The role of a personalized dietary intervention in managing gestational weight gain: A prospective, controlled study in a low-risk antenatal population

Abstract

To compare the efficacy of a personal dietary intervention on gestational weight gain control with a general intervention promoting healthy eating.
Prospective, controlled study including 154 low-risk pregnant women randomly allocated to two groups: 77 receiving a personalized diet plan and a close follow-up by a dietician (intervention group), 77 receiving standard dietary care by means of a brochure on healthy eating during pregnancy (control group). Pre-pregnancy weight, gestational age, height, weight and BMI at baseline, weight at term, gestational age at delivery and newborn weight were recorded for all participants. The primary end-point was the difference in body weight between baseline and term. Secondary end-points were the difference in body weight between pre-pregnancy and term and in newborn weights.
Maternal weight gain at term was significantly lower both as compared to pre-pregnancy weight (8.2 ± 4.0 vs. 13.4 ± 4.2 kg; p < 0.001) and to weight at baseline (7.7 ± 3.8 vs. 13.7 ± 4.3 kg; p < 0.001) in the intervention group as compared to controls. A positive, significant correlation between the delta weight between baseline and term and newborn weight was observed in both groups, but stronger in patients from the intervention group (intervention group R = 0.76, p < 0.001; control group R = 0.35, p = 0.01).
This study suggests that a personalized nutritional intervention, in which the dietician plays an active role within the obstetric team, may represent a successful approach in limiting weight gain in pregnant women.

Full text

MATERNAL-FETAL MEDICINE
The role of a personalized dietary intervention in managing
gestational weight gain: a prospective, controlled study
in a low-risk antenatal population
Costantino Di Carlo •Giuseppina Iannotti •Stefania Sparice •
Maria Pia Chiacchio •Elena Greco •Giovanni Antonio Tommaselli •
Carmine Nappi
Received: 24 June 2013 / Accepted: 4 October 2013
ÓSpringer-Verlag Berlin Heidelberg 2013
Abstract
Purpose To compare the efficacy of a personal dietary
intervention on gestational weight gain control with a
general intervention promoting healthy eating.
Methods Prospective, controlled study including 154
low-risk pregnant women randomly allocated to two
groups: 77 receiving a personalized diet plan and a close
follow-up by a dietician (intervention group), 77 receiving
standard dietary care by means of a brochure on healthy
eating during pregnancy (control group). Pre-pregnancy
weight, gestational age, height, weight and BMI at base-
line, weight at term, gestational age at delivery and new-
born weight were recorded for all participants. The primary
end-point was the difference in body weight between
baseline and term. Secondary end-points were the differ-
ence in body weight between pre-pregnancy and term and
in newborn weights.
Results Maternal weight gain at term was significantly
lower both as compared to pre-pregnancy weight
(8.2 ±4.0 vs. 13.4 ±4.2 kg; p\0.001) and to weight at
baseline (7.7 ±3.8 vs. 13.7 ±4.3 kg; p\0.001) in the
intervention group as compared to controls. A positive,
significant correlation between the delta weight between
baseline and term and newborn weight was observed in
both groups, but stronger in patients from the intervention
group (intervention group R=0.76, p\0.001; control
group R=0.35, p=0.01).
Conclusions This study suggests that a personalized
nutritional intervention, in which the dietician plays an
active role within the obstetric team, may represent a
successful approach in limiting weight gain in pregnant
women.
Keywords Weight gain Pregnancy Nutrition 
Dietician Birth-weight
Introduction
Pre-pregnancy weight, maternal body mass index (BMI)
and gestational weight gain (GWG) are important predic-
tors of pregnancy course and outcome as well as fetal
growth and development. Both the total amount and pattern
of weight gain during pregnancy impact short- and long-
term maternal and offspring health [1–8].
Current guidelines for GWG published by the Institute
of Medicine [9] recognize the impact of weight gain during
pregnancy on maternal and child health outcomes and
highlight the importance of preconceptional prevention
with nutritional recommendations being based on a balance
between the risks associated either to an excessive or to a
restricted weight gain.
Weight control of fertile women may require assistance
prior to conception, during, and after pregnancy. Obese and
overweight women should be counseled to improve the
quality of their diet and to increase their physical activity
levels to reach a healthy body weight before conceiving.
