Table 4 Results of each individual study included

1

Karamali et al. [52]

Low risk

Calcium and vitamin D supplements.

1000 mg Ca/d and two pearls containing 1250 μg (50 000 IU)

of cholecalciferol (vitamin D3) during the intervention (one at study baseline and

another at day 21 of the intervention)

Two placebos of vitamin D at the mentioned times and placebos of Ca every day

for 6 weeks.

Significant decrease in

caesarean section rate (23·3% vs 63·3%, P = 0·002) and maternal hospitalization

(0 vs 13·3%, P = 0·03) compared with those receiving placebo

Newborns of GDM women randomized to Ca + vitamin D had no case of

macrosomia, while the prevalence of macrosomia among those randomized to

placebo was 13·3% (P = 0·03).

Lower rates of hyperbilirubinaemia (20·0% v.

56·7%, P = 0·03) and hospitalization (20·0% vs 56·7%, P= 0·03) were also seen in the supplemented group of newborns than in the placebo group.

–

–

2

Louie et al., 2011 [39]

Low risk

Low–glycaemic index (LGI) diet: low GI (target GI ≤ 50)

healthy diets of similar protein (15–25%), fat (25–30%), and carbohydrate (40–45%)

content

Conventional high-fibre diet: moderate GI (target GI ≈ 60)

healthy diets of similar protein (15–25%), fat (25–30%), and carbohydrate (40–45%)

content

–

–

LGI diet and a conventional

HF diet produced similar pregnancy outcomes. Average infant birth weight, birth weight centile, and ponderal index were within healthy norms in both groups.

Fewer women in the LGI group gained an excessive amount of

weight but this was not statistically significant (LGI 25% vs.

HF 42%; P = 0·095).

Compliers in the LGI

group appeared to gain less weight than

those in the HF group although this was not statistically significant (LGI 11·2±0·9 kg vs HF 13·7±1·0 kg; P = 0·073).

No significant difference in foetal abdominal circumference at 36-37 weeks’ gestation (mean ± SEM LGI 327·6 ± 19·2

mm vs HF 322·6 ± 14·6 mm; P = 0·186).

3

de Barros et al., 2010 [30]

Moderate risk

Exercise group

underwent a resistance exercise programme until

the end of gestation PLUS routine prenatal care PLUS systematic evaluation and diabetic dietary instructions from a nutritionist. Resistance exercise was performed with an elastic band. The patients were advised to start the program about 90 minutes after consuming a meal of their preference

(breakfast, lunch, or dinner) and after the measurement of capillary glycemia with an Accu-Chek Advantage glucose meter (Roche Diagnostics, Indianapolis,

IN). If capillary glucose levels were between 100 and 250 mg/dL, exercise group patients

started the program with a stretching sequence.

If capillary glycemia was below this range, the patients were instructed to do the resistance exercise program on the next day to prevent hypoglycemia. If the values were above this range, the patients were instructed

not to undergo resistance exercise to prevent the occurrence of ketoacidosis and to contact the responsible obstetrician.

The resistance exercise program consisted of a circuit type resistance training, elaborated in such a way that the main muscle groups of the patients would be exercised (chest, back, biceps, triceps, deltoid, quadriceps, thigh, and calf muscles).

A circuit series was defined as a sequence of these eight exercises (stations). The women performed 15 repetitions of each exercise

(station), with a minimum resting period of 30 seconds and a maximum of 1 minute between each one. In the first and second week of follow-up, the women underwent 2 circuit series, followed by 3 circuit series from the third week of inclusion in the study to the end of gestation.

Exercise intensity was controlled by the women themselves using a perceived exertion scale for resistance exercise provided to them.

The women were advised to maintain an exercise intensity close to 5 or 6, which corresponds to a “somewhat heavy” exercise perception.

The patients received written guidelines of how to perform each exercise and were instructed to undergo the program on 3 non-consecutive days a week (twice a week at home).

The participants were contacted by telephone at least once a week to verify adherence to the program.

The other session was

performed during the weekly return visit, always under the supervision of the lead researcher. On that occasion, the patients were asked whether they had performed any type of physical activity

other than resistance exercise. In addition, the adequate

execution of resistance exercise at the correct intensity was verified.

