Your Baby is the size of a

Poppy seed

Are you pregnant? It’s time to find out! Some women are lucky enough to find out as soon as they’ve missed their period, and others won’t find out until week 5. You’ll get the most accurate result on your home pregnancy test at the end of this week. If your test is negative, be patient and take another test next week. If your test was positive, your baby - a blastocyst - has implanted into your uterine wall, while your body is busy getting to work on forming the placenta and amniotic sac for them!

Week 4

Length : 0.1 cm

Weight : 0 g

Week 4
Length : 0.1 cm
Weight : 0 g

Your Baby is the size of a

Poppy seed

Are you pregnant? It’s time to find out! Some women are lucky enough to find out as soon as they’ve missed their period, and others won’t find out until week 5. You’ll get the most accurate result on your home pregnancy test at the end of this week. If your test is negative, be patient and take another test next week. If your test was positive, your baby - a blastocyst - has implanted into your uterine wall, while your body is busy getting to work on forming the placenta and amniotic sac for them!

About six days after fertilization, the blastocyst is planted into your uterine wall. The inner cell mass, or embryoblast, has grown into a disk-like structure, two cell layers thick: the epiblast, which forms the amniotic cavity (the closed sac between the amniotic fluid and embryo), and the hypoblast, which forms a tiny yolk sac. The yolk sac nourishes the embryo in these early weeks until your placenta is fully developed.

The outer cell mass, or trophoblast, is becoming a large part of the placenta. But for now, your primitive version of the placenta is working hard to create space in the lining of your uterus, allowing your blood to flow and helping you provide your little one with oxygen and nutrients as they grow.

PS. Your baby's neural tube is beginning to develop. And yes, it's normal to brag about growing neural tubes. Neural tubes form the early brain and spine!

Do you feel pregnant? Chances are, you do! Mood swings, intense smells... everyone is different. You may feel more tired than usual or a slight nausea. Some pregnant individuals experience tender nipples and swollen breasts. Others feel no symptomatic difference whatsoever during the fourth week.

It's time to find out.

You'll get the most accurate result on your home pregnancy test at the end of this week. Some individuals are lucky enough to find out as soon as they've missed their period; others won't until week five. Name-brand and generic home pregnancy tests are equally sensitive and frequently stubborn about detecting the hCG hormone in your urine during the fourth week. If your test is negative, it is a good idea to wait until week five and take another test.

If your home pregnancy test detects enough of the hormone hCG in your urine this week, you'll see that glorious positive result. Even if you discover a very faint - but still positive - test result, there's a great chance you're pregnant. And yes, it's normal to wonder if you eyeballed the fabulously low-key, faint result into existence or truly see it (feel free to use the buddy system if you aren't sure), and it's equally as normal to take multiple tests (just to be extra sure).

Whether your home pregnancy test result is super positive or just appears positive, you should contact your doctor, midwife, or other healthcare practitioner to schedule your first prenatal appointment. You should also ask if the vitamin supplements, prescriptions, and over-the-counter medications are safe to continue.

Be mindful of what you put into your body during these early weeks when your little one is most vulnerable. The first trimester is the most critical, susceptible stage in your baby's formation and development. You should avoid alcohol, drugs, cigarettes, secondhand smoke, and certain medications. 

If you did not know you were pregnant, we see you, and it is okay. In these early weeks, the body has an incredible protective system. It is called the all-or-nothing. If you are pregnant, it is unlikely that unknown alcohol, drug use, and cigarettes had any harsh impact on your baby. If these things did impact your baby, it is more likely that you would have miscarried before this point.

Many women don't feel the symptoms of pregnancy during week four. However, about 50 percent of women will experience pregnancy symptoms during week five, and most women will notice symptoms around week six. If you are already experiencing pregnancy symptoms, they may include:

A positive home pregnancy test, or positive blood pregnancy test: the pregnancy hormone, human chorionic gonadotropin (hCG), is responsible for setting your pregnancy in motion and will be present in both your urine and blood. 