During pregnancy, all women should be encouraged to limit
both weight gain and loss within the recommended range. In
the post-partum period, breast-feeding should be strongly
encouraged, both for the health of the newborn and to
facilitate the return to the pre-pregnancy body weight [9].
C. Di Carlo (&)G. Iannotti S. Sparice 
M. P. Chiacchio E. Greco G. A. Tommaselli C. Nappi
Department of Neurosciences and Reproductive Sciences,
University of Naples ‘‘Federico II’’, Via Pansini 5,
80131 Naples, Italy
e-mail: costantino.dicarlo@unina.it
123
Arch Gynecol Obstet
DOI 10.1007/s00404-013-3054-y

Typically, women tend to significantly increase their
caloric intake during pregnancy far beyond their real
nutritional needs. In a recent study from our group, we
demonstrated that excessive GWG was related to an
inadequately balanced diet. However, we also observed
that in 62 % of cases the daily caloric intake of the preg-
nant women recruited was higher than the recommended
one [10].
Interventions on diet and lifestyle aimed at promoting a
healthy GWG are the objects of several studies available in
literature [11–14]. However, types of nutritional interven-
tions adopted are usually not clearly defined or confined to
general dietary and lifestyle suggestions.
The aim of the present study was to evaluate the efficacy
of a personal dietary intervention on GWG control and to
compare this with a more general intervention aiming at
the promotion of a healthy diet.
Materials and methods
This was a prospective, controlled, study performed in the
low-risk antenatal clinic of our department. Pregnant
women referred to our clinic for their first pregnancy visit
(\90 days of amenorrhea) between January 2010 and
January 2011, were evaluated for inclusion in the study.
Patients
Pregnancies complicated by any significant maternal con-
dition other than essential hypertension and thyroid dis-
eases, multiple pregnancies with more than two fetuses,
and pregnancies with maternal BMI B20 and C40 kg/m
2
were excluded from the study. Also, gestational diabetes
(GDM) as defined by the criteria established by National
Screening Policy [15] was considered an exclusion crite-
rion. Enrolled women who experienced miscarriage or pre-
term delivery during the study were excluded from the
analysis. Enrollment was carried on until the required
number of patients had concluded the study.
A total of 197 women were evaluated for inclusion, 154
satisfied the inclusion criteria and accepted to participate to
the study and were thus randomly allocated with a 1:1 ratio
into two groups. Seventy-seven women were interviewed
regarding their normal dietary habits and received a per-
sonalized diet plan (intervention group); 77 were scheduled
to receive standard dietary care with a brochure on healthy
eating during pregnancy and breast-feeding (control
group).
All patients were clearly explained the study design and
signed a written consent prior to randomization. The allo-
cation sequence was concealed from the researchers (CDC,
GAT and SS) who enrolled the participants and attached a
sequentially numbered, opaque sealed and stapled envelope
containing the allocated treatment to the patient clinical
record. The dietician opened the envelopes at the time of
the first visit.
Since both approaches used in the study are part of our
routine antenatal care, no approval by our Institutional
Review Board was required for the study.
Study design
At baseline, a thorough medical and obstetric history was
taken from all participants. Gestational age and anthropo-
metric parameters including pre-pregnancy weight (as
reported by the patient) current weight, height, and BMI
were recorded for all patients at the first visit as well.
Maternal weight at term (as measured at last follow-up
visit scheduled beyond 37 weeks gestation), gestational
age at delivery and newborn weight were also registered
for all participants.
Women allocated to the intervention group underwent
a dietary interview using a food frequency questionnaire
(FFQ) validated for use in Italian subjects [16], to eval-
uate their dietary habits and to generate a personalized
diet plan meeting both personal preferences and specific
gestational needs. Such plan takes into account the ener-
getic surplus needed by pregnant women as well as the
potential susceptibility to Toxoplasma infection, thus
imposing exclusion of some foods from the diet and
adherence to strict hygiene measures to limit the risk of
infection during pregnancy. Individualized diet plans were
elaborated in agreement with the recommended dietary
allowance (RDA) for the Italian population [17] with the
average daily caloric intake being 1,916 kcal. A typical
weekly diet plan included five meals per day, distributed
throughout the day as follows: breakfast (milk or yoghurt,
biscuits or toasted bread), snack (fruits or crackers), lunch
(pasta or rice with vegetables, limiting the association of
potatoes and tomato sauce, and a side-dish with vegeta-
bles), snack (fruits), and dinner (white meat or fish, lim-
iting to once a week dairy products, cheese, eggs, and
ham, associated with a side-dish of vegetables and bread).
