Background
Data on complications associated with classic cesarean delivery are conflicting. In extremely preterm cesarean delivery (22 0/7-27 6/7 weeks’ gestation), the lower uterine segment is thicker. It is plausible that the rates of maternal complications may not differ between classic and low transverse cesarean.
Objective
We sought to compare maternal outcomes associated with classic versus low transverse cesarean after stratifying by gestation (23 0/7-27 6/7 and 28 0/7-31 6/7 weeks’ gestation).
Study Design
We conducted a multihospital retrospective cohort study of women undergoing cesarean delivery at 23 0/7 to 31 6/7 weeks’ gestation from 2005 through 2014. Composite maternal outcome (postpartum hemorrhage, transfusion, endometritis, sepsis, wound infection, deep venous thrombosis/pulmonary embolism, hysterectomy, respiratory complications, and intensive care unit admission) was compared between classic and low transverse cesarean. Outcomes were calculated using multivariable logistic regression models yielding adjusted odds ratios with 95% confidence intervals and adjusted P values controlling for maternal characteristics, emergency cesarean delivery, and comorbidities. Analyses were stratified by gestational age categories (23 0/7-27 6/7 and 28 0/7-31 6/7 weeks’ gestation).
Results
Of 902 women, 221 (64%) and 91 (16%) underwent classic cesarean between 23 0/7 and 27 6/7 and between 28 0/7 and 31 6/7 weeks’ gestation, respectively. There was no increase in maternal complications for classic cesarean versus low transverse cesarean between 23 0/7 and 27 6/7 weeks’ gestation. However, between 28 0/7 and 31 6/7 weeks’ gestation, classic cesarean was associated with increased risks of the composite maternal outcome (adjusted odds ratio, 1.95; 95% confidence interval, 1.10–3.45), transfusion (adjusted odds ratio, 2.42; 95% confidence interval, 1.06–5.52), endometritis (adjusted odds ratio, 3.23; 95% confidence interval, 1.02–10.21), and intensive care unit admission (adjusted odds ratio, 5.05; 95% confidence interval, 1.37–18.52) compared to low transverse cesarean.
Conclusion
Classic cesarean delivery compared with low transverse was associated with higher maternal complication rates between 28 0/7 and 31 6/7 weeks, but not between 23 0/7 and 27 6/7 weeks’ gestation.
Introduction
Improved survival in extremely preterm infants (22 0/7-27 6/7 weeks’ gestation) has led to increased intervention, including cesarean delivery. The incidence of classic cesarean delivery (vertical uterine incisions) is primarily associated with gestational age, with a 50% classic cesarean delivery rate in women undergoing cesarean delivery at 23-26 weeks’ gestation and declining substantially >32 weeks’ gestation. Data on complications associated with classic cesarean delivery (infection, postoperative pain, blood loss, blood transfusion, maternal intensive care unit [ICU] admission, and death) are conflicting due to heterogeneous groups of women (term vs preterm and various inclusion criteria). The lower uterine segment is not well developed at extremely preterm gestation (22 0/7-27 6/7 weeks’ gestation). It is postulated that the thicker lower uterine segment has a larger surface area of the transected myometrium leading to larger blood loss with lower uterine incision. Therefore, it is plausible that the rates of maternal complications may not differ between classic and low transverse cesarean. Due to increased incidence of intervention in extremely preterm gestations and performance of classic cesarean delivery, detailed information on incidence and types of complications is important. We sought to examine the incidence of maternal morbidities associated with early preterm cesarean delivery by incision type and gestational age categories, between 23 0/7 and 27 6/7 and between 28 0/7 and 31 6/7 weeks’ gestation.
