Home / Conditions / Gestational Diabetes / Managing Clinical Problems in Diabetes, Case Study #13: Gestational Diabetes

Managing Clinical Problems in Diabetes, Case Study #13: Gestational Diabetes

Jul 15, 2011

Edited by Trisha Dunning AM, RN, MEd, PhD, CDE, FRCNA and Glenn Ward MBBS, BSc, DPhil (Oxon), FRACP, FRCPath


Mrs. ORA was referred to a diabetes educator when she developed diabetes at 29.5 weeks’ gestation. Mrs. ORA is a 30-year-old primigravida and is 29.5 weeks pregnant. She was referred to the diabetes educator from the antenatal clinic because her oral glucose tolerance test showed her BG was elevated at 8.7 mmol/L 2 hours after a 75-g glucose load….


Key points
  • Gestational diabetes occurs in 2-9% of all pregnancies.
  • Women who develop gestational diabetes are at increased risk of developing type 2 diabetes.
  • If diet and exercise do not control blood glucose, insulin will be required.

Gestational diabetes mellitus (GDM) occurs in 2–9% of all pregnancies (Hoffman et al. 1998). Evidence suggests that the use of insulin in treating high blood glucose levels in GDM reduces serious perinatal morbidity (Crowther et al. 2005). Pregnancy is an exciting time in a woman’s life. However, once the diagnosis of GDM is made, the pregnancy will be managed at a more intensive level of care. GDM is managed using diet and exercise but one in six women (or 16%) with GDM requires insulin. The care is usually transferred from the general practitioner to a multidisciplinary team that consists of an obstetrician, endocrinologist, diabetes educator and dietitian. Experts face the dilemma of managing GDM on a regular basis in diabetes centres. The potential need for insulin should be addressed promptly to improve fetal and maternal outcomes, and reduce maternal anxiety about the blood glucose levels and the impact they could have on the developing fetus, and the fear of the prospect of giving insulin injections.

Diabetes educator

The key educational issues for Mrs. ORA are:

  • Understand the importance of home blood glucose monitoring in gestational diabetes.
  • Decide when to start insulin in gestational diabetes mellitus.
  • Allay the woman’s fears about the impact of insulin treatment during the pregnancy.
  • Enable self-management of injections.
  • Prepare the woman for delivery and possibility of diabetes in the future.

The diabetes educator arranged for Mrs. ORA to be reviewed by the diabetes team. At the initial consultation it was important to reassure her and gain her trust. Mrs. ORA was taught to perform HBGM using a loan hospital blood glucose meter and was given dietary advice by the dietitian. Exercise within the limitations of advancing pregnancy was also encouraged. In Australia, women with GDM are registered through the National Diabetes Services Scheme (NDSS) for the duration of the pregnancy, enabling them to get blood glucose test strips at heavily subsidized prices. On review 1 week later, despite following the dietary advice and walking 20 minutes a day, Mrs. ORA’s blood glucose levels remained above the target goals.

The results in Table 10.1 clearly indicate the need for insulin, because more than 50% of the readings are > 5.5 mmol/L fasting or > 7.0 mmol/L 2 hours after meals. The Australian Diabetes in Pregnancy Society suggest that insulin should be considered if BGLs exceed the targets on two or more occasions in a 1- to 2-week period, particularly in the presence of macrosomia as determined by ultrasound. The insulin regimen should be tailored to address the times when hyperglycemia occurs. The table shows Mrs. ORA has hyperglycemia before breakfast and 2 hours after meals. She was prescribed a basal bolus regimen of a short-acting analogue with meals, and intermediate acting insulin at bedtime.

While there are no adequate well controlled studies in pregnant women, the shorter-acting insulin analogues, for example Humalog and NovoRapid, and the longer-acting insulin analogues, such as Lantus and Levemir, are preferred by some endocrinologists. This option is one that would be preferred if the benefits of improved glycemic control or well-being of the mother (decreased hypoglycemia, especially nocturnal events and anxiety) outweigh any possible risk of harm to the developing fetus. Mrs. ORA was asked to perform HBGM before and after meals to ascertain whether glycaemic targets were being met.


Time of introducing insulin is crucial to prevent fetal macrosomia. Often, only around 10–12 weeks remain before delivery, leaving only a small window of opportunity to correct the blood glucose levels. Regular review and dose titration is necessary to achieve targets without causing hypoglycemia.

