Background
Over the last decades, the global prevalence of obesity has increased considerably [
1]. A rise in the prevalence of obesity has also been observed in Germany where more than 23 % of both adult men and women are obese [
2]. Especially among young adults aged 25–34 years, including women of reproductive age, an alarming rise in the prevalence of obesity has been reported [
3]. Hence, this trend is relevant in the area of pregnancy and childbirth. Maternal overweight and obesity have become a major health problem bearing risks for both mothers and children [
4‐
9].
In addition to obesity, excessive gestational weight gain (GWG) has been identified as a risk factor for pregnancy complications [
10‐
16]. Additionally, the amount of weight gain during pregnancy may have a strong impact on maternal weight retention [
17‐
20] and seems to be a predictive factor for the long-term development of obesity in the mother [
18,
21‐
23]. Excessive GWG can also affect foetal growth and is associated with an increased proportion of large for gestational age (LGA) newborns [
16,
24‐
26]. In addition, excessive gestational weight gain was reported to be associated with childhood obesity [
27‐
35] and obesity in later stages of life [
36‐
40].
Lifestyle intervention during pregnancy seems to be a promising strategy to prevent excessive GWG [
41‐
45]. We have previously reported the first results of a lifestyle intervention in pregnancy to reduce the rate of excessive gestational weight gain (FeLIPO trial) [
46]. The lifestyle intervention resulted in a lower proportion of women exceeding the recommendations of the Institute of Medicine (IOM) for GWG (38 % vs. 60 %,
p < 0.05), and participants in the intervention group gained significantly less weight than those in the control group (14.1 vs. 15.6 kg,
p < 0.05). Furthermore, the results suggested that weight retention was higher in the control group than in the intervention group at month four postpartum (pp) (3.3 vs. 2.1 kg,
p = 0.09). There was no evidence of a difference in birth weight between the two groups.
The aim of the present study was to analyse the follow-up results of the FeLIPO trial regarding weight development of mothers and infants at 12 months pp. The main hypothesis was that a lifestyle intervention successfully limiting excessive GWG may also beneficially influence pp maternal and early childhood weight development. Next to the impact of lifestyle intervention during pregnancy on these parameters, associations with GWG were investigated. In addition, the potential association between dietary intake and physical activity during pregnancy with pp maternal and infant weight outcomes was studied.
Discussion
We investigated mothers’ and infants’ 12-month pp follow-up weight data after lifestyle intervention during pregnancy. The intervention had resulted in reduced mean GWG in pregnant women. 12 months after delivery, the amount of weight retained did not significantly differ between the former intervention and control groups. A tendency towards lower mean weight retention among women who had received the intervention was nevertheless visible. The proportion of women with relevant weight retention (>5 kg) 12 months pp was by trend higher in the group not receiving lifestyle intervention during pregnancy. At 6 months pp, a tendency towards lower weight retention was also found in other intervention studies [
43,
52,
53]. Longer-term pp weight data (>6 months) after lifestyle intervention in pregnancy is scarce and controversial. Behavioural intervention was found to be associated with reduced weight retention 12 months pp in an American study [
54]. In obese women, a difference in weight change between early pregnancy and 12 months after childbirth due to a lifestyle intervention was indicated by Claesson et al. [
52]. By contrast, weight retention was reduced by antenatal lifestyle intervention only in the subgroup of low-income overweight women in a study of Olson et al. [
55], and Althuizen et al. [
56] could not find any effect on weight retention. As evidence for long-term effects of lifestyle interventions on pp weight development of women is limited, further research in large intervention studies with adequate follow-up duration is required.
An association between GWG and pp weight retention is well established from cohort studies. For the whole cohort of the present study, higher weight gain during pregnancy was associated with increased weight retention 12 months pp (0.4 kg weight retention per 1 kg increase in GWG). High GWG has been linked to increased short-term weight retention in several observational studies [
20,
57‐
59]. Nehring et al. [
18] concluded in a meta-analysis that GWG is also associated with long-term weight retention, being in line with the results of a recently published large prospective cohort study [
60]. However, GWG is not the only factor influencing weight retention after gestation. Other factors discussed in this context are breastfeeding [
22,
61], the women’s educational level [
61], parity [
62], diet [
63] and physical activity [
22,
63]. In conclusion, the extent of GWG seems to be not the only but an important influencing factor for long-term pp weight retention. Having an effect on weight retention after pregnancy, high GWG has also been linked to women’s long-term BMI development and obesity risk [
17,
21‐
23,
61,
64‐
67]. Lifestyle counselling has the potential to favour adequate GWG and could by this means also be of help in the prevention of long-term development of overweight and obesity in women.
