You are 5 weeks and 2 days

There won't be any outward signs of pregnancy for a while, but many changes are happening inside.

243 days until your due date

At this early stage, all your baby's needs are met by the yolk sac. This balloon-like structure is attached to the embryo by a stalk and marks where the pregnancy is. It can often be seen on a scan this week as a sphere 0.1–0.2 in (3–4 mm) across, at first as big as the disk of cells that will become your baby.

The yolk sac contains cells that work like a liver: it releases several pregnancy hormones and makes the embryo's first red blood cells. After week 9, the liver takes over these jobs, and the yolk sac gradually disappears as the placenta takes over, by around week 10.

Over the next seven days, a basic circulatory system develops, well before any blood flows to the placenta in week 10. By the end of this week, the very best ultrasound equipment can just pick up the embryo's heartbeat. At this stage, the heart is simply a tube.

As a matter of fact

Keep taking folic acid

Keep taking a 400 mcg folic acid supplement every day until week 12.

Take it alongside a balanced diet that includes green vegetables and legumes. Many fortified cereals contain folic acid too, as do some fruits, such as oranges, papaya, and bananas.

Ask a Nutritionist

Should I be eating for two?

Sadly, pregnancy isn't a license to eat whatever you like. "Eating for two" is a myth that leads to too many calories and too much weight gain. Use common sense: studies show pregnant women who eat according to their appetite naturally eat the right amount and gain a healthy amount of weight.

Calorie needs vary a lot depending on your pre-pregnancy weight and activity, but in general they rise by about 300–500 calories a day, at the lower end of that range in the first trimester.

In the first trimester, up to 80 percent of women have nausea or vomiting, so getting enough calories can be hard. Many women feel sickest on an empty stomach, so snacking helps: five small meals instead of three large ones can settle your stomach and still give you the calories you need. If big plates of food are too much, mix small portions at mealtimes with snacks.

This is general information based on NHS guidance, not medical advice, and every pregnancy is different. Talk to your midwife or GP about anything that worries you. If your baby's movements slow down or change, or you have bleeding, severe pain or leaking fluid, call your maternity unit straight away. In an emergency, call 999.