# Day 123: Sleep problems

> Seventeen weeks and four days. Why sleep gets harder now, the pillow arrangement that helps, and the bedtime habits worth changing tonight.

- Series: Your fourth month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-4), day 123 of 280, 17 weeks + 4 days
- Your baby this week: about the size of a pomegranate; around 12 cm from head to bottom
- Canonical URL: https://chorevia.com/learn/pregnancy-month-4/day-123
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 123: Sleep problems." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-4/day-123

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.

Seventeen weeks and four days. Tonight you build a bed out of pillows. Everything before that is why.

## Your baby

Around 12cm from head to bottom, roughly the size of a pomegranate ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-17/)). The mouth can open and close now, and your baby reacts to loud noises ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-17/)). They may also move more while you relax ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-17/)), which is part of why bedtime gets busier from here.

## Your body

Sleep problems and tiredness are on this week's NHS list ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-17/)). MedlinePlus explains the mechanics: your kidneys filter extra blood and make more urine, and the growing baby presses on the bladder, so there are more bathroom trips at night; digestion slows, which can cause heartburn, often worse at night, and constipation ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).

What helps, from the same page: side sleeping with knees bent is likely the most comfortable position, and it keeps the baby off the large vein that returns blood from the legs to the heart; many providers recommend the left side, and it is best not to sleep flat on your back ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)). Pillows under the belly or between the legs and a rolled pillow at the small of the back relieve pressure; limit caffeinated drinks; avoid large meals or lots of fluids within a few hours of bedtime, and exercise right before bed; a 15-minute warm bath or a warm caffeine-free drink such as milk can help, and short daytime naps make up lost sleep ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).

## Try today

### The pillow arrangement

- **Time:** 5 minutes, at bedtime

1. Lie on your side with your knees bent ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).
2. One pillow between your knees, one under your belly ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).
3. Roll a third and tuck it into the small of your back ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).
4. Earlier in the evening: finish dinner and big drinks a few hours before bed, and skip exercise right before it ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).

**Make it work:** If you wake up on your back, roll over and go back to sleep. The arrangement makes the side the easy option; it isn't there to police the night.

## Watch for

- **Normal:** legs that swell by evening; limit salty foods, and lying on your left side improves circulation ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000583.htm)). **Call your provider right away** for pain and swelling in one leg but not the other, which can signal a blood clot ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000580.htm)).
- **Normal:** needing a nap; short daytime naps can make up lost sleep ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)). **Call your provider** before taking any sleep aid, over-the-counter or herbal ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).
- **Normal:** heartburn, often worse at night ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)). **Call 911 or go to the ER** for severe chest pain or shortness of breath that does not go away ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000583.htm)).

## For you

Many people sleep well in the first trimester and may need more sleep than usual ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)). If the second is worse, that's the course of things, not something you're doing wrong, and the nap is on the approved list ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)).

If you're the partner: the bed gets smaller from here, and the pillows are hers. Take the far edge without comment. If she's up at 3 a.m. for the third time, that's the kidneys and the bladder at work ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000559.htm)), not a choice. Bring the glass of water in the morning, not at night.

## Sources

- NHS. "Week 17." 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-17/
- MedlinePlus. "Problems sleeping during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000559.htm
- MedlinePlus. "Aches and pains during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000580.htm
- MedlinePlus. "Common symptoms during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000583.htm