Routine prenatal care PLUS systematic evaluation and diabetic dietary instructions from a nutritionist.

A significant decrease in the number of patients who required insulin was observed in exercise group compared with control group.

Glycemic control was significantly better in exercise group compared with control group. In exercise group, the percentage of weeks spent within the target glucose range (80% of weekly capillary glucose measurements within preestablished guideline values) was significantly higher when compared with control group.

Newborn birthweight greater than 4000 g was observed in 1 EG case and 3 CG cases.

–

No significant difference in mean (SD) glucose levels was observed between exercise and control groups.

Mean glucose levels measured by the patients at different times of the day throughout the follow-up period were lower in exercise group compared with control group, but the difference was not significant.

The 2 groups did not differ significantly in terms of the amount of insulin (international units per kilogram) required by the patients or in the time interval (weeks) between inclusion in the study and insulin use.

Exercise group patients who used insulin continued to present adequate glycemic control according to the target established for a longer percent period of weeks than control patients who used insulin (EG: 0·40 (0·24) vs CG: 0·25 (0·23), but the difference was not significant (P=0·173).

No significant difference in mean glucose levels was observed between patients of the 2 groups who used insulin (CG: 106·83 (7·45) vs EG: 109·83 (9·04) mg/dL; P=0·342).

No difference

in the frequency of cesarean section was

observed between groups (n: 21 of 32 in EG vs n 24 of 32 in CG; P=0·412).

3 cases of preterm

delivery in each group (gestational age at

birth ranging from 35 to 36 weeks).

4

Kolivand et al., 2019 [47]

Minimal risk

New self-care guide package plus three face-to-face educational sessions

Routine clinical services: physician visits and short training regarding nutrition, blood glucose control, and insulin injections

Superior effects on maternal self-efficacy and 2-h postprandial plasma glucose, Apgar scores, and neonatal hospitalization.

The mean (±SD) self-efficacy score was higher in the intervention than control group (74·4 ± 7·0 vs 36·4 ± 5·2, respectively; P < 0·001).

Mean 2-h postprandial plasma glucose was lower in the intervention than control group (105·1 ± 17·6 vs 127·2 ± 20·4 mg/dL, respectively; P < 0·001).

Newborn hospitalization rate was higher in the control group (P < 0·001).

–

No significant difference in mean fasting plasma glucose between the two groups (P = 0·163)

No significant differences in the weight and age of the neonate at delivery or in the type of delivery between the two groups.

5

Kokic et al., [31]

Minimal risk

Experimental group was treated with standard antenatal care for gestational diabetes mellitus, and regular supervised exercise programme plus daily brisk walks of at least 30 minutes. The exercise programme was started from the time of diagnosis of diabetes until birth. It was performed two times per week and sessions lasted 50–55 min.

Control group received only standard antenatal care for gestational diabetes mellitus.

The experimental group had lower postprandial glucose levels at the end of pregnancy (P < 0·001).

Neonatal body mass index was higher in the experimental group (P = 0·035).

No significant difference between groups in the level of fasting glucose at the end of pregnancy.

No significant differences in the rate of complications during pregnancy and birth, need for pharmacological therapy, maternal body mass and body fat percentage gains during pregnancy, and neonatal Apgar scores, body mass and ponderal index.

6

Tian et al., 2021 [53]

Moderate risk

Health education and lifestyle management delivered through a WeChat group chat

Participants received WeChat group management in addition to standard clinical prenatal care. Participants received management on a weekly basis. In particular, every

Monday, researchers would issue a briefing to encourage patients to take an active part in the control of their GDM and a task card to pinpoint the basic requirements, including diet advice, examples of meals from other group members, and exercise rules. Patients performed self-management according to the basic criteria provided for their actual situation and shared

photos of their meals and snacks, daily exercise, and experience regarding BG control. Researchers would give individualized

guidance for self-management or use a group member’s situation as an example for others. On weekends, the researchers prepared lessons and articles for group members to

learn different aspects of pregnancy and GDM, including rudimentary knowledge, disease management, psychology, and past cases. We encouraged the sharing of learning experiences

and notes in the form of peer interactions and support groups. If there were any questions regarding the project, pregnancy, or GDM, patients could seek answers from the group chat. This weekly management continued until delivery.

