Research ArticleOriginal Article
Open Access

Impact of body weight on the outcome of pregnancy

A prospective cohort study

Ettedal A. Aljahdali
Saudi Medical Journal October 2021, 42 (10) 1109-1116; DOI: https://doi.org/10.15537/smj.2021.42.10.20210293

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Tables

  • Table 1

    - Prevalence of obesity among participants (N=3026).

    Body mass index categoryn(%)
    Normal1073(35.5)
    Overweight996(32.9)
    Obese958(31.6)
  • Table 2

    - Demographic and medical characteristics of participants according to pre-pregnancy body mass index (N=3026).

    VariableNormal (n=1073)Overweight (n=995)Obese (n=958)P-value
    Age<0.001*
    16-2025 (43.1)15 (25.9)18 (31.0) 
    21-25240 (42.9)178 (31.8)142 (25.4) 
    26-30388 (40.8)305 (32.0)259 (27.2) 
    31-35264 (32.4)268 (32.8)284 (34.8) 
    36-40127 (25.5)179 (35.9)193 (38.7) 
    41-4527 (20.6)44 (33.6)60 (45.8) 
    > 452 (20.0)6 (60.0)2 (20.0) 
    Gravidity<0.001*
    1299 (41.9)214 (30.0)200 (28.1) 
    2 to 4639 (35.9)589 (33.1)551 (31.0) 
    >5135 (25.3)192 (36.0)207 (38.8) 
    Parity<0.001*
    0344 (40.7)265 (31.3)237 (28.0) 
    1328 (37.3)288 (32.7)264 (30.0) 
    2 to 4379 (32.3)393 (33.5)400 (34.1) 
    >522 (17.2)49 (38.3)57 (44.5) 
    Abortions0.002**
    0847 (37.7)712 (31.7)689 (30.6) 
    1158 (30.3)188 (36.0)176 (33.7) 
    2 to 464 (26.3)91 (37.4)88 (36.2) 
    >54 (30.8)4 (30.8)5 (38.5) 
    Stillbirth0.841**
    01064 (35.5)984 (32.8)949 (31.7) 
    14 (36.4)4 (36.4)3 (27.3) 
    2 to 41 (12.5)3 (37.5)4 (50.0) 
    >54 (40.0)4 (40.0)2 (20.0) 
    Medical diseases<0.001**
    None824 (39.9)678 (32.8)565 (27.3) 
    DM97 (24.6)155 (39.3)142 (36.0) 
    HTN, PET and eclampsia13 (18.3)16 (22.5)42 (59.2) 
    Cardiac1 (20.0)2 (40.0)2 (40.0) 
    Renal2 (33.3)4 (66.7)0 (0.0) 
    CNS1 (50.0)1 (50.0)0 (0.0) 
    DM + HTN12 (8.9)16 (11.9)107 (79.3) 
    Others123 (35.5)123 (35.5)100 (28.9) 

    Values are presented as number and percentage (%).

    *Chi-square test was used,

    **Monte Carlo test was used, The test of significance was carried out at the 0.05 level, significant results are in bold. DM: diabetes mellitus, HTN: hypertension, PET: pre-eclampsia toxemia, CNS: central nervous system

    • Table 3

      - Comparison of pre-pregnancy and in labor weight according to sample characteristics (n=3026).

      VariablesPre-pregnancy weightIn labor weightPercent of change %P-value
      MeanSDMeanSD
      Age (years)
      16-2062.614.971.214.213.7<0.001
      21-2563.2515.771.414.812.8<0.001
      26-3066.416.7574.215.611.8<0.001
      31-3569.917.777.716.411.2<0.001
      36-4071.516.878.816.010.4<0.001
      41-4575.518.682.116.88.8<0.001
      >4569.017.878.013.413<0.001
      Gravidity
      165.716.873.715.612.2<0.001
      2 to 467.617.275.416.111.5<0.001
      >572.017.079.315.910.2<0.001
      Parity
      066.016.773.915.512<0.001
      167.017.5574.816.511.7<0.001
      2 to 469.417.177.015.911<0.001
      >574.016.4581.314.910<0.001
      Abortions
      067.117.375.016.111.8<0.001
      169.516.777.115.411<0.001
      2 to 472.316.879.615.910.1<0.001
      >569.817.770.021.20.0030.949
      Stillbirth
      067.917.275.716.011.50.001
      163.414.269.814.5100.002
      2 to 483.819.687.515.84.50.080
      >566.012.061.017.8-7.50.343
      Medical diseases
      None65.616.173.715.1512.4<0.001
      DM70.415.478.014.310.8<0.001
      HTN, PET, eclampsia80.619.387.316.78.4<0.001
      Cardiac77.013.085.015.810.40.016
      Renal66.74.148.35.2-270.002
      CNS65.014.165.014.101
      DM+HTN91.518.096.516.75.5<0.001
      Others67.016.674.615.311.5<0.001

      Values are presented as mean and standard deviation. A paired t test was used. The test of significance was carried out at the 0.05 level. Significant results are in bold, DM; diabetes mellitus, HTN: hypertension, PET: pre-eclampsia toxemia, CNS: central nervous system

      • Table 4

        - The effect of maternal BMI on the outcome of pregnancy.