Spotting: it’s possible that as the egg buries into the uterine lining, you will notice some light spotting called “implantation bleeding”. This may be accompanied by some mild cramping, but the bleeding will generally be lighter in both volume and color without a consistent flow. If you're concerned, reach out to your midwife or healthcare practitioner.

Tender or swollen breasts: while your breasts have a while to go before they become proficient milk machines, changes are already beginning and may result in some sensitivity. 

Mood swings: hormone fluctuations may leave you feeling extreme emotions from joy to irritation; sometimes switching without warning. If your reactions seem to be irrational, know that your growing baby may be the explanation.

Morning sickness: this notorious early pregnancy symptom can vary drastically from pregnancy to pregnancy and despite the name may not be limited to the morning hours. Nausea may or may not be accompanied by vomiting and can be triggered by hunger, strong smells… or at times seemingly nothing at all. 

Cramping: often associated with your period, cramping may set off your internal alarm bells, thinking that something is wrong– but it can be a perfectly normal symptom as your body stretches and relaxes into its new role as a baby incubator. 

Fatigue: need a nap? Making a baby is hard work! Even in the early weeks, you may find yourself exhausted. Be sure to listen to your body and get some rest whenever you can.

Gas and bloating: pregnancy isn’t always glowing radiance. As your digestive system slows in response to increased progesterone causing your muscles to relax, you may experience bloating and gas (from both ends!).

Tell your partner you're pregnant.

If you're not already, start taking a prenatal vitamin with at least 400 micrograms of folic acid or preferably, folate, and remember to take it daily because it's proven to help prevent birth defects. If you are struggling to take your prenatal vitamin, a good tip is to try taking it at a different time of day, switch to a gummy, and in some cases take a break until the nausea and vomiting subside.

Select your midwife, doula, or OB doctor and make your first prenatal appointment. Interviewing with a few different providers is a good way to make sure you are getting the person who is going to fit best with you and your birth plan.

Begin the habit of going to bed early and napping when you can. Most people feel more worn out than they've ever felt before, and this is a great way to combat that fatigue.

Who knew we'd ever find cause to celebrate the rising number on a scale? Okay, maybe you aren't celebrating per say, but it is perhaps the one time in your life you should consider documenting your weight gain. Get creative! Give your baby book the perfect start with a record of your ever-expanding baby bump. Some of the best ways to document and gauge your growth include:

  • Taking a profile picture each week. Use a small marker or poster board as a sign to hold, naming the week, to help you more easily distinguish between weeks. Make this photo record even more dramatic by taking pictures in the same location each week, perhaps framed by a doorway for visual reference to your changing waistline. If you're thinking weekly photo shoots aren't your cup of tea, one-a-month photos work, too!
  • Using written word! As often as you think it, document each little landmark of gestation in a journal, like when you make the switch to maternity clothing, or your belly button no longer claims its allegiance to the "innie" club, or your partner is at the helm of all leg shaving. These moments seem unforgettable, but in years to come, you’ll treasure these tiny details.
  • Wrapping ribbon around your waist. Go to your local craft store and purchase a bag of baby-related (or any theme) charms. Each month, tie a charm at the precise point where it meets. As the charms accumulate, you'll have a tangible, charming reminder of this journey.

No matter how you choose to document your growing belly, make sure you relish in the amazing changes that are taking place inside of you. Remember, each pound and stretch is helping to nourish and sustain that little life inside.

At a Glance

  • Positive pregnancy test: A pregnancy test may detect enough of the pregnancy hormone (hCG) to show a positive result!
  • Placenta formation: The placenta is already beginning to take shape.
  • PMS or pregnancy: Many early pregnancy symptoms may be similar to PMS symptoms, except instead of expecting your period you’re going to be expecting a baby!
  • Cramping: Implantation cramps are fairly common. Unless cramping is accompanied by other symptoms like bleeding, they usually aren’t anything to worry about.
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The information on the Your Baby Club website is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always discuss any health concerns with a qualified healthcare provider and carefully review all guidance that comes with any medications or supplements before taking.