Standard clinical prenatal care

Participants were taught basic information about GDM and how

to do self-management, including how to conduct blood glucose monitoring, what the target BG values are, and how to keep a lifestyle diary.

Additional instant messaging platforms, such as WeChat, used for health education and lifestyle intervention in China tend to be more effective for blood glucose control than standard clinical prenatal care alone.

The glycemic qualification rate of the intervention group was higher than that of the control group at nearly all time points in Groups 1 to 3, among which 3 time points reached statistical significance: Group 1 at T3 (54·8% vs 83·3%) and Group 2 at T3 (62·5% vs 80·0%) and T7 (75·0% vs 100%).

–

None of the pregnancy outcomes measured, including delivery mode, premature rupture of the membranes, preterm birth, infant's birth weight, and postpartum hemorrhage, were significantly different between the control and intervention groups.

7

Barati et al., 2021 [54]

Moderate risk

30 grams of oat bran daily for 4 weeks at lunch and dinner PLUS diet for gestational diabetes.

Routine diet for gestational diabetes.

The addition of oat bran to the standard diet for pregnant women with gestational diabetes reduced fasting blood glucose and two-hour postprandial glucose.

Mean fasting blood glucose and two-hour

postprandial glucose decreased significantly in the intervention group compared with the control group

(P < 0·001).

Two weeks after the start of oat bran consumption, the mean two-hour postprandial glucose was 122·17 (3·91) in the control group and 115·37 (3·14) in the oat bran group, which was significantly different (p < 0·001).

Four weeks after start of the consumption of oat bran, the mean two-hour postprandial glucose was 117·49 (11·34) in the control group and 104·04 (5·48) in the oat bran group, which was significantly different (P < 0·001).

–

The two groups were not significantly different in terms of average fat intake (p = 0·67), average carbohydrate intake (p = 0·28), protein intake (p = 0·23) and fibre intake (p = 0·46).

8

Mohebbi et al., 2019 [32]

Moderate risk

Self-management education programme was presented in four sessions lasting 35-40 minutes for each during a month.

Phone calls as small booster were conducted which served as a quick reference to education and reminder to study participants.

Content of educational programs included basic information regarding GDM facts, figures and self-management based on HBM constructs like perceived susceptibility and severity of gestational diabetes, barriers and benefits of self-management and perceived self-efficacy and self-management incorporating cues to actions.

Strategies such as setting achievable goals and use of motivational interviewing to increase self-efficacy were also used in educational sessions.

Ways of social support from family were considered offering empathy, concern, encouragement, or caring to the women.

Moreover, self- monitoring of blood glucose was used as a way to teach participants about their disease using pictures and simple instructions.

At the end of each session, the educator reviewed the important topics of the session and women were encouraged to ask their questions which were answered accordingly.

Routine clinic-based education.

There were significant (P<0·001) improvements in the self-management education programme group compared to the control group at 3 and 6 months after the intervention in all outcomes including HbA1c, self-management, self-efficacy, cues to action, perceived benefits, perceived barriers, perceived severity, perceived susceptibility

–

–

9

Al Hashmi, 2018 [48]

Moderate risk

Self-efficacy-enhancing intervention (SEEI) PLUS standard antenatal care. The SEEI group received an additional individualised health education intervention utilising different self-efficacy-enhancing strategies (i.e. motivational messages, role modelling, goal-setting and mastery experience) designed to encourage women to maintain recommended healthy behaviours. First,

the participants watched an educational video designed solely for the purposes of the study. The video focused on general information about GDM and GDM-related maternal and neonatal complications, as well as information about the importance of healthy lifestyle behaviours— such as a healthy diet, exercise and maintaining self-monitored BG levels to prevent GDM complications— and measures to prevent post-partum T2DM. The physical activities recommended in the video conformed with standard cultural beliefs and religious practices in Oman by focusing on safe exercises which could be conducted indoors and in private (i.e. walking, swimming and dancing). After watching the video, participants in the SEEI group were encouraged to practice the recommended

activities during the session. The participants were provided with a BG metre and were trained to check and record their BG levels; they were requested to do this four times per day during the study period. In order to enhance adherence to the recommended healthy behaviours, the participants were encouraged to write down specific and measurable goals. A pamphlet summarising the content of the educational session was distributed to all participants before the end of the session. In addition, they received short biweekly motivational text messages for four weeks to reinforce the information given during the educational session. Finally, a refresher session was given at 32–35 gestational weeks via telephone.