        VariableNormal (n=1073)Overweight (n=995)Obese (n=958)P-value
        Birth weight<0.001*‡
        <2 kg29 (41.4)19 (27.1)22 (31.4) 
        2-2.5126 (43.8)74 (25.7)88 (30.6) 
        2.6-3422 (38.5)364 (33.2)310 (28.3) 
        3.1-3.5403 (33.2)423 (34.8)389 (32.0) 
        3.6-488 (27.8)106 (33.4)123 (38.8) 
        4.1-4.55 (14.3)8 (22.9)22 (62.9) 
        >4.50 (0.0)1 (20.0)4 (80.0) 
        Gestational age (weeks)0.466†
        <244 (33.3)5 (41.7)3 (25.0) 
        24-297 (63.6)1 (9.1)3 (27.3) 
        30-3533 (35.9)32 (34.8)27 (29.3) 
        35-37172 (33.3)165 (32.0)179 (34.7) 
        >38857 (35.8)792 (33.1)746 (31.1) 
        Congenital anomalies0.252†
        None1062 (35.3)994 (33.0)952 (31.6) 
        Skeletal3 (60.0)0 (0.0)2 (40.0) 
        Renal2 (66.7)0 (0.0)1 (33.3) 
        Chromosomal2 (100.0)0 (0.0)0 (0.0) 
        CNS0 (0.0)0 (0.0)1 (100.0) 
        Others4 (57.1)1 (14.3)2 (28.6) 
        Apgar score 1 minute0.114†
        Normal1034 (35.3)971 (33.1)926 (31.6) 
        Abnormal35 (41.2)24 (28.2)26 (30.6) 
        Dead4 (40.0)0 (0.0)6 (60.0) 
        Apgar score 5 minute0.147†
        Normal1055 (35.4)986 (33.1)942 (31.6) 
        Abnormal14 (42.4)9 (27.3)10 (30.3) 
        Dead4 (40.0)0 (0.0)6 (60.0) 
        Mode of delivery(26.9)<0.001*‡
        Vaginal736 (41.7)552 (31.3)475 (40.5) 
        Elective C/S181 (23.9)270 (35.6)307 (34.9) 
        Emergency C/S156 (30.9)173 (34.3)176 
        Admission0.315†
        Nursery1029 (35.3)962 (33.0)923 (31.7) 
        NICU for preterm15 (46.9)10 (31.3)7 (21.9) 
        NICU for distress21 (33.9)21 (33.9)20 (32.3) 
        NICU for anomalies2 (40.0)2 (40.0)1 (20.0) 
        Dead6 (46.2)0 (0.0)7 (53.8) 
        Placenta0.036†‡
        Complete1011 (36.1)919 (32.8)872 (31.1) 
        Incomplete1 (50.0)1 (50.0)0 (0.0) 
        Manual removal61 (27.5)75 (33.8)86 (38.7) 
        Blood loss<0.001*‡
        <100 ml7 (26.9)13 (50.0)6 (23.1) 
        100-300 ml874 (38.3)745 (32.6)665 (29.1) 
        301-500 ml165 (25.6)217 (33.6)263 (40.8) 
        501-1000 ml27 (38.0)20 (28.2)24 (33.8) 

        Values are presented as number and percentage (%).

        *Chi-square test was used.

        †Monte Carlo test was used The test of significance was carried out at the 0.05 level.

        ‡Significant resultst

        • Table 5

          - Relative risk of adverse pregnancy outcome due to obesity.

          OutcomeOverweight or obese (BMI >25)Normal BMI (<25)Relative risk (95% CI)P-value
          Macrosomia35 (1.8)5 (0.5)3.846 (1.511-9.787)0.002*
          Preterm415 (21.2)216 (20.1)1.056 (0.912-1.222)0.469
          Apgar 1 min56 (2.9)39 (3.6)0.789 (0.528-1.1790.247
          Apgar 5 min25 (1.3)18 (1.7)0.763 (0.418-1.392)0.377
          Cesarean section926 (47.4)337 (31.4)1.510 (1.366-1.668)<0.001*
          Incomplete and manual placenta removal162 (8.3)62 (5.8)1,436 (1.082-1.905)0.011*
          >300 ml blood loss524 (26.8)192 (17.9)1.499 (1.294-1.738)<0.001*

          Values are presented as number and percentage (%). Chi-square test was used. The test of significance was carried out at the 0.05 level.

          *Significant results

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