10 weeks pregnant: baby is the size of a kumquat

Your baby this week

The embryonic period, when organs are first formed, is nearly over. The heart, brain, lungs, kidneys, liver and intestines are all present, although they are still small and immature. Your baby's wrists and ankles are visible, and the fingers and toes are separate. Eyelids have formed, and the outer ears are taking shape.

The bones are starting to harden, beginning in areas such as the skull and collarbones. Tooth buds are developing under the gums. Your baby is also moving more, with kicks, stretches and rolls that you cannot feel yet.

How it happens. Many of your baby's organs work at a small scale before birth. The kidneys, for example, begin making urine soon, and your baby adds it to the amniotic fluid. Your body, through the placenta, does most of the work until your baby is born.

Your body this week

Your uterus is about the size of a grapefruit, and your waistline may be thicker. The placenta is growing quickly and will take over hormone production from the ovary by around week 12. Your blood volume continues to rise, and your heart is working harder.

Many people find that nausea peaks about now and eases soon after. If you are queasy, it can help to know that your body is doing an enormous amount of work.

How to read a prenatal vitamin label

A prenatal vitamin is a safety net, not a substitute for food. Its job is to cover nutrients that are hard to get in enough amounts from diet alone, or that matter most in a specific window. These are the ones to check.

Folic acid. This prevents neural tube defects, which are problems with the brain and spinal cord that develop in the first weeks. Most national advice is 400 micrograms (mcg) a day, with an end date of week 10 in the Netherlands, week 12 in the UK, Denmark, Norway and Finland, and later in Canada, which advises continuing through pregnancy and breastfeeding. Some people, such as those with certain health conditions or a family history, need a higher prescribed dose. If that may apply to you, ask your provider.

Folate on a label can be listed as dietary folate equivalents (DFE), and the DFE number can be higher than the actual folic acid content. Do not add the two together.

Vitamin D. Many countries advise a daily supplement: 10 mcg in the UK (especially in fall and winter, and all year for some groups, such as people with darker skin), Denmark and the Netherlands, and 15 mcg in Ireland. Sunlight is not a reliable source in many places. Check what is advised in your country.

Iron. Reference intakes are 27 mg a day in the US and 16 mg in Europe (EFSA), and the WHO recommends 30 to 60 mg of elemental iron daily in places where anemia is common. Denmark starts routine iron at week 10, while Norway and Ireland test first. Iron needs vary. Do not take extra iron to treat tiredness until a blood test shows a need, because more is not better and it can worsen constipation.

Iodine. Iodine supports your baby's brain development. Sources include iodized salt, dairy, eggs and seafood, but availability differs. Australia's NHMRC, for example, advises a 150 mcg supplement during pregnancy, and Germany's BfR describes 100 to 150 mcg after medical consultation. Check whether your vitamin has it, and whether your country recommends a supplement. If you have a thyroid condition, ask your provider.

Calcium and choline. Reference intakes are 950 to 1,000 mg of calcium a day and 450 to 480 mg of choline (US and EFSA). Many prenatal vitamins contain little of either. Dairy, fortified drinks, calcium-set tofu, eggs and meat are useful sources.

Omega-3 (DHA). This is found in oily fish and in algae-based supplements. Research on supplements is mixed, and one dose does not suit everyone. Ask your provider whether you need one, and check the DHA amount, not only the fish oil weight.

Vitamin A. Choose a product where vitamin A is in a safe range and avoid extra vitamin A or cod liver oil unless advised.

Vitamin B6. Add up the total from every product. The European upper intake for adults is 12 mg a day and the US limit is 100 mg a day, and a prenatal, a B-complex and a nausea product can add up.

Practical tips for choosing and taking your vitamin

• Compare the whole serving. Some brands ask for two or three tablets a day.
• Avoid doubling up. A multivitamin, a separate vitamin D and an iron pill can add up. Add the amounts.
• Take it with food or at bedtime if it upsets your stomach. If it makes nausea worse, ask about another form, such as a chewable or a lower-iron version.
• Do not stop at week 10 or 12 without asking. The high-priority window for neural tube protection ends around then, but nutrition needs continue. Many providers advise continuing a prenatal vitamin throughout pregnancy.
• Keep a food-first approach. Vegetarian and vegan diets need extra attention to vitamin B12, iodine, iron, calcium and DHA. The diet and supplements guide covers this.