Materials and Methods
We performed a multihospital retrospective cohort study of all women with a singleton pregnancy between 23 0/7 and 31 6/7 weeks’ gestation who delivered via cesarean delivery. Data were collected from January 2005 through December 2014 at 4 hospitals within the same health care organization: MedStar Washington Hospital Center and MedStar Georgetown University Hospital in Washington, DC, and MedStar Franklin Square Medical Center and MedStar Harbor Hospital in Baltimore, MD. We limited the analysis to singleton deliveries between 23 0/7 and 31 6/7 weeks’ gestation because the rate of classic cesarean delivery rapidly declines >32 weeks. We excluded women with severe maternal conditions (renal failure, acute respiratory distress syndrome, cardiovascular disease, placenta accreta, eclampsia, stroke, and major trauma) because it is difficult to separate the morbidity of these conditions from the morbidity of preterm cesarean delivery. Women with history of cesarean delivery were not excluded. We selected the first delivery for women who had >1 eligible cesarean delivery during the study time period. Using electronic medical record data, women who underwent cesarean delivery between 23 0/7 and 31 6/7 weeks’ gestation were identified. Gestational age was established by last menstrual period and ultrasound. If gestational age by last menstrual period and by ultrasound was not in agreement, we used the guidelines of American Congress of Obstetricians and Gynecologists to adjust gestational age. Subsequent chart abstraction was undertaken by the primary author to collect maternal demographics, indications for cesarean delivery, and intraoperative and maternal outcomes. MedStar Institutional Review Board approved this study.
Uterine incision type was classified as recorded in the medical record. Uterine incisions were classified as classic, low transverse, or other cesarean delivery. For the analysis of maternal outcomes, uterine incisions that were started as low transverse incisions but were extended into the upper uterine segment (J or inverted T incisions) were included as part of the classic cesarean delivery group. Low vertical incisions and mid or high transverse uterine incisions were categorized into other cesarean delivery group.
Maternal demographics (age, race/ethnicity, body mass index [BMI] [kg/m 2 ], and number of prior cesarean deliveries), maternal comorbidities such as pregestational diabetes, gestational diabetes, chronic hypertension, and pregnancy-associated hypertensive disease (gestational hypertension, preeclampsia, HELLP syndrome [hemolysis, elevated liver enzyme, low platelet count]), and information on cesarean delivery (emergent delivery, skin incision type, fetal presentation, and indication) were evaluated according to type of uterine incision. BMI was categorized as underweight (<18.5 kg/m 2 ), normal weight (18.5-24.9 kg/m 2 ), overweight (25.0-29.9 kg/m 2 ), and obese (≥30.0). Indications for cesarean delivery including noncephalic presentation, nonreassuring fetal heart tracing, failure to progress, placenta abnormalities, intrauterine growth restriction, preeclampsia with severe features, cord prolapse, HIV, active herpes simplex virus, chorioamnionitis, and fetal anomaly were collected from medical record and evaluated according to type of uterine incision. Placenta abnormalities included placenta previa and placenta abruption. Rates of cesarean incision type (classic, J or T, low transverse, and other) were grouped according to the gestational age.
Intraoperative and maternal outcomes were ascertained according to type of cesarean incision (classic, low transverse, and other) and by gestational age (between 23 0/7-27 6/7 and between 28 0/7-31 6/7 weeks’ gestation). This gestational age category was chosen because of declining classic cesarean delivery rates >28 weeks’ gestation. Intraoperative outcomes included skin incision to delivery time, total operative time (skin incision to skin closure time), and estimated blood loss. A composite maternal adverse outcome included the occurrence of at least 1 of the following: postpartum hemorrhage, blood transfusion, endometritis, sepsis, wound infection/separation, deep venous thrombosis/pulmonary embolism, respiratory complications (pulmonary edema/acute respiratory distress syndrome/congestive heart failure), hysterectomy, and ICU admission. Duration of hospital stay after delivery was also ascertained. Postpartum hemorrhage was defined as total estimated blood loss >1000 mL. Endometritis was defined as fever 38.0°C as well as abdominal tenderness. Sepsis was defined as bacteremia confirmed by blood culture. Wound infection was based on findings of cellulitis or purulent drainage from the wound. Women could have multiple morbidities. For example, if a woman had hemorrhage and required ICU admission, the woman was counted in both hemorrhage and ICU admission.
