From Positive Test to Birth

Two lines on a stick, and suddenly there's a whole calendar of appointments nobody explained. Here's the map.

Start here 1st trimester 2nd trimester 3rd trimester Real labor? When to call

At a glance

Visits: monthly to 28 weeks, every two weeks to 36, then weekly.
The big tests: anatomy scan ~20 weeks, glucose screen 24–28, GBS swab 36–37.
Real labor is regular, strengthening contractions that don't care what you do.
Call now for leaking fluid, bleeding, less movement, or plain old "I'm not sure."

You're pregnant. Now what?

Three phone calls start everything: your OB or midwife (book the first prenatal visit as soon as the test is positive OWH), your insurance (what's covered, which hospitals are in network), and, later in pregnancy, a pediatrician for the baby (yes, you pick one before birth; see Building Your Village).

The visit rhythm for a typical low-risk pregnancy: about once a month until 28 weeks, every two weeks until 36, then weekly until birth, and more often if you're 35+ or high-risk. OWH MedlinePlus

Tracking week by week If you want the "your baby is the size of a kumquat" experience, the week-by-week trackers at BabyCenter and What to Expect are the classics of the genre, and both run birth-month community groups of parents due the same month as you. Fun, and useful for remembering what week you're in. Just treat medical claims there as a starting point, and the pages below as the checked version.

First trimester (to ~14 weeks)

The first visit is the long one: a full blood panel (blood type and Rh, blood count, immunity and infection screens, urinalysis), a pelvic exam, your history, and prenatal vitamins with iron if you're not already taking them. A dating ultrasound (often transvaginal this early) sets your official due date. MedlinePlus

Optional genetic screening happens on a clock, so decide early: cell-free DNA (NIPT) from about week 10 MedlinePlus, and the nuchal translucency ultrasound + blood screen at weeks 11–14. MedlinePlus These are screens, not diagnoses — your provider will explain the follow-up options if anything is flagged.

Normal right now Exhaustion that feels like a personality change, nausea at any hour despite the name, food aversions, needing to pee constantly, and mood swings. Most of it eases in the second trimester.

Second trimester (14–28 weeks)

Usually the good part: energy returns, nausea fades, and you start to show. The medical calendar:

~20 weeks: the anatomy scan. The big ultrasound checks the heart, kidneys, spine, and limbs, plus the sex if you want to know. MedlinePlus
15–22 weeks: quad screen blood test, if you're doing it (most accurate 16–18 weeks). MedlinePlus
24–28 weeks: glucose screen for gestational diabetes. The famous sugary drink, then a blood draw. An abnormal result just means a longer follow-up test. MedlinePlus
~28 weeks: if your blood type is Rh-negative, a RhoGAM shot. MedlinePlus

This is also the sweet spot to book a childbirth class (aim to finish before the due date; your labor coach should come too MedlinePlus), tour the hospital, and start the registry while you still have energy.

Third trimester (28 weeks–birth)

Tdap vaccine, 27–36 weeks (earlier in the window is better): your antibodies cross to the baby and cut whooping-cough risk in babies under 2 months by 78%, and babies get no shots of their own until 2 months. CDC
RSV protection: either a maternal RSV vaccine at 32–36 weeks (September–January in most of the US) or an antibody shot for the baby after birth. Families choose one; ask your OB which fits your timing. CDC
Group B strep swab, week 36–37. Painless swab; if positive (common, and no danger to you), you get IV antibiotics during labor to protect the baby. CDC
Movement matters. The baby should keep moving daily right up to birth, and "babies slow down at the end" is a myth worth ignoring. If movement seems reduced: have a snack, lie down on your side, and pay attention. If it still seems quiet, call. Don't sit on it overnight. MedlinePlus
Car seat, installed and checked, well before the due date. The AAP says to sort the car seat out before birth, and certified technicians will check your installation for free (details in Gear). AAP
Hospital bag: there's no official week, but convention says have it ready by ~36 weeks, because babies keep their own schedules. Chargers, snacks, going-home outfits for both of you, your ID and insurance card, and the installed car seat cover most of it.

Is this labor, or a false alarm?

Braxton Hicks "practice" contractions can start any time after the first trimester: typically short, irregular, not painful, and they fade if you move, rest, or drink water. MedlinePlus

True labor doesn't care what you do: contractions come at regular, shrinking intervals (around every 5–10 minutes), last 30–70 seconds and get longer, radiate to your lower back and upper belly, and intensify until you can't talk or laugh through them. MedlinePlus

Losing the mucus plug can precede labor by days, which is interesting but not an emergency. Water breaking (a gush or a steady trickle) is a call-now event. OWH

For calibration: a typical first labor runs ~12–19 hours of first stage, 20 minutes to 2 hours of pushing, and 5–30 minutes for the placenta. OWH

When to call your OB or midwife

Call immediately, day or night

Leaking or gushing fluid
Decreased fetal movement
Vaginal bleeding beyond light spotting
Regular painful contractions every 5–10 minutes for an hour
Any labor signs weeks before your due date (possible preterm labor)
Severe headache, vision changes, or sudden swelling of face/hands (possible preeclampsia; see urgent maternal warning signs)

And MedlinePlus's own last line, which every anxious 3 a.m. googler should frame: call "for any other reason if you are unsure what to do." That's what the answering service is for. MedlinePlus OWH

Idea worth borrowing, from Alice Callahan's The Science of Mom: before any decision (tests, interventions, gear), ask "what's the actual evidence, and how good is it?" Ranges beat single numbers, and your baby's pattern beats the calendar. That mindset is the spine of every page on this site.

Next: The First Twelve Weeks → Your wellbeing (blues, PPD & recovery) →