Year: 2012
Type: dissertation
Study design: Observational Study
Abstract: Objectives. The Pregnancy, Nutrition & Diabetes (PND) study aimed to evaluate the \ndietary status of urban Black pregnant women attending the Antenatal Clinic at the Charlotte \nMaxeke (Johannesburg General) Hospital. In addition, the study investigated the effects of \nmaternal dietary intake and hormonal levels during pregnancy on fetal growth, birth size and \nthe early postnatal development of risk factors for future Type 2 diabetes. The study analysis \nprecedes a detailed description of the study population, including its comparison with other \npopulations. \nMethods. 126 women were enrolled in the study before 24 weeks of gestation. Twice \nduring pregnancy (weeks 20-24 and 30-36, visits V1 and V2) and approximately six months \nafter the delivery (visit V3), volunteers participated in a standard 75 g oral glucose tolerance \ntest (OGTT). Blood pressure, anthropometric and socio-demographic data were taken and a \nfood frequency questionnaire was administered at each visit. The daily maternal intakes of \ntotal energy and macronutrients expressed as a % of total energy intake (%E) were calculated \nand further evaluated. A comparison with the crude nutrients intakes was also performed. \nDuring both pregnancy visits, an ultrasound examination was carried out to obtain estimates of \nfetal biometry and fetal well-being and the postnatal anthropometric parameters were also \nmeasured. Blood samples were collected at fasting, 30min, 60min and 120min of the OGTT \nfor the measurements of maternal glucose (GLC), insulin (INS), C-peptide (C-PEP) and \nproinsulin (PI) and fasting samples for the determination of placental lactogen (HPL), insulinlike \ngrowth factor 1 (IGF-1), insulin-like growth factor binding protein 1 (IGF-BP1), free thyroxin (FT4), cortisol (CORT) and leptin (LEPT). Infant fasting blood samples were used \nfor the analysis of the GLC, INS, PI, IGF-BP3 and LEPT. The plasma glucose samples were \nanalysed on the Beckman Glucose Analyser 2, whilst all the other analytes were measured by \nan immunoassay method on 96-well plates. \nResults – DESCRIPTIVE DATA. \nStudy participants. The majority of the study participants had completed high school \neducation, however were unemployed and of low and very poor socio-economic levels. In \ncomparison with another study from the developing world, the Pune study in India, the women \nfrom the current study were older, heavier with greater body mass index (BMI) and they were \nalso taller. They had higher head and arm circumference. \nBirth outcomes. The birth size of African babies in the current study, although smaller \nin all parameters, was still relatively closer to the size of the Caucasian babies seen within the \nSouthampton (Godfrey et al. 1996) or Helsinki (Forsén et al. 1997) studies than to the birth \nsize of the babies from Trivandrum (Jaya et al. 1995) or Pune (Rao et al. 2001) in India. \nThese relatively smaller African babies have comparable (or even larger) maternal placental \nsizes in relation to the mothers of both European studies. However, in comparison with the \nsmall Indian babies, the major difference noted was a substantially smaller placental size of \nthe Pune mothers. \nCompared to z-scores from the World Health Organization (WHO) child growth \nstandards (WHO Anthropo 2010), the PND study babies were born lighter and shorter with a \nlarger head circumference (HC). A growth delay observed near the neonatal visit was followed by catch up growth in weight for age, however no catch-up growth was observed for length for \nage by the second postnatal visit. \nDietary intakes. The PND study women had pregnancy energy intakes slightly below \nthe national level intakes (Steyn et al. 2006), except for the energy intake at V3, which \nexceeded the national level. The lower energy intake during pregnancy is attributable to a \nlower intake of dietary protein and total carbohydrate. The fat intake was substantially higher \nin the PND study, with levels almost double at the second postnatal visit. This discrepancy \nmay be due to differences between investigated populations or due to increased requirements \nof energy during lactation. \nIn comparison with the Recommended Dietary Allowances (RDA), during the \npregnancy period women in the current study had lesser crude protein and higher carbohydrate \nintake. Intake of the crude protein after delivery was low in comparison to the RDA for \nlactating women. Total carbohydrate intake exceeded the RDA. The relation between the \nintake of macronutrients expressed as a percentage of total energy (%E) and RDA was similar. \nThe current study participants had a lower intake of energy, especially during the \npregnancy period, when compared to populations in the developed world. They had a lower \nintake of protein at all visits in comparison with the national average for women or with that \nfound in the Southampton study or when compared to the usual American diet. The energyadjusted \nintake of fat and carbohydrate were comparable with the Southampton and American \ndata. This population in our study was therefore more comparable to that of Pune than to \nAmerican or Southampton populations. However, despite similar total energy intakes as the Pune Study, total protein and fat intakes were higher in the African mothers, which may \nexplain their higher weights and birthweights of their babies. \nResults – ANALYTICAL DATA \nDietary intakes. Maternal dietary intakes showed significant effects on the fetal \nbiometrical measurements, mainly involving the fetal head, femur length and the size of \nabdomen. The outcomes also show a significant relationship between maternal protein intake \nand baby’s birth weight. Associations were also found for maternal dietary intakes and the \nneonatal length and BMI and the markers of the infant β-cell function. Intakes of the plant \nprotein and polyunsaturated fat supported the linear growth. There was no correlation between \nmaternal dietary intake and the fetal growth rate. Effects of the total energy intake and \ncarbohydrate seemed to be direct, while the effect of protein and fat may be delayed, possibly \ninvolving metabolic adaptation of the mother and the partitioning of nutrients between the \nmother, placenta and fetus. (See Table: Associations between the maternal dietary intake and \nthe neonatal INSF1 levels, Pg. xiv). \nMaternal hormones. The data of the current study show significant relationships \nbetween maternal pregnancy hormones and fetal growth rate and the postnatal growth rate, \nalthough maternal anthropometry and fetal gender and BMI are also significantly involved. \nThe maternal thyroid hormones seem to play an important role in fetal and postnatal growth \nand insulin metabolism (N=76, p=0.002, ß=-0.343; AR2=0.106) in the association with the \nneonatal fasting insulin. Discussion. The outcomes of the current study show that the African pregnant women \nin the study had lower energy intakes attributable to a lower intake of dietary protein and total \ncarbohydrate. \nMaternal dietary intakes showed significant effects on the fetal biometrical parameters. \nProtein dietary intake was positively associated with baby’s birth weight and was shown to be \nstatistically significant. Associations were also found for maternal dietary intakes and the \ninfant postnatal BMI and the markers of the infant β-cell function. Quality of the protein and \nfat has different effects on fetal/infant growth. \nMaternal hormones showed correlations with fetal growth rate and the outcomes of the \ncurrent study also show that maternal hormones can affect neonatal and early postnatal infant \nglucose levels and β-cell function. They are also linked to the programming of early obesity. \nThe maternal thyroid hormones seem to play an important role. \nThe maternal low energy, protein (especially plant protein) and PUFA intakes during \ngestation may be the reasons for the lower z-score birth parameters of the infants in \ncomparison with the World Health Organization (WHO) child growth standards (WHO Anthro \n2010). The disproportionally larger head of the newborn may be an outcome of the brain \nsparing effect. A suggestion for an increased maternal dietary intake of energy, protein and \nPUFA has been made.
Author: M Toman
Language: English
Subfield: Obstetrics and Gynecology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2248202424