Ginekologia Polska 2018, vol. 89, no. 1, 25–29 Copyright © 2018 Via Medica ORIGINAL PAPER / OBSTETRICS ISSN 0017–0011 DOI: 10.5603/GP.a2018.0005 Does reactive hypoglycemia during the 100 g oral glucose tolerance test adversely affect perinatal outcomes? Ilhan Bahri Delibas1, Sema Tanriverdi2, Bulent Cakmak1 1Department of Obstetrics and Gynecology, Gaziosmanpasa University, Tokat, Turkey 2Neonatalogy Clinic, Merkez Efendi State Hospital, Manisa, Turkey ABSTRACT Objectives: To determine whether pregnant women who have reactive hypoglycemia during the 100 g oral glucose toler- ance test (OGTT) are at an increased risk of poor pregnancy outcomes. Material and methods: We retrospectively analyzed perinatal data from 413 women who underwent a 3 h OGTT at 24–28 weeks of gestation and gave birth in our clinics between January 2012 and December 2014. Results: According to OGTT results, the majority of the subjects were normoglycemic (n = 316, 76.5%), while 49 (11.9%) were diagnosed with gestational diabetes, and 33 (8.0%) had single high glucose values. Reactive hypoglycemia was de- tected in only 15 patients (3.6%). The mean age of the women in the reactive hypoglycemia group was significantly lower than that of the women in the gestational diabetes and single high glucose value groups (26.4 ± 4.4 years, 31.4 ± 5.4 years, and 31.8 ± 4.3 years, respectively; p < 0.05). The newborns of the women in the reactive hypoglycemia group had higher rates of APGAR scores < 7, increased admission to the neonatal intensive care unit (NICU), and lower birth weights compared with the other groups (p < 0.001, p < 0.001, and p = 0.009, respectively). Conclusion: Reactive hypoglycemia during the 3 h 100 g OGTT is significantly associated with low APGAR scores, low birth weights, and prenatal admission to the NICU. Therefore, pregnant women who develop hypoglycemia during the 100 g OGTT performed at 24–28 weeks of gestation should receive attentive follow-up care to decrease the possibility of adverse perinatal outcomes. Key words: gestational diabetes, oral glucose tolerance test, perinatal outcome, pregnancy, reactive hypoglycemia Ginekologia Polska 2018; 89, 1: 25–29 INTRODUCTION ziness, nausea, tachycardia, and perspiration, a condition An evaluation for gestational diabetes mellitus (GDM) known as reactive hypoglycemia [3, 4]. Concomitant blood is widely performed between 24–28 weeks of gestation in samples may reveal very low blood glucose levels in the- women without pre-gestational diabetes. Two methods are se women. There is no precise cut-off blood glucose level commonly used: a one-step approach, the 75 g oral glucose that can predict hypoglycemic symptoms. Some patients tolerance test (OGTT); and a two-step approach, the 50-g with normal glucose values may experience hypoglycemic glucose challenge test (GCT) followed by an 100 g OGTT if symptoms, while others may not have any symptomatic the threshold is exceeded. An estimated 95% of obstetric indications of hypoglycemia, even at very low blood gluco- patients in the United States undergo sequential model uni- se concentrations [5, 6]. However, various reports suggest versal screening for GDM using the two-step approach [1, 2]. a blood glucose level of 45–50 mg/dL (2.5–2.78 mmol/L) is Some women who have abnormal test results indicative of reactive hypoglycemia [7–9]. (≥ 140 mg/dL) on the 50 g GCT experience hypoglycemia Hypoglycemic symptoms or low blood glucose levels during the 3 h 100 g OGTT, with symptoms including diz- during the test may be sources of anxiety for both patients Corresponding author: Ilhan Bahri Delibas Gaziosmanpasa University Obstetrics and Gynecology Department Tokat, Turkey e-mail: [email protected] 25 Ginekologia Polska 2018, vol. 89, no. 1 and healthcare providers. Despite the known associations be- and 140 mg/dL for 3 h OGTTs [11]. Reactive hypoglycemia is tween elevated maternal glucose levels and adverse maternal defined as a plasma glucose level of < 45 mg/dL (2.5 mmol/L) and neonatal outcomes, the potential relationship between according to the 1986 Consensus Statement of the Third In- low maternal glucose levels during the 100 g OGTT and ad- ternational Symposium on Hypoglycemia [7]. Another reason verse perinatal and neonatal outcomes remains unknown. for choosing this cut-off plasma glucose level (45 mg/dL) for The aim of the present study was to determine whether hypoglycemia was that it was detected in less than 10% of pregnant women who have reactive hypoglycemia during our study population during OGTTs. the 100 g OGTT are at an increased risk for poor pregnancy outcomes, such as preterm delivery, cesarean delivery, pre- Study procedures eclampsia, small-for-gestational age (SGA) fetuses, increased The following data were recorded from patients’ hospital birth weight, or low Apgar scores. files and compared among the study groups: demographics; results of fetal assessment tests, including