This is an observational study at the Obstetrical outpatient clinic at Stavanger University Hospital, Norway. The purpose of the study is to compare glycated albumin and glycated hemoglobin (HbA1c), both markers of "long-term blood sugar" with oral glucose tolerance test (OGTT). The OGTT is a screening test for gestational diabetes, a condition that increases risk of adverse pregnancy outcome for mother and child. The risks are reduced with good glycaemic control throughout pregnancy, therefore, it is important to screen for gestational diabetes.

According to the new guideline by the Norwegian Directorate of Health published april 2017, screening for gestational diabetes is increased. All pregnant women with a slight risk, approximately 70 % of pregnant women i Norway, should have an OGTT performed in gestational week 24-28. Among those women, all primiparas above the age of 25 years old.

The investigators will include 150 primiparas above the age of 25 years old in the study. The women will be asked to participate in the study when they attend an ultrasound examination at the Obstetric outpatient clinic in gestational week 18-20. Prior to inclusion, participants need to sign written informed consent.

Included women will get an appointment for OGTT in gestational week 24-28 at the Clinical trial unit, Stavanger University hospital. The OGTT will be performed according to national guidelines. The participants will fill in a single questionaire with information on age, height, ethnicity, whether there is diabetes in close family, any other illnesses, smoking habits and other medications/supplements.

In addition, to blood sugar levels, markers of importance for glycaemic control, iron status and vitamin-D status will be analyzed.

Women diagnosed with gestational diabetes or overt diabetes mellitus, will be followed up according to national guidelines.

Inclusion Criteria:

• primiparas >25 years old
• singleton pregnancy

Exclusion criteria:

- prior diagnosed with diabetes

Primiparas above the age of 25 years old at conception. Women will be asked to participate in the study when they atttend an ultrasound examination at the Obstetrical outpatient clinic, Stavanger University Hospital, in gestational week 18-20.