# Day 103: Amniocentesis, explained once

> Fourteen weeks and five days. What amniocentesis is, who it's offered to, what it risks, and the fact that it's a choice. One card, so you never have to look it up in a hurry.

- Series: Your fourth month of pregnancy, day by day (https://chorevia.com/learn/pregnancy-month-4), day 103 of 280, 14 weeks + 5 days
- Your baby this week: about the size of a kiwi fruit; around 8.5 cm from head to bottom
- Canonical URL: https://chorevia.com/learn/pregnancy-month-4/day-103
- Last reviewed: 2026-10-22
- Publisher: Chorevia (https://chorevia.com)
- Cite as: Chorevia. "Day 103: Amniocentesis, explained once." Last reviewed October 22, 2026. https://chorevia.com/learn/pregnancy-month-4/day-103

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.

Fourteen weeks and five days. Amniocentesis comes up in waiting rooms and group chats with a lot of fear attached. Today you read what it actually is, once, and put it on a card.

## Your baby

Around 8.5cm long from head to bottom, about the size of a kiwi fruit ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-14/)). The baby is kicking, though you probably won't feel it yet, and swallows small amounts of the amniotic fluid ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-14/)). That fluid is what the test is named for.

## Your body

Amniocentesis is a diagnostic test, not a screening test done for all pregnant women; it's offered to women at increased risk, such as those 35 or older at delivery, a positive screening test, a previous baby with birth defects, or a family history ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)). It's most often done between 15 and 20 weeks ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)); OWH gives 14 to 20 weeks ([OWH](https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests)).

The procedure removes about 4 teaspoons (20 milliliters) of fluid, with ultrasound before and during, in an office or medical center with no hospital stay; genetic results usually take about 2 weeks ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)). The risks are minimal but real: infection or injury to the baby, miscarriage, leaking amniotic fluid, vaginal bleeding ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)). Genetic counseling is recommended beforehand, and cell-free DNA testing can sometimes replace the test altogether ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm); [MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000557.htm)).

## Try today

### The amnio explainer

- **Time:** 10 minutes

1. One index card, titled "Amnio". Line one, who it's offered to: 35 or older at delivery, a positive screen, a previous baby with a birth defect, or family history ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)).
2. Line two, what it is: about 4 teaspoons of fluid, taken with ultrasound guidance, in an office; genetic results in about 2 weeks ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)).
3. Line three, the risks the page lists: infection or injury to the baby, miscarriage, leaking fluid, vaginal bleeding; MedlinePlus calls them minimal ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)).
4. Line four, in your own handwriting: "Saying no is allowed." It is not a test done for all pregnant women ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)).
5. If it's on your plan, ask for genetic counseling first; the page recommends it ([MedlinePlus](https://medlineplus.gov/ency/article/003921.htm)).

**Make it work:** Keep the card with your appointment notes. If nobody ever offers you the test, you've lost ten minutes.

## Watch for

- **Normal:** round ligament pains, on the NHS's list of symptoms around now ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-13/)). **Call your provider right away** for constant, severe abdominal pain, or pain with bleeding or fever ([MedlinePlus](https://medlineplus.gov/ency/patientinstructions/000580.htm)).
- **Normal:** light spotting is among the earlier symptoms the NHS says may continue, and it says to seek advice for any bleeding ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-13/)). **Go to the ER** for bleeding from here on: in months 4 to 9, MedlinePlus says to treat it as a potential emergency ([MedlinePlus](https://medlineplus.gov/ency/article/003264.htm)).
- **Normal:** white, milky discharge ([NHS](https://www.nhs.uk/best-start-in-life/pregnancy/week-by-week-guide-to-pregnancy/2nd-trimester/week-13/)). **Call your provider** for fluid leaking from the vagina; it's on the CDC's list of urgent warning signs ([CDC](https://www.cdc.gov/hearher/maternal-warning-signs/index.html)).

## For you

Read [the MedlinePlus page](https://medlineplus.gov/ency/article/003921.htm) once, together, and then put it away. You don't need to hold it in your head; you need to know where it is.

The CDC's framing is the calm one: genetic counseling can explain how genetic conditions may affect you or your family, and screening tests can help identify whether there may be a concern ([CDC](https://www.cdc.gov/pregnancy/during/index.html)). Genetic testing is recommended based on personal or family history and often considered at age 35 or older ([AAP](https://www.healthychildren.org/English/ages-stages/prenatal/Pages/tests-during-pregnancy.aspx)). If none of that describes you, this may never come up.

If you're the partner: the useful question isn't "should we?" It's "what would we do with the answer?" Ask it before anyone offers the test, when there's no clock running.

## Sources

- NHS. "Week 14." 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-14/
- NHS. "Week 13." 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-13/
- MedlinePlus. "Amniocentesis." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/003921.htm
- MedlinePlus. "Prenatal care in your second trimester." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000557.htm
- MedlinePlus. "Aches and pains during pregnancy." National Library of Medicine. https://medlineplus.gov/ency/patientinstructions/000580.htm
- MedlinePlus. "Vaginal bleeding in pregnancy." Medical Encyclopedia, National Library of Medicine. https://medlineplus.gov/ency/article/003264.htm
- Office on Women's Health. "Prenatal care and tests." U.S. Department of Health and Human Services. https://womenshealth.gov/pregnancy/youre-pregnant-now-what/prenatal-care-and-tests
- 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
- Centers for Disease Control and Prevention. "During Pregnancy." Healthy Pregnancy. https://www.cdc.gov/pregnancy/during/index.html
- American Academy of Pediatrics. "Tests & Screenings During Pregnancy." HealthyChildren.org, 2025. https://www.healthychildren.org/English/ages-stages/prenatal/Pages/tests-during-pregnancy.aspx