Standard antenatal care, including routine antenatal visits, monthly blood sugar profiles, fasting blood sugar testing at every visit, glucose monitoring at home and individualised

educational sessions with a diabetes dietician.

The SEEI was found to significantly improve perceived self-efficacy and actual adherence to healthy behaviours among a group of Omani women with GDM.

There was a significant positive difference between the SEEI and control groups in terms of pre-post change in scores for both perceived self-efficacy: 9·9 (19·6) versus −1·8 (17·6); P <0·05 and actual adherence to healthy behaviours – diet, exercise, BG monitoring: 1·5 (1·1) versus 0·4 (0·8); P <0·01.

–

–

10

Bartholomew et al., 2015 [35]

Moderate risk

The use of cell phone–Internet technology (CIT) for self-management (monitoring) of hyperglycemia during pregnancy

3-hour diabetes education class taught by certified diabetes educators.

Women who required medication (insulin or glyburide) were provided personalized instruction regarding correct usage. All women received equivalent education, training, and consultation regarding a carbohydrate-controlled diet, exercise, SMBG, and reporting SMBG results.

All women received the same glucose meters (OneTouch; LifeScan, Inc., Milpitas, Calif.) and testing supplies. They were instructed to perform SMBG four times per day (fasting and 2 hours postprandially) and record values using the reporting method to which they were assigned.

PLUS

Women using the CIT method were advised to upload their blood glucose results at least weekly, although they could upload at every test, every day, or at their convenience within that timeframe. The system uploaded every value in the meter each time an upload occurred. Uploading began by turning on the cell phone and glucose meter. The wireless device was plugged in to the glucose meter and turned on. The phone was placed within 3 feet of the wireless device. Participants pressed a menu button and then selected the “collect” option on the phone menu to start the application. A confirmation of data receipt was displayed on the phone. Supplementary Figure 1 shows the components of the CIT glucose meter system. Each week, MFM physicians reviewed the blood glucose values on the Web site. The nurses communicated the recommendations to patients by telephone.

Those using the CIT method could review their progress on the Web site or in graphs created on the phone.

They also received automatic encouraging text

messages. Sample text messages were:

• “You didn’t submit readings for

the second week in a row. Try to

submit your readings every week.”

• “Did you notice your overall glucose

average rose over the past

week?”

• “Thanks for submitting your readings.

Keep up the good work!”

CIT technical support was available by telephone 12 hours/day.

All women received equivalent education, training, and consultation regarding a carbohydrate-controlled diet, exercise, SMBG, and reporting SMBG results.

3-hour diabetes education class taught by certified diabetes educators. Women who required medication (insulin or glyburide) were provided personalized instruction regarding correct usage.

All women received the same glucose meters (OneTouch; LifeScan, Inc., Milpitas, Calif.) and testing supplies. They were instructed to perform SMBG four times per day (fasting and 2 hours postprandially) and record values using the reporting method to which they were assigned.

PLUS

Women using the control method were advised to record blood glucose values in a log book and report their handwritten glucose results to the program nurse each week by dictating the values on the voicemail system. Nurses listened to the voicemail messages and recorded the values on paper. MFM physicians reviewed the paper records weekly to make recommendations. Nurses then communicated the recommendations to the women by telephone.

Compliance with SMBG reporting was higher during use of the CIT method for total, fasting, and 2-hour postprandial glucose values.

The mean 2-hour postprandial SMBG value was 108·3 mg/dL when the CIT method was used first and 112·7 mg/dL when the control method was used first (P = 0·023).

The mean fasting blood glucose value was 89·5 mg/dL when CIT was used first and 92·5 mg/dL when voicemail was used first (P = 0·049).

With regard to the secondary outcome of satisfaction, 68·9% of women preferred (“liked best”) the CIT method compared to 24·3% who said they preferred (“liked best”) the voicemail method (P <0·001);

More than half (59·5%) of the women found the automatic text messages to be “always helpful,” whereas 24·3% found them “often helpful,” 10·8% found them “rarely helpful,” and 5·4% found them “never helpful.”