Outcomes of classic cesarean delivery and other cesarean delivery were compared with those of low transverse cesarean delivery after stratifying by gestational age (between 23 0/7-27 6/7 and between 28 0/7-31 6/7 weeks’ gestation). Descriptive statistics were calculated for all study variables. We performed χ 2 , Fisher exact, or Wilcoxon rank-sum tests to determine associations between outcomes and type of uterine incision. Cochran-Armitage trend test was conducted to calculate the trend of the classic cesarean delivery rates. Multivariable logistic or linear regression analysis was performed to evaluate the study outcomes: skin incision to delivery time, total operative time, estimated blood loss, postpartum hemorrhage, blood transfusion, endometritis, sepsis, wound infection, respiratory complications, ICU admission, hospital stay, and composite maternal outcome between classic cesarean delivery or other cesarean delivery and low transverse cesarean delivery (referent group). Adjusted analyses were performed by controlling for maternal age, race or ethnicity, gestational age, preterm premature rupture of membrane, preterm labor, hypertension (chronic, gestational, preeclampsia), diabetes (gestational and pregestational), emergent delivery, skin incision type, number of previous cesarean deliveries, placenta abnormalities, and BMI on admission. Analyses were repeated to compare extreme preterm (between 23 0/7-27 6/7 weeks’ gestation) and later (28 0/7-31 6/7 weeks’ gestation) gestation among different cesarean delivery types (classic and low transverse). All statistical analyses were performed using software (SAS 9.3; SAS Institute Inc, Cary, NC).
Materials and Methods
We performed a multihospital retrospective cohort study of all women with a singleton pregnancy between 23 0/7 and 31 6/7 weeks’ gestation who delivered via cesarean delivery. Data were collected from January 2005 through December 2014 at 4 hospitals within the same health care organization: MedStar Washington Hospital Center and MedStar Georgetown University Hospital in Washington, DC, and MedStar Franklin Square Medical Center and MedStar Harbor Hospital in Baltimore, MD. We limited the analysis to singleton deliveries between 23 0/7 and 31 6/7 weeks’ gestation because the rate of classic cesarean delivery rapidly declines >32 weeks. We excluded women with severe maternal conditions (renal failure, acute respiratory distress syndrome, cardiovascular disease, placenta accreta, eclampsia, stroke, and major trauma) because it is difficult to separate the morbidity of these conditions from the morbidity of preterm cesarean delivery. Women with history of cesarean delivery were not excluded. We selected the first delivery for women who had >1 eligible cesarean delivery during the study time period. Using electronic medical record data, women who underwent cesarean delivery between 23 0/7 and 31 6/7 weeks’ gestation were identified. Gestational age was established by last menstrual period and ultrasound. If gestational age by last menstrual period and by ultrasound was not in agreement, we used the guidelines of American Congress of Obstetricians and Gynecologists to adjust gestational age. Subsequent chart abstraction was undertaken by the primary author to collect maternal demographics, indications for cesarean delivery, and intraoperative and maternal outcomes. MedStar Institutional Review Board approved this study.
Uterine incision type was classified as recorded in the medical record. Uterine incisions were classified as classic, low transverse, or other cesarean delivery. For the analysis of maternal outcomes, uterine incisions that were started as low transverse incisions but were extended into the upper uterine segment (J or inverted T incisions) were included as part of the classic cesarean delivery group. Low vertical incisions and mid or high transverse uterine incisions were categorized into other cesarean delivery group.
Maternal demographics (age, race/ethnicity, body mass index [BMI] [kg/m 2 ], and number of prior cesarean deliveries), maternal comorbidities such as pregestational diabetes, gestational diabetes, chronic hypertension, and pregnancy-associated hypertensive disease (gestational hypertension, preeclampsia, HELLP syndrome [hemolysis, elevated liver enzyme, low platelet count]), and information on cesarean delivery (emergent delivery, skin incision type, fetal presentation, and indication) were evaluated according to type of uterine incision. BMI was categorized as underweight (<18.5 kg/m 2 ), normal weight (18.5-24.9 kg/m 2 ), overweight (25.0-29.9 kg/m 2 ), and obese (≥30.0). Indications for cesarean delivery including noncephalic presentation, nonreassuring fetal heart tracing, failure to progress, placenta abnormalities, intrauterine growth restriction, preeclampsia with severe features, cord prolapse, HIV, active herpes simplex virus, chorioamnionitis, and fetal anomaly were collected from medical record and evaluated according to type of uterine incision. Placenta abnormalities included placenta previa and placenta abruption. Rates of cesarean incision type (classic, J or T, low transverse, and other) were grouped according to the gestational age.
