# Day 18: Smoke and the first weeks

> Smoking slows a baby's growth and raises the risk of preterm birth. The best time to quit was before; the next best is now. A circle on a calendar and one person told.

- Series: Your first month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-1), day 18 of 280, 2 weeks + 4 days
- Your baby this week: a single cell, then a ball of cells
- Canonical URL: https://chorevia.com/learn/pregnancy-month-1/day-18
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 18: Smoke and the first weeks." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-1/day-18

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.

If nobody in your house smokes, today is short. If someone does, today is the most useful note of the month.

## Your baby

Around now, the cells that will become your baby and the placenta are days from settling into the womb ([NICHD](https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo)). Smoking before or during pregnancy harms both the pregnant woman and the baby ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). It slows fetal growth, so a baby may be too small even at full term, and it raises the risk of preterm delivery, birth before 37 weeks, and of birth defects such as cleft lip and cleft palate ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). Pregnant smokers face a greater risk of stillbirth, and smoking increases the risk of sudden infant death syndrome after birth ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)).

## Your body

The best time to quit smoking is before you try to get pregnant; the next best time is as early in pregnancy as possible, and quitting at any point helps ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). Smoking roughly doubles the risk of abnormal bleeding during pregnancy and delivery ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)).

Secondhand smoke matters on its own. During pregnancy it can cause lower birth weight and may cause preterm delivery, and babies exposed after birth face higher SIDS risk, ear and lung infections, and reduced lung function ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). The NHS week 4 list of things to do starts the same way: stop smoking, give up alcohol, cut back on caffeine ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/1st-trimester/week-4/)).

## Try today

### The quit-date circle

- **Time:** 5 minutes

1. If you smoke, pick a date within the next seven days and circle it on the calendar from day 14.
2. Tell one person today, out loud or by text: the date, and that you want them to ask about it.
3. Write "ask about quitting help" on the first-visit list; don't start any quit medicine on your own, since the rule is to talk to your providers before starting or stopping any medicines ([CDC](https://www.cdc.gov/medicine-and-pregnancy/about/index.html)).
4. If nobody in the house smokes, write the household's smoke-free rule instead: no smoking indoors, in the car, or around her, by anyone, visitors included ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)).

**Make it work:** Quitting at any point helps ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). A circle you miss gets redrawn, not abandoned.

## Watch for

- **Normal:** needing to pee more often, because hCG, produced in the first few weeks, increases blood flow to the pelvic region ([NICHD](https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signs)). **Call your provider** if it hurts to pee or your urine changes odor or color ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000583.htm)).
- **Normal:** being more tired than the week asks of you; fatigue can appear as early as 1 week after conception ([NICHD](https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signs)). **Call your provider** for overwhelming tiredness, or for trouble breathing ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)).
- **Normal:** breast tenderness or tingling in the first weeks ([NICHD](https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signs)). **Call your provider right away** about any vaginal bleeding in the first 3 months ([MedlinePlus](https://medlineplus.gov/ency/article/003264.htm)); smoking roughly doubles the risk of abnormal bleeding in pregnancy ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)).

## For you

If you're the partner who smokes, this is the week to quit alongside her. Secondhand smoke during pregnancy can lower birth weight and may cause preterm delivery ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)), and smoking damages sperm and makes it harder to conceive ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)), so this was always partly yours. Circle your own date. Tell her the date. Make it the same one.

If neither of you smokes, there is still a rule to write: the car, the porch, the visiting uncle. Babies exposed to smoke after birth face higher SIDS risk and more ear and lung infections ([CDC](https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html)). Rules are easier to set nine months early than at the door.

## Sources

- Eunice Kennedy Shriver National Institute of Child Health and Human Development. "About Pregnancy." National Institutes of Health. https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo
- Centers for Disease Control and Prevention. "Health Effects of Cigarettes: Reproductive Health." https://www.cdc.gov/tobacco/about/cigarettes-and-reproductive-health.html
- NHS. "Week 4." 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-4/
- Centers for Disease Control and Prevention. "Medicine and Pregnancy: An Overview." https://www.cdc.gov/medicine-and-pregnancy/about/index.html
- Eunice Kennedy Shriver National Institute of Child Health and Human Development. "What are some common signs of pregnancy?" National Institutes of Health. https://www.nichd.nih.gov/health/topics/pregnancy/conditioninfo/signs
- MedlinePlus. "Common symptoms during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000583.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
- MedlinePlus. "Vaginal bleeding in pregnancy." National Library of Medicine, Medical Encyclopedia. https://medlineplus.gov/ency/article/003264.htm