Keywords obesity - overweight - pregnancy - nutrition counseling - neonatal macrosomia
Introduction
The health risks associated with overweight (body mass index, BMI 25–29,9 kg/m2 ) and obesity (BMI ≥ 30 kg/m2 ) are socially very important because of the increasing prevalence of overweight and
obesity [1 ]. The percentage of overweight and obese adults in Germany in 2021 was 53% [2 ]. According to the German Perinatal Statistics, the percentage of overweight/obese
pregnant women has increased continually from 35.0% in 2013 to more than 38.2% in
2019 and 43.82% in 2022 [3 ]
[4 ]
[5 ]. Maternal overweight and obesity in pregnancy lead to higher birth weights and higher
neonatal macrosomia rates [6 ]
[7 ]
[8 ]
[9 ]. Neonatal macrosomia is associated with a higher lifelong risk of overweight, obesity,
cardiovascular disease and metabolic diseases such as diabetes mellitus [10 ]
[11 ]. In addition to postnatal lifestyle factors, prenatal imprinting from “fetal programming”
is assumed to be an important risk factor [12 ]
[13 ]. Factors which promote neonatal macrosomia and/or childhood overweight or obesity
are not just higher maternal BMI but also lack of exercise and the consumption of
carbohydrate-rich foods which lead to excessive weight gain in pregnancy and the development
of gestational diabetes [1 ]
[14 ]
[15 ]
[16 ]
[17 ]. If a glucose-rich intrauterine milieu develops due to a high overall energy intake
and the consumption mainly of energy-dense processed foods, this is not just likely
to result in the birth of significantly heavier infants but can also lead to “erroneous
neuroendocrine programming” of the body weight and metabolic regulation of the child
over the longer term [18 ]
[19 ]. Fetal macrosomia also increases the rates of obstetric complications such as shoulder
dystocia, higher-grade maternal childbirth injuries, and postnatal adaptation disorders,
especially if gestational diabetes mellitus (GDM) is also present [20 ]
[21 ].
There is no consistent international definition of neonatal macrosomia and the term
“neonatal obesity” is not yet established. Absolute birth weights of 4000 g and 4500 g
are used as lower limits [1 ]
[3 ]
[4 ]
[5 ]. But this definition does not take account of regional differences [22 ], gestational age, or sex, and it is useful to use population-based standard values
rather than specified birth weights. Neonates with a birth weight of more than the
90th percentile are considered large for gestational age (LGA) or hypertrophic. Both
terms are used in the German-language guideline on GDM (since 2018) and in German
perinatal statistics [3 ]
[21 ].
There are also percentage-related classifications similar to BMI which take the length
of the infant at birth (> 90th length-related weight percentile) into consideration
as well as individualized percentile curves which take account of maternal weight.
However, these figures are not yet recorded across all of Germany [23 ]. Because the definitions are inconsistent, this study has included all possible
definitions of macrosomia in the form of an overall macrosomia rate.
In principle, lifestyle changes can modify BMI, weight gain in pregnancy, and ultimately
the macrosomia rate. The success of such measures depends on the timing of the start
of the intervention and the motivation for and intensity of the intervention [8 ]. The aim is to establish physiological changes in dietary and exercise habits starting
in early pregnancy. Healthy foodstuffs with a high percentage of dietary fiber can
reduce the risk of excessive weight gain in pregnancy and prevent excessive intrauterine
fetal growth in the context of primary prevention of obesity. Professional nutrition
counseling is currently not part of standard antenatal care. However, the motivation
of women to address the issue of healthy eating is especially high in this stage of
life [24 ].
This pilot study aimed to test the feasibility and practicability of methods and processes
of nutrition counseling in pregnancy. The question was whether the macrosomia rate
of term-born neonates in the study could be effectively reduced compared to comparative
figures for 2020 from University Gynecological Hospital (UFK) Rostock.
