Excessive weight gain during pregnancy predisposes women to higher postpartum weight retention and possibly to long-term overweight and associated health problems. Little has been published on gestational weight gain among Finnish women. Studies from other countries have reported that some of the women gain weight excessively during pregnancy and retain substantial amounts of weight after pregnancy, which may partly be due to unhealthy diet and low level of physical activity. Few studies have aimed at preventing excessive pregnancy-related weight gain by counselling women on diet and physical activity during or after pregnancy. The aim of this dissertation was to study trends in mean gestational weight gain in Finland since the 1960s and to evaluate the feasibility and the effects of implementing a lifestyle intervention designed to prevent excessive pregnancy-related weight gain in a primary health care setting.
Data on three population based samples of pregnant women were used to study trends in gestational weight gain. The women were pregnant in Helsinki 1954-1963 (n=2,262) or in the city of Tampere 1985-1986 (n=1,771) or 2000-2001 (n=371). The intervention study was a controlled trial conducted in three intervention and three control maternity and child health clinics in Tampere and in the town of Hämeenlinna. The participants were pregnant women with no earlier deliveries (n=132) and postpartum primiparas (n=92). The intervention consisted of individual counselling on diet and physical activity at five routine visits to a public health nurse (PHN) and an option for supervised group exercise once a week until 37 weeks’ gestation or 10 months postpartum. In the control clinics, the PHNs continued their usual dietary and physical activity counselling practices.
Pregnancy data were obtained from maternity cards. Pre-pregnancy weight was self-reported, but the other weight data were based on measurements. In the intervention study, information on diet and physical activity was collected by questionnaire and the pregnant participants also kept food records. The components of the feasibility evaluation of the study protocol of the intervention study were 1) recruitment and participation, 2) completion of data collection, 3) realization of the intervention and 4) PHNs’ experiences.
The comparison of the three samples of pregnant women showed that the mean gestational weight gain, adjusted for age, prepregnancy body mass index (BMI) and parity, increased from 13.2 (95% confidence interval (CI) 13.0-13.4) kg in the 1960s to 14.3 (95% CI 14.1-14.5) kg in the mid-1980s (p<0.05). The increase was observed in all age, BMI and parity groups. Since the mid-1980s, the mean gestational weight gain has remained at the same level. Implementation of the study protocol of the intervention study was mostly feasible. 1) The average participation rate of eligible women was high (77%) and the drop-out rate low (15%). The recruitment period was prolonged from the three months initially planned to six months. 2) Altogether, 99% of data on weight development, diet and leisure time physical activity (LTPA) and 96% of the blood samples were obtained. 3) In the intervention clinics, 98% of the counselling sessions were carried out as intended and 87% of the participants regurlarly kept the weekly records for diet and LTPA. The mean participation percentage in the group exercise sessions was 45%. 4) The PHNs considered the extra training to be a major advantage for them and the additional workload to be a major disadvantage of the study.
Among the pregnant participants, the intervention group increased the intake of vegetables, fruit and berries by 0.8 (95% CI 0.3-1.4) portions/d (p=0.004) on average and maintained the proportion of high-fibre bread of the total amount of bread (a difference of 11.8 (95% CI 0.6-23.1) %-units between the groups, p=0.04) compared to the control group when adjusted for confounders. No significant effects were observed regarding the intake of high-sugar snacks, total LTPA or proportion of participants exceeding the recommendations for gestational weight gain. However, there were no high birth weight (≥4000 g) infants in the intervention group, but eight (15%) of them in the control group (p=0.006). Among the postpartum participants, the intervention group increased the proportion of high-fibre bread of the total amount of bread (a difference of 16.1 (95% CI 4.3-27.9) %-units between the groups, p=0.008) and returned to their pre-pregnancy weight by 10 months postpartum mor! e often than the control group (odds ratio 3.89 (95% CI 1.16-13.04, p=0.028)), when adjusted for confounders. On the other hand, the intervention had no effect on the intake of vegetables, fruit and berries or high-sugar snacks or on the total LTPA.
In conclusion, the mean gestational weight gain has increased after the 1960s, which may increase the risk of pregnant women for postpartum weight retention and subsequent overweight. These data warrant intensified health promotion actions to prevent excessive weight gain during and immediately after pregnancy. The study protocol designed to prevent excessive pregnancy-related weight gain was mostly feasible to implement in a primary health care setting. As some beneficial effects of the intervention were also observed, the results of this study encourage conducting larger trials in comparable settings.
