Indian Journal of Medical Specialities

ORIGINAL ARTICLE
Year
: 2021  |  Volume : 12  |  Issue : 4  |  Page : 211--215

Number of relationships between abnormal values in oral glucose tolerance test and adverse pregnancy outcome


Burak Bayraktar, Meriç Balikoglu, Miyase Gizem Bayraktar, Ahkam Göksel Kanmaz 
 Department of Obstetrics and Gynecology, University of Health Sciences Tepecik Training and Research Hospital, Izmir, Turkey

Correspondence Address:
Dr. Burak Bayraktar
Department of Obstetrics and Gynecology, University of Health Sciences Tepecik Training and Research Hospital, Izmir
Turkey

Abstract

Objective: The aim of this study is to investigate the effect of detecting one or more positive values in 75 g oral glucose tolerance test (OGTT) performed between 24 and 28 gestational weeks on neonatal biometry (macrosomia, newborn weight, head circumference, and body length of newborn), obstetric results, and treatment requirement. Materials and Methods: Between January 2019 and December 2020 at the University of Health Sciences Tepecik Training and Research Hospital, pregnant women who underwent 75 g OGTT between 24 and 28 gestational weeks and had singleton pregnancy were included in the study. Multiple pregnancies, pregnancies with gestational age <37 and ≥42 weeks, pregestational diabetes mellitus, pregnancies with intrauterine growth retardation, those with chromosomal and/or congenital anomalies, those with thyroid disease, pregnant women whose information could not be reached, and/or whose information was deficient were excluded from the study. These pregnant women were classified into Group 1 with a positive single value, Group 2 with two positive values, and Group 3 with all positive values according to 75 g OGTT values. Results: Two hundred and eighty-three singleton-term and gestational diabetic pregnant women who met the inclusion criteria were included in the analysis. The age of pregnant women and their body mass index (pre-pregnancy and at during test) increased from Group 1 to Group 3, and the differences between all groups were significant (P < 0.001, P < 0.001 and P < 0.001, respectively). The number of pregnant women treated with insulin increased significantly from group 1 to group 3 (P<0.001). Birth weight and body length of new-borns were significantly higher in Group 3 as compared to Group 1 and Group 2 (P = 0.033 and P = 0.017, respectively). Macrosomia prevalence was the highest in Group 3 with 21.7% (P < 0.001). Conclusion: The number of positive values detected between 24 and 28 weeks of gestation in 75 g OGTT was associated with the birth weight, body length, and macrosomia of the newborn and also could be used as an early biomarker to mother's insulin requirement.



How to cite this article:
Bayraktar B, Balikoglu M, Bayraktar MG, Kanmaz AG. Number of relationships between abnormal values in oral glucose tolerance test and adverse pregnancy outcome.Indian J Med Spec 2021;12:211-215


How to cite this URL:
Bayraktar B, Balikoglu M, Bayraktar MG, Kanmaz AG. Number of relationships between abnormal values in oral glucose tolerance test and adverse pregnancy outcome. Indian J Med Spec [serial online] 2021 [cited 2022 May 23 ];12:211-215
Available from: http://www.ijms.in/text.asp?2021/12/4/211/328641


Full Text



 Introduction



Maternal fasting blood glucose value is lower in the first trimester as compared to the pre-pregnancy period and decreases to the lowest level at the end of the first trimester.[1],[2] In the second and third trimesters, blood glucose is kept high in both fasting and satiety to meet the increased glucose need of the fetus.[1],[2] This is achieved by the formation of a diabetogenic environment by acting primarily on human placental lactogen, estrogen, progesterone, cortisol, and prolactin with anti-insulin effects.[2] During pregnancy, an increase in insulin secretion is expected due to hyperplasia and hypersensitivity in the beta cells of the pancreas. However, in some pregnant women, gestational diabetes mellitus (GDM) occurs as a result of insufficient adaptation and inadequate functions of the maternal pancreas.[3] GDM is defined for the first time as various degrees of glucose intolerance disorder detected during pregnancy, it is also predisposing to the development of type 2 diabetes.[4]