Methods
Study design and participants
The “Gesund mal Zwei” (GemaZ) [= Healthy times Two] study was carried out as a single
center, one-arm, interventional pilot study from October 2018 to December 2021. Women
with an intact singleton pregnancy were included. Exclusion criteria were maternal
age < 18 years, multiple pregnancy, inability to communicate properly in German, or
preexisting diabetes mellitus. Participants were enrolled in the study in the first
trimester of pregnancy between 10 and 14 weeks of gestation (GW). Initially, only
women with a preconception BMI ≥ 25 kg/m2 were included but because of the limited recruitment numbers, the protocol was amended
in September 2019 to allow women to be included irrespective of their BMI. The aim
of this change was to destigmatize participants and thereby increase willingness to
participate in the study. Primary endpoint of the study was the overall macrosomia
rate of term-born neonates born to overweight and obese pregnant women, defined as
a gestational age at delivery of ≥ 37 GW. The due date was determined based on the
date of the last menstruation. The date was amended if there was a deviation of ≥ 7
days when the crown-rump length was determined by sonography in early pregnancy. The
overall macrosomia rate was compiled based on by the presence of at least one of the following criteria: birth weight ≥ 4000 g, > 90th weight percentile relating
to GW and sex (LGA), > 90th length-related weight percentile (similar to BMI) or > 90th
weight percentile after adjusting for preconception maternal weight and height [23 ] (Fig. S1 ) (supplementary material, online).
Secondary endpoints were maternal weight gain during pregnancy based on the recommendation
of the Institute of Medicine (IOM), development of GDM, and evaluation by dieticians.
The IOM recommends that normal-weight women should have a weight gain of 11.5–16 kg,
overweight women should limit their weight gain to 7–11.5 kg and obese women should
only gain 5–9 kg in pregnancy [25 ]. Based on these recommendations, weight gain was classified into “below to adequate”
and “excessive.”
The definition of GDM was based on the criteria of the consensus recommendation of
the International Association of Diabetes and Pregnancy Study Groups (IADPSG) [26 ].
The intervention consisted of repeated nutrition education sessions led by certified
dieticians who received study-related training beforehand. The training focused on
pregnancy-specific aspects of metabolic regulation and diet. Test subjects received
three counselling sessions of 60 minutes each which consisted of both individual discussions
and group discussions in the period from 10 to 14 GW after inclusion in the study,
between 20 and 24 GW, and between 30 and 34 GW ([Fig. 1 ]). The contents of the training sessions build upon each other and are easily understandable
by non-experts. In addition to practical lifestyle-relevant recommendations on nutrition
and diet including a daily schedule and physical activities, the sessions also provided
theoretical information about the association between carbohydrate-dense maternal
diet and intrauterine fetal growth. The contents of the different sessions were adjusted
to the specific metabolic situation in the respective trimester of pregnancy. The
contents of each session were also provided to participants in writing. After each
session, the test persons were asked to evaluate the training session on a voluntary
and anonymous basis. Otherwise, antenatal care was provided in accordance with standard
recommendations. The anthropometric data of the neonates were evaluated and classified
postnatally.
Fig. 1
Protocol of the methodology of the study. Counseling sessions included the following
aspects: basic principles behind the building blocks of a healthy diet with a focus
on carbohydrates and dietary fiber, energy metabolism, weight gain during pregnancy
including the recommendation of the Institute of Medicine, specific examples of a
balanced diet, creation of a daily schedule, individual exercise counseling (e.g.,
walking with recommendations about the duration and calculation of energy consumption),
pathophysiology of gestational diabetes, importance of breastfeeding, discussion of
counseling experiences.
Sample size calculation, statistics
As this was a one-arm interventional study, a comparison with data of women and neonates
receiving standard care at UFK Rostock was planned. The overall macrosomia rate for
term-born singletons born to mothers with a preconception BMI ≥ 25 kg/m2 from 2017 of 29.0% was taken as the basis for calculating the sample size (Table
S1 ) (supplementary material, online). If the assumption was an estimated reduction of
10% in absolute terms as clinically relevant, an initial sample size of 300 participants
was calculated. Recruitment proved to be slow and the study protocol was therefore
amended in September 2019 by opening the study to women with a BMI < 25 kg/m2 . In addition, the recruitment goal was lowered to 100 participants.
To evaluate the obtained data, the overall macrosomia rates of University Gynecological
Hospital Rostock from 2020 were used as the comparison group.
In accordance with the relative distribution of BMI classes in the GemaZ study (< 25 kg/m2 14.44%, 25–29.9 kg/m2 34,44% and ≥ 30 kg/m2 51.11%), the weighted means of the macrosomia rates of University Gynecological Hospital
Rostock for these classes were determined for 2020. These were then used as comparison
rates for binomial macrosomia percentages in binomial tests and for exact confidence
intervals. The significance level for the statistical tests was 5%. The secondary
endpoint was maternal weight development and this was categorized in accordance with
the recommendation of the Institute of Medicine (IOM) [25 ].
