J. Perinat. Med. 2015; 43(2): 141–146
Katharina Hancke*, Theresa Gundelach, Birgit Hay, Sylvia Sander, Frank Reister and Jürgen M. Weiss
Pre-pregnancy obesity compromises obstetric and neonatal outcomes Introduction
Abstract Objective: Obesity is an important issue among fertile women as it may affect obstetric and neonatal outcomes. Methods: Obstetric and neonatal outcomes of primiparous women were retrospectively analyzed in non-obese (n = 11387) and obese (n = 943) women. A subgroup analysis was performed in obese women divided into three groups: Grade I obesity (Group A, n = 654), Grade II obesity (Group B, n = 192), and Grade III obesity (Group C, n = 97). Odds ratios (OR) were expressed with the corresponding 95% confidence intervals (CI). Results: The incidence of gestational diabetes (non-obese, 1.9%; obese, 7.6%; Group C, 19.6%) and preeclampsia (nonobese, 3.3%; obese, 13.5%; Group C, 17.5%) increased with rising weight. The risk of non-elective cesarean section was significantly higher in obese women than in non-obese women (21.7% vs. 13.2%). The risk of extreme preterm birth (before 28 weeks of gestation) doubled in the Grade I obesity group (OR, 2.1; 95% CI, 1.4–3.2) and nearly tripled in women with body mass index ≥ 35 kg/m2 (OR, 2.9; 95% CI, 1.7–4.9). Conclusion: Pre-pregnancy obesity is associated with higher incidences of gestational diabetes and preeclampsia. Our study shows that obese women have a higher risk of non-elective cesarean section and preterm birth. Keywords: Neonatal outcome; obesity; obstetric outcome; preeclampsia. DOI 10.1515/jpm-2014-0069 Received February 25, 2014. Accepted May 26, 2014. Previously published online June 25, 2014.
*Corresponding author: Katharina Hancke, MD, Department of Gynecology and Obstetrics, University of Ulm, Prittwitzstr. 43, 89075 Ulm, Germany, Tel.: +0049 (0) 731 50058582, Fax: +0049 (0) 731 50058664, E-mail: [email protected] Theresa Gundelach and Frank Reister: Department of Obstetrics and Gynecology, University of Ulm, Ulm, Germany Birgit Hay and Sylvia Sander: Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany Jürgen M. Weiss: Hospital of Luzern, Reproductive Endocrinology, Luzern, Germany
Obesity is a rising concern globally, with an approximately 40% increase in prevalence within the last 20 years [14]. Obesity is classified according to the body mass index (BMI), and is calculated as the proportion of body weight in kilograms (kg) divided by the squared height in meters (m). The World Health Organization categorizes BMI into four groups as follows: underweight, BMI 30.0 kg/m2. A BMI of 30.0–34.9 kg/m2 is further classified as Grade I obesity, a BMI of 35.0–39.9 kg/m2 is classified as Grade II obesity, and a BMI > 40 kg/m2 is classified as Grade III obesity or morbid obesity. In Germany, the prevalence of overweight individuals and obesity is on the rise. In 2012, up to 50% of all women in Germany were overweight, whereas 23.9% had a BMI ≥ 30.0 kg/m2 [1]. Approximately 5% of these obese women were 18–29 years of age and 12.9% were 30–44 years of age [1]. Therefore, obesity is a relevant topic to fertile women. Obesity has been suggested to be a major risk factor for pregnancy, as both maternal and fetal morbidities are compromised by excess weight and obesity [4, 19]. A large retrospective analysis in the UK, including singleton pregnancies, showed a significantly higher rate of gestational diabetes, preeclampsia, delivery by unplanned (non-elective) cesarean section, postpartum hemorrhage, and wound infection associated with excess weight [17]. That study demonstrated that the fetal birth weight was above the 90th percentile, and intrauterine death occurred more often with increasing maternal BMI [17]. Analyses of German perinatal statistics demonstrated similar results with increasing obstetric and perinatal risks to both mother and child, which are associated with pregnancy in obese women [5, 18]. However, the extent to which obesity can negatively affect obstetric and neonatal outcomes remains to be fully investigated. Therefore, we conducted this unicentric, retrospective analysis of singleton primiparous women, in order to investigate the obstetric, prenatal, and neonatal morbidity and outcomes in overweight and obese women.