Maternal hyperglycemia exposes the fetus to the intrauterine environment with increased glucose concentration due to transplacental transmission. This intrauterine environment causes an increase in hyperinsulinemia, macrosomia, and related cesarean rates in the baby.[2] Macrosomia is the most common complication in babies of mothers with gestational diabetes and while the proportion of babies with a birth weight above 4000 g in the general obstetric population is approximately 2%, it is observed that this rate increases two times to 4% in women with GDM.[1] Congenital anomaly, need for neonatal intensive care, and stillbirth risk increase with GDM.[2] The World Health Organization (WHO) and International Association of Diabetes and Pregnancy Study Groups (IADPSGs) recommend GDM screening with a one-step 75 g oral glucose screening test (OGTT) to protect both the mother and the baby from these complications.[5],[6]

In the diagnosis of gestational diabetes according to IADPSG presence of a single value that exceeds the limit in 75 g OGTT made in the second trimester is enough to make the test positive. However, it has been suggested that the prognosis may vary between single value and more than one value positivity.[7],[8]

The aim of this study is to investigate the effect of detecting one or more positive values in 75 g OGTT performed between 24 and 28 weeks of gestation on neonatal biometry (macrosomia, newborn weight, head circumference, and body length of newborn), obstetric results and treatment requirement.

 Materials and Methods



Study design

This study is a retrospective cohort study of pregnant women who were diagnosed with GDM after 75 g OGTT and delivered at term (37–42 weeks) between January 2019 and December 2020.

Pregnant women who underwent 75 g OGTT between 24 and 28 weeks of gestation and had singleton pregnancy were included in the study. Multiple pregnancies, pregnancies with gestational age <37 and ≥42 weeks, pre-GDM (Type 1 and Type 2 diabetes), pregnancies with intrauterine growth retardation, those with chromosomal and/or congenital anomalies, those with known thyroid disease, pregnant women whose information could not be reached, and/or whose information was deficient, were excluded from the study.

In our clinic, all pregnant women are administered 75 g OGTT between 24 and 28 weeks of gestation according to the recommendations of the IADPSGs. To diagnose GDM, values ≥92 mg/dL after fasting, 180 mg/dL after the 1st h, and 153 mg/dL after the 2nd h are used during the 75 g OGTT as accepted by IADPSG.[5] The deepest vertical pocket >8 cm and/or total AFI >24 cm is used in the diagnosis of polyhydramnios.

The pregnant women who met the inclusion criteria were divided into three groups according to their 75 g OGTT values, and those with a positive single value were classified as Group 1, those with two positive values as Group 2, and those with all positive values were classified as Group 3. Neonatal weight and newborns below 2500 g were accepted as low birth weight and newborns over 4000 g as macrosomic. The study was approved by the University of Health Sciences Tepecik Training and Research Hospital Local Ethics Committee. The research was conducted in accordance with the 1964 Helsinki Declaration. Informed consent is not required as it is a retrospective study.

Statistical analysis

Statistical Package for the Social Sciences software version 22.0 (IBM Corporation, Armonk, New York, USA) was used in the analysis of the data, and the significance level was taken as P < 0.05 in all analyzes. Numerical data were given as mean ± standard deviation. Qualitative data were calculated as a percentage. The Chi-square test was used for the categorical variables between the groups. Analysis of variance (ANOVA) was used for multiple comparisons of continuous variables. In case of significant difference as a result of the analysis, the homogeneity of the variances was checked to determine between which groups the difference was. If the variances were homogeneous, the Scheffe test, one of the post hoc multiple comparison tests, was used. In cases where the Scheffe test did not determine between which groups the difference was, Bonferroni test, one of the post hoc multiple comparison tests, was used. If the variances were heterogeneous, the Tamhane T2 test, one of the post hoc multiple comparison tests, was used.

 Results



Two hundred and eighty-three singleton-term and gestational diabetic pregnant women who met the inclusion criteria were included in the analysis. The demographic data of these pregnant women are summarized in [Table 1]. The age of pregnant women and their body mass index (BMI) (pre-pregnancy and at during test) increased from Group 1 to Group 3, and the differences between all groups were significant (P < 0.001, P < 0.001, and P < 0.001, respectively). The groups were similar in terms of parity.{Table 1}

Maternal results of pregnant women are shown in [Table 2]. The groups were similar in terms of polyhydramnios prevalence, mode of delivery (vaginal-cesarean), and gestational age at delivery. However, when the treatment requirements were examined, the number of pregnant women treated with insulin increased significantly from group 1 to group 3 (P<0.001). {Table 2}

The neonatal results of the pregnancies are shown in [Table 3]. The gender of the newborns was similar in all three groups. Birth weight and body length of newborns were significantly higher in Group 3 as compared to Group 1 and Group 2 (P = 0.033 and P = 0.017, respectively). Macrosomia prevalence was the highest in Group 3 with 21.7% (P < 0.001). The proportion of newborns with APGAR scores (at 1 and 5 min) below 7, and the requirement of need for neonatal intensive care unit admission was similar between the groups.{Table 3}

 Discussion



Hyperglycemia and hyperinsulinemia develop in pregnant women whose pancreatic functions are insufficient due to increasing insulin resistance during pregnancy. It seems reasonable that this situation affects prenatal and neonatal results and increases the insulin requirement.