–

–

11

Asemi et al., 2014 [40]

Moderate risk

Dietary Approaches to Stop Hypertension (DASH) eating plan.

The DASH diet was rich in fruits, vegetables, whole grains, and low-fat dairy products, and contained lower amounts of saturated fats, cholesterol, and refined grains with a total of 2400mg/day sodium.

The control diet was designed to contain 45–55% carbohydrates, 15–20% protein and 25–30% total fat.

Consumption of DASH diet for 4 weeks among pregnant women with GDM resulted in improved

pregnancy outcomes.

46·2% of women in the DASH diet needed to have a caesarean section, this percentage for the control group was

80·8% (P= 0·01).

The percentage of those who needed to commence insulin therapy after intervention was also significantly different between the two groups (23% for DASH vs 73% for control group, P<0·0001).

Consumption of the DASH diet led to a significant reduction in the birth of macrosomic infants compared with the control diet (3·8 vs 38·5%, P=0·002).

Infants born to mothers on the DASH diet had significantly lower weight (3222·7 vs 3818·8 g, P<0·0001), head circumference (34·2 vs 35·1 cm, P= 0·01) and ponderal index (2·50 vs 2·87 kg/m3, P<0·0001) compared with those born to mothers on the control diet.

–

No significant difference in mean gestational age was found when comparing the DASH and control diets.

Prevalence of polyhydramnios was not significantly different between the two groups.

No significant difference in mean length and Apgar score of the newborns when comparing the DASH and control diets.

12

Grant et al., [41]

Moderate risk

Low-glycaemic-index (LGI) diet

Routine diabetic diet

More postprandial glucose values were within target on low-GI (58·4% of n=1891) than control (48·7% of n=1834; p<0·001).

–

Glycaemic control improved on both diets.

13

Mendelson et al., 2008 [45]

Moderate risk

Supplementary 1-hour education session for diabetes education PLUS usual obstetric care reinforcement by a Parish Nurse.

Usual obstetric care

Significantly improved Health Promoting Lifestyle Profile II scores (self-reported health promoting behaviors) in the Parish Nurse Intervention Program group post-intervention compared with usual obstetric group.

–

No significant differences between groups regarding glycemic control, macrosomia, or days of maternal or neonatal hospitalization were found.

14

Daniel et al., 2014 [29]

High risk

8 weeks aerobic dance exercise consisting of three exercise sessions per week, 40 minutes per session for the first 4 weeks and 60 minutes per session for the last 4 weeks.

Routine care and activities of daily living

Significant improvement in the fasting blood sugar (p= 0·001) of the exercise group.

–

–

15

Hu et al., 2014 [38]

High risk

Low glycaemic index diet

Routine diabetic control diet

A low-GI staple diet significantly reduces postprandial glucose levels

Glucose levels were significantly reduced in the low-GI staple diet group (all P < 0·01) and the control group (all P < 0·008).

Postintervention glucose values after breakfast, lunch, and dinner were significantly reduced in the treatment group compared with those in the control group (all P < 0·05).

The percentage changes from baseline of all glucose values were significantly greater in the treatment group than in the control group (all P < 0·05).

–

–

16

Ural & Beji, 2021 [46]

High risk

Health-Promoting Lifestyle Education Programme and usual care

Usual care

Improvement in the healthy lifestyle behaviours and quality of life in the intervention group.

The rates of macrosomia were low for the neonates in the intervention group.

–

–

17

Yang et al., 2018 [33]

High risk

WeChat platform-based using both a smartphone-based telemedicine system and articles providing continuous health education PLUS routine outpatient treatment and health education guidance

Routine outpatient treatment and health education guidance

Fasting blood glucose (FBG) and 2-h postprandial blood glucose (PBG) were significantly lower and premature delivery was significantly less likely in intervention group than in control group (all P < 0·05).

Pregnancy-induced hypertension had a higher incidence in control group (P <0·05)

Compared with control group, caesarean section was more likely in intervention group (P < 0·05).