The only fat allowed, as a preparation or dressing for all
meals, was olive oil. Women in this group were sched-
uled for monthly follow-up appointments with a dietician
who monitored their weight gain, discussed any potential
issues, gave further suggestions and answered questions,
as needed.
Women allocated to the control group, at first visit,
received a standard brochure containing dietary sugges-
tions to be followed during pregnancy and breast-feeding.
Such brochure provided information on healthy eating
during pregnancy, including how to eat a balanced diet,
eating a variety of foods, healthy weight gain during
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123

pregnancy, and food safety concerns specific to pregnant
women. In addition, it included a frequently asked ques-
tions (FAQs) section, with an answer to the most frequent
questions that may rise during pregnancy and breast-feed-
ing regarding diet and weight gain. All the information and
the suggestions were in accordance to the indications of the
Italian Society for Nutrition. The dietician never saw
patients from this group during the rest of their pregnancy.
All patients enrolled in the study were administered folic
acid 4 mcg/daily until 12 weeks either as a single formu-
lation or within a multivitamin supplement and all patients
took a standard pregnancy multivitamin supplement
throughout pregnancy.
The primary end-point was the difference in body
weight between baseline and term. Based on a preliminary
study [10], where we observed a difference of 4 kg with a
standard deviation (SD) of 5.0 between two treatment
groups, we calculated that a sample size of 59 in the
intervention group and 59 in the control group were needed
to give 80 % power to detect a significant difference with a
one-sided type 1 error of 5 %. Considering a hypothetic
dropout rate of 22 %, we recruited 77 patients per group.
Secondary end-points were the difference in body weight
between pre-pregnancy and term, birth weight of
newborns.
Statistical analysis
Statistical analysis was performed using the statistical
package for Social Science, version 13.0 (SPSS, Chicago,
IL, USA). Data distribution for continuous variables was
assessed with the Shapiro–Wilk’s test and all variables
displayed a normal distribution. Differences between
groups in age, height, bodyweight, newborn weight, ges-
tational age at delivery and body weight deltas were
evaluated with the Student’s ttest for uncoupled samples.
Difference for continuous, normally distributed variables
within the same group (body weight) was evaluated using
the Student’s ttest for coupled samples. Differences in
cigarette smokers between groups were assessed with the
v
2
test. Correlation between delta of body weight and
newborn weight was assessed using Spearman’s Rtest.
Significance was set for a value of p\0.05. Analysis was
performed per-protocol, excluding dropouts.
Results
The flow of patients is reported in Fig. 1. Forty-three
women did not satisfy the inclusion criteria and were thus
excluded from the study. A total of 16 women in the
intervention group (eight who had a miscarriage, one who
delivered pre-term and seven lost to follow-up) and 18 in
the control group (nine who had a miscarriage, three who
delivered pre-term and six lost to follow-up) did not attend
the final follow-up visit and were excluded from the ana-
lysis. Thus, a total of 61 patient in the intervention group
and 59 in the control group were included in the final
analysis.
Characteristics of the patients included in the study are
shown in Table 1. No differences in the variables analyzed
were observed between the two groups, with the exclusion
of maternal age, which was significantly lower in the
control group. Racial and socio-cultural factors were not
included in the variables analyzed, as all patients were
Caucasian and of homogeneous social, economic and cul-
tural backgrounds.
Median gestational age at baseline was 8 weeks (range
6–13) in the intervention group and 9 weeks in the control
group (range 5–13) (p=0.5). Median gestational age at
delivery was 39 weeks in both groups (range intervention
group 34–41; range control group 35–41) (p=0.7).
Twenty-six women from the intervention group (44.3 %)
and 33 from the control group (54.1 %) (p=0.3) were
delivered by cesarean section.