Ethics vote and consent
The study was registered in the German Registry of Clinical Studies (Deutsches Register Klinischer Studien , DRKS-No. 00014914). The initial study protocol and necessary subsequent amendments
due to changes in the General Data Protection Regulation as well as the changes to
the study protocol including adjustments of the sample size and inclusion criteria
was approved by the appropriate ethics commission (ethics vote A 2018–0077). Participation
in the study was voluntary after having been informed about the study and having given
written consent.
Results
Characteristics of the study cohort
A total of 99 test persons were included in the study ([Fig. 2 ]). 85 of them (85.9%) had a BMI ≥ 25 kg/m2 . Over the course of the study, 90 children with a gestational age ≥ 37 GW were born
(90.9%). There were three miscarriages, one of which was a late miscarriage in week
22 of gestation and one stillbirth in week 33 of gestation. Five children were preterm
(5.9%), all of them born to women with a BMI ≥ 25 kg/m2 . 77 children with a gestational age ≥ 37 GW (90.6%) were born to the group of 85
women with a BMI ≥ 25 kg/m2 .
Fig. 2
Flow diagram of the study participants.
Additional data on the study cohort differentiated according to BMI class is listed
in [Table 1 ].
Table 1
Patient data of the study population according to BMI class. Mean and standard deviation
as well as absolute and relative frequencies are presented.
All BMI classes
n = 99
BMI < 25 kg/m2
n = 14
BMI 25–29.9 kg/m2
n = 34
BMI ≥ 30 kg/m2
n = 51
P value
BMI = body mass index; GemaZ = “Gesund mal Zwei” study; GW = week(s) of gestation
Age (years)
32.3 (3.93)
32.6 (3.52)
31.8 (4.26)
32.6 (3.83)
0.596
Height (cm)
169 (6.17)
170 (7.80)
169 (5.39)
170 (6.28)
0.971
Preconception weight (kg)
90.4 (22.5)
64.5 (6.17)
77.3 (7.12)
106 (19.6)
< 0.001
Preconception BMI (kg/m2 )
31.4 (6.91)
22.4 (1.47)
26.9 (1.38)
36.8 (5.08)
< 0.001
Gravidity after inclusion in the GemaZ study
1.82 (0.92)
1.57 (0.85)
1.79 (0.88)
1.90 (0.96)
0.487
Parity after giving birth during the GemaZ study
1.46 (0.69)
1.57 (0.85)
1.41 (0.66)
1.47 (0.67)
0.767
Attended 1st training session, n (%)
99 (100)
14 (100)
34 (100)
51 (100)
Attended 2nd training session, n (%)
83 (100)
13 (92.9)
29 (85.3)
41 (80.4)
Attended 3rd training session, n (%)
73 (100)
11 (78.6)
26 (76.5)
36 (70.6)
Birth data, n
n = 95
n = 13
n = 33
n = 49
Maternal weight at delivery (kg)
102 (22.5)
76.2 (6.82)
89.8 (8.61)
118 (20.1)
< 0.001
Maternal weight gain during pregnancy (kg)
11.8 (6.54)
11.7 (3.85)
12.6 (4.16)
11.4 (8.23)
0.715
Gestational week at delivery
39.1 (1.52)
39.5 (1.2)
38.8 (1.81)
39.2 (1.36)
0.318
Preterm birth < 37 GW, n (%)
5 (5.3)
0
2 (6.1)
3 (6.1)
Birth ≥ 37 GW, n (%)
90 (94.7)
13 (100)
31 (93.9)
46 (93.9)
Sex of the infant
47 (49.5)
8 (61.5)
16 (48.5)
23 (46.9)
0.639
48 (50.5)
5 (38.5)
17 (51.5)
26 (53.1)
Body measurements of the infant
3469 (485)
3626 (428)
3340 (566)
3515 (426)
0.127
50.7 (2.5)
51.3 (3.01)
50.2 (2.86)
50.9 (2.05)
0.321
35.1 (1.61)
35.7 (1.48)
34.8 (1.89)
35.1 (1.4)
0.172
Neonatal macrosomia rates
The overall macrosomia rate irrespective of maternal BMI of live-born singletons born
at term in UFK Rostock in 2020 was 24.9% (n = 620/2491, [Table 2 ]). Overall, 29.9% (n = 314/1049) of term-born children born to pregnant women with
a BMI ≥ 25 kg/m2 met at least one criterion of macrosomia. The BMI distribution in the study population
differed from the BMI distribution in the comparison population with a higher rate
of obesity reported for the study population (BMI ≥ 30 kg/m2 : 51.1% GemaZ cohort vs. 42.8% comparison group). Because of this difference between
the two groups, the expectation of macrosomia in children born to women with a BMI
≥ 25 kg/m2 in the GemaZ cohort was also higher at 31.3% instead of 29.9%.
