What may change in your body
For many pregnant women, energy starts to come back. The growing uterus can cause a pulling sensation on the sides of the abdomen. Gums may swell or bleed easily and the nose may become more sensitive due to vascular and hormonal changes.
Care for this week
Look after your gums without stopping brushing and flossing out of fear of bleeding.
Get up slowly if you're feeling dizzy.
Choose clothes for comfort, without waiting until you 'need to look pregnant' to wear looser pieces.
Prenatal care focus
- Go over the tests and screenings done in the first trimester with your team, and what's planned for the second.
If you're expecting twins
With twins, the ultrasound schedule depends even more on chorionicity and individual findings.
For those by your side
This can be a good time to start planning appointments, the budget and the baby's logistics without trying to sort everything out at once.
Questions for this week
Is week 13 already the second trimester?
Some references use different cut-offs. At Nilu, week 13 is still part of the first trimester; the second begins in week 14.
Is it normal to feel pulling in my belly?
Mild discomfort can come with the growth of the uterus, but severe or persistent pain should be evaluated.
When to seek care
- Vaginal bleeding during pregnancy should be reported to your care team; how heavy it is, pain and gestational age change how urgent it is.
- Severe, worsening or persistent abdominal pain deserves evaluation.
- Fever, fainting, significant shortness of breath, chest pain or feeling very unwell need medical care.
In an emergency, go to the urgent care service in your area. This content does not replace a professional assessment.
The next chapter
In week 14, many officially enter the second trimester and the focus shifts more and more to fetal growth and body changes.
See week 14Was this helpful?
Sources and transparency
- Brazil's Ministry of Health — Brazilian Pregnancy Booklet, the official prenatal record (Caderneta Brasileira, updated in 2026)
- Brazil's Ministry of Health — Prenatal care (Ministério da Saúde — Pré-natal)
- Brazil's Ministry of Health — High-Risk Pregnancy Manual — Multiple pregnancy (Manual de Gestação de Alto Risco — Gestação múltipla)
- NHS — Week-by-week guide to pregnancy
- ACOG — How Your Fetus Grows During Pregnancy
- Brazil's Ministry of Health — Prenatal tests and vaccines (Ministério da Saúde — Exames e vacinas no pré-natal)
Nilu editorial content, written from the official sources above. Individual clinical review of each week is in progress — this text is for information and does not replace your prenatal care.