while Filipino (9.4%) and other Asian (9.1%) women had the lowest.
Table 1.
Demographics and Health Characteristics
| Japanese | Hawaiian/part-Hawaiian | Filipino | Caucasian | Chinese | Micronesian | Multi-Racial (non-Hawaiian) | Other Pacific Islander | Other Asian | Other | Total Study Population | |
| N (% of total population) | 453 (24.6) | 338 (18.3) | 277 (15.0) | 152 (8.3) | 94 (5.1) | 56 (3.0) | 225 (12.2) | 57 (3.1) | 143 (8.7) | 47 (2.6) | 1842 |
| Mean Age in Years, mean (sd) | 30.0 (5.8) | 29.8 (6.2) | 30.5 (5.9) | 29.4 (6.2) | 30.6 (5.7) | 28.9 (5.3) | 30.2 (6.1) | 30.5 (6.6) | 30.0 (6.3) | 28.6 (6.8) | 30.0 (6.1) |
| Gestational Age in Weeks, mean (sd) | 39.0 (1.6) | 38.9 (2.9) | 39.0 (2.3) | 39.1 (1.6) | 38.6 (3.8) | 38.7 (3.0) | 38.8 (2.9) | 39.1 (1.2) | 39.0 (1.4) | 38.7 (5.9) | 39.0 (2.5) |
| Birth Weight in Grams, mean (sd) | 3287.6 (486.2) | 3243.0 (460.15) | 3270.1 (444.8) | 3238.2 (488.8) | 3260.1 (439.0) | 3197.6 (439.5) | 3237.1 (463.8) | 3391.33 (477.3) | 3244.8 (491.0) | 3283.9 (413.9) | 3262.2 (467.5) |
| Parity (n [%])** None 1 2 or more |
184 (40.9) 147 (32.7) 119 (26.4) |
135 (40.3) 119 (3.5) 81 (24.2) |
117 (42.2) 94 (33.9) 66 (23.8) |
69 (45.7) 39 (25.8) 43 (28.5) |
35 (37.6) 36 (38.7) 22 (23.7) |
31 (55.4) 13 (23.2) 12 (21.4) |
89 (39.7) 78 (34.8) 57 (25.4) |
22 (39.3) 20 (35.7) 14 (25.0) |
63 (44.1) 43 (30.1) 37 (25.9) |
20 (42.6) 13 (27.7) 14 (29.8) |
765 (41.8) 602 (32.9) 465 (25.4) |
| Maternal BMI at Delivery kg/m2, mean (sd) | 28.5 (6.4) | 28.3 (7.0) | 27.8 (8.1) | 27.9 (7.5) | 27.5 (6.9) | 28.4 (6.3) | 28.0 (6.9) | 29.2 (4.9) | 27.7 (7.5) | 28.3 (8.6) | 28.2 (7.0) |
| Diabetes, n (%) Diet Controlled Insulin Dependent |
20 (4.5) 11 (2.5) |
17 (5.1) 7 (2.1) |
17 (6.2) 11 (4.0) |
3 (2.0) 2 (1.4) |
6 (6.5) 2 (2.2) |
3 (5.5) 1 (1.8) |
11 (5.0) 4 (1.8) |
1 (1.8) 3 (5.5) |
10 (7.2) 4 (2.9) |
0 (0.0) 0 (0.0) |
88 (4.9) 45 (2.5) |
| Operative delivery* n (%) | 52 (11.5) | 44 (13.0) | 26 (9.4) | 28 (18.4) | 15 (16.0) | 13 (23.2) | 25 (11.1) | 8 (14.0) | 13 (9.1) | 6 (12.8) | 230 (12.5) |
| Occiput Anterior Position, n (%) | 432 (95.4) | 317 (93.8) | 267 (96.4) | 146 (96.1) | 91 (96.8) | 53 (94.6) | 211 (93.8) | 53 (93.0) | 137 (95.8) | 44 (93.6) | 1751 (95.1) |
| Episiotomy n (%) | 186 (41.1) | 145 (42.9) | 108 (39.0) | 72 (47.4) | 41 (43.6) | 24 (42.9) | 79 (35.1) | 26 (45.6) | 64 (44.8) | 11(23.4) | 756 (41.0) |
Indicates P < .05 (p-value determined using chi-square tests for categorical variables and analysis of variance for continuous factors),
Missing data for 10 subjects.
