MATERIALS AND METHODOLOGY

This study was carried out at the Clinica Versalles in Cali, Colombia, was approved by the Institutional Review Committee of Human Ethics at the Universidad del Valle via Act No. 009-017 and by the Ethics Committee of the Versalles Clinic, Act No. 36-Cal-5. All participants provided written informed consent before study enrollment and received no financial contribution for their participation.

RESULTS

DISCUSSION

The principal objective of this study was to correlate pregestational BMI and weight gain during pregnancy with epidemiological variables. The findings indicate that 44% of pregnant women started their pregnancy within a BMI within the normal range. However, although this was the prevalent classification (44%), more than half the pregnant women started their pregnancy in unhealthy nutritional states, whether underweight, overweight, or obese. Almost a third (30.3%) of the participants were overweight and 21% were obese. This data concurs with the majority of studies from western countries where the prevalence of obesity was found to be 30% in 2015 ⁴. When comparing our data with studies on European populations, similar prevalence levels of maternal overweight have been reported in Norway (20%), and in other European countries ^4,15,16. Although the percentages of overweight and obese pregnant women in this study are high, they are not comparable to those found in the United States, where 64% of women of reproductive age are overweight and 35% are classified as obese ⁴.

Being overweight or obese prior to pregnancy, as well as experiencing excessive weight gain during pregnancy, are negative factors associated with complications for both the pregnant woman and her offspring ^1,7,17. Excess weight makes women high-risk patients as these conditions are associated with complications in pregnancy such as gestational diabetes, hypertension, pre-eclampsia, instrumented birth, impaired fetal growth, among other complications ^18-20,19-23.

Our research showed that increased BMI in early pregnancy, classified as pre-pregnancy obesity, correlates positively with maternal age and the presence of gestational diabetes, data supported in the literature where it is reported that prevalence of obesity in pregnant women has occurred concurrently with an increase in gestational diabetes, associated with adverse metabolic adaptations in the mother. These include increased risks to compromise fetal and newborn survival and health [19]. These findings coincide with research conducted in Argentina over four years ²⁴, in which it was determined that women starting pregnancy aged 30 or more (49.30%) and with a BMI equal to or greater than 27 kg/m² were a combined risk factor for developing gestational diabetes.

Arterial hypertension during pregnancy is a serious public health problem and is the main cause of maternal and fetal morbimortality in many world countries. In our study, we found that an increased final BMI also correlated positively with the risk of hypertensive disorder in pregnancy. It is known that most cases of hypertension during pregnancy occur in healthy women, therefore, it is important to establish the epidemiological characteristics that can influence the development of this pathology. However, several studies indicate a relationship between hypertension in pregnancy and increased body mass index, explained by several mechanisms: insulin resistance and hyperinsulinemia, increased adrenergic activity and aldosterone concentrations, sodium retention, water and alteration. of endothelial function, through molecules such as leptin and adiponectin and genetic factors ²⁵.

Several studies report that this disorder is associated with increased maternal BMI, such as those conducted in the Netherlands, Norway and Spain. Gaillard et al (2013) ²⁶ conducted a prospective study in the Netherlands with 6,959 patients and found maternal obesity to be associated with an increased risk of gestational hyper-tension (OR 6.31 (95% CI 4.30, 9.26)) and gestational diabetes (OR 6.28 (95% CI 3.01, 13.06)). In addition, they reported an increase in maternal complications when excess weight was acquired during the first trimester of pregnancy ²⁴. In Norway, similar findings were published by Huagen et al (2014) ¹⁵ in a prospective study involving 56,101 pregnant women. A Spanish study following 500 pregnant women, found that those who gained weight above recommended levels had gestational hypertension (3.4%) and gestational diabetes (1.4%) as the most frequent pathologies. ^18-20.

Intrauterine growth restriction (IUGR) is one of the reported complications associated with unhealthy maternal weight. In this study, a low initial BMI correlated positively with an IUGR diagnosis, a condition reported in the literature as occurring when there is a structural and functional deficiency of the placenta that can be caused by inadequate placental angiogenesis associated with a deficiency in essential fatty acids required for fetoplacental growth and development ^27,28. Essential fatty acids are known to be fundamental and involved in every stage of pregnancy by supporting cell growth and development, cell signaling, and modulation of other critical aspects of structural and functional processes ²⁷. On the contrary, in a study carried out in Romania in 2012, a higher incidence of IUGR was observed in patients with obesity ²⁸. Therefore, it is possible to suggest that an unfavorable uterine environment generated by an initial high or low BMI is associated with IUGR, a pathology considered an important cause of fetal, perinatal and neonatal morbidity and mortality ^29-31.