The IADPSGs and WHO recommend one-step 75 g OGTT in the diagnosis of GDM, and nowadays, in addition to the “two-stage” diagnostic approach, the “single-stage” diagnostic approach is becoming increasingly common.[7],[8] Single value positivity in 75 g OGTT is sufficient for the diagnosis of GDM, but if more than one value is positive, the possibility of complication of pregnancy may increase.[7],[8]

There are few studies in the literature examining the relationship between the number of positive OGTT values and birth weight.[7],[8],[9],[10] Considering these studies, as the number of positive values increases, similar to our results, birth weight and the prevalence of macrosomia increases.[7],[8],[9] However, contrary to both the literature and our results, in a study using 100 g OGTT,[10] no relationship was found between newborn weight and macrosomia prevalence and the number of positive values in OGTT.

Although studies often focused on macrosomia and newborn weight in the past, in recent years, it has become important to evaluate the growth curve of the newborn as a whole and to evaluate all anthropometric measurements together.[11],[12] Therefore, in our study, unlike the literature, whether GDM has an effect on body length of newborns and head circumference measurements was evaluated for the first time. In our study, while the body length of newborns significantly differed between the groups, the difference between the head circumference of the newborns was not significant. This may be due the effect of fetal insulin. Since maternal insulin cannot pass through the placenta, the fetus will have to increase its own insulin release. While fetal insulin causes hypertrophy and hyperplasia in tissues such as liver, adipose tissue, bone tissue, muscle tissue, heart, adrenal glands, pancreas which are sensitive to insulin; It does not have the same effect on the brain and head structure.[13] As a result, these affected fetuses are typically tall and have excessive fat deposits, especially in the shoulder and trunk.[14],[15] Compared with macrosomic babies of normoglycemic mothers, these babies have a reduced head/shoulder ratio.[16],[17]

In our study, the age of pregnant women and their BMI (pre-pregnancy and at during test) increased from Group 1 to Group 3, and the differences between all groups were significant (P < 0.001, P < 0.001 and P < 0.001, respectively). Hence, increasing age[18],[19],[20],[21] and BMI[22],[23],[24] increase the risk of developing gestational diabetes; as seen in our study, it also increases the number of positive values in OGTT. In terms of polyhydramnios and APGAR score, Ding et al. compared the pregnant women and found no significant difference between the groups similar to our study.[7]

Insulin requirement increased significantly from Group 1 to Group 3 in our study (P < 0.001). Therefore, we can say that as the number of positive values increases in 75-g OGTT, the rate of dietary regulated gestational diabetes decreases. Similarly, the analysis of Ding et al.[7] and Ketumarn and Boriboonhirunsarn[10] also found that as the number of positive values increased, the need for insulin increased in direct proportion. Saisho et al. modeled beta cell dysfunction in women with GDM and found that the degree of dysfunction correlated with the total insulin dose required.[3] Our result supports this mechanism.

It is known that behavioral and lifestyle factors as well as genetics have an effect on the development of diabetes.[25] There is clear evidence that healthy lifestyle behaviors such as ideal weight, healthy eating, and regular exercise prevent the development of gestational diabetes.[26] Since our study is retrospective, one of our limitations is that we cannot examine the diet and exercise status clearly. Despite these limitations, we think that our study results will make an important contribution to the literature in recognizing the risks and treatment needs of gestational diabetes at an early stage.

 Conclusion



In this study, it was determined that the number of positive values detected between 24-28 weeks of gestation in 75-g OGTT was associated with the birth weight, body length and macrosomia of the newborn and also could be used as an early biomarker to mother's insulin requirement. It is important to keep in mind that maternal and neonatal complications will be detected higher in pregnant women with an increase in the number of positive values in OGTT, and the earlier insulin requirement in terms of treatment method. Pregnant women with the increased number of positive values in OGTT should be followed up more closely and more frequently.

Financial support and sponsorship

None.

Conflicts of interest

There are no conflicts of interest.

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