Introduction
Nutritional status of women has been given due importance in the health of mother and foetus. Women who conceive in the under -weight (UW) category have been noted to have earlier births and babies were of low birth weight, whereas gestational diabetes mellitus (GDM), gestational hypertension (GHTN), and preeclampsia were more frequent in the overweight/obese category of mothers.1, 2
Pre-pregnancy BMI is known to have an impact on infant weight at birth. Weight gain during pregnancy also is said to have a role in determining the pregnancy outcome. 3 Gaining desirable gestational weight has been known to be effective in supporting the foetal growth and development. Excessive GWG has been associated with a higher fat mass in childhood and continued add- on of fat reserves.
WHO in 20044 and Institute of medicine (IOM) revised the gestational weight gain guidelines in 2009. Four categories of BMI in kg/m2 categories such as underweight (< 18.5), normal (18.5 - 22.9), overweight (23 - 24.9) and obese (> 25)5 were categorised. The recommended weight gain (kg) in the underweight is 12.5 - 18 kg, 11.5 - 16 kg in average /normal, 7 - 11.5 kg in overweight category. 5 - 9 kg is the expected weight gain in obese BMI group.6
Materials and Methods
This descriptive study was conducted at the Department of Obstetrics and Gynaecology, KMCT Medical College Hospital over a period of 6 months from September 1, 2021 to March 31, 2022. Three hundred pregnant women attending the hospital, either in antenatal clinic or ward, at or beyond 12 weeks with documented pre-pregnancy body weight were the participants. There were four subjects who were lost to follow up. WHO in 2004 and Institute of medicine (IOM) revised the pregnancy weight gain guidelines in 2009 by including four categories of BMI in kg/m2 categories such as underweight (< 18.5), normal (18.5 - 22.9), overweight (23 - 24.9) and obese (> 25). Mothers with singleton pregnancies willing to participate and had fetus presenting by vertex were selected for this research.
The ethics committee approval was given by the following institutions, KMCT Medical College, and conducted according to the principles of the Helsinki Declaration. [KMCT/RP 2021/ IEC/39. Bodyweight was measured at the first visit and at subsequent check-ups and documented. Presence of maternal medical disorders were enquired and carefully surveilled for any growth disorders in the foetus. Need for operative delivery, new -born birth weight, gestational age at birth were asked. Days of stay in the NICU was taken as the predictor of foetal morbidity. Based on the gestational weight gain for their respective BMI, three categories, i.e. below recommended gestational weight gain (GWG), recommended GWG and above recommended GWG group were the headings under which 296 mothers could be placed.
GWG recommendations according to IOM 2009 guideline were used on BMI recommendation for Asian population, as described in (Table 3). Statistical evaluation performed with standard statistical methods.
Results
The recommended weight gain (kg) -- underweight (12.5 - 18 kg), normal (11.5 - 16 kg), overweight (7 - 11.5 kg), and obese (5 - 9 kg) were in these four categories.6 (Table 1)
Table 1
Pre-pregnancy weight (Mean-SD): 55.2 (0.7)
Weight at delivery (Mean-SD): 63.8 (0.8)
BMI (Mean-SD): 23.0 (0.3)
Pregnancy weight gain (Mean-SD): 8.6 (0.2)
Proportions of below, recommended, or excessive gestational weight gain cases according to maternal pre-pregnancy {GWG and BMI category.
Table 2
Pre-pregnancy BMI and gestational weight gain
82.8% under- weight women gained less than recommended weight, 15.5% gained recommended weight and only 1.7% gained above recommended weight in BMI <18.5.
84% normal weight women gained less than recommended weight, 14.2% gained recommended weight and only 1.9% gained above recommended weight.
46.9% women in obese group gained above recommended weight and 11.8% women in overweight group gained above recommended weight. (Table 2), implying that majority of obese mothers put on more that that was expected in that category.
Table 3
BMI and Morbidities
Pre-pregnancy BMI and GDM: A statistically significant higher odds of 3.03 of developing GDM was computed with per unit increase in pre-pregnancy BMI.
