[CG] COVID-19 and GDM Screening


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In the current covid 19 outbreak, clinics will find it difficult to provide the usual pattern of screening for gestational diabetes.  OGTT is now not recommended due to the need to minimise patient contacts.  All clinics are converting to as much remote working as possible.

Recent RCOG guideline bases second trimester screening around 28 week HbA1c and fasting OR random glucose.  To avoid footfall into antenatal areas find local modified version of the RCOG guidance based on the option of HbA1c and random glucose at booking and 26-28 weeks.

 It should be noted that this will detect fewer women than existing screening but is designed to detect those with highest glucose level.  All women but particularly those with risk factors should be encouraged to follow general healthy eating advice in their pregnancy https://www.nhsinform.scot/ready-steady-baby/pregnancy/looking-after-yourself-and-your-baby/eating-well-in-pregnancy

 It is expected that screening based on the combination of fasting and HbA1c and eventually OGTT may be possible in the future.   If fasting used then teams could consider previous IADPSG criterion (³5.1mmol/l).



  1. At time of usual Tuesday morning antenatal clinic at PRM which will continue throughout
  2. At other times at least Monday – Friday 9-4 at Stobhill using contact number 0141 355 1078 – in this context if meter/ equipment / insulin problems


  1. Wednesday antenatal will continue-list will be reviewed to determine who needs to be physically seen
  2. Contact details:
    1. GGH: [email protected] and mobiles GGH 1 (Consultants) 07943 585890, GGH2 (DSNs)  07943 585907
    2. QEUH/Victoria [email protected] and mobiles Vic 1 (Consultants) 07943 585877, Vic 2 (DSNs)  07943 585884


  1. Wednesday clinic 11.30 will continue as normal (afternoon clinic under review)
  2. Urgent contact via secretary at 0141 314 6882 in hours or in emergency medical “registrar” 3rd on RAH

Remote consultations

All teams have implemented this where possible

Note that useful general advice for patients and specific training modules available at

Revision of gestational diabetes criteria and diagnosis

First trimester

At booking in women with NICE/ SIGN risk factors (BOX 1) perform HbA1c + random glucose.  All women with risk factors given access to online resources on healthy eating in pregnancy with advice that routine screening may not be available eg


Box 1. Risk factors

Previous GDM

  • BMI >= 35 kg/m2 at booking
  • Previous pancreatitis
  • First degree relative with diabetes (sibling , parent, child NOT grandparent)
  • Previous macrosomic baby weighing 4.5kg or above
  • Family origin with high prevalence of diabetes (South Asian/black Caribbean/Middle eastern)

Box 2. Interpretation at booking

If HbA1c ³ 48mmol/mol or random glucose ³11.1 mmol/l  then treat as pre-existing diabetes

If HbA1c 41-47 or random glucose 9-11 mmol/ then treat as GDM, refer to diabetes teams

All others, random glucose and HbA1c at 26-28 weeks


Later pregnancy

26-28 weeks

All women with risk factors (Box 1) have random glucose and HbA1c (Box 3).

Box 3   Interpretation of HbA1c /RBG third trimester

 If HbA1c ³ 48 then treat as diabetes

If HbA1c 39-47 then treat as GDM

If random glucose ³ 9.0 mmol/l then treat as GDM

Note HbA1c lower in later pregnancy hence lower cut off


At any point in pregnancy if clinical concern (Box 4) then random glucose and HbA1c  (interpret as Box 3 )

Box 4

Baby with AC / EFW >95th centile 


Fasting glycosuria (>=2+)


After pregnancy. for women felt to be at high risk of diabetes immediately after pregnancy (small minority)  follow up will be arranged by diabetes teams. For majority HbA1c at 6 months is suggested .

Last reviewed: 03 April 2020

Next review: 03 April 2021

Author(s): Robert Lindsay