Maternal age influence in human colostrum fat composition

Introduction: Colostrum is the first milk secretion produced and contains the nutrients necessary for the development of the neonate. Objectives: To compare the chemical level of colostrum fats from adolescent nursing mothers and those of advanced maternal age and to describe their gestational characteristics. Methods : A prospective cross-sectional study, including 98 nursing adolescent mothers (up to 24 years of age) and 33 nursing mothers of advanced maternal age (over 35) attending the Maternity Hospital of Presidente Prudente. Colostrum samples were obtained through manual extraction between 48 and 72 hours postpartum. The determination of fats and calories was performed by means of the Creamatocrit technique. Statistical analysis was performed using the Student's t-test or Mann-Whitney test. Results : The mean age of the nursing mothers of advanced maternal age was 37 years, statistically higher than that of the adolescent mothers with a mean age of 20 years. In total, 66.3% of the adolescent nursing mothers were primiparous and 66.7% of the mothers of advanced maternal age underwent a cesarean delivery. Gestational BMI was statistically higher in the women of advanced maternal age (31.3±5.6 vs 26.06±3.6). Although the colostrum fat and cream composition was significantly higher in nursing mothers of advanced maternal age, the number of calories was similar between the groups. Conclusion: Advanced maternal age influenced gestational BMI and the biochemical composition of colostrum and its components.


Introduction
Gestation is the result of a complex network of events, regulated by a variety of mechanisms and mediators of the endocrine, nervous, and immune systems. Three distinct and interdependent processes characterize the moment when gestation ends: cervical remodeling, myometrial contractility, and weakening and rupture of the fetal membranes, which, together, enable the expulsion of the fetus after the 37th week of gestation, characterizing a term gestation 1-3 . The gestational period is a physiological phenomenon which, in most cases, develops without complications 4 . However, despite the numerous studies and existing technology, the pathophysiology of gestation has not yet been fully elucidated, 5,6 making it difficult to diagnose and recognize complications that may occur during this period. In this context, High Risk pregnancies are defined as "those in which the life or health of the mother and/or the fetus and/or the newborn are more likely to be affected than those of the average population considered" 4 . These clinical conditions are associated with unfavorable socio-demographic conditions, such as maternal age less than 15 years or greater than 35 years, low educational level, mental disorders, conflictive affective situations, undue or accidental exposure to toxic or teratogenic agents, smoking, alcoholism, and contact with illicit drugs 7 . Nowadays, incidences of pregnancy at the extremes of reproductive life, before the age of 20 years and after the age of 35, are a reality. Adolescent pregnancy is considered a substantial public health problem in some developing countries, with social and biological repercussions 8 Gestation during adolescence is highly relevant due to its increasing incidence and maternal repercussions, such as social isolation and discontinuation of studies. In addition, due to biological immaturity involving the growth and development of adolescents, the perinatal outcomes can be adverse, such as an increase in newborns with low birth weight (LBW, < 2500 g), risk of intrauterine growth restriction (IUGR), an Apgar score less than 7 in the fifth minute, and a high rate of preterm birth (< 37th gestational week) 9 .
Pregnancy after the age of 35 is considered as late and has become increasingly frequent due to improved birth control, advances in assisted reproductive technology, and late marriages, among others 10 . Pregnancy in mothers of advanced maternal age may lead to a higher risk of developing hypertension, preeclampsia, and diabetes, as well as being associated with fetal complications. The most frequent of these are chromosomal anomalies, fetal distress, neonatal death, low birth weight, and IUGR. 11 . Although these gestational and perinatal outcomes are well elucidated in the literature, no studies were found associating maternal age with the colostrum composition of these mothers.
The main strategy of the World Health Organization (WHO) to reduce unfavorable perinatal outcomes and infant mortality is the promotion of breastfeeding around the world 12 . Breastfeeding can be considered a traditional practice with recognized nutritional, immunological, cognitive, economic, and social benefits for the mother/newborn binomial 13 . Colostrum is the first milk secretion produced, secreted between the second and third day postpartum, and contains the nutrients necessary for the development of the neonate 14 . The main components of colostrum are fats, immunoglobulins, proteins, carbohydrates, vitamins, leukocytes, lymphocytes, cytokines, lactoperoxidase, lactoferrin, and lysozyme, in addition to hormone and peptide growth promoters 14,15 .
After birth the neonate requires a very high energy intake and to satisfy this energy need, colostrum has a fundamental component, which represents approximately 50% of the energy content of human In pregnancies affected by diabetes, the amount of fat in the colostrum of diabetic mothers is lower when compared to non-diabetic mothers 14 , and among obese pregnant women a higher concentration of fat in the colostrum was identified 20 .. Furthermore, some studies evaluated the concentration of fats in colostrum with the gestational age of the newborn, categorizing them into preterm (< 37th gestational week) and term (≥ 37th gestational week). The results found no relevant difference in colostrum fat composition; however the studies included mothers with an average age of 28 years 21, 22 . As no studies were found in the literature that relate maternal age during the period of pregnancy, adolescent mothers and those of advanced maternal age, with the colostrum fat composition of these women, investigating the composition of the milk of these mothers becomes extremely important, mainly to reinforce the incentive to breastfeed in these mothers in order to avoid premature weaning and to promote the quality of life of both mothers and their children and to stimulate the mother/newborn bond. This study aims to compare the chemical level of colostrum fats from adolescent nursing mothers and nursing mothers of advanced maternal age and to describe the gestational characteristics.