Brought to you by | Karolinska Institute Authenticated Download Date | 5/30/15 2:11 AM
142 Hancke et al., Obesity and obstetric outcomes
Methods We retrospectively analyzed data collected on pregnant women who gave birth between 1994 and 2007 at the Department of Obstetrics and Gynecology of the University of Ulm. The population attending our university clinic is representative of the whole pregnant population in the Ulm area. This closely reflects the German population because it is the only maternity clinic in the city of Ulm, and in the whole area. Moreover, there are only very small hospitals with a minor number of deliveries. The catchment area recruited patients within a radius of 100 km and it was one of the most frequented obstetrics units in Germany at the time of data collection. The database of the routinely used maternity documentation system of the Department of Obstetrics of the University of Ulm, which was customized by the gynecologists and midwives, was utilized for the analyses. In total, data of 23,729 pregnant women who presented at the Department of Obstetrics and Gynecology were collected. For final analyses, the inclusion criteria were as follows; primiparity, singleton pregnancy, and documented BMI before and after pregnancy. The exclusion criteria were incomplete data on primiparity with singleton pregnancy, multiparity, multiple pregnancies, and underweight (BMI 140/90 mm Hg) and proteinemia ( > 300 mg/day), with or without edema. Gestational diabetes was determined by a pathological 75 g oral glucose tolerance test [fasting glucose > 92 mg/dL (5.0 mmol/L), 1-h glucose > 180 mg/dL (10.0 mmol/L), and 2-h glucose > 153 mg/dL (8.9 mmol/L)] [8]. The duration of labor was measured in hours. The first stage of labor was defined as the beginning of labor until full dilatation of the cervix. The second stage of labor was defined as the time from full dilatation of the cervix until the birth of the child. The incidence of surgical delivery (e.g., vacuum extraction, forceps, or cesarean section) and the type of anesthesia were also included in the analysis. The number of vacuum extractions and forceps use were also recorded. The cesarean section category was subdivided into elective cesarean sections and non-elective cesarean sections (i.e., a cesarean section that was not planned and was associated with immediate threat of life of the woman or fetus) [12]. Blood loss was estimated by the midwives and gynecologists using kidney basins (500 mL), as documented in the birth protocol. The type of anesthesia was differentiated as regional (epidural and spinal) anesthesia or general anesthesia.
Neonatal outcome Regarding neonatal outcome, the incidence of preterm birth (delivery before 34 weeks of gestation) and extreme preterm birth (delivery
before 28 weeks of gestation) were determined. The birth weight, the number of infants with birth weight more than 4000 g, and the incidence of transfer to the neonatal intensive care unit (NICU) were documented.
Statistical analysis Exploratory statistical data analysis was performed using absolute values and percentages, in order to represent frequencies for qualitative variables and means and standard deviations (SD) for continuous variables. The χ2-test was used to determine differences among the groups. Logistic regression models were employed for non-elective cesarean sections and preterm births. Regarding nonelective cesarean sections, the confounding factors were BMI [in the three subgroups: normal weight, overweight ( = non-obese) and obese], fetal birth weight (
Katharina Hancke*, Theresa Gundelach, Birgit Hay, Sylvia Sander, Frank Reister and Jürgen M. Weiss
Pre-pregnancy obesity compromises obstetric and neonatal outcomes Introduction
Abstract Objective: Obesity is an important issue among fertile women as it may affect obstetric and neonatal outcomes. Methods: Obstetric and neonatal outcomes of primiparous women were retrospectively analyzed in non-obese (n = 11387) and obese (n = 943) women. A subgroup analysis was performed in obese women divided into three groups: Grade I obesity (Group A, n = 654), Grade II obesity (Group B, n = 192), and Grade III obesity (Group C, n = 97). Odds ratios (OR) were expressed with the corresponding 95% confidence intervals (CI). Results: The incidence of gestational diabetes (non-obese, 1.9%; obese, 7.6%; Group C, 19.6%) and preeclampsia (nonobese, 3.3%; obese, 13.5%; Group C, 17.5%) increased with rising weight. The risk of non-elective cesarean section was significantly higher in obese women than in non-obese women (21.7% vs. 13.2%). The risk of extreme preterm birth (before 28 weeks of gestation) doubled in the Grade I obesity group (OR, 2.1; 95% CI, 1.4–3.2) and nearly tripled in women with body mass index ≥ 35 kg/m2 (OR, 2.9; 95% CI, 1.7–4.9). Conclusion: Pre-pregnancy obesity is associated with higher incidences of gestational diabetes and preeclampsia. Our study shows that obese women have a higher risk of non-elective cesarean section and preterm birth. Keywords: Neonatal outcome; obesity; obstetric outcome; preeclampsia. DOI 10.1515/jpm-2014-0069 Received February 25, 2014. Accepted May 26, 2014. Previously published online June 25, 2014.