Intraoperative and maternal outcomes were ascertained according to type of cesarean incision (classic, low transverse, and other) and by gestational age (between 23 0/7-27 6/7 and between 28 0/7-31 6/7 weeks’ gestation). This gestational age category was chosen because of declining classic cesarean delivery rates >28 weeks’ gestation. Intraoperative outcomes included skin incision to delivery time, total operative time (skin incision to skin closure time), and estimated blood loss. A composite maternal adverse outcome included the occurrence of at least 1 of the following: postpartum hemorrhage, blood transfusion, endometritis, sepsis, wound infection/separation, deep venous thrombosis/pulmonary embolism, respiratory complications (pulmonary edema/acute respiratory distress syndrome/congestive heart failure), hysterectomy, and ICU admission. Duration of hospital stay after delivery was also ascertained. Postpartum hemorrhage was defined as total estimated blood loss >1000 mL. Endometritis was defined as fever 38.0°C as well as abdominal tenderness. Sepsis was defined as bacteremia confirmed by blood culture. Wound infection was based on findings of cellulitis or purulent drainage from the wound. Women could have multiple morbidities. For example, if a woman had hemorrhage and required ICU admission, the woman was counted in both hemorrhage and ICU admission.
Outcomes of classic cesarean delivery and other cesarean delivery were compared with those of low transverse cesarean delivery after stratifying by gestational age (between 23 0/7-27 6/7 and between 28 0/7-31 6/7 weeks’ gestation). Descriptive statistics were calculated for all study variables. We performed χ 2 , Fisher exact, or Wilcoxon rank-sum tests to determine associations between outcomes and type of uterine incision. Cochran-Armitage trend test was conducted to calculate the trend of the classic cesarean delivery rates. Multivariable logistic or linear regression analysis was performed to evaluate the study outcomes: skin incision to delivery time, total operative time, estimated blood loss, postpartum hemorrhage, blood transfusion, endometritis, sepsis, wound infection, respiratory complications, ICU admission, hospital stay, and composite maternal outcome between classic cesarean delivery or other cesarean delivery and low transverse cesarean delivery (referent group). Adjusted analyses were performed by controlling for maternal age, race or ethnicity, gestational age, preterm premature rupture of membrane, preterm labor, hypertension (chronic, gestational, preeclampsia), diabetes (gestational and pregestational), emergent delivery, skin incision type, number of previous cesarean deliveries, placenta abnormalities, and BMI on admission. Analyses were repeated to compare extreme preterm (between 23 0/7-27 6/7 weeks’ gestation) and later (28 0/7-31 6/7 weeks’ gestation) gestation among different cesarean delivery types (classic and low transverse). All statistical analyses were performed using software (SAS 9.3; SAS Institute Inc, Cary, NC).
Results
Of 95,469 deliveries, 1188 (1.2%) were cesarean deliveries between 23 0/8 and 31 6/7 weeks’ gestation. Of 1188 cases of cesarean delivery, 213 deliveries with multiple gestations and 53 deliveries accompanied by severe comorbidities (20 renal failure, 10 acute respiratory distress syndrome, 8 cardiovascular disease, 6 placenta accreta, 5 eclampsia, 2 stroke, and 2 major trauma) were excluded. After excluding 20 pregnancies that represented repeat pregnancies, 902 remained for analysis, of which 312 (34.6%) were classic cesarean delivery, 552 (61.2%) were low transverse cesarean, and 38 (4.2%) were other cesarean delivery.
Maternal demographic data, pregnancy outcomes, and indications for cesarean delivery are presented in Tables 1 and 2 . Between 23 0/7 and 27 6/7 weeks’ gestation, the classic cesarean delivery group was more likely to have higher BMI ( P = .03), lower birthweight ( P < .001), and noncephalic presentation ( P = .001) compared to the low transverse cesarean group. Between 23 0/7 and 27 6/7 weeks’ gestation, the classic cesarean delivery group had higher rate of cesarean delivery indicated for noncephalic presentation ( P < .001). Between 28 0/7 and 31 6/7 weeks’ gestation, the classic cesarean delivery group was more likely to have lower birthweight ( P < .01), emergent delivery ( P = .03), vertical skin incision ( P < .001), noncephalic presentation ( P < .001), and chronic hypertension ( P = .02) compared to the low transverse cesarean group. Between 28 0/7 and 31 6/7 weeks’ gestation, other cesarean delivery group was more likely to have prior uterine scar ( P < .01).
