"Convenient diagnosis of gestational diabetes";Using Continuous Glucose Measurement as an alternative to the golden standard Oral Glucose Tolerance Test (OGTT).

Gestational Diabetes Mellitus (GDM) is a common complication during pregnancy,
with a prevalence of 5-10% depending on the WHO-criteria used (WHO 1999 or
WHO2013). Early diagnosis of GDM is necessary to minimize the negative effects
on the health of both the baby and the mother.

GDM is diagnosed using the oral glucose tolerance test (OGTT) which is the
golden standard. This test is experienced as very uncomfortable and stressful
by many pregnant women because of the following reasons; (i) the patients are
not allowed to eat or drink for eight hours before the test and during the
test. (ii) Patients have to drink 200 ml of a syrupy glucose solution
containing 75 grams glucose. (iii) The patients are subjected to two
venipunctures in a time span of 2 hours in which patients are not allowed to
move around.

The measurement of blood glucose levels using inconvenient venipunctures could
be replaced by the use of a Continuous Glucose Meter (CGM), which can be easily
applied in a pain free manner to the upper arm prior to the oGTT. Because a CGM
eliminates the need for venipunctures, the oGTT can be performed in a home
setting instead of in an outpatient clinic in the hospital.

The CGM can measure blood glucose levels over a period of five days and
therefore provide insight in the glucose metabolism of an individual under
physiological load of carbohydrates. Therefore this tool can be used to
generate a risk assessment whether the patient suffer from gestational
diabetes. In principle, this approach offers the possibility to avoid
unnecessary use of the inconvenient oGTT.

The main goal of this study is to determine whether the CGM can replace
venipunctures to measure blood glucose values during the oGTT.

The second goal of this study is to investigate to what extent glucose
profiles, measured at home using the CGM, can be used as a (partial)
replacement for the inconvenient oGTT.

This study has a single-arm observational blinded non-randomized design.

The study lasts 5 days per participant and has two observation periods using
CGM, namely during the oGTT and four days during the home situation.

Burden for the participants:
The total duration of the study for a participant is 5 days and consists of two
observational periods using CGM, namely during the oGTT and four days during
the home situation. During the first observational period, day 1, an oGGT will
be performed as part of standard care, during this outpatient hospital visit
the CGM will be placed and a short questionnaire will be taken.

During the second observational period, 4-day observational period at home,
participants are asked to keep track of their food intake, exercise and sleep.

On day 5 of the study, the patch will be removed and participants are asked to
hand in the CGM during a short outpatient hospital visit. In addition, a short
questionnaire will take place.

Assessment of possible risks:
- Allergic reaction to the patch: this will be a mild (non-systemic) reaction.
Participants remain in the hospital for three hours after application. In case
of skin irritation/discoloration, the patch will be removed and the participant
will be excluded from the study.

- Breaking off the microneedle in the skin: this is unlikely to cause a
reaction (given the small volume and inertness of the microneedle). If the
microneedle is found to be missing from a removed patch, it can be removed with
tweezers.

Due to the known mechanisms of action and the materials used, the probability
of complications is very low and will be of a non-health threatening nature if
they may occur.

The importance of the innovation, as described under C4, set-out against the
low risk level for the participants, generates a risk-benefit ratio that we
believe is acceptable to justify participation in the study.