*Corresponding author: Katharina Hancke, MD, Department of Gynecology and Obstetrics, University of Ulm, Prittwitzstr. 43, 89075 Ulm, Germany, Tel.: +0049 (0) 731 50058582, Fax: +0049 (0) 731 50058664, E-mail: [email protected] Theresa Gundelach and Frank Reister: Department of Obstetrics and Gynecology, University of Ulm, Ulm, Germany Birgit Hay and Sylvia Sander: Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany Jürgen M. Weiss: Hospital of Luzern, Reproductive Endocrinology, Luzern, Germany
Obesity is a rising concern globally, with an approximately 40% increase in prevalence within the last 20 years [14]. Obesity is classified according to the body mass index (BMI), and is calculated as the proportion of body weight in kilograms (kg) divided by the squared height in meters (m). The World Health Organization categorizes BMI into four groups as follows: underweight, BMI 30.0 kg/m2. A BMI of 30.0–34.9 kg/m2 is further classified as Grade I obesity, a BMI of 35.0–39.9 kg/m2 is classified as Grade II obesity, and a BMI > 40 kg/m2 is classified as Grade III obesity or morbid obesity. In Germany, the prevalence of overweight individuals and obesity is on the rise. In 2012, up to 50% of all women in Germany were overweight, whereas 23.9% had a BMI ≥ 30.0 kg/m2 [1]. Approximately 5% of these obese women were 18–29 years of age and 12.9% were 30–44 years of age [1]. Therefore, obesity is a relevant topic to fertile women. Obesity has been suggested to be a major risk factor for pregnancy, as both maternal and fetal morbidities are compromised by excess weight and obesity [4, 19]. A large retrospective analysis in the UK, including singleton pregnancies, showed a significantly higher rate of gestational diabetes, preeclampsia, delivery by unplanned (non-elective) cesarean section, postpartum hemorrhage, and wound infection associated with excess weight [17]. That study demonstrated that the fetal birth weight was above the 90th percentile, and intrauterine death occurred more often with increasing maternal BMI [17]. Analyses of German perinatal statistics demonstrated similar results with increasing obstetric and perinatal risks to both mother and child, which are associated with pregnancy in obese women [5, 18]. However, the extent to which obesity can negatively affect obstetric and neonatal outcomes remains to be fully investigated. Therefore, we conducted this unicentric, retrospective analysis of singleton primiparous women, in order to investigate the obstetric, prenatal, and neonatal morbidity and outcomes in overweight and obese women.
Brought to you by | Karolinska Institute Authenticated Download Date | 5/30/15 2:11 AM
142 Hancke et al., Obesity and obstetric outcomes
Methods We retrospectively analyzed data collected on pregnant women who gave birth between 1994 and 2007 at the Department of Obstetrics and Gynecology of the University of Ulm. The population attending our university clinic is representative of the whole pregnant population in the Ulm area. This closely reflects the German population because it is the only maternity clinic in the city of Ulm, and in the whole area. Moreover, there are only very small hospitals with a minor number of deliveries. The catchment area recruited patients within a radius of 100 km and it was one of the most frequented obstetrics units in Germany at the time of data collection. The database of the routinely used maternity documentation system of the Department of Obstetrics of the University of Ulm, which was customized by the gynecologists and midwives, was utilized for the analyses. In total, data of 23,729 pregnant women who presented at the Department of Obstetrics and Gynecology were collected. For final analyses, the inclusion criteria were as follows; primiparity, singleton pregnancy, and documented BMI before and after pregnancy. The exclusion criteria were incomplete data on primiparity with singleton pregnancy, multiparity, multiple pregnancies, and underweight (BMI 140/90 mm Hg) and proteinemia ( > 300 mg/day), with or without edema. Gestational diabetes was determined by a pathological 75 g oral glucose tolerance test [fasting glucose > 92 mg/dL (5.0 mmol/L), 1-h glucose > 180 mg/dL (10.0 mmol/L), and 2-h glucose > 153 mg/dL (8.9 mmol/L)] [8]. The duration of labor was measured in hours. The first stage of labor was defined as the beginning of labor until full dilatation of the cervix. The second stage of labor was defined as the time from full dilatation of the cervix until the birth of the child. The incidence of surgical delivery (e.g., vacuum extraction, forceps, or cesarean section) and the type of anesthesia were also included in the analysis. The number of vacuum extractions and forceps use were also recorded. The cesarean section category was subdivided into elective cesarean sections and non-elective cesarean sections (i.e., a cesarean section that was not planned and was associated with immediate threat of life of the woman or fetus) [12]. Blood loss was estimated by the midwives and gynecologists using kidney basins (500 mL), as documented in the birth protocol. The type of anesthesia was differentiated as regional (epidural and spinal) anesthesia or general anesthesia.
Neonatal outcome Regarding neonatal outcome, the incidence of preterm birth (delivery before 34 weeks of gestation) and extreme preterm birth (delivery
before 28 weeks of gestation) were determined. The birth weight, the number of infants with birth weight more than 4000 g, and the incidence of transfer to the neonatal intensive care unit (NICU) were documented.
Statistical analysis Exploratory statistical data analysis was performed using absolute values and percentages, in order to represent frequencies for qualitative variables and means and standard deviations (SD) for continuous variables. The χ2-test was used to determine differences among the groups. Logistic regression models were employed for non-elective cesarean sections and preterm births. Regarding nonelective cesarean sections, the confounding factors were BMI [in the three subgroups: normal weight, overweight ( = non-obese) and obese], fetal birth weight (
