Gestational weight gain and adverse pregnancy outcomes among pregnant women attending primary health centres in Puducherry: Results from the JANMAM pregnancy cohort

Methods

This study was undertaken by the department of Preventive and Social Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India. Approval from the scientific and ethics committee was obtained prior to initiating the study. After explaining the study's purpose, written informed consent was obtained in their local language (Tamil) (Supplementary Material 1).

Results

Out of 600 pregnant women approached, 465 women with singleton pregnancies in their first trimester were included in the study and 408 were included in the final analysis ( Figure). The socio-demographic and obstetric profiles of the study participants, categorised by GWG, are shown in Table I.

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Figure Flow diagram of the selection process of pregnant women attending primary health centres in Puducherry.

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In our study, 48.5% (95% CI: 43.6–53.5; n=198) of pregnant women had inadequate GWG, 32.4% (95% CI: 27.8–37.1; n=132) had adequate GWG, and 19.1% (95% CI: 15.4–23.3; n=78) had excessive GWG. The mean and median GWG in categories of pre-pregnancy BMI is shown in Table II, along with a comparison with IOM guidelines. Anthropometry, body composition, physical activity, and dietary characteristics of study participants are shown in Table III.

A multivariable linear regression analysis was undertaken to determine the factors associated with mean GWG at delivery. Women from joint families gained significantly more weight, with a mean (95% CI) increase of 1.08 (0.09, 2.07) kg compared to those from nuclear families (P=0.03). Nulliparous women gained 1.89 (0.97, 2.8) kg more GWG than multiparous women (P<0.001). Women in socioeconomic classes I and II gained 1.22 (0.06, 2.39) kg more, and those in class III gained 1.57 (0.40, 2.75) kg more GWG compared to those in the lowest-income groups, with these associations being statistically significant (P<0.001). Compared to underweight women, women with a normal pre-pregnancy weight gained significantly 1.70 kg (3.12, 0.27) less (P=0.01), while overweight or obese women gained 2.40 (3.87, 0.94) kg less GWG (P<0.001).

In terms of pregnancy complications, 17.9% (n=69) of the participants were diagnosed with gestational diabetes mellitus, while 5.7% (n=22) presented with gestational hypertension. Maternal adverse outcomes included caesarean delivery in 39.9% (n=154), labour induction in 8.8% (n=34), and preterm delivery at <37 weeks in 11.1% (n=43) of the study participants. One stillbirth was reported. Regarding neonatal outcomes, hyperbilirubinemia was reported in 7.3% (n=28) of neonates, and 11.9% (n=46) required admission to the neonatal intensive care unit (NICU). Nearly 27.2% (n=105) of neonates were classified as SGA, and 5.4% (n=21) as LGA, according to the INTERGROWTH-21st standards. Of the total newborns, 44.3% (n=171) were female. The mean (SD) birth weight was 2.9 (0.5) kg, with 24.4% (n=94) of newborns weighing less than 2.5 kg (Supplementary Fig. 1).

The risks of adverse pregnancy outcomes for GWG are presented in Supplementary Figure 2. Although variations in GWG were observed, neither inadequate nor excessive GWG showed a statistically significant association with pregnancy outcomes relative to adequate GWG. Although the proportions of caesarean deliveries, GDM, and NICU admissions were higher among women with inadequate GWG (34.7%, 18.7%, and 10.4%, respectively) and excessive GWG (45.3%, 14.5%, and 16.0%, respectively) compared to those with adequate GWG, these differences were not statistically significant (P>0.05). (Supplementary Tables I and II).

