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Pregnancy and Type 1 or Type 2 Diabetes

This page is in development. 

Please refer to your program's policies and procedures when caring for women with diabetes in pregnancy.

The following information is meant to guide current and new staff of Calgary Diabetes in Pregnancy Clinics. For referral information please visit our Calgary Diabetes Services page.

1. What are the metabolic changes in pregnancy that can affect glucose control? 

 Complex metabolic changes occur in pregnancy to support fetal development and maternal nutrient needs during pregnancy as well as to create energy stores for labour and lactation. The most simple explanation of metabolic changes is that women are most sensitive to insulin early in the pregnancy, followed by increasing insulin resistance as the pregnancy progresses. This poses the following clinical implications for women with pre-existing type 1 and type 2 diabetes:

  • Risk for hypoglycemia is highest in the first trimester- in particular from week 9 to week 16. 
  • As resistance to insulin climbs from aound week 16, insulin needs can increase significantly. Insulin adjustments are usually required 1-2 times/week. 
  • Decrease in insulin requirements during the 3rd trimester could be normal, or could also indicate poor placental health. A decrease in total insulin needs of greater than 15% should be discussed with the patient's endocrinologist. 
  • Insulin needs fall significantly postpartum with the delivery of the placenta. The endocrinologist provides postpartum insulin doses to the patient as she nears delivery. Doses are usually slightly less than pre-pregnant insulin doses. 

For more detailed information educators can read the following optional articles: (AHS staff can request from Knowledge Resource Service):
Meltzer, S. (2005). Management of diabetes in pregnancy: Challenges and trends. Canadian Journal of Diabetes, 29(3), 246-256.
Garcia-Patterson, A., Gich, I., Amini, S.B., et al. (2010). Insulin requirements throughout pregnancy in women with type 1 diabetes mellitus: three changes of direction. Diabetologia, 53, 446-451. 


2. Complications associated with pre-existing diabetes and pregnancy 

Educators are required to read and understand the 2018 Diabetes Canada Clinical Practice Guidelines, Chapter 36: Diabetes in Pregnancy. Supplemental notes to the guidelines include additional information on placental insufficiency and steroids as follows:

  • Placental insufficiency: A variety of placental hormones cause insulin resistance in pregnancy and increased insulin needs, particularly in the 2nd and 3rd trimesters. A poorly developed or early separated placenta will result in lower levels of HPL and less insulin resistance. Women whose insulin needs inexplicably decrease in the third trimester, particularly those with type 1 diabetes, may be experiencing a form of placental insufficiency. Placental insufficiency is a serious condition that describes failure of the placenta to adequately deliver nutrients and oxygen to the fetus. If insulin needs decrease, or hypoglycemia increases in the 2nd and 3rd trimesters, this should be communicated to the obstetric and endocrinology specialists as this may be suggestive of placental insufficiency. However, dropping insulin requirements after 35 weeks is very common, and usually without negative consequences. Therefore, it is important to notify the physician of this development, without unduly alarming the patient. Poor glycemic control in pregnancy poses a much greater risk of poor pregnancy outcomes. 

  • Steroid medication in pregnancy: Steroid medication, betamethasone, may be given in preterm labour, if early delivery is planned or early labor is expected, usually at 22-34 weeks to help mature the fetal lungs. Steroids are administered as inpatient or outpatient (on antepartum unit) so both mom and baby can be monitored. The patient usually receives two injections, 24 hours apart. If the patient is on insulin, dosing may require large and frequent increases. Diabetes educators should consult with the endocrinologist if patient has received steroids. Refer to the 2018 Diabetes Canada Clinical Practice Guidelines for management of pregnant women with diabetes on insulin receiving betamethasone (Table 1). 


3. Management of pre-existing diabetes and pregnancy 

Educators are required to read and understand the 2018 Diabetes Canada Clinical Practice Guidelines, Chapter 36: Diabetes in Pregnancy. Refer to the Topics Catalogue for the 'Pregnancy and Type 1 or Type 2 Diabetes' handout, along with a link to access Nutrition Food Services handouts. 

Additional information as follows: 

a) Preconception (Prior to Conception): 

Preconception planning is strongly encouraged for all women with pre-existing diabetes. Calgary Diabetes in Pregnancy clinics will accept referrals for women with type 1 or type 2 diabetes who are planning pregnancy within the next 6 months- 1 year. The following topics in addition to patient agenda, clinic expectations and safety are reviewed at a preconception appointment: 

  • Contraception: Women not yet pregnant should be counselled on reliable birth control until glycemic targets are achieved and/or advised by endocrinologist. An HBA1c of 7% or less at the time of conception is recommended to prevent birth defects. The following website from the Society of Obstetricians and Gynaecologists of Canada may help review contraceptive options:
  • Complications: In addition to achieving glycemic targets, screening for complications of diabetes should occur prior to conceiving. Women should be advised not to conceive until they receive the go ahead from the endocrinologist. 
    Women with obesity need to discuss additional risks of conceiving with excess weight with their physician. The educator may discuss the importance of weight loss in the preconception period to help with improved health, fertility and reduced risk for complications. 


b) Intrapartum (During Pregnancy): 

Refer to our Diabetes in Pregnancy page to help understand the similarities and differences between managing diabetes in a pregnant and non-pregnant state. 


c) Labour and Delivery: 

  • Refer to your local program for specific information on hospital order sets and management of insulin antepartum, during delivery and postpartum.
  • The endocrinologist should review insulin and medication needs for delivery and postpartum with the patient prior to delivery.
  • Glycemic control during labour and delivery with pre-existing type 1 and type 2 diabetes aims to minimize neonatal hypoglycemia. Insulin adjustment prior to a planned c-section should be done with this in mind. 


d) Postpartum (After Delivery): 

The postpartum appointment is usually scheduled for 6 weeks to 3 months postpartum, however patients are encouraged to call for support as needed. The purpose of the postpartum appointment is to ensure safe glycemic management, discuss future pregnancy planning and arrange for appropriate follow-up. 

Patients are reminded of the importance of reliable contraception postpartum and the need for future pregnancy planning. Breastfeeding is not a form of contraception and a woman can conceive in the months immediately postpartum even without the return of a menstrual cycle. 

  • Type 1 diabetes: Postpartum insulin doses are similar to or slightly less, especially if breastfeeding, than pre-pregnancy insulin dosing. Women should be encouraged to call the DIP clinic in the postpartum period for support, assistance with insulin adjustment and hypoglycemia prevention. 

  • Type 2 diabetes: The endocrinologist will often consider the use of Metformin during breastfeeding. The patient may need insulin if blood sugars are inadequately controlled with lifestyle and Metformin.