# Day 42: The size of a pea

> Six weeks: limb buds, the start of ears, and the week morning sickness tends to arrive. Today you set a snack every one to two hours.

- Series: Your second month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-2), day 42 of 280, 6 weeks
- Your baby this week: about the size and shape of a pea; around 6 mm from head to bottom
- Canonical URL: https://chorevia.com/learn/pregnancy-month-2/day-42
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 42: The size of a pea." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-2/day-42

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.

Six weeks exactly. A pea has replaced the sesame seed, and your stomach may have opinions about it. Today's plan is small, frequent, and boring on purpose.

## Your baby

The NHS puts the embryo at around 6mm long, "about the size and shape of a pea" ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). Limb buds are forming, and the ears are beginning to take shape ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). The heart that started to form last week now beats at a regular rhythm during weeks 6 and 7, which can be seen on a vaginal ultrasound ([MedlinePlus](https://medlineplus.gov/ency/article/002398.htm)).

## Your body

Morning sickness and tiredness are common this week, and the NHS says symptoms often ease after the first trimester ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). MedlinePlus dates it from conception: symptoms often begin 4 to 6 weeks after conception and may continue until the 4th month ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)). Conception happens about two weeks into the way your weeks are counted, since weeks 1 and 2 occur before it ([MedlinePlus](https://medlineplus.gov/ency/article/002398.htm)), so "4 to 6 weeks after conception" is around now.

What helps, from the same page: "Avoid large meals. Instead, have a snack as often as every 1 to 2 hours during the day" ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)). Prenatal vitamins go down better at night and with food, since the iron can irritate the stomach ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)). And the NHS's other instruction for this week is the one nobody follows: rest as much as possible ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)).

## Try today

### The snack clock

- **Time:** 5 minutes to set up, then all day

1. Set a quiet reminder every 90 minutes from waking to bed. The MedlinePlus rule is a snack as often as every 1 to 2 hours ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)).
2. Pack the snacks tonight for tomorrow: plain, small, and nothing from yesterday's smell map. Put one by the bed and one in your bag.
3. Move the prenatal vitamin to the evening, with food ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)).
4. Shrink the three meals to make room. The point is to never be empty, not to eat more.

**Make it work:** Sips go between the snacks, not with them; seltzer, ginger ale, and sparkling water may help, taken between meals rather than with them ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)).

## Watch for

- **Normal:** nausea, with or without vomiting, most days ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). **Call your provider** if you lose more than 2 pounds (1 kilogram) in a week, or if vomiting doesn't improve with home remedies ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)).
- **Normal:** light spotting, on the NHS's list for this week ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). **Call your provider right away** about bleeding in the first 3 months; up to 1 in 4 women have some bleeding during pregnancy, and it's a reason to be seen, not to wait ([MedlinePlus](https://medlineplus.gov/ency/article/003264.htm)).
- **Normal:** tiredness that makes you want to lie down ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-6/)). **Go to the ER** or seek care immediately for severe swelling, redness, or pain in a leg or arm ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)).

## For you

The line to keep: mild morning sickness does not harm the baby ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)). It is miserable for you and fine for them, which is a strange thing to hold, but true.

If you're the partner: the snack clock runs on supplies. Tonight's job is the packing, and tomorrow's is not commenting on how often the crackers come out. If she's carrying more than one baby, the symptoms are more likely to last the whole pregnancy ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000604.htm)), so plan for a long season rather than a short one.

## Sources

- NHS. "Week 6." 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/1st-trimester/week-6/
- MedlinePlus. "Fetal development." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/002398.htm
- MedlinePlus. "Morning sickness." National Library of Medicine, 2024. https://medlineplus.gov/ency/patientinstructions/000604.htm
- MedlinePlus. "Vaginal bleeding in pregnancy." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/003264.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