Self-Monitoring of Blood Glucose: A Complementary Method Beyond the Oral Glucose Tolerance Test to Identify Hyperglycemia During Pregnancy.

Objectives: To compare: 1) 75 g oral glucose tolerance test (OGTT) and self-monitoring of blood glucose (SMBG) in identifying gestational diabetes mellitus (GDM) and other hyperglycemic statuses in pregnant women; 2) pregnancy outcomes according to glycemic status; and 3) participants' opinions regarding both methods.

Methods: A prospective study in women with a 50 g glucose load test ≥7.2 mmol/L at 24 to 28 weeks' gestation and singleton pregnancy. Women underwent OGTT (blinded) at day 1, followed by 7 days of SMBG (4 daily measurements: fasting and 2 h postprandially) without modifying diet or lifestyle. GDM (OGTT+) was diagnosed using the criteria of the International Association of the Diabetes and Pregnancy Study Groups, while pregnancy hyperglycemia (SMBG+) was defined as ≥4/7 glucose values ≥5.3 after fasting or ≥6.7 mmol/L 2 h postprandially for any meal of the day. Equivalent management was provided to women with GDM and/or pregnancy-related hyperglycemia.

Results: We divided 103 participants (age: 29.5±5.0 years; prepregnancy body mass index: 25.3±5.4 kg/m) into 4 groups according to test results: OGTT+/SMBG+ (n=12, 11.7%); OGTT+/SMBG- (n=14, 13.6%); OGTT-/SMBG+ (n=9, 8.7%); and OGTT-/SMBG- (n=68, 66.0%). Clinical characteristics and maternal outcomes were statistically similar between groups. Neonatal complication rates were greater in groups with hyperglycemia than in the OGTT-/SMBG- group, notably neonatal hypoglycemia (9/12, 7/14, 5/9 vs. 6/68; p<0.001). Participants reported no convenience difference between methods but would prefer OGTT for a future pregnancy.

Conclusions: More than half of the women with OGTT+ were normoglycemic in daily life. Conversely, 11.7% of women with OGTT- had pregnancy hyperglycemia. OGTT+ and/or SMBG+ were equally associated with greater neonatal complications. This study suggests that alongside OGTT, SMBG could improve the care of pregnant women.