In the present study, counselling lessons were given only during pregnancy. Prolonging the intervention to the pp period may reinforce the reducing effect on maternal weight retention. However, Wilkinson
et al. [
68] recently found no impact of a pp intervention programme on pp body weight, whereas Huang
et al. [
53] showed that starting intervention during pregnancy and continuing it pp can lead to reduced weight retention. Additional counselling lessons after childbirth subsequent to lifestyle intervention during pregnancy may thus be beneficial, but need to be evaluated in more clinical studies.
Weight data of children were collected for U2 (3
rd to 10
th day pp) to U6 (10
th to 12
th month pp). At U6, infants born to mothers in the intervention group tended to weigh less than control group infants. This may partly be explained by a beneficial effect of lifestyle counselling during pregnancy on the offspring’s weight development. Next to intrauterine mechanisms during gestation potentially related to a healthier lifestyle of women in the intervention group, other triggers could be responsible for this observation. For example, breastfeeding and its duration [
69‐
73] seems to be of relevance for the weight development of children. Lifestyle counselling was not continued after delivery and topics such as nutrition of the infant were not covered in the lessons. It can nevertheless not be completely ruled out that women encouraged towards a healthy lifestyle during pregnancy developed increased consciousness to healthy feeding their children. Following adjustment for breastfeeding, the estimated weight difference between the groups was reduced. Although mothers in the intervention group tended to breastfeed their offspring a bit longer, no statistically significant group difference could be found.
Independently of the allocation to the intervention or control group, there was some evidence for an association between higher GWG and increased infant body weight at the age of 10–12 months. An association between high GWG and increased weight of children has also been reported in observational studies [
74,
75]. This speaks in favour of intrauterine effects during pregnancy on later weight development of children. Nevertheless, the genetic background as well as the environment shared by mother and infant are factors that should not be neglected in this context [
76,
77]. Breastfeeding, for example, seems to mitigate the association between GWG and childhood anthropometrics [
73]. As implied by the slight weight difference only visible at the 12 months measurement point in this study, differences in body weight may arise delayed in time. As also proposed by others [
78], follow-up of children after lifestyle intervention in pregnancy is essential for the clarification of in utero effects during gestation on later overweight or obesity. Intervention studies targeting GWG with adequate follow-up periods are thus urgently required.
As published previously [
46], lifestyle counselling during pregnancy could be shown to have an impact on the caloric intake of the pregnant women. In the context of this follow-up analysis, energy and macronutrient intake during pregnancy was analysed with respect to maternal weight retention (12 months pp) and weight development of their children. However, no association with weight retention or infant body weight at the age of 12 months could be found. It seems to be difficult to establish a relation between nutrient intake in pregnancy and maternal weight retention or weight development of their children. However, this may be also due to the fact that the pp situation is too complex as there are many factors which could influence this association. Potential associations between the intake of single nutrients and outcome parameters may be too weak to be clearly identifiable. Analysing dietary patterns instead of single nutrients could be a more promising approach in the identification of potential associations with the mentioned weight parameters.
A limitation of this study is the difference in baseline characteristics, e.g. pre-pregnancy weight, between intervention and control group. Despite including these parameters as adjustment variables, an impact of these differences on the results cannot be excluded. Additionally, more women participated in practices allocated to the intervention group than in control practices, causing unequal group sizes. Another limitation is the missing verifiability of maternal weight data. While body weights of children were documented by pediatricians as part of the routine health care, maternal pre-pregnancy and 12 month pp weight data were self-reported. However, self-reported maternal weight data have been reported to provide valid estimates [
79] and are widely used in lifestyle intervention studies during pregnancy [
80]. Additional controlling for paternal anthropometrics might also have an influence on infant weight data. Physical activity and nutrition behaviour of women after birth as well as food intake of children was not studied, which may have added valuable additional information.
To confirm the outcomes of the present pilot study, we initiated another large lifestyle intervention study (GeliS, acronym for “Gesund leben in der Schwangerschaft”/healthy living in pregnancy) [
81]. This currently ongoing large-scale intervention study aims to recruit and follow-up 2500 pregnant women. With a study population tenfold as large as the one of the FeLIPO study spread over ten regions of Bavaria, we aim to overcome these limitations. An enhanced number of counselling sessions, reaching from early pregnancy to the pp period, will intensify the lifestyle intervention. In order to investigate long-term effects on weight trajectories of children, an extended follow-up period up to the age of 5 years including assessment of dietary behaviour of children is planned.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
HH and KR contributed to the design of the study. KR and JK conducted the research (enrollment of participants, lifestyle counselling, data collection, trial management). LS analysed the data and gave further statistical advice. JG, LS, JK, KR and HH wrote the manuscript. All authors read and approved the final manuscript.