What is gestational diabetes?
During normal pregnancy, there is a rise in hormones which causes the mother’s body to become relatively insensitive to insulin, the hormone your body produces to lower blood sugar. A woman with gestational diabetes cannot make sufficient insulin to overcome this insensitivity and so develops diabetes, which usually disappears after delivery.
What is the treatment for gestational diabetes?
In many cases, adjusting the diet so as to avoid sugar will be enough. However, if the blood sugars are still too high when measured on home glucose meters, the next step is to start treatment. In the past, treatment was only with insulin injections. Now, there is an alternative to insulin called Metformin.
What is Metformin?
This is a tablet taken by mouth, which works by making the body more sensitive to insulin. It has been used for several years to treat diabetics, but has only been used recently to treat pregnant women with diabetes. It has been found to be as effective as insulin in controlling the blood sugar levels in pregnancy.
Is Metformin safe for the baby?
Experience from using metformin in a condition called Polycystic Ovary Syndrome, shows that it does not cause harmful effects to the baby when used in pregnancy. A very big study in Australia confirmed its safety and effectiveness in gestational diabetes. The government agency that looks at all treatments (NICE, the National Institute of Clinical Excellence) has recently approved its use in gestational diabetes. Despite this, at the present time, metformin is not licensed for use in pregnancy.
Can I choose to have metformin or insulin?
Certainly! We recognise that some women will prefer insulin injections and others will opt for metformin tablets. However, the studies show that most women prefer metformin to insulin.
Are there any side effects?
Metformin can cause abdominal discomfort, nausea, vomiting, diarrhoea, and disturbed taste. These side-effects are reduced by starting with a low dose and slowly building up. Also side-effects are much less if the drug is taken with food rather than on an empty stomach. Very rarely, it can cause a skin rash, in which we would have to discontinue it. The study in Australia found no significant difference in serious risk to mothers taking metformin when compared to the insulin group.
Are there any side-effects of insulin injections?
Insulin is an injection and cannot be given by mouth. It does not cross over to the baby, so the side-effects only relate to the mother. Obviously, if the dose is too high or the mother didn’t eat enough after her injection, insulin can cause ‘’hypo’s’’ where the blood sugar goes too low. ‘’Hypo’s’’ make patients feel faint and sweaty and need to be treated by taking sugar to bring the blood level back to normal. Another side-effect is weight-gain which is more likely with higher doses.
Does metformin cause ‘’hypo’s’’ or weight gain?
No. These are not side-effects of Metformin. In fact, women taking metformin were found to gain less weight in pregnancy when compared to those taking insulin both in the Australian study and from our findings at Epsom and St Helier.
Is metformin always sufficient?
Very occasionally we come across women whose blood sugar is poorly controlled on the maximum dose of metformin. Many times adjusting the diet corrects this. If not, we would need to commence insulin in addition to metformin. It is therefore important to continue monitoring your sugar levels and controlling your diet while on Metformin.
References:
1. Rowan J. et al. Metformin versus insulin for the treatment of gestational diabetes. N Engl J Med 358; 19. May 2008.
2. Diabetes in pregnancy. NICE clinical guideline 63. (www.nice.org.uk) March 2008.