–

18

Ibrahim & Saber, 2019 [34]

High risk

4 educational sessions each one lasted for 30 minutes included lectures, PowerPoint, and group discussion. The educational programme involved notes on the general knowledge of gestational diabetes including definition, aetiology, high-risk groups, clinical manifestation, maternal and foetal complications, diagnosis, management, self-care practice such as following a dietary regimen, physical exercise, drug regimen with insulin, and postnatal management. Health education were for the women, and their families. Modules for education included power point, lectures, and brochures that contained pictures for self-measuring of random blood glucose level, dietary recommendations to maintain blood sugar within the normal range, drug regimen.

Routine pre-natal care

Statistically significantly higher proportions of women had satisfactory knowledge in the study group compared to the control group.

Significantly more women were satisfied with their knowledge about gestational diabetes after the intervention in the study group was than in the control group.

Significantly higher proportions of favourable practices were found in the study group compared to the control group.

Significantly more women had more total favourable self-care practices after the intervention in the study group than in the control group.

Statistically significantly higher proportions of complications in the control group than the study group were found.

The rate of normal delivery was higher in the study group, and the rate of caesarean section was higher in the control group.

The rates of foetal health problems were significantly higher in the control group than the study group e.g., jaundice, macrosomia etc.

–

–

19

^bYu et al., 2014 [36]

High risk

Continuous glucose monitoring (CGM) PLUS standard antenatal care.

Visits included downloads and analysis of data in meter and sensor (only for patients in CGM group), nutrition consultation, education of information on blood glucose testing and self-care activities, and getting an individualized diabetes care prescription, which was arranged by the same obstetric diabetes team.

Standard antenatal care using intermittent SMBG test from capillary

blood obtained by the finger prick technique.

Visits included nutrition consultation, education of information on blood glucose testing and self-care activities, and getting an individualized diabetes care prescription, which was arranged by the same obstetric diabetes team.

Better glycaemic control and improved pregnancy outcomes in the CGM group by reducing the risk of pre-eclampsia and caesarean delivery, decreasing the birth weight, and improving neonatal complications.

–

–

20

^cSunsaneevithayakul et al., 2004 [37]

High risk

^bPrescribed intensive diet therapy for 3 days. received extensive dietary counseling by a well-trained diabetes nurse educator and physicians. The diabetic counseling and teaching, as well as the obstetric management, were done during admission.

^bStandard treatment of all subjects involved diabetes education, control of hyperglycemia, with fetal and maternal surveillance. Daily caloric assignment was calculated based on ideal body weight, 30-35 Kcal/kg.

Short course of intensive dietary therapy during the 3 days of admission enabled good glycemic control such that 57·4% did not require insulin therapy.

–

–

21

Artal et al., 2007 [42]

High risk

Exercise and diet. Exercise was equivalent to a 60% symptom-limited VO2 max.

Diet alone

Maternal weight gain per week was significantly lower in the exercise and diet group.

–

Other pregnancy and foetal outcomes such as complications, gestational age at delivery, and rate of caesarean delivery were similar in both groups.

22^a

^aKgosidialwa, et al., 2015 [43]

High risk

^aDiet and exercise. Each patient received an hour-long, individual consultation with a dietician at time of GDM diagnosis and additional consultations were arranged if deemed necessary. Exercise was

tailored to the individual woman basing on the American Congress of Obstetrics and Gynaecology. In addition, women had access to a phone service to contact the midwife/diabetes nurse specialist during office hours for advice. Women were advised to monitor their blood glucose levels

using a glucometer (capillary glucose monitoring) at least 7 times a day (premeal, 1-hour post meals, and at bedtime). Blood glucose targets were set at 5·3 mmol/L for fasting/premeal glucose levels and 7·8 mmol/L 1 hour post meals.

^aWomen with normal glucose tolerance – received routine antenatal care

^aLGA and macrosomia

rates were lower in the MNT and exercise treated GDM group compared with the NGT group.

–

All other adverse outcomes were similar between groups.

23

^a,dWang et al., 2015 [44]

High risk

^dExercise intervention.

Exercise intervention means sit less, take more steps, be

more active, incorporate light and moderate physical activity as much as possible into their daily life et al., and diet intervention means reduce intake of sugar, eat more vegetables, reduce fat intake, and the total energy intake 1800 calories a day in all.