Table 2
Macrosomia rates of Voigt et al. [23 ] according to gestational age and maternal BMI. Comparison of births in University
Gynecological Hospital Rostock in 2020 (comparison population) and in the GemaZ cohort.
Only live-born singletons were included.
All singleton births
Overall macrosomia
Weight ≥ 4000 g
Weight > 90th perc. (LGA)
Length-related weight > 90th perc.
Weight > 90th perc. after adjustment for maternal data
BMI = body mass index; GemaZ = “Gesund mal Zwei” study; LGA = large for gestational
age; perc. = percentile; GW = week(s) of gestation
Comparison population, total number of singletons
All GW
2671
635 (23.7%)
373 (14.0%)
326 (12.2%)
566 (21.2%)
259 (9.7%)
< 37 GW
180
15 (8.3%)
0 (0%)
12 (6.7%)
15 (8.3%)
9 (5.0%)
≥ 37 GW
2491
620 (24.9%)
373 (15.0%)
314 (12.6%)
551 (22.1%)
250 (10.0%)
Maternal BMI classes
Comparison population, only term-born singletons born ≥ 37 GW
< 25 kg/m2
1442
306 (21.2%)
186 (12.9%)
145 (10.1%)
264 (18.3%)
150 (10.4%)
25–29.9 kg/m2
600
159 (26.5%)
93 (15.5%)
81 (13.5%)
144 (24.0%)
46 (7.7%)
≥ 30 kg/m2
449
155 (34.5%)
94 (20.9%)
88 (19.6%)
143 (31.8%)
54 (12.0%)
≥ 25 kg/m2
1049
314 (29.9%)
187 (17.8%)
169 (16.1%)
287 (27.4%)
100 (9.5%)
GemaZ study cohort, all singletons
All GW
95
20 (21.1 %)
13 (13.7 %)
11 (11.6 %)
15 (15.8 %)
6 (6.3 %)
< 37 GW
5
1 (20%)
0
1 (20%)
1 (20%)
0
≥ 37 GW
90
19 (21.1%)
13 (14.4%)
10 (11.1%)
14 (15.6%)
6 (6.6%)
Maternal BMI classes
GemaZ study cohort, only term-born singletons born ≥ 37 GW
< 25 kg/m2
13
4 (30.8%)
3
2
3
2
25–29.9 kg/m2
31
4 (12.9%)
2
2
4
1
≥ 30 kg/m2
46
11 (23.9%)
8
6
7
3
≥ 25 kg/m2
77
15 (19.5%)
10 (13.0%)
8 (10.4%)
11 (14.3%)
4 (5.2%)
The overall macrosomia rate irrespective of BMI for all term-born infants in the study
just missed statistical significance at 21.1% (n = 19/90; 95% CI 13.2%–31.0%, p = 0.083).
In contrast, the overall macrosomia rate of the neonates born ≥ 37 GW from the target
group with a preconception BMI ≥ 25 kg/m2 was 19.5% (n = 15/77; 95% CI: 11.3%–30.1%, p = 0.026) and was therefore significantly
below the adjusted comparison rate ([Fig. 3 ]).
Fig. 3
Relative frequency of macrosomia of term-born singletons of women with a maternal
BMI ≥ 25 kg/m2 born in UFK Rostock in 2020, after BMI adjustment according to BMI distribution in
the GemaZ study cohort and in the GemaZ study cohort (with 95% CI [confidence intervals]).