Pre-pregnancy BMI and Anaemia: A statistically significant difference was not noted in pre-pregnancy BMI between anaemic and non-anaemic groups of women.
Gestational weight gain and Anaemia: A statistically significant difference was not noted in Gestational weight gain between anaemic and non-anaemic groups of women.
Pre-pregnancy BMI and HTN: A statistically significant higher odds of 1.116 of developing Hypertensive disorders of pregnancy was computed with per unit increase in pre-pregnancy BMI.
Gestational weight gain and HTN: A statistically significant difference was not noted in gestational weight gain between hypertensive and non-hypertensive groups of women.
Pre-pregnancy BMI and LSCS outcomes: A statistically significant difference was not noted in pre-pregnancy BMI between LSCS and non- LSCS outcomes.
Gestational weight gain and LSCS outcome: A statistically significant difference was not noted in gestational weight gain between LSCS and non- LSCS outcomes.
Pre-pregnancy BMI and IUGR: A statistically significant difference was not noted in pre-pregnancy BMI between IUGR and non-IUGR outcomes of pregnancy.(Figure 1)
Figure 1
Correlation between pre-pregnancy BMI and Birth weight of Baby
Pearson correlation: r = + 0.209, p<0.001
Interpretation: A statistically significant positive correlation was obtained between pre-pregnancy BMI and baby weight.(Figure 2)
Figure 2
Correlation between Gestational weight gain and Birthweight of baby (95% CI)
Pearson correlation: r = + 0.163, p=0.005
Interpretation: A statistically significant positive correlation was obtained between gestational weight gain and baby weight.(Figure 2 )
Table 4
Adverse outcome based on pre-pregnancy BMI
Discussion
In the present study, underweight BMI mothers achieved less than recommended weight during pregnancy [82.8%] as compared to obese women [18.4%]. Mothers who weighed on the higher side [46.9%] had excess weight gain in their gestation in comparison to women with BMI<16 [1.7%] and those with normal BMI [1.9%] in this analysis as well as that observed in Heerman et al.7 Singh K et al8 Mishra KG et al5 also supported these observations.
Li et al.9 opined that overweight and obese women who gained extra kilograms than required in the present pregnancy had 16 to 22 fold risk of gestational diabetes than those with normal weight gain. Singh et al10 had shown similar results. A statistically significant higher odds of 3.03 in development of GDM was computed with per unit increase in pre-pregnancy BMI in the present study as well as that in Najafi et al. [2018] where 4% increased risk of GDM with per unit increase in BMI was noted.11
A large multicentric prospective study in women during pregnancy made it clear that women who belonged to the obese category were 2.5 times and 1.6 times more likely to develop gestational hypertension and preeclampsia, respectively.12 Rahman et al. conducted a meta-analysis in which overweight and obese mothers were at higher odds of developing pre-eclampsia13 as in the present research. As every unit is added to pre-pregnancy BMI, total body fat content multiplies resulting in metabolic morbidities such as gestational diabetes mellitus and hypertensive disorders in pregnancy14, 15, 16 which bring a negative impact to the quality of life.
Rate of LSCS and operative vaginal delivery was compared between the groups as in Singh K et al. and Rosemarie Farquharson et al.17
Pre-pregnancy BMI was not a predictor of caesarean according to this study as well as in Edwards et al18 and Graham et al.19 Seligman and Bhavadharini noted that greater weight gain among obese women during pregnancy was particularly associated with higher risk of caesarean delivery in contrast to the present study.20, 21
Underweight women are known to deliver preterm infants. In addition, underweight women gaining less weight than recommended can have higher risk of delivering low birth weight infants as in Patel K et al which is in contrast to that in our study.22 A statistically significant positive correlation was obtained between pre-pregnancy BMI and baby weight in the present study as in Gul R et al.23
Conclusions
Gestational weight gain had no impact on maternal pregnancy outcomes and caesarean delivery.
Author Contribution
Dr. Heera Shenoy T has prepared the conceptual framework, designed the draft and collected the data. Dr. Remash K and Naseemabeevi A has done manuscript writing and final editing. Dr. Nirupama AY has done the statistical analysis.
