What pregnancy symptoms should I expect week by week?

Each week brings a different mix of hormonal, physical, and emotional changes — from implantation spotting around week 4 to round-ligament pain in the second trimester and Braxton Hicks contractions near the end of the third. Our week-by-week articles cover the symptoms most women experience and flag the ones that warrant a call to your provider, all reviewed by a board-certified clinician.

When should I call my doctor about a pregnancy symptom?

Call your OB-GYN or midwife right away for heavy vaginal bleeding, severe one-sided abdominal pain, sudden severe swelling in the face or hands, a persistent severe headache, vision changes, fever above 100.4°F, or a sudden dramatic decrease in fetal movement after 28 weeks. When in doubt, call — your care team would rather hear from you.

How often are MommyBabySite pregnancy articles re-reviewed?

Every article receives a clinical review within 72 hours of publication or update and is re-reviewed in full every 18 months by our 14-person medical advisory board to keep guidance aligned with current ACOG and AAP recommendations.

Is the week-by-week pregnancy guide really free?

Yes — the personalized week-by-week guide and email tracker are free, with no credit card required. You can unsubscribe in one click at any time, and we do not sell or share your email address.

What is the difference between the first, second, and third trimester?

Pregnancy is divided into three trimesters of roughly 13 weeks each. The first trimester (weeks 1–13) focuses on implantation, early development, and the highest miscarriage-risk window. The second trimester (weeks 14–27) is often called the 'golden window' for reduced symptoms and the anatomy scan around week 20. The third trimester (weeks 28–40) tracks rapid fetal growth, birth preparation, and labor signs.

Do you have guidance for high-risk pregnancies?

We publish medically reviewed content on common high-risk categories including gestational diabetes, preeclampsia, multiples, and pregnancy after loss. These articles are co-reviewed by a maternal-fetal medicine specialist or OB-GYN on our advisory board, but they are educational — not a substitute for your own specialist's plan.

The Pregnancy Hub

A calmer, clearer pregnancy — guided by a pediatrician, week by week.

From the first flutter to the first contraction, every symptom, scan, and decision is explained by board‑certified clinicians and read by 3.2 million moms who've already been there.

A pregnant woman resting her hand on her belly in soft window light.

Find your chapter

Pick the trimester you're in — we'll meet you there.

Each chapter opens with what to expect, what's changing in your body and baby, and what's been clinically reviewed this season.

01 Weeks 1 – 13

First Trimester

Morning sickness, the first prenatal visit, what the dating ultrasound actually shows, and which symptoms deserve a call to your OB.

Open the first trimester chapter →

02 Weeks 14 – 27

Second Trimester

The anatomy scan at 20 weeks, glucose screening, the first real kicks, and how to build a birth plan that actually fits your hospital.

Open the second trimester chapter →

03 Weeks 28 – 40+

Third Trimester

Braxton‑Hicks versus real labor, the group B strep test, packing the hospital bag, and what the last few weeks really feel like.

Open the third trimester chapter →

The questions our readers ask at 2 a.m. — the spotting, the round‑ligament pain, the 'is this normal?' — those are the questions we write for first. Every article on this hub has been read, revised, and signed off by a clinician before it goes live.

Dr. Lena Park, MD Board‑Certified OB‑GYN · Member, MommyBabySite Medical Advisory Board

Reviewers' full names and credentials appear on every article. We re‑review the entire library every 18 months.

Pregnancy symptoms by week

Drop into any week — get a reviewed answer, not a forum thread.

The four symptom windows moms Google most. Each one opens into a full week‑by‑week tracker with what's normal, what's not, and when to call your provider.

Weeks 4 – 12 8 min read

First‑trimester symptoms, decoded: what's normal and what isn't.

Nausea that lasts all day, spotting that makes your heart stop, breast tenderness that feels different from PMS — a clinically reviewed guide to the symptoms that show up before anyone can see you're pregnant.

Read the first‑trimester symptom guide →

Weeks 13 – 27 7 min read

Round‑ligament pain, backache, and the second‑trimester aches explained.

When the pulling on either side of your belly is just growth — and when it's worth a same‑day call.

Read the second‑trimester symptoms →

Weeks 28 – 36 9 min read

Braxton‑Hicks vs. real contractions: a clinician's checklist.

Timing, location, and the three questions your OB will actually ask before telling you to come in.

Read the third‑trimester symptoms →

Weeks 37 – 40+ 6 min read

Late‑pregnancy signs: nesting, bloody show, and the mucus plug.

The final‑week signals that labor is close — and which ones mean it's time to grab the hospital bag.

Read the late‑pregnancy signs →

The cornerstone reads

Four articles every pregnant reader should bookmark before week 32.

Longer, deeper, and more decision‑heavy — the pieces our readers email to their partners and re‑read at every appointment.

A handwritten list of questions for a prenatal visit on a wooden table.

Prenatal care 12 min read

Your first prenatal visit, and the 11 questions worth asking before you leave the room.

A printable checklist co‑written with a certified nurse‑midwife — what to ask about screening, supplements, and the things your provider might not bring up unless you do.

Open the prenatal visit guide →

The 20‑week scan 10 min read

What the anatomy scan actually looks at — and how to read the report.

A line‑by‑line walkthrough of every measurement on the second‑trimester ultrasound, with a glossary of terms your sonographer might use.

Read the 20‑week scan guide →

Birth planning 14 min read

Writing a birth plan that fits your hospital, not Pinterest.

How to draft a one‑page plan your L&D team will actually read — with prompts on labor comfort, monitoring, and the decisions that come up fast.

Read the birth‑plan guide →

Third trimester 8 min read

Packing the hospital bag: the OB‑approved checklist, week by week.

What to have ready at 28 weeks, what to add at 36, and the things most parents forget — written with two L&D nurses and reviewed by a pediatrician.

Read the hospital‑bag checklist →