Sensitivity analysis showed a significant reduction compared to the comparison cohort
for the macrosomia criterion “length-related weight > 90th percentile” for both the
overall cohort of term-born neonates and for the subgroup of term-born singletons
born to mothers with a BMI ≥ 25 kg/m2 ([Table 3 ]). Analysis also showed a trend to reduction for the other macrosomia definitions
(birth weight > 4000 g, birth weight > 90th percentile and birth weight adjusted for
maternal data > 90th percentile).
Table 3
Frequency of macrosomia according to Voigt et al. [23 ] of term-born singletons born to the GemaZ study cohort compared to BMI-adjusted
comparative rate for births born in UFK Rostock in 2020.
Definition
UFK 2020 rate, %
Adjusted comparative UFK 2020 rate, %*
Macrosomia in the GemaZ cohort, n/N
Point estimation rate, % (95% CI)
P value
BMI = body mass index; CI = confidence interval; GW = week(s) of gestation; UFK =
University Gynecological Hospital
* Adjustment for BMI distribution in the GemaZ cohort using weighted means
All singleton births born ≥ 37 GW
15.0
17.9
13/90
14.44 (7.92–23.43)
0.491
12.6
16.1
10/90
11.11 (5.46–19.49)
0.250
22.1
27.2
14/90
15.56 (8.77–24.72)
0.012
10.0
10.3
6/90
6.67 (2.49–13.95)
0.301
24.9
29.8
19/90
21.11 (13.21–30.99)
0.083
Only singleton births at term ≥ 37 GW born to mothers with a BMI ≥ 25 kg/m2
17.8
18.7
10/77
12.99 (6.41–22.59)
0.242
16.1
16.1
8/77
10.39 (4.59–19.45)
0.214
27.4
28.7
11/77
14.29 (7.35–24.13)
0.005
9.5
10.3
4/77
5.19 (1.43–12.77)
0.186
29.9
31.3
15/77
19.48 (11.33–30.09)
0.026
Maternal weight changes and prevalence of GDM
The majority of normal-weight test persons (n = 11/13, 84.6%) had a physiological
weight gain consistent with the recommendation of the IOM. The physiological pregnancy
weight gain of 54.5% of overweight test persons (n = 18/33) and 44.9% of obese test
persons (n = 22/49) was within the recommended range.
The higher the BMI category, the higher the rate of excessive weight gain during pregnancy
which increased from 15.4% (normal weight) to 45.5% (overweight) to 55.1% (obese)
([Table 4 ]).
Table 4
Weight changes in the GemaZ cohort and prevalence of GDM. Classification according
to BMI class. Weight gain based on the recommendation of the IOM.
All BMI
n = 95
BMI < 25 kg/m2
n = 13
BMI ≥ 25 kg/m2
n = 33
BMI ≥ 30 kg/m2
n = 49
Total p value
BMI = body mass index; GDM = gestational diabetes mellitus; IOM = Institute of Medicine
Absolute weight gain
0.001
4
0
0
4
4
0
1
3
26
3
8
15
22
6
9
7
20
2
8
10
19
2
7
10
Weight change, range
+5 to +18 kg
+4 to +23 kg
−9 to +33 kg
Weight gain according to the recommendation of the IOM
Below to adequate
11 (84.6%)
18 (54.5%)
22 (44.9%)
Excessive
2 (15.4%)
15 (45.5%)
27 (55.1%)
Gestational diabetes mellitus
58 (61.1%)
12 (92.3%)
23 (69.7%)
23 (46.9%)
14 (14.7%)
1 (7.7%)
7 (21.2%)
6 (12.2%)
23 (24.2%)
0 (0.0%)
3 (9.1%)
20 (40.8%)
Overall GDM frequency was 38.9% (n = 37/95); the higher the BMI category, the higher
GDM frequency (7.7% vs. 30.3% vs. 53.0%). The relative percentage of GDM managed with
insulin similarly increased (0% vs. 30% vs. 76.9%).
Evaluation of questionnaires
The attendance rate at the education sessions decreased slightly over the course of
pregnancy and the attendance rate at the final session was 73% (n = 73/99) ([Table 1 ]). After the first education session, 97% (n = 96/99) of participants completed the
evaluation questionnaire and 100% (n = 73) of participants completed the questionnaire
after the third session. The quality of the training sessions was overwhelmingly assessed
as good to very good (Table S2 ) (supplementary material, online). The recommendations on diet and nutrition were
new for 52% of the participants (Table S3 ) (supplementary material, online). All the pregnant women, including those who were
already familiar with the details presented in the first training session, came away
from the event with information which was relevant for their daily life. Almost everyone
rated the training materials as useful and an interest in nutritional issues going
beyond the counseling sessions was awakened in 96% (1st session) and 89% (3rd session)
of participants. At the end of the 3rd training session, 97% of the test persons stated
that counseling had inspired them to pay more attention to healthy eating after the
end of the pregnancy.
