You and Your Baby at Week 13 of Your Pregnancy

Your baby is the size of a peach!

(10 minute read)

Article at a glance

  • How big is baby at 13 weeks?
  • Your body at week 13
  • Nutritional needs at week 13

13 Weeks Pregnant

Week 13

Welcome to the 2nd trimester!

Now you are a third of the way through your pregnancy, the worst of your pregnancy symptoms should now be subsiding. Week 13 marks the end of the first trimester, which is often accompanied by a sense of relief and excitement.

This could be the week that you have your first scan and the first time you see your baby. This can be an exciting and anxious time - we hope that however you're feeling, you get to enjoy the experience of hearing and seeing them for the very first time.

How Big is Baby at 13 Weeks?

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At 13 weeks, your baby weighs about 25g and is about 7.4cm long from crown to rump, roughly the size of a peach! This measurement may vary slightly from baby to baby. Despite being small, the baby's body proportions are starting to become more balanced, with the head no longer dominating the size as much as in earlier weeks. Your baby is now fully formed and actually resembles a human being. They won't be ready to be born for another 6 months. 

The internal sex organs (ovaries or testes) are now fully developed, and the genitals are forming on the outside. It is still too early, however, to determine the sex of your baby on an ultrasound scan. If you do want to know the gender of your baby then you can book a Harmony Test. There is an associated cost to a Harmony Test. Most parents wait until their 2nd scan at around 20 weeks of pregnancy, and some opt to find out at birth!

Baby will be moving around a lot with small, jerky movements, but you will not be able to feel anything until you're mid-way through the 2nd trimester. If this isn't your first baby, then you could feel your baby move sooner. Where your placenta is also effects what you will and won't feel. If your placenta is at the front of your bump, then this can mask kicks.

Your baby may be sucking his or her thumb - this helps to develop the sucking reflex, which is needed when starting to feed.

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Your Body at Week 13

As you enter the second trimester, you might notice some changes in your body. You may now notice your bump developing as your womb grows and moves upwards. Other changes you may notice are:

  • Reduced Morning Sickness: Many women find that nausea and vomiting decrease or even disappear around this time.
  • Increased Energy: The fatigue of the first trimester often diminishes, leading to a boost in energy levels.
  • Increased Sex Drive: If this is happening to you, it is probably a result of pregnancy hormones or increased blood flow to the pelvic area.
  • Increased Thirst: This is due to the increase in blood volume. Make sure you stay hydrated.
  • Change in Appetite: Appetite may increase as morning sickness wanes.
  • Gum Problems: Your gums may be swollen, painful or bleeding.
  • Breast Changes: Your breasts may continue to grow and feel tender as they prepare for breastfeeding.
  • Visible Veins: Increased blood supply may make the veins in your breasts more visible.
  • Increased Discharge: A thin, milky vaginal discharge is normal due to increased estrogen and blood flow to the vaginal area.
  • Mood Swings: Hormonal changes can continue to contribute to emotional ups and downs.


Nutritional Needs at Week 13

Good nutrition is essential for both your health and the baby's development. If you feel able to, focus on:

  • Balanced Diet: A diet rich in fruits, vegetables, whole grains, lean protein, and healthy fats.
  • Hydration: Drinking plenty of water is important to support the increased blood volume.
  • Prenatal Vitamins: Continue taking prenatal vitamins to ensure you're getting enough folic acid, iron and calcium.

Exercise and Activity

Moderate exercise is beneficial during pregnancy, and the second trimester is often a great time to engage in physical activity as energy levels may be higher:

  • Safe Exercises: Walking, swimming, and prenatal yoga are excellent choices.
  • Listen to Your Body: Avoid overexertion and contact sports.
  • Regular Movement: If you have a sedentary job, try to take short, frequent breaks to move around.

Medical Care and Checkups

Regular prenatal checkups are crucial throughout pregnancy:

  • Ultrasound Scans: Around week 13, you might have an ultrasound to check your baby's development.
  • Discuss Symptoms: Always discuss any concerns or unusual symptoms with your doctor or midwife.

Emotional Well-being

Emotional health is just as important as physical health during pregnancy:

  • Support Network: Stay connected with your partner, family, and friends.
  • Relaxation Techniques: Practices like meditation and mindfulness can help manage stress.
  • Antenatal Classes: Consider joining antenatal classes for information and support.

Preparing for the Future

This stage of pregnancy is also a great time to start planning:

  • Baby's Needs: Start thinking about baby gear, clothing, and nursery preparations.
  • Financial Planning: Consider the financial costs of your new baby.
  • Parental Leave: Look into your options for maternity and paternity leave.


As the first trimester comes to a close, many women find relief in diminishing symptoms and enjoy a renewed sense of energy. It's important to continue taking care of your physical and emotional health and to stay informed about the changes and developments occurring during this exciting time.

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