^dWomen without GDM PLUS women with GDM without exercise intervention

Women with GDM with exercise intervention (GDM-E) had the lowest BMI increase during late and mid-pregnancy than women with GDM without exercise

intervention (GDM-nE) (2·05 ± 1·32 kg/m² vs. 2·40 ± 1·30 kg/m², p < 0·01) and non-GDM women (2·05 ± 1·32 kg/m² vs 2·77 ± 1·21 kg/m², p < 0·01).

Moreover, GDM-E group experienced a significantly lower risk of preterm birth (5·58 % vs. 7·98 %, p < 0·001), low birth weight (1·03 % vs. 2·06 %, p < 0·001) and macrosomia (9·51 % vs. 11·18 %, p < 0·05) than GDM-nE group.

Women with GDM with both dietary and exercise intervention had the lowest rate of macrosomia.

–

–

24

^a Shi et al., 2016 [49]

High risk

Pregnant women with GDM were routinely advised to receive MNT counselling where trained nutritionists provide individualized MNT programs for pregnant women with confirmed GDM. They also established daily energy requirements and calorie supply proportions of the three major nutrients in accordance with the China Medical Nutrition Therapy

Guideline for Diabetes (2010) based on the pre-pregnancy body type,

gestational age at the time of GDM diagnosis, increase in body weight during pregnancy, blood pressure, and lipid outcomes. They then provided suggestions with regard to the type of food, specifically quantifying the recommended intake for each type of food. They also assisted in the selection of foods among similar food types via the “method of food exchange serving” to diversify the patients' diets while ensuring a balanced intake of all necessary nutrients. Finally, they suggested reasonably arranged meal times and foods in each meal based on blood glucose monitoring data,

recommended staple foods with low glycemic index values, and emphasized eating many small meals to reduce each meal's glycemic load. Regular postprandial exercise was also recommended. Pregnant women were encouraged to obtain private fast blood glucose meters, kitchen scales, and body weight scales for self-monitoring of finger-prick blood glucose, food intake, and body weight at home.

No MNT

The fasting plasma glucose, 2-hour blood glucose, and weight gain at 28 weeks, 32 weeks, and 36 weeks as well as intrapartum were lower in the MNT group than in the non-MNT group.

Total weight gain during pregnancy and the rates of adverse events during pregnancy were lower in the MNT group compared to the non-MNT group (all p < 0.05).

Moreover, 92·2% of the participants in the MNT group had a normal oral glucose tolerance test result, and the rate of exclusive breastfeeding within 4 months after delivery was 54·4% in the MNT group; both were higher than those of the non-MNT group (66·3%, p < 0·001; 29·3%, p < 0·05).

–

–

25

Perichart-Pereraet al., 2009 [50]

High risk

Intensive MNT programme

The MNT program consisted of individual nutrition counseling with an intensive education component performed

by one clinical dietitian. The program included

nutrition assessment, nutrition intervention, and capillary glucose self-monitoring. Specific materials were designed

for nutrition therapy and self-monitoring education.

Nutrition recommendations were based on nutrition practice guidelines for gestational diabetes developed and published by the American Dietetic Association. Women received a glucose meter (Optium MediSense, Abbott Laboratories, Bedford, MA) and strips to perform capillary blood glucose self-monitoring 2 days a week, 6 times a day (before and 2 hours after each meal). Fasting and 2 hours postprandial serum glucose was also measured

every 2 weeks by a glucose oxidase method. Until the end of pregnancy, all women received follow-up every 2 weeks by the dietitian and the endocrinologist, who was responsible for prescribing insulin, as needed, to meet

glycaemic goals.

Routine antenatal care in a historical control.

Usual routine care in the control group included monthly medical visits with the endocrinologist before 28 weeks of gestation, and every 2 weeks thereafter. Most women attended 1 initial nutrition orientation group session where they received dietary information from a

technician. Less than 5% of them had a glucose meter to

perform capillary glucose self-monitoring

Serum 2 hours postprandial glucose values during the

last visit tended to be lower in women in the MNT programme compared with women in the control group (107·05 ± 23·83 vs 115·64 ± 36·11).