Table 2 describes the relationship between severe perineal laceration and various demographic and health related factors. Patient age, operative vaginal delivery, episiotomy and parity affected the rate of severe perineal laceration (P<.001). Episiotomy was performed in 756 patients, resulting in an episiotomy rate of 41.0%. Table 3 describes the unadjusted and adjusted odds ratios for severe perineal laceration for various racial groups compared to Caucasians. After adjusting for episiotomy and operative vaginal delivery, no significant differences emerged in the risk of severe lacerations for various racial groups when compared to Caucasians.
Table 2.
Association Between Severe Lacerations and Demographic and Health Related Factors
| N | Severe Laceration, n (%) | P value* | |
| Race | |||
| Other Asian | 143 | 13 (9.1) | .51 |
| Japanese | 453 | 31 (6.8) | |
| Hawaiian/Part-Hawaiian | 338 | 30 (8.9) | |
| Filipino | 277 | 21 (7.6) | |
| Caucasian | 152 | 19 (12.5) | |
| Chinese | 94 | 4 (4.3) | |
| Micronesian | 56 | 6 (10.7) | |
| Multiracial (non- Hawaiian) | 225 | 20 (8.9) | |
| Other Pacific Islander | 57 | 4 (7.0) | |
| Other | 47 | 3 (6.4) | |
| Age | |||
| 25 or younger | 451 | 28 (6.2) | .05 |
| 26–35 | 1023 | 98 (9.6) | |
| Older than 35 | 368 | 25 (6.8) | |
| Diabetes | |||
| Diet Controlled | 88 | 8 (5.4) | .90 |
| Insulin Dependent | 45 | 3 (6.7) | |
| Non-Diabetic | 1709 | 138 (8.2) | |
| Operative Delivery | |||
| Yes | 230 | 62 (27.0) | <.001 |
| No | 1612 | 89 (5.5) | |
| Episiotomy | |||
| Yes | 756 | 112 (14.8) | <.001 |
| No | 1086 | 39 (3.6) | |
| Parity** | |||
| 0 | 765 | 134 (17.5) | <.001 |
| 1 | 602 | 12 (2.0) | |
| 2 or more | 465 | 5 (1.1) | |
| Birth weight (Grams) | |||
| <4000g | 1732 | 140 (8.1) | .47 |
| >4000g | 110 | 11 (10.0) | |
P-value determined using chi-square tests for categorical variables and analysis of variance for continuous factors,
Missing data for 10 subjects.
Table 3.
Unadjusted and Adjusted* ORs and 95% CIs for Race and Severe Llaceration
| Race | Unadjusted OR | Unadjusted [95% CI] | Adjusted OR* | Adjusted (95% CI)* |
| Other Asian | 0.70 | [0.33, 1.48] | 0.84 | [0.38, 1.85] |
| Japanese | 0.51 | [0.28, 0.94] | 0.60 | [0.32, 1.14] |
| Part-Hawaiian /Hawaiian | 0.68 | [0.37, 1.25] | 0.78 | [0.41, 1.50] |
| Filipino | 0.57 | [0.30, 1.11] | 0.72 | [0.36, 1.44] |
| Caucasian | Reference | Reference | Reference | Reference |
| Chinese | 0.31 | [0.10, 0.95] | 0.34 | [0.11, 1.08] |
| Micronesian | 0.84 | [0.32, 2.22] | 0.75 | [0.26, 2.13] |
| Multiracial (non-Hawaiian) | 0.68 | [0.35, 1.33] | 0.89 | [0.44, 1.79] |
| Other Pacific Islander | 0.27 | [0.53, 1.72] | 0.56 | [0.17, 1.81] |
| Other | 0.48 | [.135, 1.69] | 0.751 | [0.20, 2.82] |
Adjusted for episiotomy and operative delivery.
