Source: aksljeme.com
Strict blood sugar level control is very important in pregnant women. Uncontrolled or high levels of blood sugar in pregnancy can have several adverse effects on the fetus such as;
- Excessive birth weight (big baby)
- Early (preterm) labour
- Respiratory distress syndrome
- Low blood sugar (hypoglycaemia)
- Type 2 Diabetes Mellitus in later life
Patients with Type 2 Diabetes Mellitus on oral blood sugar lowering medication known as oral anti-hyperglycaemic agent (OHA) are often switched to insulin for better control.
Metformin is an effective OHA commonly used to manage Type 2 Diabetes Mellitus. Since Metformin is able to cross the placenta, its use during pregnancy raises concerns regarding potential adverse effects on the mother and fetus. Metformin is a category B drug for use during pregnancy. This means that animal reproduction studies have failed to demonstrate a risk to the fetus and that there are no adequate and well-controlled studies in pregnant women. However, recent studies in both animals and humans indicate that although Metformin does cross the placenta, it does not necessarily cause fetal defects or other serious adverse effects.
The most important issue should always be to maintain good glycaemic control or normal levels of glucose during pregnancy. Although an oral medication may be preferable to patients compared to insulin injections, Metformin alone may not be able to control blood sugar levels in patients with multiple risk factors for insulin resistance and may require supplementary insulin.
Even though there are studies that support the efficacy and safety of Metformin during pregnancy with respect to immediate pregnancy outcomes such as no teratogenic effects, number of intra uterine deaths, stillbirths and preterm labour, follow-up is still needed to determine whether long term effects of Metformin. Such as whether Metformin decreases or increases the development of obesity and diabetes in the babies later in life. As of now, whether or not Metformin should be administered throughout pregnancy is still a controversial issue. Currently, there are no clear guidelines regarding this, therefore the choice to use Metformin and duration of treatment is based on clinical judgment on a case-by-case basis. Larger studies need to be conducted to determine whether Metformin can be considered a reasonable alternative to insulin in pregnant women with Type 2 Diabetes Mellitus. For now, what is most important is for mothers at risk of GDM to be screened via Modified Oral Glucose Tolerance Test (MOGTT), affectionately known as “test air gula” so that those with GDM can be detected and followed up properly. Patients with GDM and Type 2 Diabetes Mellitus need to take their blood sugar control seriously and follow their obstetrician’s advice, regardless of whether they are on diet control (GDM), on Metformin or Insulin treatment. Working together with their doctor will help ensure a non-eventful pregnancy and labour for the mother and a healthy baby as the prize at the end of the journey.
Dr. Hidayah is a medical lecturer in a local university with a Masters in Pharmacology. She is also the Chief Editor of The Malaysian Medical Gazette.
References:
- Metformin a rising standard in gestational diabetes, Medical Tribune, 15-31 October 2013
- Fantus I. G. (2015), Is metformin ready for prime time in pregnancy? Probably not yet, Diabetes Metab Res Rev, 31, 36–38, doi: 1002/dmrr.2587
- Efficacy and safety of metformin during pregnancy in women with gestational diabetes mellitus or polycystic ovary syndrome: a systematic review, ME Lautatzis et al. – Metabolism, 2013
- A Pilot Randomized, Controlled Trial of Metformin versus Insulin in Women with Type 2 Diabetes Mellitus during Pregnancy. JS Refuerzo et al. American Journal of Perinatology 2015 DOI: 10.1055/s-0034-1378144
[This article belongs to The Malaysian Medical Gazette. Any republication (online or offline) without written permission from The Malaysian Medical Gazette is prohibited.]