The number of total perinatal complications was higher in the control group than the MNT programme (P = 0·005).

Fewer women

in the MNT programme (27·3%) had ≥1 perinatal complications,

than the control group (45·3%, P = 0·013).

Fewer women developed

preeclampsia in the MNT programme than the control group (2·3% vs 16·3%; P = 0·001).

First maternal hospitalization

(due to uncontrolled hyperglycemia) was less frequent in the MNT programme (5·7% vs 62·8%; P < 0·001).

Moreover, women in the MNT programme did not require a second hospitalization.

No neonatal deaths and lower NICU admissions were also observed in the MNT programme (P = 0·001).

–

Among women with gestational diabetes, more women in

the control group used insulin than women in the MNT programme (56·4% vs 35·9%) but the doses prescribed were not statistically different (16 vs 0 unit/day, P = 0·052).

Fasting glucose values were not different between women in the MNT programme and the women in the control group.

Although there were no statistically significant differences, a greater proportion of women in the control group had elevated values of serum fasting

and 2 hours postprandial glucose levels (fasting: 37·2% vs 33·0%, P = 0·715; 2 hours postprandial: 37·2% vs 26·1%,

P = 0·169).

Although the frequency of prematurity, macrosomia, and low birth weight were not statistically different among the

groups, the MNT programme showed lower rates.

Intrauterine death was similar between the 2 groups.

26

Murphy et al., 2004 [51]

High risk

Nutrition counselling for patients with gestational diabetes mellitus (GDM) in small group.

Nutrition counselling, provided by a registered dietitian, consisted of a 1-hour interactive education session using a tabletop flip chart. Supporting written materials were used in both categories

to reinforce the topics discussed. Subjects completed a knowledge assessment test based on the content of the counselling session, which consisted of 12 multiple choice questions, at 3 time points: prior to nutrition counselling, immediately after counselling and 1 week after counselling.

Nutrition counselling for patients with gestational diabetes mellitus (GDM) in individual counselling.

Nutrition counselling, provided by a registered dietitian, consisted of a 1-hour interactive education session using a tabletop flip chart. Supporting written materials were used in both categories to reinforce the topics discussed. Subjects completed a knowledge assessment test based on the content of the counselling session, which consisted of 12 multiple-choice questions, at 3 time points: prior to nutrition counselling, immediately after counselling and 1 week after counselling.

A total of 27 dietitian hours were saved with small-group counselling.

Women with GDM can be effectively and cost-efficiently counselled on nutrition in small-group settings.

–

Post counselling results showed a significant improvement in knowledge,

regardless of counselling method (p<0·0001).

Post counselling

results showed no difference in knowledge improvement

between participants in small-group counselling and those who received individual counselling, based on equivalence testing (95% confidence interval [CI]: -3·7 to 5·5).

One-week follow-up results demonstrated that knowledge was retained in both counselling categories (95% CI: -6·2 to 2·4).

^c27

^cHayashi et al., 2018 [4]

High risk

^cDaily walking for GDM

management.

The total amount of daily walking was estimated from the number of steps taken and the amount of exercise performed daily, as measured with an accelerometer Participants attached the accelerometer to the waistbands of their skirts or pants, as instructed at the time of recruitment by investigators. The accelerometers assessed daily

walking for a total of 7–12 weeks because periodic

pregnancy examinations were performed every 4 weeks on the basis of the number of steps taken and the amount of exercise performed every day from the

second trimester to the third trimester. The accelerometers

were removed during sleeping and bathing. In the third trimester, the participants removed the accelerometers

permanently and completed questionnaires that assessed dietary intake.

^cNo control group

^cSimple walking for light intensity physical activity is effective for controlling the CGL in pregnant women with GDM.

^cThere was a significant negative correlation (r = −0·603, P = 0·014) between the post- to pre-research casual glucose level (CGL) ratio and the number of steps walked daily.

When the study was completed, the 11 participants who walked ≥6000 steps/day showed significantly lower CGL (95 + 10 mg/dL [mean + SD]) than the 13 participants in the <6000 steps/day group (111 + 18 mg/dL) (P = 0·013).

^cNo significant correlation (r = −0·004, P = 0·986) was detected between the

ratio of hemoglobin A1c and the number of steps taken.