Discussion
Contrary to previous studies by Hopkins, et al, Goldberg, et al, and Green and Soohoo, this study did not find higher rates of severe lacerations in Asian women, specifically Asian and Pacific Islander subgroups.6,12,13 “Asian” as a racial category has been used in other studies to combine diverse subgroups including Chinese, Filipino, Laotian, Hmong, Korean, Japanese, and Vietnamese, into a single large group. Frequently, this is done to overcome the challenge of finding an adequate sample size. Given the racial diversity and large number of Asian and Pacific Islander patients in Hawai‘i, this study was able to analyze subjects by racial subgroups. Of note, this is the only study to the authors' knowledge that has addressed perineal laceration rates in Hawaiian/part-Hawaiian and Micronesian women.
This study confirmed findings noted in other studies regarding increased rates of severe perineal laceration associated with episiotomy and operative vaginal delivery.2,6,14 The higher than expected rate of episiotomy noted in this population is reflective of the time period in which this study took place. If this study was repeated today we would expect the rate of episiotomy to be lower. Interestingly, the study found that rates of operative vaginal delivery varied by racial group. Although this study was not designed to explore why this was the case, it suggests women of different races are treated differently when they receive medical care.
Several limitations must be noted. Importantly, data were collected between 2002 and 2003 making our results reflective of the population and medical practices for that time period. In the last 10 years, the rate of episiotomy has decreased, markedly affecting the generalizability of our findings to current clinical practice. Our findings still have merit as the purpose of this study was to explore differential rates of severe lacerations between racial groups rather than the effect of episiotomy on severe laceration. We did attempt to control for differences in episiotomy using multiple logistic regression. Secondly, patient information was extracted from the medical record and thus relied on the accuracy of the record. At QMC, patients self-reported race upon admission to the hospital. Maternal race was also reported in the neonate's record. Self-report is considered to be the best way to collect information on race.15 The completeness of reporting for this variable in our study, however, raises the question of whether those who entered race into the medical record truly collected this variable by self-report. This is an observation; we were not able to determine the reason for the completeness of our data through this chart review. Additionally, because of the complexity of race, particularly in a multiracial population, it can be difficult to incorporate this variable into an analysis. Most studies group women into larger racial groups such as Asian, Pacific Islander or even Asian/Pacific Islander. Although our division of the study population into racial subgroups decreased the power of the study to detect differences, it was our intention to explore rates of severe laceration among these subgroups. Clinical practice would suggest that differences in body shape and stature exist among the Asian/Pacific Islander racial subgroups. These findings represent an important contribution to the medical literature because it is the first to describe rates of severe perineal laceration in several racial subgroup categories including Micronesians and part-Hawaiian/Hawaiians.
Women are frequently concerned about their risk of perineal laceration at the time of delivery. Over the last few years, research has provided a better understanding of factors which can increase or decrease that risk. The results of this study allow providers to advise women that their risk of severe perineal laceration does not appear to differ significantly solely based on their race.
Conflict of Interest
None of the authors identify a conflict of interest.
