Planning a pregnancy: what should I look at in my diet?

When you start planning a pregnancy, look at five things in your diet: how often you eat folate-rich foods such as dark leafy greens, beans and peanuts; alcohol; caffeine; high-mercury fish; and liver. England's NHS lists a healthy diet and not drinking alcohol among the steps when you are trying to get pregnant. The Thai Reference Daily Intake (Thai RDI) for folate, set for the general population, is 400 µg DFE a day, and a 2023 study from Chiang Mai found that female university students there got on average 155 µg DFE a day from food. Talk to a doctor about regular medicines and other health matters before you start trying.

What is worth reviewing in my meals before pregnancy?

Planning ahead gives you time to change habits slowly rather than all at once. The table below brings together what public health bodies say about each item.

Five things to look at

Regular medicines

The NHS says not to stop any prescribed medicine until you have talked to your doctor or specialist. What to discuss with a doctor before you start trying is gathered in the last section of this article.

Do Thai women get enough folate from food?

Folate is a B vitamin found naturally in food. Thai studies, although small, point the same way: many women in the groups studied got less folate from food than the cut-offs the researchers used.

What Thai studies found

The limits of these numbers

Both studies were small and each came from one place, and the Bangkok study is now more than 20 years old. Food recall also depends on memory. They do not tell you about your own intake, but they suggest that leafy greens and beans are worth a closer look in a typical Thai diet.

The daily reference amount

The Thai RDI for folate is 400 µg DFE a day. It is a single value for the general population aged 3 and over, and it does not cover pregnant women, so ask a doctor or antenatal clinic about amounts before and during pregnancy. DFE (dietary folate equivalents) is the unit used to count folate from food and folic acid on one scale.

Which Thai foods have the most folate?

Per 100 g, dark leafy greens, dried beans and peanuts have the most folate among everyday plant foods, while white rice has very little.

Folate per 100 g of food

Figures from the US Department of Agriculture's FoodData Central database (SR Legacy), compared with the Thai RDI of 400 µg DFE. Thai varieties and cooking may give somewhat different amounts.

Why liver is not in the table

Chicken liver is very high in folate, at 578 µg DFE per 100 g in the same database. But the NHS advises avoiding liver and foods containing liver in pregnancy, because they are high in vitamin A, which can be harmful to the baby. If liver dishes, such as pork blood soup with liver or sweet stir-fried liver (tub wan), are a regular part of your meals, ask your doctor about them when you start planning.

Cooking keeps more folate when you steam

A 2002 UK study by McKillop and colleagues measured folate before and after typical home cooking. Boiling left about 49% of the folate in spinach and 44% in broccoli, while steaming caused no significant loss. The study did not measure stir-frying. In Thai cooking, that means steaming greens rather than boiling them, adding raw vegetables such as lettuce and bean sprouts as sides, and adding beans and peanuts to dishes you already eat.

Should I stop drinking alcohol while trying to get pregnant?

The US CDC says there is no known safe amount of alcohol use during pregnancy or when you are trying to get pregnant, and that all types of alcohol, including red or white wine, beer and liquor, can be harmful. The NHS also lists not drinking alcohol among the steps when trying for a baby, and says a doctor can help you find support if you need it.

How common drinking is among Thai women

The 2014 analysis found that women were more likely to drink regularly when family members and close friends drank, which is worth knowing when a partner or friends drink at meals. Both surveys rely on what people reported.

Making it easier in daily life

• choose soft drinks, soda water or iced tea with less sugar at parties and meals out
• tell close friends and family early, if you are comfortable, so you are not offered drinks
• if your partner drinks often, plan drink-free evenings together

Can I still drink coffee and tea?

The NHS advises limiting caffeine to 200 mg a day in pregnancy. The amounts it gives for common drinks:

Caffeine in common drinks

Thai drinks to keep in mind

Iced coffee and milk tea from coffee shops are often larger than a cup and may contain more than one shot, so the amount varies a lot. Energy drinks sold in small bottles also contain caffeine. If you have several coffee-shop drinks a day, counting them for a week before you try is a practical first step.

Which fish should I be careful with?

Fish is part of many Thai meals. The US FDA and EPA advice about eating fish is written for people who might become pregnant, are pregnant or are breastfeeding. It advises 2 to 3 servings a week (one adult serving is about 4 ounces, roughly 113 g) from the "Best Choices" list and avoiding the fish highest in mercury.

Best choices and fish to avoid

The NHS gives different figures

England's NHS advises that in pregnancy oily fish, such as salmon, trout, mackerel, sardines and herring, should be limited to 2 portions a week, and tuna to 4 cans or 2 tuna steaks a week, and that swordfish, shark and marlin should be avoided. Health bodies use different figures, so ask your doctor or antenatal clinic which guidance to follow.

Raw fish and seafood

The NHS advises avoiding raw fish and raw shellfish in pregnancy. In Thai dishes, that includes shrimp in fish sauce and som tam with raw crab. For more on food hygiene in pregnancy, see Pregnant and want to stay well. What can I safely do?

What should I talk to a doctor about before trying?

A visit before you start trying lets a doctor look at your whole picture, not just your diet.

What to bring and ask

• any medicines, supplements, health products or herbal products you already take, including ones you buy yourself; do not stop a prescribed medicine on your own
• your weight: the NHS notes that a weight that is too low or too high can make it harder to get pregnant
• how much you drink and smoke; the NHS lists getting support to stop smoking among the steps
• any regular health problems that a doctor already follows

When the NHS suggests seeing a doctor

The NHS suggests speaking to a GP if you want to get pregnant and live with a health condition or take regular medicines, or if you have been trying for a year or more without getting pregnant.

If you are pregnant, thinking of becoming pregnant, breastfeeding or take prescription medication, speak to a doctor or pharmacist before supplementing.

Dietary supplements are not intended to prevent, treat or cure any disease.