Michal Kovo 1, Elena Saruhanov 1,Letizia Schreiber 2,Noa Mevorach 1, Jacob Bar 1
| Depts. of Obstetrics & Gynecology1 and Pathology2, the E. Wolfson Medical Center, Holon, and Sackler Faculty of Medicine, Tel Aviv University, Israel |
Objectives: To investigate the effect of maternal obesity on pregnancy outcome and placental histopathology.
Study design: Pregnancy outcome and placental histology from complicated term pregnancy, between 2007- 2012, were reviewed. Women were divided according to their pre-pregnancy body mass index (BMI) (kg/m2); normal weight (18-24.9), overweight (25-29.9) and obese (≥30). Results were compared between the groups. In addition, pregnancy outcome and placental histology were compared between obese and control group with uncomplicated pregnancies, matched on 1:2 basis by mode of delivery. Placental lesions were classified as lesions of maternal or fetal vascular supply, and maternal (MIR) and fetal (FIR) inflammatory responses.
Results: Of the 1,047 women analyzed, 615 were with normal weight (BMI 21.75±1.8), 211 with overweight (BMI 27±1.3) and 221 obese (BMI 35.2±4.3). Overweight and obesity were associated with higher rate of diabetes and hypertensive disorders (p=0.001 for all), higher rate of birth-weight >90th(p<0.001), and higher rate of CS, p<0.001. Placental weight was higher in obese than in overweight or normal weight women, p<0.001. No difference was observed in the rate of placental lesions related to maternal or fetal vascular supply, MIR or FIR between the three sub-groups. However, higher rate of maternal placental vascular lesions, 46.8% vs. 28.2%, p=0.012, were observed in uncomplicated obese patients (n=62) as compared with healthy normal-weight (n=124) uncomplicated controls.
Conclusion: Pregnancy outcome is worse without different placental component in obese vs. normal weight women, with complicated pregnancies. However, in uncomplicated pregnancies, more maternal placental vascular supply lesions exist in obese vs. normal-weight women.
Table: Placental pathology of healthy obese and non-obese patients with uncomplicated pregnancies
| p-value | Controls
n=124 |
Obese
n=62 |
|
| 0.316 | 476.5±104.7 | 494.2±127.4 | Placental weight (gr) |
| 0.857 | 6.7±1.1 | 6.8±1.2 | Fetal-placental ratio |
| 0.012 | 35 (28.2%) | 29 (46.8%) | Composite maternal vascular supply lesions (%) |
| 0.615 | 1 (0.8%) | 1 (1.61%) | Placental hemorrhage (%) |
| 0.073 | 1 (0.8%) | 3 (4.9%) | Vascular lesions related to maternal under perfusion (%) |
| 0.060 | 35 (28.2%) | 26 (41.9%) | Villous changes related to maternal under perfusion (%) |
| 0.224 | 14 (11.3%) | 11 (17.7%) | Composite fetal vascular supply lesions (%) |
| 0.468 | 7 (5.6%) | 2 (3.2%) | Vascular lesions consistent with FTOD (%) |
| 0.199 | 12 (9.7%) | 10 (16.1%) | Villous lesions consistent with FTOD (%) |
| 1 | 24 (19.3%) | 12 (19.3%) | MIR |
| 0.357 | 8 (6.4%) | 2 (3.2%) | FIR |
Continuous variables are presented as mean ± SD and categorical variables as n (%). FTOD – fetal thrombo-occlusive disease, FIR- fetal inflammatory response, MIR- maternal inflammatory response