fetal biometry; MATERIAL AND METHODS amniotic fluid index; gestational age at delivery; neonatal Study design and population results, including APGAR scores; fetal birth weight; rates We conducted a retrospective cohort study by reviewing of admission to the neonatal intensive care unit (NICU); the perinatal data of all women who underwent a 3 h OGTT administration of phototherapy; and obstetrical results, and gave birth at the Obstetric and Clinics Department of including the mode of delivery and the presence of dysto- Gaziosmanpasa University and Tokat State Hospital between cia. Large-for-gestational-age (LGA) status was defined as January 2012 and December 2014. Women with single- a birth weight above the 90th percentile for age, and SGA ton pregnancies who had abnormal 1 h 50 g GCT results was defined as a birth weight below the 10th percentile for (≥ 140 mg/dL) at 24–28 weeks of gestation and thus under- age [12]. Macrosomia was defined as an estimated fetal went the 3 h 100 g oral GTT were included in the study [10]. weight of 4,000 g or more, regardless of gestational age The exclusion criteria were twin pregnancies, documented [13]. All patients underwent ultrasound examinations before type I or II diabetes mellitus, multiple GCTs in the same proceeding to the delivery ward. In accordance with the pregnancy (only one entry per pregnancy was allowed), guidelines of the Ministry of Health of Turkey, we recom- and incomplete medical records. A total of 421 women met mend elective cesarean delivery to women with GDM and the inclusion criteria. Eight women (1.9%) were excluded estimated fetal weights of 4,000 g or more and to women due to incomplete medical records; thus, 413 women were without GDM and estimated fetal weights of 4,500 g or more. included in the study. The study was approved by the institutional ethics Statistical analysis committee (Approval number: 14-KAEK-237, Registered Statistical analysis was performed using the PASW so- date: 23.12.2014) and conducted in accordance with the ftware package for Windows (Statistical Package for Social latest version of the Declaration of Helsinki. The informed Sciences, Version 18.0, SPSS Inc., Chicago, Illinois, USA). The consent requirement was waived due to the retrospective data collected were summarized using descriptive statistics design of the study. (e.g., mean, standard deviation, range, frequency, and per- centage). For a comparison of categorical variables betwe- Study groups en study groups, a chi-square test was used. For multiple Based on the OGTT results, patients were classified as comparisons of continuous variables, analysis of variance follows: patients with reactive hypoglycemia (Group 1: pla- (ANOVA) and the Scheffé post-hoc test were used. The sta- sma glucose ≤ 45 mg/dL), patients with normoglycemia tistical level of significance was set at p < 0.05. (Group 2: normal plasma glucose values), patients with only one abnormal glucose value (Group 3), and patients with RESULTS GDM (Group 4: two or more high plasma glucose values). According to the 100 g OGTT results, the majority of In our clinic, we screen non-diabetic pregnancies for GDM the 413 pregnant women were normoglycemic (n = 316, at 24–28 weeks of pregnancy using a two-step standard 76.5%) and 33 (8.0%) had single high glucose values, whi- protocol during a routine prenatal visit. This protocol is a 1 h le 49 (11.9%) were diagnosed with gestational diabetes 50 g GCT, followed by a 3 h 100 g diagnostic OGTT if the GCT (Tab. 1). Reactive hypoglycemia was detected in only 15 pa- plasma glucose result is ≥140 mg/dL. GDM is diagnosed when tients (3.6%). two or more OGTT plasma glucose levels meet the criteria for a positive test as recommended by the National Diabetes Data Maternal and prenatal parameters Group (NDDG), which include plasma glucose thresholds of Regarding maternal and prenatal characteristics, only 95 mg/dL for fasting, 180 mg/dL for 1 h, 155 mg/dL for 2h, age and gestational week at delivery were significantly dif- 26 www. journals.viamedica.pl/ginekologia_polska Ilhan Bahri Delibas et al., Significance of hypoglycemia during OGTT Table 1. Distribution of patients according to 100 g oral glucose tolerance test results 100 g OGTT result Number of patients (%) Reactive hypoglycemia Group 1 15 (3.6%) (glucose ≤45 mg/dL) Normoglycemia Group 2 316 (76.5%) (all plasma glucose values are normal) Single high glucose value Group 3 33 (8.0%) (only one abnormal glucose value) Gestational diabetes Group 4 49 (11.9%) (two or more high plasma glucose values) Total 413 (100.0%) OGTT — oral glucose tolerance test ferent among the groups (p < 0.001 and p = 0.029, respec- (p < 0.001, p < 0.001, and p = 0.009, respectively; Tab. 3). On tively; Tab. 2). The mean age of the women in the reactive the other hand, neonatal gender and SGA and LGA rates hypoglycemia group was significantly lower than that of were similar among the groups (Tab.