In all patients, from both groups, a significant weight
gain was observed at the last follow-up visit (term) as
compared to both pre-pregnancy weight and weight at
baseline (intervention group 75.4 ±13.2 vs. 67.4 ±15.0
and 67.7 ±14.8 kg; control group 76.5 ±10.5 vs.
63.1 ±10.3 and 63.8 ±10.4; p\0.001) (Fig. 2).No
significant differences in the pattern of weight gain were
observed between the two groups throughout pregnancy
(Table 1; Fig. 2).
Differences between pre-pregnancy weight and weight
at term, and maternal weight at baseline and at term for
both groups are expressed as delta values and shown in
Fig. 3. Maternal weight gain at term was significantly
lower both as compared to pre-pregnancy weight
(8.2 ±4.0 vs. 13.4 ±4.2 kg; p\0.001) and to weight at
baseline (7.7 ±3.8 vs. 13.7 ±4.3 kg; p\0.001) in the
intervention group as compared to controls.
Assuming that a pregnancy weight gain up to 12 kg is
considered healthy in patients with pre-pregnancy BMI
within the normal range (BMI 18.5–24.9 kg/m
2
), we
stratified our population from both groups in two sub-
groups: women with a healthy pregnancy weight gain
(equal or lower than 12 kg) and women with an excessive
pregnancy weight gain (greater than 12 kg). This analysis
showed that 95.1 % (58) patients from the intervention
group and only 41 % (25) from the control group had a
healthy pregnancy weight gain (relative risk 2.4; 95 % CI
1.9–2.5; p\0.001).
A positive, significant correlation between the delta
maternal weight between baseline and term and newborn
weight was observed in both groups (intervention group
Arch Gynecol Obstet
123

R=0.76, p\0.001; control group R=0.35, p=0.01).
However, such correlation was stronger for patients from
the intervention group.
Fig. 1 Flow diagram of
progress of patients through the
trial
Table 1 Characteristics of patients included in the study
Intervention group
(n=59)
Control group
(n=61)
p
Age (years) 31.3 ±4.7 28.2 ±5.3 0.002
Height (cm) 159.8 ±6.3 159.1 ±6.4 0.6
Pre-pregnancy body
weight (kg)
67.4 ±15.0 63 ±10.3 0.08
Pre-pregnancy BMI
(kg/m
2
)
26.5 ±6.3 25.0 ±4.2 0.3
Body weight I
trimester (kg)
67.7 ±14.8 63.8 ±10.4 0.1
Body weight at term
(kg)
75.4 ±13.2 76.5 ±10.5 0.6
Gestational age at first control
Gestational age at
delivery (weeks)
39 (34–41) 39 (35–41) 0.6
Primigravidae 17 (28.8) 23 (37.7) 0.3
Newborn
birthweight (g)
3,078.2 ±372.3 3,121.5 ±430 0.6
Former cigarette
smokers [n(%)]
19 (32.2) 22 (37.3) 0.6
Current cigarette
smokers [n(%)]
6 (10.1) 8 (13.5) 0.6
Data are reported as mean ±SD, median (range) or n(%), as
appropriate
Fig. 2 Gestational weight gain in the two groups. *p\0.001 vs.
both pre-pregnancy weight and maternal body weight at baseline
Fig. 3 Differences (delta values) between pre-pregnancy weight and
weight at term, and maternal weight at baseline and at term between
the two groups *p\0.001 vs. intervention group
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Discussion
This study provides evidence to suggest that women who
receive a personalized nutritional intervention during
pregnancy experience a significantly reduced GWG in
comparison with women who receive only nutritional
suggestions. Moreover, women receiving personalized
nutritional advice have a significantly higher chance to
remain within the recommended GWG of 12 kg.
Studies monitoring GWG in the Italian population are
not well documented. In addition, the types of nutritional
interventions adopted are usually not clearly defined [12–
14]. Indeed, most of these studies report that pregnant
women were given general dietary and lifestyle sugges-
tions such as to reduce fat intake, to increase the intake of
fruit and vegetables and to maintain an adequate physical
activity level.
Since obesity is becoming more prevalent in the Italian
population, with an observed trend towards excessive
weight gain in our pregnant women, we aimed at assessing
the efficacy of a more structured and personalized nutri-
tional intervention in limiting the excessive gestational
weight gain. Our nutritional intervention was designed in
accordance with the RDA for the Italian population [17].
