Things to avoid during pregnancy

The genuine list is shorter than the one your relatives will give you. No alcohol, no smoking, caffeine under 200 mg a day, no raw or undercooked fish and meat, no unpasteurised dairy, and nothing that raises your core temperature. Most other rules you will hear are custom rather than evidence.

Food and drink

The American College of Obstetricians and Gynecologists sets the caffeine ceiling at under 200 mg a day, about two cups of brewed coffee. Hawker kopi varies by stall and is often stronger than that implies, so one a day is a safer assumption than two.

On fish, the US Food and Drug Administration advises avoiding the highest-mercury species, such as shark, swordfish, king mackerel, marlin and bigeye tuna, and eating 2 to 3 servings a week of lower-mercury fish instead. Salmon, prawns, sardines and anchovies all sit in its lowest group, which contradicts a popular belief that all seafood is risky.

Our longer list of foods to avoid during pregnancy goes into the detail.

Raw fish, and a local outbreak worth knowing about

In 2015 the Ministry of Health investigated a cluster of invasive Group B Streptococcus infections in Singapore and linked it to raw Chinese-style freshwater fish dishes, after which advice against eating raw freshwater fish followed.

That history is the reason this warning is stronger here than in a general pregnancy guide. Raw freshwater fish, including the sliced fish served raw in porridge and in some yusheng preparations, is best left alone entirely.

Cooked is fine. Fish soup, steamed fish and fried fish are all good food during pregnancy, and the issue is temperature rather than the fish.

Smoking, vaping and secondhand smoke

Smoking restricts the oxygen and nutrients reaching your baby and raises the risk of low birth weight, prematurity and stillbirth. Vaping is not a safe substitute, since nicotine itself affects fetal development.

Secondhand smoke counts. A corridor or a coffee shop where someone smokes beside you is worth moving away from, politely or otherwise.

HealthHub, the Ministry of Health's public portal, lists smoking cessation support, and your polyclinic can start you on it. Quitting at any point in pregnancy helps, and quitting early helps most.

Medicines and supplements

Check before you take anything, including things that feel harmless.

Paracetamol is the usual first-line painkiller. Ibuprofen and similar painkillers (the NSAID group) are generally avoided unless your doctor advises otherwise, particularly from around 20 weeks. Herbal and traditional preparations are not automatically safe, and several are not recommended in pregnancy. Ask your doctor or pharmacist before taking any of them.

Bring every bottle to your antenatal visit, supplements included. Doubling up on vitamin A is a genuine risk once several well-meaning relatives start buying tubs, and high-dose vitamin A is one of the few supplements with clear harm in pregnancy.

Heat, saunas and hot yoga

The concern is your core temperature rather than comfort. Raising it substantially, particularly in the first trimester, is linked to neural tube defects, which is why saunas, steam rooms, hot tubs and hot yoga all come off the list.

A warm shower is fine. A long soak in a hot bath, less so, and a 40 °C studio class is the clearest one to drop.

This matters locally in a quieter way too. An afternoon walk in full Singapore sun can leave you overheated and dizzy, so shift exercise to early morning, a pool, or an air-conditioned room.

Mosquitoes, dengue and Zika

This is the Singapore section most imported pregnancy guides lack.

Dengue circulates here all year and the National Environment Agency publishes cluster information and case numbers. Dengue in pregnancy carries added risks, including bleeding complications around delivery and early birth, so prevention deserves real attention.

Zika is the other one. The Ministry of Health maintains advice for pregnant women on Zika, because infection during pregnancy can cause serious birth defects. That advice covers both local transmission and travel.

Practical measures: repellent on exposed skin, long sleeves outdoors (Aedes bites mostly by day, especially early morning and late afternoon), screens or air-conditioning, and no standing water in plant pots or trays on the balcony. Our article on dengue prevention covers the repellents and the housekeeping in detail.

Fever in pregnancy is not something to wait out. Call your doctor the same day.

Skincare and salon treatments

Retinoids come off the list, as does hydroquinone. Strong peels and laser work are generally deferred until after delivery, mainly because the data is thin and pregnancy skin reacts unpredictably, rather than for any reason involving radiation reaching your baby.

Unregistered skin-lightening creams are a real hazard rather than a precaution, since products outside the regulated system still turn up containing mercury. Buy from Guardian, Watsons, Unity or an established retailer.

Ordinary cosmetics, hair colouring after the first trimester, manicures and gentle facials are all generally considered acceptable. Our article on harmful chemicals in pregnancy and breastfeeding separates the established risks from the marketing.

Fluoride toothpaste belongs in neither list. Dental authorities recommend brushing twice a day with it, pregnancy included, and gums that bleed more easily in pregnancy are worth mentioning to your dentist. Our piece on choosing a toothpaste in pregnancy covers the choice for those who prefer a non-fluoride formula.

What you do not need to avoid

• Foods you are not allergic to. Avoiding peanuts or seafood to prevent allergy in your baby is not recommended, and routine allergy testing is unnecessary without symptoms
• Washed raw vegetables and fruit. Salad is fine; unwashed produce is the risk
• Exercise. Regular moderate activity is recommended for most pregnancies
• Sex, in a straightforward pregnancy
• Cats, provided someone else changes the litter tray
• Flying, in most straightforward pregnancies up to around 36 weeks, after checking with your doctor and the airline's policy
• Cold drinks and cold water, which several confinement traditions restrict without evidence

Weight-loss dieting is the one to be careful with in the other direction. The American College of Obstetricians and Gynecologists sets weight gain targets by starting weight, and restricting intake during pregnancy is a conversation with your doctor rather than a project to start alone.

Our article on avoiding things that cause birth defects covers the narrower set of exposures with the strongest evidence behind them.