References
- 1.Kammerer-Doak D, Rogers RG. Female sexual function and dysfunction. Obstet Gynecol Clin North Am. 2008 Jun;35(2):169–183, vii. doi: 10.1016/j.ogc.2008.03.006. [DOI] [PubMed] [Google Scholar]
- 2.Wheeler TL, 2nd, Richter HE. Delivery method, anal sphincter tears and fecal incontinence: new information on a persistent problem. Curr Opin Obstet Gynecol. 2007 Oct;19(5):474–479. doi: 10.1097/GCO.0b013e3282ef4142. [DOI] [PubMed] [Google Scholar]
- 3.Ogunyemi D, Manigat B, Marquis J, Bazargan M. Demographic variations and clinical associations of episiotomy and severe perineal lacerations in vaginal delivery. J Natl Med Assoc. 2006 Nov;98(11):1874–1881. [PMC free article] [PubMed] [Google Scholar]
- 4.Nichols CM, Lamb EH, Ramakrishnan V. Differences in outcomes after third- versus fourth-degree perineal laceration repair: a prospective study. Am J Obstet Gynecol. 2005 Aug;193(2):530–534. doi: 10.1016/j.ajog.2005.03.045. discussion 534–536. [DOI] [PubMed] [Google Scholar]
- 5.Aytan H, Tapisiz OL, Tuncay G, Avsar FA. Severe perineal lacerations in nulliparous women and episiotomy type. Eur J Obstet Gynecol Reprod Biol. 2005 Jul 1;121(1):46–50. doi: 10.1016/j.ejogrb.2004.10.013. [DOI] [PubMed] [Google Scholar]
- 6.Goldberg J, Hyslop T, Tolosa JE, Sultana C. Racial differences in severe perineal lacerations after vaginal delivery. Am J Obstet Gynecol. 2003 Apr;188(4):1063–1067. doi: 10.1067/mob.2003.251. [DOI] [PubMed] [Google Scholar]
- 7.Minaglia SM, Kimata C, Soules KA, Pappas T, Oyama IA. Defining an at-risk population for obstetric anal sphincter laceration. Am J Obstet Gynecol. 2009 Nov;201(5):526 e521–526 e526. doi: 10.1016/j.ajog.2009.07.021. [DOI] [PubMed] [Google Scholar]
- 8.Hamilton EF, Smith S, Yang L, Warrick P, Ciampi A. Third- and fourth-degree perineal lacerations: defining high-risk clinical clusters. Am J Obstet Gynecol. 2011 Apr;204(4):309 e301–309 e306. doi: 10.1016/j.ajog.2010.12.048. [DOI] [PubMed] [Google Scholar]
- 9.Christianson LM, Bovbjerg VE, McDavitt EC, Hullfish KL. Risk factors for perineal injury during delivery. Am J Obstet Gynecol. 2003 Jul;189(1):255–260. doi: 10.1067/mob.2003.547. [DOI] [PubMed] [Google Scholar]
- 10.Williams MK, Chames MC. Risk factors for the breakdown of perineal laceration repair after vaginal delivery. Am J Obstet Gynecol. 2006 Sep;195(3):755–759. doi: 10.1016/j.ajog.2006.06.085. [DOI] [PubMed] [Google Scholar]
- 11.Landy HJ, Laughon SK, Bailit JL, et al. Characteristics associated with severe perineal and cervical lacerations during vaginal delivery. Obstet Gynecol. 2011 Mar;117(3):627–635. doi: 10.1097/AOG.0b013e31820afaf2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Hopkins LM, Caughey AB, Glidden DV, Laros RK., Jr Racial/ethnic differences in perineal, vaginal and cervical lacerations. Am J Obstet Gynecol. 2005 Aug;193(2):455–459. doi: 10.1016/j.ajog.2004.12.007. [DOI] [PubMed] [Google Scholar]
- 13.Green JR, Soohoo SL. Factors associated with rectal injury in spontaneous deliveries. Obstet Gynecol. 1989 May;73(5 Pt 1):732–738. [PubMed] [Google Scholar]
- 14.Kudish B. Trends in major modifiable risk factors for severe perineal trauma, 1996–2006. International Journal of Gyneology and Obstetrics. 2008;102:165–170. doi: 10.1016/j.ijgo.2008.02.017. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Azar KM, Moreno MR, Wong EC, Shin JJ, Soto C, Palaniappan LP. Accuracy of data entry of patient race/ethnicity/ancestry and preferred spoken language in an ambulatory care setting. Health Serv Res. Feb;47(1 Pt 1):228–240. doi: 10.1111/j.1475-6773.2011.01305.x. [DOI] [PMC free article] [PubMed] [Google Scholar]