A lot of women ask ‘why can’t I have tablets?’ Unfortunately, oral hypoglycaemic agents (OHAs) are not approved for use in GDM. Further research is needed to assess the long-term risks of fetal exposure to OHAs because of their possible teratogenic effect. Some endocrinologists do use metformin to reduce insulin resistance (Simmons et al. 2004), for example in the presence of polycystic ovary syndrome and type 2 diabetes, because the potential benefits outweigh the potential for harm to the fetus. Currently there are insufficient data to support using metformin in lieu of insulin in GDM.

Fetal monitoring is also increased depending on the individual woman. Weekly to twice-weekly cardiotocograph is performed from 32 weeks and ultrasound at 32 weeks to assess for fetal growth abnormalities and polyhydramnios. Repeat ultrasounds may be needed if there is any doubt about the diagnosis.


In the main, women with GDM are extremely motivated and proactive in their management because their main concern is the well-being of their babies. However, they often express concern about having to give themselves an injection. Once the technique is demonstrated and they experience the first injection they realize the needle is less painful than the fingerprick. They often comment afterwards ‘the injection was not that bad.’ Usually women with GDM are taught to use a disposable insulin delivery device such as a FlexPen or a cartridge pen. Syringes are rarely used. Disposal of used sharps is important and initially the woman is supplied with a disposable container until she is able to acquire one from her local council. If this is not possible a solid plastic bottle with a screw top can be used as an alternative. Disposal of sharps in household garbage is discouraged. Advice should be sought from the local council about disposal regulations.

In the event of needle phobia, the PenMate, a device designed for people who dislike needles, can be used. It has an auto self-inject mechanism that slips over the NovoPen and hides the needle from view when injecting. 

Reinforcing rotating injection sites, using a new needle every time, and gentle insertion enable most women to confidently manage their GDM well. Occasionally, family may be required to assist. When discussing the need for insulin, asking the woman and her family whether they have any questions or fears helps ascertain whether there are likely to be any issues such as needle phobia or failure to follow advice as recommended. Insulin stabilization is best achieved on an ambulatory basis with close communication among the woman, the diabetes educator and endocrinologist.

The endocrinologist decides on a delivery date, usually around 37 weeks. The plan depends on the timing of delivery and becomes obsolete if the woman goes into spontaneous labor. In this situation, the woman should contact the diabetes service regarding her insulin therapy or go directly to the delivery suite and her insulin requirements and blood glucose levels will be reassessed. However, insulin is usually not required in active labor. If the blood glucose is >126mg/dL.(7.0 mmol/L) the doctor may order a dose of rapid-acting insulin. The pre-delivery plan needs to be recorded in the medical history or a letter that includes insulin instructions that the woman takes to the hospital with her. The labor ward should be aware of the insulin plan and who to contact for advice about blood glucose levels. The diabetes educator can also assist the midwives to interpret the blood glucose pattern while the woman is in labor. Usually BGM is performed 2-hourly during labor.

Insulin is not given postpartum. Occasionally it takes 24-48 hours for the blood glucose levels to return to normal. Hyperglycemia in a normal postpartum may be directly linked to a change in dietary habits. After having spent the past few weeks being very careful, the woman may be tempted to splurge on treats initially. Accepting that the birth is a time of celebration, the diabetes educator can gently remind the woman that these treats should always remain just that — treats.

The aims of the book are to: (1) address commonly encountered diabetes management problems; (2) develop comprehensive responses from a range of relevant health professionals who suggest management approaches relevant to their area of practice. The specific health professionals who provide comments about each case depend on the specific clinical issue; and (3) stimulate thought and discussion. 

The target readership is health professionals from a range of professional backgrounds and general as well as specialist professionals such as general practitioners, nurses, dietitians, and podiatrists. The book will be particularly useful for beginner practitioners specializing in diabetes. In addition, it will provide suggestions or food for thought for more experienced practitioners. The cases will be excerpts from the book are all real and are presented exactly as the information was received from the person making the referral. General practitioners, diabetes educators and people with diabetes referred most of the cases; some were self-referrals by people with diabetes. They represent referrals to various diabetic health professionals and concern commonly encountered clinical issues.

Next Week: Case Discussion

For more information on the book, just follow this link to Amazon.com, Managing Clinical Problems in Diabetesalt

Copyright © 2008 by Blackwell Publishing Ltd, UK

Edited by Trisha Dunning AM, RN, MEd, PhD, CDE, FRCNA and Glenn Ward MBBS, BSc, DPhil (Oxon), FRACP, FRCPath