Numerous experimental and epidemiological studies have demonstrated that nutritional changes in the maternal pregestational and gestational stages have a significant impact on maternal and fetal health, and child development. Globalization has led to cultural changes in food consumption by flooding the world market with high-calorie products, including those high in fructose and cheap, refined fats which lead to an increase in the consumption of carbohydrates consumed compared to more traditional diets ^2,14. The impact that these processed products have on the population is difficult to quantify. However, their contribution to the increase in overweight and obese people is evident. Factors such as education, income level, physical activity, smoking, and alcohol consumption, however, are also related to the percentage of calorie intake from different macronutrients ¹⁴. In this study, a high final BMI was linked to low socioeconomic status, findings that concur with research by Ohlsson and Manjer ¹⁴ indicating that sociodemographic factors and lifestyle habits affect body weight and body composition. Furthermore, as reported by Manrique (2017) ¹⁸, the inverse relationship between socioeconomic status and obesity in women could be mediated by the fact that women in developed societies have developed dieting habits, perform more physical activity and can adopt a healthy diet, which typically involves a greater economic investment, conditions that are not so common in those from lower socioeconomic backgrounds ¹⁸. This data also coincides with research carried out in the Nether-lands, in which a lower family income was associated with a higher risk of maternal obesity (p<0.05) ²⁶. These are some ways in which sociodemographic factors can be predictors of gestational weight gain. There is a complex interaction between biological, psychological and social contextual factors that influence the amount of weight a woman gains in pregnancy ³², as indicated in research by McLaren ³³, in a review of 333 studies. This review found a close relationship between obesity and economic and sociocultural factors, revealing a greater prevalence of this condition in women from developing countries.

Although the implications on fetal and neonatal health were not examined in this study, the literature highlights the consequences of obesity and how these extend beyond the women themselves, impacting their offspring ^1,7,17. Newborns of mothers obese during pregnancy are more likely to have greater complications in the perinatal period ¹⁸. At the same time, an obesogenic environment during the preconception and gestational periods will increase the child's risk of developing obesity over the long term ¹⁸. Similarly, children of obese women have a higher incidence of congenital defects of the central nervous system, larger blood vessels, abdominal wall and intestine, defects that may be caused by an insufficient absorption or insufficient distribution of essential nutrients such as folic acid, or an effect of the incipient hyperglycemia caused by insulin resistance at the time of organogenesis ¹⁸. Although this study did not find a positive correlation between pregestational or gestational obesity with malformations in the fetus, it found that 2% of fetuses presented one of the following diagnoses; right kidney dilation, small femur, nasal hypoplasia, malformed feet, a narrowed pulmonary artery or an intracardiac focus on the left ventricle. In relation to these findings, there are studies that indicate that excess maternal body weight before pregnancy increases the absolute risk of many ultrasound-detected, adverse outcomes in the fetus ³⁴. Furthermore, maternal factors such as diet, obesity and endocrine dysfunction can modulate the expression and activity of placental fatty acid distribution and, therefore, affect fetoplacental growth and development ²⁷.

Finally, the participants were asked if they were concerned about physical changes or weight gain during pregnancy. A positive association was found between the participants with an affirmative answer and an increased BMI both at the beginning and at the end of their pregnancy. Participants expressing this concern were expected to be become more cautious in their food consumption and this would be reflected in a final BMI within the recommended range. However, this was not the case. As Rodríguez-Guzmán et al³⁵ explain, although BMI is an objective indicator of weight, body image scales are subjective. These researchers in their study on self-perception of body image and its correlation with BMI, found that overweight or obese women frequently perceive themselves as being of normal weight. A similar study carried out in Argentina in 2015 ³⁶, reported that 15% of young women in pregnancy underestimated their body image size, where the majority were overweight and obese. Our work also found a significant association between concern about body weight and advanced maternal age. A study by Borelli et al, also found a significant association between these two factors (x2 = 12.639; gl=4; p=0.013) ³⁶. With regard to the self-perception of body image and weight gain, it can be concluded that, although these variables may be a concern during pregnancy, overweight or obese women tend to have a distorted perception of their body size in relation to reality.

Excessive weight gain before and during pregnancy is a predictive factor in the appearance of gestational diabetes and hypertensive disorders, both of which differentially affect women from low socioeconomic backgrounds. While pregnancy is a critical period in a woman's life and can be the motivation to make positive lifestyle changes, excess weight is not yet perceived as a significant health problem. These results and those of previous studies conducted on this subject worldwide highlight the impact of maternal obesity beyond the intrauterine and newborn phase of life to the increased risks of generating long-term health complications into adult life. In addition, there is a strong associated sociocultural component in that, via an overweight mother, an overweight family is likely born through transmission of behaviors and eating habits ♣