| LTCD, n = 126 | Classic CD, n = 221 | Other CD, n = 16 | P value, classic vs LTCD | P value, other vs LTCD | |
|---|---|---|---|---|---|
| Maternal age, y, mean (SD) | 28.4 (6.4) | 29.7 (6.5) | 31.44 (6.1) | .08 | .08 |
| Race/ethnicity | |||||
| Non-Hispanic white | 22 (17.5) | 40 (18.1) | 2 (12.5) | .30 | 1.00 |
| Non-Hispanic black | 81 (64.3) | 154 (69.7) | 11 (68.8) | ||
| Other | 23 (18.3) | 27 (12.2) | 3 (18.8) | ||
| BMI at admission, kg/m 2 | 31.3 (7.6) | 33.4 (8.4) | 33.9 (9.3) | .03 | .26 |
| Underweight/normal | 21 (18.0) | 33 (16.2) | 2 (13.3) | .05 | .87 |
| Overweight | 35 (29.9) | 39 (19.1) | 4 (26.7) | ||
| Obese | 61 (52.1) | 132 (64.7) | 9 (60.0) | ||
| No. of prior uterine scar | |||||
| 0 | 92 (73.0) | 169 (76.8) | 15 (93.8) | .67 | .27 |
| 1–2 | 29 (23.0) | 45 (20.4) | 1 (6.3) | ||
| ≥3 | 5 (4.0) | 6 (2.7) | 0 (0.0) | ||
| Birthweight, g, mean (SD) | 827.4 (192.7) | 724.3 (188.0) | 752.2 (216.5) | <.001 a | .18 |
| Emergent delivery | 50 (39.7) | 108 (49.1) | 10 (62.5) | .09 | .08 |
| Skin incision | |||||
| Pfannenstiel | 122 (97.6) | 210 (95.5) | 16 (100.0) | .39 | 1.0 |
| Vertical | 3 (2.4) | 10 (4.6) | 0 (0.0) | ||
| Presentation | |||||
| Breech | 60 (47.6) | 134 (60.9) | 11 (68.8) | .001 a | .24 |
| Cephalic | 60 (47.6) | 63 (28.6) | 5 (31.3) | ||
| Transverse | 6 (4.8) | 23 (10.5) | 0 (0.0) | ||
| Pregestational diabetes | 3 (2.4) | 10 (4.5) | 1 (6.3) | .39 | .38 |
| Gestational diabetes | 4 (3.2) | 3 (1.4) | 1 (6.3) | .26 | .45 |
| Chronic hypertension | 14 (11.2) | 29 (13.1) | 2 (12.5) | .60 | 1.00 |
| Pregnancy-associated hypertensive disease | 40 (31.8) | 56 (25.3) | 2 (12.5) | .15 | .20 |
| Indications for CD | |||||
| Noncephalic presentation | 58 (46.0) | 149 (67.4) | 11 (68.8) | <.001 a | .09 |
| Nonreassuring fetal heart tracing | 44 (34.9) | 87 (39.4) | 6 (37.5) | .41 | .84 |
| Failure to progress | 0 (0.0) | 0 (0.0) | 0 (0.0) | – | – |
| Placenta abnormalities | 23 (18.3) | 31 (14.0) | 3 (18.8) | .30 | 1.00 |
| Intrauterine growth restriction | 18 (14.3) | 34 (15.4) | 0 (0.0) | .78 | .22 |
| Preeclampsia with severe features | 35 (27.8) | 42 (19.0) | 3 (18.8) | .06 | .56 |
| Cord prolapse | 7 (5.6) | 9 (4.1) | 1 (6.3) | .53 | 1.00 |
| HIV/active HSV | 2 (1.6) | 2 (0.9) | 0 (0.0) | .62 | 1.00 |
| Chorioamnionitis | 18 (14.3) | 25 (11.3) | 5 (31.3) | .42 | .14 |
| Fetal anomaly | 0 (0.0) | 0 (0.0) | 0 (0.0) | – | – |
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