Materials And Methods
A cross-sectional study was conducted with adolescent mothers and those of advanced maternal age and their newborns who attended the maternity unit of the Regional Hospital of Presidente Prudente,

Subjects
Nursing mothers and their newborns were recruited using the following inclusion criteria: gestational age at birth between 37 and 41 weeks and negative serological reactions for hepatitis, human immunodeficiency virus (HIV) and syphilis. Twin pregnancies, fetal malformations or loss of data regarding delivery and the neonatal period were the exclusion and/or discontinuity criteria.
Subjects were divided in two groups of study: adolescent mothers (between 10 and 24 years old) 23 and advanced maternal age (over 35 years of age). Mothers aged between 25 and 34 years old were considered the control group.
The weight classification of the newborns was small for gestational age (SGA), appropriate for gestational age (AGA), and large for gestational age (LGA) (weight/gestational age ratio) according to the service protocol.

Colostrum collection
The colostrum was collected by manual expressing, always in the morning (from 8 to 10 am) and in the interval between two feedings, considering the period between 48 and 72 hours after delivery.
Half of the samples from each study group and the control group were collected at 48 h postpartum and half at 72 h postpartum in order to avoid variations in the fat concentrations over time. A maximum colostrum volume of 10 mL was collected into sterile plastic tubes, immediately transported to the laboratory and then frozen and stored at -80°C until analysis. postpartum.

Determination of fat concentration
After collection, the colostrum was submitted to fat determination using the Creamatocrit method as described by Lucas et al. (1978) 24 .
The colostrum samples were placed in capillary tubes in triplicate and centrifuged at 12,000g for 15 minutes. After centrifugation, the cream was separated from the whey. The length of the cream column and total product column [cream column + serum column, expressed in millimeters (mm)] were measured. To determine the fat content and the calorie concentration, after performing the cream column and total column measurements, the following formulas were used: 1. Fat content =% cream (mm) -0.59 / 1.46, where the % cream = cream column (mm) x 100/total column (mm); Kcal/L = (66.8% cream) + 290.

Statistical analysis
Data on the sociodemographic and gestational variables were submitted to the X² or Fisher's exact test, or to the Kruskal-Wallis non-parametric test for comparison between the two study groups, after analysis of data normality by the Kolmogorov-Smirnov test. The concentration of fat and calorie in colostrum was analyzed by the Kruskal-Wallis test, followed by the Mann-Whitney test test. Statistical analysis was performed using Graph Pad Prism software, version 6.0 (San Diego, CA), and the level of significance adopted for all tests was 5%.

Results
The sociodemographic and obstetric data are described in Tables 1 and 2. Fat and calorie dosages are presented in box plots in Figures 1, 2, and 3. Table 1 presents the demographic characteristics of the mothers in the extremes of reproductive age: adolescents and advanced maternal age. As expected, the median maternal age was statistically lower in the adolescents (p<0.0001) compared to nursing mothers of advanced maternal age. The predominant marital status was a stable relationship in the adolescent group with 66 cases and in mothers of advanced maternal age 30 women were single (p = 0.008). The smoking habit was highlighted in the advanced maternal age group (9 cases) compared to the group of adolescent mothers (7 cases) (p=0.0047).  Table 2 describes the gestational and obstetric characteristics of the adolescent nursing mothers and those of advanced maternal age included in the study. The body mass index at the beginning and end of gestation was statistically higher in the advanced maternal age group (p<0.0001). The parity variable presented a higher index of multiparous women in the advanced maternal age group and primigravidae in the group of adolescent mothers (p<0.0001). Regarding the type of delivery, there was a contrast between the groups, as in the advanced maternal age group, cesarean delivery predominated and in the adolescents, vaginal delivery (p = 0.0009). The parity variable showed a higher number of primigravidae in adolescent mothers (65 cases).

Discussion
The present study compared the composition of colostrum fats in nursing mothers at the extremes of reproductive age with term gestation as well as describing the socio-demographic and obstetric characteristics.
Despite recent studies on the subject, little is known about the influence of maternal age on the In the present study, we diverged from the above findings as we found a difference between the BMI of adolescent mothers and advanced maternal age as well as in the colostrum of these mothers (p < 0.0001). Confidentiality was ensured by assigning an identification number to substitute personal identifiers.

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Availability of data and materials: All datasets used and/or analysed during the current study are available from the text and other informations you are need just ask to corresponding author.

Competing interests:
The authors declare that they have no competing interests.