Login
Search

Search
Search

Diabetes in Pregnancy

NICE Guideline NG3 Diabetes in pregnancy: management from preconception to the postnatal period. Last updated: Dec 2020.

Background Information

Gestational Diabetes Guidelines

Any of the following:
  • Previous gestational diabetes
  • Previous macrosomic baby (≥4.5 kg)
  • 1st degree relative with diabetes mellitus
  • Ethnicity with high prevalence of diabetes mellitus 
  • BMI >30 kg/m2

If glycosuria is detected by routine antenatal testing → consider further testing to exclude gestational diabetes

If the patient had previous gestational diabetes → offer either:
  • Early self-monitoring of blood glucose
 
  • Screening test (OGTT) ASAP after booking appointment
    • If first OGTT is normal → repeat at 24-28 weeks

If any other indications:
  • Offer screening at 24-28 weeks

Test of choice: 75mg 2-hour oral glucose tolerance test (OGTT)

Diagnostic criteria (either):
 
Test Cut-off
Fasting plasma glucose ≥5.6 mmol/L
2-hour plasma glucose  ≥7.8 mmol/L
 

A way to remember the diagnostic criteria for gestational diabetes is 56-78.

Newly diagnosed women should be seen in a joint diabetes and antenatal clinic within a week
  • Advice about changes in diet and exercise regularly 
  • Refer to dietitian 
  • Self-monitoring blood glucose (all patients but more frequent monitoring needed if uses insulin)
 

The following targets apply for BOTH gestational diabetes and pre-existing diabetes
 
Timing Glucose Target
Fasting <5.3 mmol/L
1 hour after meals <7.8 mmol/L
2 hours after meals <6.4 mmol/L
All time >4.0 mmol/L (to prevent hypoglycaemia)


 

Extra practical details on frequency of self-monitoring blood glucose in gestational diabetes:

  • If the patient uses multiple daily insulin injections → more frequent (fasting, pre-mela, 1 hour post-meal, bedtime glucose daily)
  • Otherwise (including using single dose insulin) → less frequent (fasting and 1 hour post-meal glucose daily)

The approach depends on fasting plasma glucose levels.
 
Scenarior Management
Fasting plasma glucose <7.0 mmol/L
  • 1st line: trial of diet and exercise change
 
  • If target not met within 1-2 weeks: start metformin (in addition to diet and exercise)
 
  • If target still not met: add short-acting insulin (in addition to diet and exercise and metformin)
Fasting plasma glucose ≥7.0 mmol/L Offer:
  • Diet and exercise changes
  • Short-acting insulin +/- metformin immediately 
Fasting plasma glucose 6.0-6.9 mmol/L + complications (e.g. macrosomia or hydramnios) Consider:
  • Diet and exercise changes
  • Short-acting insulin +/- metformin immediately 
 

Pre-existing Diabetes Guidelines

NICE advises using contraception until good blood glucose control.
  • Advise women with diabetes who are planning a pregnancy to aim HbA1c <48 mmol/mol (6.5%)
  • Strongly advise NOT to get pregnant if HbA1c >86 mmol/mol (10%), until their HbA1c level is lower

Additional management:
  • Individualised dietary advice
  • Weight loss if BMI >27 kg/m2
  • High-dose folic acid (5mg/day) from planning until 12 weeks of gestation
  • Retinal and renal assessment before pregnancy 

The following medications should be stopped before pregnancy or as soon as pregnancy is confirmed:
  • ALL oral anti-diabetic medications (apart from metformin) → start insulin ( rapid-acting insulin analogue preferred)
  • ACE-I / A2RB
  • Statins

This is not an exhaustive list of medications to stop in pregnancy, these are outlined only because they are often implicated in diabetic patients. 

 

The only diabetic medications that are safe in pregnancy are:

  • Metformin
  • Insuiln

Explain to women that good glucose control before contraception and throughout their pregnancy will reduce risk of:
  • Miscarriage
  • Congenital malformation
  • Stillbirth
  • Neonatal death

NICE recommends providing the following information to patients (not exhaustive and expanded):
  • Maternal risk:
    • Pregnant women are more prone to hypoglycaemia and impaired awareness of hypoglycaemia
    • Nausea and vomiting in pregnancy can affect blood glucose control
    • Pregnancy may worsen diabetic retinopathy
    • Diabetic nephropathy may worsen and increase the risk of pre-eclampsia
    • Poor blood glucose control during labour and birth may increase the risk of neonatal hypoglycaemia after birth
 
  • Neonatal risk:
    • Macrosomia (increases risk of birth trauma, induction of labour, instrumental and caesarean section deliveries)
    • Increased risk of health problems in first 28 days (e.g. hypoglycaemia, jaundice, respiratory distress)
    • Increased risk of developing obesity / type II diabetes in later life
 

The following are in addition to standard antenatal care due to diabetes.

Additional intervention:
  • Aspirin 75-150mg from 12 weeks until birth (to reduce risk of pre-eclampsia)

Additional monitoring: (?turn into table)
  • HbA1c (to determine risk for pregnancy)
    • Offer at booking appointment 
    • Consider in 2nd and 3rd trimester
  • Self-monitoring of blood glucose
  • Retinal assessment (by digital imaging with mydriasis)
  • Renal assessment (do not use eGFR in pregnancy)
  • Additional ultrasound monitoring for fetal growth and amniotic fluid volume
    • Every 4 weeks from 28-36 weeks
 

The following targets apply for BOTH gestational diabetes and pre-existing diabetes
 
Timing Glucose Target
Fasting <5.3 mmol/L
1 hour after meals <7.8 mmol/L
2 hours after meals <6.4 mmol/L
All time >4.0 mmol/L (to prevent hypoglycaemia)
 

Extra practical details on frequency of self-monitoring blood glucose in pre-existing diabetes:

  • If type I diabetes → more frequent (fasting, pre-meal, 1 hour post-meal, bedtime glucose daily)
  • If type II diabetes on multiple daily insulin injections → more frequent (fasting, pre-meal, 1 hour post-meal, bedtime glucose daily)
  • If type II diabetes not using multiple daily insulin injections → less frequent (fasting and 1 hour post-meal glucose daily)

Rapid-acting insulin analogues (aspart and lispro) are preferred during pregnancy.

CSII (continuous subcutaneous insulin infusion) or insulin pump therapy should be offered if:
  • Patient using multiple daily insulin injections, AND
  • Not achieving blood glucose control without significant hypoglycaemia 
 

In addition to the above, also offer:
  • Real-time continuous glucose monitoring (rtCGM)
    • Alternative: intermittently scanned continuous glucose monitoring (isCGM)
 
  • Blood ketone testing strips and meter 
    • Advise to test for ketonaemia and seek urgent medical advice if they become hyperglycaemic or unwell
 

Give birth in hospitals where advanced neonatal resuscitation skills are available.

In the absence of other complications / indications:
  • Type I / II diabetes → elective birth between 37-38+6 weeks
  • Gestational diabetes → before 40+6 weeks

Detecting and preventing neonatal hypoglycaemia:
  • Carry out blood glucose testing routinely at 2-4 hours after birth
 
  • Mother should feed the baby ASAP (within 30 minutes)
  • Then, feed at frequent intervals (every 2-3 hours) until maintaining pre-feed blood glucose >2.0 mmol/L
 

Do not transfer babies of women with diabetes to community care until:

  • At least 24 hours old
  • Baby is feeding well and maintaining blood glucose levels

References

Author: Adams Lau
Reviewer: 
Last edited: 11/04/25