Discussion

In our study, conducted among 465 pregnant women from southern India, the mean GWG was 10.1 kg, which was lower than the 11.6 kg reported in the REVAMP cohort. ¹⁸ REVAMP participants were predominantly upper class, urban residents with higher education, whereas our cohort mainly comprised middle and upper-middle class women. ¹⁸ The median weight gain in our study participants (9.9 kg) was higher compared to those in the GARBH-Ini cohort (7.86 kg at 36 weeks) from northern India. ¹⁹ Geographical dietary differences between northern and southern India likely contributed to this variation in weight gain. The Intergrowth-21st study, conducted in eight countries including India, China, and Oman, reported a median GWG of 13.7 kg among normal-weight women, ⁶ which is higher than the 10.0 kg observed in normal-weight women in our study. This difference may be due to the fact that the Intergrowth study specifically recruited healthy, well-nourished women with optimal population health status to determine recommendations for ideal weight gain. The proportion of inadequate GWG in our study was lower compared to the 52.5% reported by Bhavadharini et al ¹⁰ among 2,728 pregnant women from Chennai, South India. However, Radhakrishnan et al ²⁰ reported that 37.4% of pregnant women had inadequate GWG, which is lower than the proportion observed in our study. This difference might be attributed to variations in the study populations, including differences in socioeconomic status, access to prenatal care, and measurement methods used for assessing weight and gestational age. The proportion of excessive GWG in our study was consistent with findings from previous studies. A systematic review among Indian women reported a pooled proportion of excessive GWG as 16.5%. ²¹ Similarly, a study conducted by Radhakrishnan et al ²⁰ in southern India reported an excessive GWG of 21.4%. ²⁰ A retrospective study from Chennai, South India among 2,728 pregnant women found that 17.3% had excessive GWG. ¹⁰ Women from joint families showed significantly higher GWG, which may reflect better household support, shared responsibilities, and improved dietary intake. In contrast, women from lower SES often experience poor diet quality, psychosocial stress, and limited access to quality antenatal care, which may contribute to imbalanced GWG. Nulliparous women gained 1.89 kg more GWG than multiparous women, which was consistent with the REVAMP cohort. ¹⁸ Women in their first pregnancy may tend to consume more calories and engage in less physical activity out of caution. Normal and overweight/obese women had lower GWG than underweight women, which aligns with other studies from India. ^18,19 Underweight women are often advised to gain more weight during pregnancy. Additionally, due to their lower fat and nutrient reserves, the body prioritises weight gain to support fetal growth and maternal energy needs.

In our study, 17.9% of the participants developed GDM. A systematic review and meta-analysis of 117 Indian studies reported a pooled GDM prevalence of 13%, ranging from 9 to 16%, with higher rates observed in southern India. ²² Gestational hypertension was observed in 5.7% of the women, aligning with findings from other Indian studies. ^23,24 Around half of the women (51.5%) developed at least one pregnancy complication. Rates of caesarean delivery (39.9%) and preterm birth (11.1%) in our study were comparable to the national prevalence reported in NFHS-5 (36.3% and 12%, respectively). ^12,25 Premature rupture of membrane occurred in 4.7% of women in our study, compared to a prevalence of 1.5% in the Intergrowth-21st study, likely due to the inclusion of healthy women with normal weight in their cohort. ²⁵ The most commonly observed neonatal outcomes were SGA (27.2%) and LBW (24.4%). A study in eastern India found a 34.3% prevalence of SGA among 1451 live singleton newborns, using the National Institute of Child Health and Human Development Fetal Growth Studies' Asian population chart, ²⁶ whereas we used the INTERGROWTH-21st standard to classify newborns as SGA. Secondary analysis of the NFHS-5 data shows a slightly lower proportion of LBW in India (18%). ²⁵ The discrepancy could be attributed to methodological differences.

One of the main strengths of this study is its prospective cohort design. Key variables, such as serial maternal weights, were measured by trained staff at every antenatal visit, thereby minimising recall and misclassification bias often encountered in retrospective studies. Additionally, the inclusion of participants from both urban and rural primary health centres enhanced the generalisability of the findings. However, women seeking antenatal care exclusively from private healthcare institutions were not part of the study. This exclusion may limit the generalisability of findings and potentially underestimate complication rates typically observed in higher-risk or less-monitored populations. Early pregnancy weight (<14 weeks' gestation) was used as a surrogate for preconception weight, as preconception care is not a customary practice in the Indian setting. Dietary and physical activity data were collected only at baseline, and possible changes during gestation were not assessed.

In our cohort, nearly half of the pregnant women experienced inadequate GWG, and only one-third achieved adequate GWG as per IOM guidelines. The study identified family type, socioeconomic status, parity, and pre-pregnancy BMI as significant predictors of GWG. Our findings highlight the need for continued monitoring of GWG patterns during pregnancy and underscore the importance of identifying sociodemographic and anthropometric factors that influence weight gain. Further research with larger samples or longitudinal follow-up is needed to better understand the implications of GWG patterns on maternal and neonatal health within this population.