According to their own assessment, 8% of the participants had not previously thought
much about a healthy diet and 32% of participants had only partially considered it;
only about 27% of test persons had tried to ensure that they ate a healthy diet prior
to the first counseling session (Table S4 ) (supplementary material, online). For 93% of the test persons, the information conveyed
in the session was easy to understand and they did not feel overwhelmed by the information.
After the last consultation, 85% of women planned to concentrate more on their diet
in the future. More than half were motivated to eat healthier in the future (Table S4 ) (supplementary material, online). The counseling was overwhelmingly evaluated as
positive. 98% of the test persons wanted the counseling sessions to be integrated
in the routine antenatal care offered to pregnant women (Table S4 ) (supplementary material, online).
Discussion
Maternal overweight and obesity, and excessive weight gain in pregnancy increase the
risk of complications of pregnancy, fetal macrosomia, and infant obesity and predispose
the infant to develop metabolic disorders and chronic disease in later life [6 ]
[11 ]
[19 ]
[27 ]
[28 ]
[29 ]
[30 ].
There are some indications that an unfavorable intrauterine milieu of abundance may
affect the fetal energy metabolism prenatally and may also affect fetal metabolism
postnatally over the longer term [17 ]
[19 ]
[20 ]
[31 ]
[32 ]. A possible cause of fetal macrosomia is a (pre-)diabetic metabolic state, often
found in obese women, characterized by insulin resistance, high maternal blood sugar
levels, and elevated placental glucose transport [33 ]. The HAPO study of more than 23000 mother-child pairs found that even a moderately
elevated maternal blood glucose level identified using the 75 g oral glucose tolerance
test between week 24 and 32 of gestation led to an increase in the prevalence of LGA
infants [10 ]. One prospective study reported that high preconception BMI did not just lead to
higher fetal BMI and total body fat but was also associated with changes to metabolic
parameters at the age of 6–10 years. This included increased insulin resistance and
higher leptin levels [16 ].
A number of controlled studies, some of which investigated large randomized cohorts,
have investigated whether lifestyle counseling or dietary changes could have a positive
influence [34 ]
[35 ]
[36 ]. A summary of recent meta-analyses shows that these measures were largely unable
to fulfil expectations [37 ]
[38 ]. Weight gain during pregnancy was most likely to be affected by measures. No effects
on neonatal birth weight, macrosomia rates and neonatal obesity were found [38 ]. One meta-analysis studied follow-up data on the development of children from the
age of one month to seven years and was unable to detect an influence on weight and
BMI development as a function of lifestyle interventions during pregnancy [39 ]. A meta-analysis based on individual participant data with a follow-up of between
three and five years (six studies with n = 2529) of pregnant women with a BMI ≥ 25 kg/m2 who were randomized to receive dietary and/or a lifestyle intervention or standard
antenatal care came to the same conclusion [40 ]. About 30% of these children between 3–5 years of age had a standard BMI score above
the 90th percentile, irrespective of the previous intervention. The long-term results
of the LIMIT study with up to ten years of follow-up have confirmed the high rate
of overweight and obese children in this high-risk cohort as well as the lack of any
effect of lifestyle interventions in pregnancy [41 ]. Preconception factors such as age and initial BMI of the pregnant women as well
as pre- and postnatal factors such as nutrient availability to the fetus, maternal
weight gain, and physical exercise up until the birth, rate and duration of breastfeeding,
and the relation between energy supply and energy metabolism in later life are likely
to be relevant. An intervention limited to the pregnancy alone does not appear to
be sufficient [42 ]
[43 ].
A general problem was that women found it difficult to implement the recommendations
to increase physical activity. This also applied during pregnancy where the reported
adherence rates under study conditions were just 50% despite the comparatively higher
motivation in this cohort [44 ].
