In association with professional midwife experts at birthEd, find out everything you need to know about pregnancy at 13 weeks, including how your baby is growing, changes to expect in your body and pregnancy health, nutrition and wellness advice.

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13 Weeks Pregnant – Your baby, your body & you

Your Baby

At this point, your baby is approximately 8cm long and 28grams. Not only is your baby growing rapidly, so is your placenta. This will weigh anywhere between 450gm and 1kg.

Placenta at 13 weeks

Your baby has started swallowing amniotic fluid and excreting it as urine. This is practice for eating and digesting in the outside world. This practice also helps maintain the right amount of fluid in the amniotic sac. Too much or too little amniotic fluid can be an indicator of digestive or urinary system issues in your baby.

Your baby is also starting to accumulate meconium in their colon. Meconium is made up of waste products from ingesting amniotic fluid, mucus, skin cells, and it is a thick, green – brown and a tar like substance. This will be expelled as the first bowel movement once the baby is born and is usually passed within the first 24 hours.

Your Body

As you are now coming out of the first trimester, you will hopefully start to feel a bit better if you have been experiencing nausea, vomiting, or fatigue.

Whilst this is a common progression, for some, these symptoms can last longer for others. Contact your LMC if you are concerned about these or any other symptoms.

With this newfound energy, many women find a welcome increase in their sex drive. It is completely safe to have sex during pregnancy. Unless you have been advised by your LMC or doctor to not have sex, you are safe to have sex whenever and however you feel, provided you are comfortable.

Although it is obvious you do not need to use condoms to prevent pregnancy, if you are having sex with someone new, continue to practice safe sex for the prevention of sexually transmitted infections.


This time between the first and second trimester can feel scary and uncertain, particularly if you have had a previous miscarriage. It is important to talk to someone you trust when you are feeling scared.

A happy mama is a healthy mama.

Looking after yourself is paramount, stress and anxiety can manifest in various ways. Talk to your midwife or health professional if you are feeling anxious about this stage of your pregnancy, there are some great free resources in New Zealand for maternal mental health and speaking with your midwife is a great way to open the door to an opportunity you might find supportive.

Perinatal Anxiety and Depression Aotearoa is also an excellent resource and we recommend exploring their website.

Your Relationships

Now is the time many like to share the news with extended family and friends.

If you feel comfortable, you may want to consider telling your place of work as well. This gives plenty of time for you and your work to start planning when you will take leave and when or if you will return to work.

It is a good time to start discussing with your partner, family, and whanau what you would like to or are going to be able to manage when it comes time to give birth and having time off work. Find out all about parental leave entitlements as well as working for families entitlements.

This Week’s Preparation

Tell family and friends the good news
Discuss maternity leave with support people (partner, whanau etc)
Talk to your employer

Back to 52 Weeks of pregnancy.

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This information was compiled by the Kiwi Families team.

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