4 Weeks Pregnant: What to Know After a Positive Test

At four weeks pregnant, you have probably only just found out. The positive test may still be sitting on the bathroom bench, and somewhere between deciding who to tell and working out when your baby might be due, you may already be wondering what you should be doing differently.

The first thing worth knowing is that you have not actually been pregnant for four weeks in the way you might imagine. Pregnancy is counted from the first day of your last period, so conception probably happened around two weeks ago. It is a slightly confusing convention, particularly when you are trying to make sense of dates, but it is the one your GP and midwife will use throughout pregnancy.

For women with irregular cycles or later ovulation, those dates may change as the pregnancy progresses.

There is a lot happening in your body already, although you may not feel particularly different yet. And while a positive test brings a few things worth thinking about, there is no need to spend the rest of the day redesigning your life around it.

What's happening at four weeks

By this stage, implantation has usually begun, and the developing pregnancy is establishing itself in the lining of your uterus. Cells that will eventually contribute to the placenta are producing increasing amounts of hCG, the hormone detected by pregnancy tests.

That is why a test taken several days ago may have been negative while today's is positive.

The embryo itself is still extraordinarily small. Over the coming weeks, its early structures will develop into the brain, spinal cord and other major organs. Much of this development happens long before there is anything particularly recognisable on an ultrasound.

You may also be surprised by how ordinary you feel.

Some women notice breast tenderness, tiredness, mild cramping or changes in their appetite and sense of smell around this time. Others have very few symptoms, and nausea often does not arrive until a little later.

There is no particular way you need to feel at four weeks. Symptoms vary considerably, and their presence or absence is not a reliable measure of how a pregnancy is progressing.

Light spotting can also occur in early pregnancy, although bleeding should not automatically be attributed to implantation. Contact your GP or maternity care provider if you notice bleeding. Heavy bleeding, severe abdominal pain, shoulder-tip pain or feeling faint need urgent medical assessment.

A few things worth organising early

One of the more useful things to do after a positive test is to make sure your folic acid and iodine are covered.

Current Australian guidance recommends 400 to 800 micrograms of folic acid daily for most women without additional risk factors, continuing through the first 12 weeks of pregnancy. Iodine supplementation at 150 micrograms daily is also recommended during pregnancy, with individual medical advice needed for women who have an existing thyroid condition.

Ideally, supplementation begins before conception, but that is not always how pregnancy happens. You may have been planning for months, or you may only just be getting your head around the positive test. Starting now is still worthwhile, and your GP or pharmacist can help you work out what is appropriate for you.

A prenatal can be a convenient way to cover several nutrients, although it is worth checking what you are already taking rather than adding another product automatically. Some women need different supplementation because of their medical history, medications or individual circumstances.

This is also a good time to book your first pregnancy appointment.

You do not need to arrive knowing everything about antenatal care. Your GP can help you work through your dates, review any medicines or supplements you take and discuss what appointments and screening options are coming up.

There will be time for the rest of the questions as they arise.

What to eat this week

Your meals do not need to look dramatically different because you have had a positive pregnancy test.

The broad nutritional foundations remain much the same: eating enough, having some variety across the week and including regular sources of protein, fruit, vegetables, wholegrains, legumes, nuts and seeds. Folate-rich foods such as leafy greens, avocado and legumes are useful alongside your folic acid supplement, while iron-containing foods remain an important part of a varied diet.

There is no need to begin measuring every nutrient or making each meal specifically about pregnancy.

A breakfast you enjoy, a substantial lunch and something satisfying for dinner are still perfectly good places to begin. If you have been eating well in the months before pregnancy, much of that routine can continue. If your meals have become repetitive or you have been skipping them because life is busy, there is value in making a little more room for food that leaves you feeling nourished.

The coming weeks may change what you feel like eating. Nausea and food aversions can make previously familiar meals difficult, and you may find yourself relying on simpler foods for a while.

For now, there is no reason to borrow those difficulties before they arrive.

Food safety is the part worth learning early

Pregnancy does bring some changes to how food should be prepared and stored. Listeria is one of the main concerns because it can grow even in refrigerated foods, making certain chilled, ready-to-eat products higher risk during pregnancy.

Cold deli meats, refrigerated ready-to-eat seafood, pre-prepared salads and certain soft cheeses are among the foods that need extra care. Freshly cooked meals, properly washed produce and hard cheeses such as cheddar are generally safer choices when handled and stored correctly. Meat and eggs should also be cooked thoroughly, and perishable food should be refrigerated promptly.

Fish remains a useful part of the diet during pregnancy, although Australian guidance places specific limits on higher-mercury species such as shark, swordfish, marlin, orange roughy and catfish. There is no need to stop eating fish altogether.

You do not have to memorise every food-safety rule today. The official Australian guidance is worth keeping handy for the next several months, particularly when you are eating out or wondering whether a familiar food needs to be prepared differently.

A positive test can have a strange effect on the previous few weeks. Something that seemed completely unremarkable at the time can suddenly feel important because you now know you were pregnant.

You might remember having wine with dinner, eating something that appears on a pregnancy food-safety list or exercising harder than you would have if you had known.

The useful response is to make the changes that apply from now and bring any particular concerns to your GP, especially questions about medications, illness or possible exposures. Australian guidance recommends avoiding alcohol during pregnancy, and your first appointment is a good opportunity to discuss the parts of your usual routine that you are unsure about.

It is also worth remembering that you do not have to change every aspect of your life at once. You can still go to work, enjoy your usual meals with the appropriate food-safety adjustments, spend time with friends and continue many of the activities that were part of your life before pregnancy, subject to your own health and medical advice.

At four weeks, much of pregnancy is still ahead of you. There will be appointments, new information, decisions to make and probably some changes to how you feel along the way.

For now, make the appointment, check the supplements that apply to you and take care of yourself in the ways you already know how.

You have time to learn the rest.

Next week

At five weeks, the embryo's early development continues, and you may begin noticing more of the symptoms commonly associated with the first trimester. We will look at what is happening, how your appetite might begin to change and what is worth knowing as pregnancy progresses.