# Day 147: Heavier than the placenta

> Twenty-one weeks. Your baby now outweighs the placenta, and your balance is shifting. Today you write a three-line plan for a fall.

- Series: Your fifth month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-5), day 147 of 280, 21 weeks
- Your baby this week: about the size of a carrot; around 26.7 cm from head to toe
- Canonical URL: https://chorevia.com/learn/pregnancy-month-5/day-147
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 147: Heavier than the placenta." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-5/day-147

This guide is general education that summarizes published research and guidance from groups like the American Academy of Pediatrics, the CDC, and the WHO. It isn’t medical advice, and every child develops on their own timeline. Your pediatrician knows your child; if something feels wrong, call them. In an emergency, call 911.

Twenty-one weeks. A new week, a new number, and a small shift you may already have noticed on the stairs.

## Your baby

Around now your baby is around 26.7cm long from head to toe, about the size of a carrot, and now heavier than the placenta ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)). The placenta keeps growing, providing food and removing waste, but the baby has overtaken it ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)). They're getting ready for life outside the womb by developing sucking and breathing skills ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)).

## Your body

As the bump grows you may feel less steady on your feet: your centre of gravity has shifted and your joints are looser ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)). The hormone relaxin loosens ligaments, so your back, knees and ankles have less support than they used to ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-19/)).

The NHS advice for a fall is short: stay calm, but tell your midwife as soon as possible ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)). One group has an extra reason to call. If your blood type is Rh-negative, MedlinePlus says you should get RhoGAM after an abdominal injury in pregnancy, because your body can make antibodies against an Rh-positive baby's blood ([MedlinePlus](https://medlineplus.gov/ency/article/001600.htm)). Your blood type was checked at your first visit; the result belongs in your paperwork folder.

## Try today

### The fall plan

- **Time:** 5 minutes

1. Write three lines on the card by the phone: sit down, breathe, call the midwife or provider.
2. Under them, write "no wait and see". The NHS says to tell your midwife as soon as possible, not to wait ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)).
3. Add your blood type. If it's Rh-negative, write "tell them I'm Rh-negative" ([MedlinePlus](https://medlineplus.gov/ency/article/001600.htm)).
4. Read it aloud once to your partner, so it lives in two heads.

**Make it work:** If you don't know your blood type, ask at the next visit. It's one of the first-visit blood tests ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000544.htm)).

## Watch for

- **Normal:** feeling wobbly as the bump grows ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)). **Call your provider** as soon as possible after any fall, even if you feel fine ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/)).
- **Normal:** a bruised knee and a fright. **Call your provider today** after any blow to your belly if you're Rh-negative; RhoGAM is recommended after an abdominal injury ([MedlinePlus](https://medlineplus.gov/ency/article/001600.htm)).
- **Normal:** feeling shaken for an hour afterwards. **Seek care immediately** for vaginal bleeding or fluid leaking, or severe belly pain that doesn't go away ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)).

## For you

Slow is the safe speed now. Use the handrail, keep a hand free on the stairs, and let the door and the phone wait. This isn't a phase that passes next week: the NHS gives the same advice again at 29 weeks, when balance can feel off as your centre of gravity keeps shifting ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-29/)).

If you're the partner: take the laundry basket, the shopping, the stepladder jobs. Not because she can't, but because her balance has changed and yours hasn't. And if she does fall, you're the one who makes the call, calmly, straight away.

## Sources

- NHS. "Week 21." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-21/
- NHS. "Week 19." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-19/
- NHS. "Week 29." Week-by-week guide to pregnancy, Best Start in Life. https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/3rd-trimester/week-29/
- MedlinePlus. "Rh incompatibility." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/001600.htm
- MedlinePlus. "Prenatal care in your first trimester." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000544.htm
- Centers for Disease Control and Prevention. "Urgent Maternal Warning Signs and Symptoms." HEAR HER campaign, 2024. https://www.cdc.gov/hearher/maternal-warning-signs/index.html