As part of the cooperation project “Gesund leben in der Schwangerschaft” (GeliS) [=
Healthy Living in Pregnancy], the option to provide pregnant women with health counseling
in the context of routine antenatal care in Germany was evaluated. Maternal weight
gain in 1152 pregnant women in the intervention group (three health counseling sessions)
compared to weight gain in 1134 participants in the comparison group (standard antenatal
care in accordance with the German Maternity Guidelines) was investigated. Lifestyle
counseling was provided by previously trained gynecologists, midwives, and physician
assistants, certified dieticians were not involved [36 ]. More than 90% of the intervention group receiving standard antenatal care attended
all three training sessions. The analysis of implemented dietary measures, however,
showed that total energy intake did not decrease despite selective dietary changes
following counseling [45 ]. The expectation that birth weight would be reduced by implementing the recommendations
on healthy eating was not fulfilled [46 ]. However, an association was found between implementation of the recommendations
on physical activity and lower birth weight [47 ]. When maternal weight gain in the GeliS study was compared with maternal weight
gain in the GemaZ study, the rate of excessive weight gain in the group of obese participants
was 9% lower in the GemaZ study than in the intervention arm of the GeliS study [36 ]. The GemaZ study investigated the impact of three nutrition counseling sessions
provided to pregnant women by certified dieticians on the overall neonatal macrosomia
rate and, in more detail, on macrosomia rates calculated according to varying criteria.
Test persons were provided with theoretical information on maternal diet and pregnancy-specific
aspects of metabolic regulation and the relationship with intrauterine fetal growth.
The training content also included practical recommendations for healthy eating and
physical activity. 73.7% of test persons still attended the third nutrition counseling
session ([Table 1 ]). Counseling was overwhelmingly rated as positive and participants supported the
inclusion of nutrition counseling in standard antenatal care.
In the GemaZ study, the overall neonatal macrosomia rate of term-born singletons born
to test persons with a BMI ≥ 25 kg/m2 decreased compared to the comparison group ([Table 3 ]). A comparison of our results with those of other studies is difficult because of
the definition of macrosomia chosen for the GemaZ study. An analysis of the different
macrosomia definitions showed that the effect can be primarily attributed to a decrease
in the percentage of children with a length-related birth weight above the 90th percentile.
With regard to the other macrosomia definitions, analysis only showed a trend toward
a decrease in frequency. The use of length-related birth weight, which has some parallels
with BMI, is possibly the most sensitive macrosomia criterion and therefore useful
for interventional studies, but it is still rarely used. Particularly noteworthy was
the high percentage of macrosomic infants when this criterion was used. However, the
prognostic significance for developments later in childhood remains unclear as studies
are lacking.
This study has some limitations. Because the recruitment of pregnant women was slow,
the case number fell considerably short of the planned target number, meaning that
the study must be assessed as underpowered. Expanding the study protocol to include
normal-weight women additionally reduces the scope of the results. The reasons for
the poor recruitment levels were not investigated further but were due, at least in
part, to the COVID-19 pandemic. In view of the difficult recruitment conditions, it
must be assumed that the study population consisted of a group of highly motivated
women. This must have contributed to the positive outcome of the study. It is therefore
not possible to directly transfer these results to a non-selected population. The
one-arm design of the study additionally complicates the interpretation of results.
Nevertheless, these results support the benefit of a lifestyle intervention for motivated
high-risk patients.
Conclusion
A reduction in the overall macrosomia rates of term-born singletons born to women
with a BMI ≥ 25 kg/m2 and singletons with length-related birth weight above the 90th percentile irrespective
of maternal BMI appears to be possible by means of targeted nutrition advice given
in pregnancy. Certified nutrition counseling provided with the aim of primary obesity
prevention should become a mandatory part of antenatal care. Based on recent studies,
lifestyle interventions should already be initiated prior to conception and must be
continued over the longer term for mother and child.
Supplementary Material
Table S1 : Macrosomia rate of term-born neonates in % based on preconception maternal BMI.
Percentage of macrosomic term-born singletons as a function of preconception maternal
BMI and overall macrosomia rates in 2014 and 2017–2020.
Table S2 : Assessment of the quality of the counseling after the 1st and 3rd sessions.
Table S3 : Assessment of the educational contents after the 1st and 3rd sessions.
Table S4 : Personal data after the 1st and 3rd sessions.
Fig. S1 : Example of neonatal classification (data from Voigt M et al. [23 ]). In addition to gestational age, the classification takes account of fetal and
maternal biometric and gender-specific factors.
