Pregnancy week 3: fertilisation done — one cell starts the journey

What happened, nobody can feel

This week's event is too small for any instrument to see and too large for anything to be the same afterwards. In the fallopian tube, egg and sperm have met — fertilisation is done.

What exists is a single cell, thousands of times smaller than a sesame seed. In it, your genes and your husband's have joined, half and half: looks, height, eye colour, a good many habits — much was settled in that instant.

You will feel none of it. No nausea, no fatigue, nothing — those belong to later weeks. This week passes silently, and its silence is normal.

Your baby this week

After fertilisation the cell begins dividing — one to two, two to four, four to eight. In three-four days it's a mulberry-like cluster science calls a morula.

That cluster floats down the tube toward the uterus — a four-to-five-day journey. By arrival it has hollowed into a fluid-filled ball, the blastocyst, over a hundred cells strong.

Two destinies are already assigned in that ball: the inner clump becomes the baby; the outer shell becomes the placenta — the organ that will feed and breathe for the baby for nine months.

Changes in your body

Your body hasn't received the news yet. Hormones are unchanged, the cycle is on schedule, and a pregnancy test would find nothing — hCG production hasn't begun.

Some women later swear they 'felt it'. The truth is nothing perceptible happens this week — what's felt is hope, which is a precious thing in its own right.

Next week's end brings implantation and the first faint possibilities. This week's only job is continuing what you've already been doing.

What to do this week

Folic acid daily — more important now than ever. The tube that forms the brain and spine closes over the coming weeks, and folic acid is what that process needs.

Live as if already pregnant — because you may be. Alcohol and tobacco at zero, no new medicines unasked, and if an X-ray comes up, say 'possible pregnancy' first.

Measure the caffeine — a cup or two of tea or coffee is fine, more isn't. And drop raw and undercooked food (raw egg, undercooked meat, unboiled milk) from here.

Don't rush the test. A test this week reads negative even if you've conceived. Waiting until the missed period is the correct move.

Week 3 at a glance

The week's essentials in one place. Everything is internal — nothing shows yet.

When to see a doctor at once

Nothing warns this week — what's happening is below the threshold of feeling. One thing only: no medicine, home remedy or 'cleansing kadha' without asking the doctor from here on — the pregnancy's most delicate foundations are laid in exactly these weeks.

Sharp, worsening one-sided pain low in the belly — especially with a previous ectopic pregnancy — is worth showing the same day. There's no reason to suspect anything yet, but that symptom is never one to sit on.

This article is general information only and no substitute for personal medical advice. The person who can advise you knowing your health, your medicines and your previous pregnancies is your obstetrician, or the doctor at your nearest health centre.

Work out your due date

Enter the first day of your last period and your cycle length — your estimated due date, this week's count and the anomaly scan window all appear right here.

It is only an estimate — most babies aren't born on the exact date. A first-trimester scan dates a pregnancy more accurately; in the end, your doctor's date is the one that counts.

Frequently asked questions