There were 826 women screened, 295 were recruited at a mean age of 12.95 weeks (SD 1.51) and randomly assigned to the fiber group (n = 98) or the control group (n = 197). In total, 20 (6.8%) women were lost to follow-up before the OGTT screening, and 26 (8.8%) women dropped out prior to delivery outcomes (Fig. 1). Baseline characteristics for both groups are shown in Table 1, and there were no statistically significant differences between the groups on demographic or clinical characteristics (all P > 0.05).
The OGTT was performed between 25 and 28 weeks of gestation. The fiber group had a significantly lower incidence of GDM (n = 10, 11.2%) than the control group (n = 44, 23.7%) (P = 0.015); the levels of 2hBG in the control group were significantly higher than the intervention group (6.69 ± 1.65 vs. 6.45 ± 1.25, P = 0.026); The difference of blood glucose from 0 to 1 hour (BG1 − 0) and the difference of blood glucose from 0 to2 hour (BG2 − 0) showed significantly higher values in the control group compared with the fiber group (3.55 ± 1.53 vs. 3.13 ± 1.48, 2.43 ± 1.50 vs. 2.02 ± 1.18, respectively; all P < 0.05); in addition, the Areas Under Curves (AUC) and the incremental Area Under Curve (IAUC) for 0–2 hour of blood glucose levels also significantly increased in the control group compared with the intervention group (13.61 ± 2.63 vs. 12.99 ± 2.00, 4.76 ± 2.08 vs. 4.14 ± 1.77, respectively; all P < 0.05). There were no significant differences in FBG, 1hBG, lipid profiles (TC, TG, HDL-C, and LDL-C), HOMA-, or TyG index levels between groups (all P > 0.05), as shown in Table 2. The pre and post intervention weight and BMI values did not differ statistically (Table 3).
When considering maternal and neonatal secondary outcomes, the mean gestational age at delivery in the intervention group significantly increased compared with the control group (39.07 ± 1.08 vs. 38.58 ± 1.44, P = 0.006). The percentage of women who developed preterm in the fiber group was significantly lower than that in the control group (9.4% vs. 2.3%, P = 0.032). Furthermore, there were no other statistically significant differences in any maternal or neonatal outcome measures between the intervention and control groups (Table 4).
Table 1
Maternal General Characteristics at Baseline
| Control Group (n = 186) | Fiber Group (n = 89) | P Value |
Gestational age at enrollment (weeks) | 12.97 ± 1.58 | 12.89 ± 1.41 | 0.726 |
Gestational age at OGTT (weeks) | 25.25 ± 1.88 | 25.67 ± 0.87 | 0.064 |
Age (years) | 31.02 ± 4.11 | 30.70 ± 3.74 | 0.466 |
BMI (kg/m2) | 23.40 ± 3.90 | 23.40 ± 3.25 | 0.601 |
Systolic blood pressure, (mmHg) | 114.66 ± 12.19 | 115.49 ± 13.78 | 0.610 |
Diastolic blood pressure, (mmHg) | 70.45 ± 10.05 | 71.36 ± 9.79 | 0.480 |
College or university education, n (%) | 134(72.0) | 57(64.0) | 0.178 |
Primipara, n (%) | 87(46.8) | 45(50.6) | 0.556 |
Previous PCOS, n (%) | 8 (4.3) | 4(4.5) | 1.000 |
Previous GDM, n (%) | 7(3.8) | 2(2.2) | 0.508 |
Family history of diabetes, n (%) | 28 (15.1) | 17(19.1) | 0.396 |
FBG (mmol/L) | 4.55 ± 0.46 | 4.47 ± 0.38 | 0.125 |
TC (mmol/L) | 4.80 ± 0.78 | 4.78 ± 1.03 | 0.862 |
TG (mmol/L) | 2.06 ± 0.55 | 1.96 ± 0.45 | 0.140 |
HDL-C (mmol/L) | 1.40 ± 0.27 | 1.39 ± 0.28 | 0.711 |
LDL-C (mmol/L) | 2.59 ± 0.63 | 2.65 ± 0.94 | 0.599 |
TyG index | 8.88 ± 0.25 | 8.82 ± 0.21 | 0.069 |
Values are presented as mean ± SD or n (%). BMI, body mass index; PCOS, polycystic ovary syndrome; FBG, fasting blood glucose; TC, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TyG index, triglyceride-glucose index;
Table 2
Group Differences in the Incidence of GDM and Concentrations of OGTT Blood Glucose, Lipid Profiles, and Insulin Resistance
| Control Group (n = 186) | Fiber Group (n = 89) | P Value |
GDM | 44 (23.7) | 10 (11.2) | 0.015 |
