If you have PCOS and you are planning a pregnancy, one term worth knowing early is GDM, short for gestational diabetes mellitus, the form of diabetes that appears during pregnancy. This is not meant to frighten you. Because the risk can be reduced, knowing about it early actually works in your favour. Women with PCOS are indeed more prone to GDM, but there is a great deal you can do before and during pregnancy to keep blood sugar steady.

Why PCOS raises GDM risk

The common thread between PCOS and GDM is insulin resistance. In many women with PCOS, the body is already less sensitive to insulin before pregnancy even begins. Once you are pregnant, the placenta releases hormones that naturally make every mother’s body more resistant to insulin, so that enough glucose reaches the baby. For a woman who starts with existing insulin resistance, this added load more easily exceeds what the pancreas can keep up with, and blood sugar climbs.

How large is the risk? Pooled analyses of several studies find that women with PCOS have roughly two to three times the odds of developing GDM compared with women without PCOS. That is an average estimate, not a prediction about you personally. Factors such as body weight, family history of diabetes, and ethnicity all contribute. For Malaysian women, Asian ethnicity is itself a recognised GDM risk factor, so the combination of PCOS and this background deserves to be taken seriously, not with anxiety, but with preparation.

It is also worth understanding that GDM is not a personal failing. It is a biological mechanism, and it can be managed.

What you can do before pregnancy

The most valuable window for lowering GDM risk is before you conceive, not afterwards. This is when lifestyle effort gives the biggest return.

  • Pre-pregnancy weight. If you carry excess weight, a modest loss of 5 to 10 percent before conceiving is enough to improve insulin sensitivity meaningfully. You do not need to reach an “ideal” weight to benefit.
  • Eating pattern. Favour foods that release sugar slowly: brown or mixed rice, more fibre-rich vegetables, protein at every meal, and fewer sweet drinks and sugary kuih. Local dishes such as nasi lemak or roti canai do not have to be banned outright; just manage how often and how much.
  • Daily movement. Brisk walking, light resistance training, or anything you can keep up a few times a week all help your muscles take up glucose more efficiently.
  • Folic acid and early checks. Start folic acid before trying to conceive, and if you can, ask for a baseline blood-sugar check at a pre-pregnancy visit so you know your starting point.

Malaysian women often say that weight and fertility are the hardest parts of PCOS, more so than symptoms like excess hair. If that is true for you, know that the same effort to manage weight also protects your future pregnancy. For the bigger picture on improving PCOS fertility, see our PCOS fertility guide, and if you are newly diagnosed, start with the first steps after diagnosis.

The role of inositol and metformin (what the evidence really shows)

This is the part most often misunderstood, so let us be honest about the level of evidence.

Myo-inositol. This naturally occurring compound has been studied for reducing GDM. The doses used in studies are typically 2 grams twice daily (4 grams total), sometimes with 200 micrograms of folic acid, starting around the first trimester. Some studies show fewer cases of GDM. However, the 2023 Cochrane review rated the certainty of evidence as low to very low, partly because most trials were small and run in a single country (Italy), so they may not represent Malaysian women. In other words, inositol may well help and is generally safe, but it is not a guarantee and not a substitute for monitoring. Do not start it on your own during pregnancy without discussing it with your doctor, and if you do choose a supplement, check its halal status and NPRA registration.

Metformin. The 2023 international PCOS guideline notes that observational data suggest continuing metformin through pregnancy may reduce GDM in some women with PCOS, with no sign of harm to the baby. But metformin is not routinely recommended purely to prevent GDM in every woman; this decision is highly individual and must be made by your doctor, not by yourself. If you were already on metformin before pregnancy, do not stop it on your own; ask your specialist first.

No supplement makes PCOS go away or fully removes GDM risk. Think of inositol and metformin as add-on tools to discuss, not magic wands.

GDM screening in Malaysia: what to expect

In Malaysia, the main screening test for GDM is the 75-gram OGTT (oral glucose tolerance test). You fast overnight, blood sugar is taken while fasting, then you drink a glucose solution and blood is taken again after one and two hours.

The OGTT is usually done around weeks 24 to 28 of pregnancy. But because PCOS is a risk factor, your doctor may screen you earlier, sometimes at the first antenatal visit, and repeat it later if the early result is normal. The Ministry of Health Malaysia has indeed been moving towards earlier and more universal screening, so do not be surprised if you are asked to do an OGTT sooner than expected. Tell your antenatal team that you have PCOS so they can plan monitoring appropriately.

On cost, pregnancy follow-up at a government Klinik Kesihatan is very affordable for citizens, with a basic fee of around RM1 per visit that includes basic investigations, while private clinics and hospitals charge more and vary. If you conceived through fertility treatment, learn more in our guide to IVF for PCOS in Malaysia.

If you are diagnosed with GDM: it is not the end

Many women with PCOS who do develop GDM still deliver healthy babies. Management usually begins with home blood-sugar monitoring, dietary adjustments, and movement. If diet alone is not enough, your doctor may add medication, and insulin is safe to use in pregnancy when needed.

One thing many Malaysian women do not realise: GDM is a signal that you are at higher risk of type 2 diabetes later in life. After delivery, blood sugar usually returns to normal, but you should repeat an OGTT around six weeks postpartum and continue regular checks. For women with PCOS, this is an important reminder that metabolic health is a long-term journey, not just a pregnancy issue.

When to see a doctor

Speak with an obstetrician or endocrinologist before trying to conceive if you have PCOS, so monitoring and medication can be planned early. During pregnancy, seek prompt advice if you have extreme thirst, unusually frequent urination, or a high OGTT result. To understand the basics of the condition, see our article on what PCOS is. Diagnosis and treatment of GDM must be managed by your medical team, and the information here is guidance, not a replacement for personal clinical advice.