5 weeks pregnant: Pregnancy Symptoms & Baby Development

In week 5 of pregnancy, your baby, technically called an embryo, measures a little over 1mm long¹ – that’s roughly the size of a sesame seed. But already their brain, spinal cord and blood vessels are beginning to develop, albeit on a microscopic scale². Their circulatory system is also developing and it’s at around the end of week 5 that your baby’s heart starts to beat¹.

Meanwhile, the umbilical cord, which will deliver nutrients to your baby, is beginning to form². The amniotic sac, soon to be filled with a clear, pale fluid to cushion your baby, starts to take shape too³.

This may be the week that you find out for certain that you’re pregnant. If you’re not convinced by the absence of your period or other symptoms such as tender breasts and tiredness, at 5 weeks your hormone levels should be high enough to confirm the news on a home pregnancy test⁴.

Early pregnancy symptoms vary from person to person. At 5 weeks⁵, you may experience any of the following signs of pregnancy, or no symptoms at all:

A healthy, balanced diet should provide all the vitamin A your baby needs. In fact, there’s little to no risk of deficiency for pregnant mums in the UK – it’s more common in developing countries where malnutrition is a problem.

• Cheese
• Some yogurts (those with a higher fat content)
• Eggs
• Fortified low-fat spreads
• Green, leafy vegetables, such as kale and spinach
• Cantaloupe melon, mangoes and apricots
• Orange and yellow vegetables, including carrots, peppers, sweet potatoes, butternut squash and pumpkin

The richest sources of vitamin A, including liver, liver pâté and non-pregnancy supplements that contain it, should be avoided¹². If you’re taking a multivitamin, switch to a prenatal multivitamin that’s tailored to the needs of you and your baby.

Weight gain during pregnancy depends on your pre-pregnancy weight, and varies a great deal from mother to mother. Most women gain between 10kg and 12.5kg (22–28lb) while pregnant, some of which is the weight of the growing baby¹⁴. Learn everything you need to know about weight gain in pregnancy.