FBG (mmol/L) | 4.42 ± 0.58 | 4.43 ± 0.35 | 0.928 |
1hBG (mmol/L) | 7.78 ± 1.85 | 7.56 ± 1.58 | 0.060 |
2hBG (mmol/L) | 6.69 ± 1.65 | 6.45 ± 1.25 | 0.026 |
BG1 − 0 | 3.55 ± 1.53 | 3.13 ± 1.48 | 0.031 |
BG2 − 0 | 2.43 ± 1.50 | 2.02 ± 1.18 | 0.023 |
BG1 − 2 | 1.12 ± 1.30 | 1.11 ± 1.56 | 0.964 |
TC (mmol/L) | 5.87 ± 1.06 | 5.96 ± 1.31 | 0.573 |
TG (mmol/L) | 2.78 ± 0.90 | 2.94 ± 1.09 | 0.249 |
HDL-C (mmol/L) | 1.70 ± 0.34 | 1.66 ± 0.31 | 0.292 |
LDL-C (mmol/L) | 2.86 ± 0.96 | 2.94 ± 1.09 | 0.328 |
TyG index | 9.14 ± 0.33 | 9.18 ± 0.37 | 0.311 |
HOME-β | 2.26 ± 1.29 | 2.53 ± 1.40 | 0.108 |
AUC | 13.61 ± 2.63 | 12.99 ± 2.00 | 0.032 |
IAUC | 4.76 ± 2.08 | 4.14 ± 1.77 | 0.010 |
Values are presented as mean ± SD. *Significantly different values (P < 0.05). FBG, fasting blood glucose; 1hBG, 1 hour blood glucose; 2hBG, 2 hour blood glucose; BG1 − 0, the difference of blood glucose from 0 to 1 hour; BG2 − 0, the difference of blood glucose from 0 to 2 hour; BG1 − 2, the difference of blood glucose from 1 to 2 hour; TC, total cholesterol; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TyG index, triglyceride-glucose index; HOMA-β, homeostasis model assessment-β, ACU, the Areas Under Curves for 0–2 hour of blood glucose levels; IAUC, the incremental Area Under Curve for 0–2 hour of blood glucose levels.
Table 3
Group Differences in the Weight and BMI before and after intervention
| Control Group (n = 186) | Fiber Group (n = 89) | P Value |
W 20 (kg) | 64.42 ± 10.33 | 63.28 ± 9.05 | 0.650 |
W 25 (kg) | 66.86 ± 10.21 | 65.73 ± 9.04 | 0.619 |
W 25−20 (kg) | 2.48 ± 1.32 | 2.43 ± 1.07 | 0.830 |
BMI 20 (kg/m2) | 24.83 ± 3.81 | 24.74 ± 3.21 | 0.718 |
BMI 25 (kg/m2) | 25.77 ± 3.75 | 25.70 ± 3.19 | 0.649 |
BMI 25−20 (kg/m2) | 0.93 ± 0.61 | 0.96 ± 0.44 | 0.860 |
W 20, weight at 20 weeks; W25, weight at 25 weeks; W25 − 20, the difference of weight between 20 and 25 weeks; BMI 20, BMI at 20 weeks; BMI 25, BMI at 25 weeks; BMI 25−20, the difference of BMI between 20 and 25 weeks.
Table 4
Maternal and Neonatal Outcomes in Both Groups
| Control group (n = 181) | Fiber group (n = 88) | P Value |
Maternal outcomes | | | |
Gestational hypertension | 9 (5.0) | 4 (4.5) | 1.000 |
Pre-eclampsia | 3 (1.7) | 3 (3.4) | 0.636 |
Premature rupture of membranes | 26 (14.4) | 12 (13.6) | 0.872 |
Postpartum hemorrhage | 7 (3.9) | 1 (1.1) | 0.393 |
Excessive weight gain ⁋ | 46 (25.4) | 23 (26.1) | 0.899 |
Inadequate weight gain ⁋ | 61 (33.7) | 32 (36.4) | 0.667 |
Cesarean section | 92 (50.8) | 47 (53.4) | 0.691 |
Neonatal outcomes | | | |
Gestational age at delivery (weeks) | 38.58 ± 1.44 | 39.07 ± 1.08 | 0.006 |
Preterm (< 37 weeks) | 17 (9.4) | 2 (2.3) | 0.032 |
Birth weight (g) | 3307.10 ± 431.35 | 3314.49 ± 398.83 | 0.726 |
Macrosomia (≥ 4000 g) | 12 (6.6) | 5 (5.7) | 0.764 |
Low birth weight (< 2500 g) | 5 (2.8) | 1 (1.1) | 0.684 |
Stillbirth | 1 (0.6) | 0 (0.0) | 1.000 |
Values are presented as mean ± SD or n (%). ⁋ According to Chinese standards for pre-pregnancy BMI categories and IOM recommendations: gestational weight gain for underweight (BMI < 18.5 kg/m2), normal weight (18.5 kg/m2 ≤ BMI < 24.9 kg/m2), overweight (25kg/m2 ≤ BMI < 29.9 kg/m2), and obese women (BMI ≥ 30 kg/m2) were 12.5–18 kg, 11.5–16 kg, 7-11.5 kg, and 5 to 9 kg, respectively[17].
Safety and Tolerability
Adverse effects of the dietary fiber powder were reported by 11 of 98 (13.30%) of the women, including diarrhea, flatulence, bloating, and abdominal pain. Six participants reported mild diarrhea at the beginning of dietary fiber intake, and five participants were dropped out of the study due to flatulence and mild to moderate abdominal pain. Among women who completed the study, 83.1% (74/89) took 90% or more and 14.6% (13/89) took between 50 and 80% of the provided dietary fiber powder, and 94.2% of the powder had been eaten.