As such, the mean protein intake represented 16 % of
caloric intake, lipids accounted for 28 % (with saturated
fats representing 7 % of total), carbohydrates 56 % (solu-
ble CI 15 %), mean cholesterol intake was 153 mg and
fiber intake 29 g. Our diet plans were well balanced and
tailored according to patients’ preferences. Indeed, it is
likely that the high compliance to the diet regime observed
by women allocated to the intervention group may lie in
the fact that their nutritional habits were maintained.
The active role played by the dietician both in achieving
adherence to the dietary plan and successful target weight
gain during pregnancy in the intervention group appears
central. It has been demonstrated that achieving a GWG as
per guidelines has a beneficial impact on both pregnant
women and newborns’ well-being, by reducing the risks of
adverse outcomes including cesarean section, gestational
hypertension, gestational diabetes as well as small and
large for gestational age fetuses (birth weight \2,500 g or
birth weight C4,000 g) [5,6].
Limiting nutritional intervention during pregnancy to
simple general advices on diet and lifestyle in the form of
an information brochure did not prove to be as efficient, at
least in our population.
It may well be that other populations with different
social, cultural backgrounds and different dietary customs
might be compliant to a healthier diet and lifestyle during
pregnancy without the need for a structured, personalized
nutritional intervention, thus reducing costs, which
undoubtedly are the major limits of this approach.
However, whether the results of this study may be
extrapolated to other populations needs to be proven by
further studies.
In this study, we observed a positive correlation between
GWG and neonatal birth weight in both groups. This datum
is in accordance with those available in literature [6] and
highlights the contribution of fetal weight to the total
increase of maternal body weight. Women from the inter-
vention group showed a stronger positive correlation, and
this might be explained by the fact that GWG was better
controlled in comparison with the control group. Indeed,
being the positive correlation stronger, neonatal body
weight accounted for a greater part of maternal body
weight gain at term.
Both groups showed a high proportion of deliveries by
cesarean section. However, this is similar to that reported
in our geographic area. Indeed, in most cases the indication
for cesarean section was a previous cesarean section with
patients declining a trial of labor for vaginal birth.
The major drawbacks of this study are the non-ran-
domized design and the overweight at baseline of the
population studied. We decided not to attempt a random-
ized trial but to opt for a random allocation mainly because
we were not sure about the compliance of subjects allo-
cated to the intervention group. We feared that a significant
number of patients would dropout or migrate to the other
group. The results of this study might induce us to perform
a future randomized study to confirm these data and to
gather new ones. However, when comparing the two
groups, we did not observe significant differences in the
most important variables that might have been affected by
selection bias related to the non-randomized design of the
study. The only variable that was significantly different
between the two groups was maternal age, with patients
allocated to the control group being significantly younger
than those in the intervention group. We do not know how
any such differences might have impacted the outcome of
this study.
The other limit of this study may lie in the composition of
our population sample, where most patients were over-
weight. Indeed, pre-pregnancy BMI was higher than
24 kg/m
2
in both groups. This might have impacted the
study mainly because overweight patients tend to make
poor nutritional decisions. Therefore, patients allocated to
the intervention group might have shown a lower GWG in
comparison with the group of women allocated to the
control group, simply because they kept having bad nutri-
tional habits and high caloric intake. Essentially, the dif-
ference in GWG between the two groups may reflect more
the bad nutritional habits of the control group rather than the
positive effect of a personalized diet intervention in the
treated group. In our study, we did not record and analyze
the body mass composition either at baseline, at term or
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123

postpartum; to speculate the extent to which GWG was due
to water, rather than to fat retention in our groups is not
possible. However, studies seem to suggest that both water
and fat retention are positively related to GWG. Further-
more, post-partum weight and fat retention have been
shown to correlate with GWG and fat mass gain but not with
total body water.
In conclusion, this study strongly suggests that a per-
sonalized nutritional intervention in which the dietician
plays an active, supporting and counseling role alongside
the obstetric team may represent a useful approach in
limiting weight gain in a population of low-risk pregnant
women.
Such findings need to be confirmed in larger studies to
achieve external validation and generalization to other
populations.
Conflict of interest We declare that we have no conflict of interest.
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