Your first trimester at a glance

The first trimester — from your last period to the end of week 13 — is the strangest stretch of pregnancy: the most is happening, the least is visible, and you’re probably telling almost no one. If it feels like living a secret double life while mildly seasick, you’ve got the idea. Here’s the shape of the whole thing.

What’s happening with your baby. Everything, basically. In these thirteen weeks your baby goes from a single cell to a fully-formed miniature human about the size of a peach — heart beating from around week 6, all the major organs laid down, arms, legs, fingers and even fingernails by the end. This is the great construction phase; the rest of pregnancy is mostly growing and refining what gets built now. (The week articles walk through it stage by stage if you want the running commentary.)

What’s happening with you. The classic first-trimester experience is being exhausted and queasy while looking completely normal. Blame progesterone and the sheer metabolic effort of building a placenta. Common companions: nausea (any time of day, despite the name), food aversions and a weirdly keen sense of smell, tender breasts, needing to wee constantly, bloating, mood swings, and tiredness like being unplugged at the wall. Symptoms typically peak around weeks 8 to 10 and begin easing after week 12 — and their comings and goings vary hugely between people, so a mild version doesn’t mean anything is wrong.

The admin, in order. A positive test → a GP visit to confirm and get referrals → choosing your model of care (public hospital, midwifery program, GP shared care, or private obstetrician — your GP can explain what’s available near you) → the longer booking visit with routine blood tests, usually somewhere between 8 and 12 weeks. Along the way you’ll be offered screening choices: NIPT from 10 weeks and/or the combined first-trimester screen with the nuchal translucency scan around 11–13 weeks, plus a dating scan if your dates are uncertain. All optional, all explained when offered.

The daily-life rules that matter most now: a pregnancy vitamin with folic acid and iodine; the food-safety short list (skip raw/undercooked meat and eggs, soft cheeses, cold deli meats, raw seafood — the foods-to-avoid article has the full rundown); caffeine capped around one to two coffees a day; and no alcohol or smoking. Beyond that, ordinary life continues: exercise, work, sex and travel are all generally fine in the first trimester unless your care team says otherwise.

Surviving work while secretly pregnant is its own little art form. You don’t owe anyone the news before you’re ready, but a few tricks help: keep bland snacks in your desk drawer (an empty stomach makes nausea worse), claim a “stomach bug” without elaboration if you need a day, and schedule demanding tasks for your least-queasy window if you have one. If your job involves physical risks — heavy lifting, chemicals, long stints on your feet — telling your employer earlier than planned unlocks adjustments they’re required to consider, so weigh the trade-off.

The emotional weather deserves naming. Weeks of feeling rubbish, with no bump, no scan photo yet, and a secret you’re carrying alone through work meetings — it’s a strange, inward, sometimes anxious time even for a much-wanted pregnancy. Worry about miscarriage is extremely common in these weeks; it may help to know the risk drops steadily as the weeks pass, and most pregnancies that reach a heartbeat on scan continue just fine. When you announce is entirely yours to choose — the traditional “wait until 12 weeks” is a convention, not a rule, and telling a few trusted people early means support if you need it.

When to call rather than wait: bleeding more than light spotting, strong one-sided pain, pain in your shoulder tip, feeling faint, or being unable to keep any fluids down. Your GP or early pregnancy unit would always rather hear from you.

The first trimester ends better than it begins: energy returning, nausea lifting, the 12-week scan showing an actual baby doing actual somersaults. If you’re in the thick of week 8 right now — fed up, queasy and telling no one — hang in there. The golden trimester is genuinely coming, and your GP or midwife is on hand for everything in between.