1 Week Pregnant

39 Weeks to Go!

Key Takeaways at 1 Week Pregnant

  • At this stage of your journey, you’re not actually pregnant yet. In fact, you probably have your period; the symptoms you’re experiencing are a result of PMS, not pregnancy.
  • Now is the time to start prepping for pregnancy: Track your days to chart your cycle, begin taking a prenatal vitamin and make lifestyle changes to get ready for the long road ahead.
  • Just got a positive pregnancy test? You’ll want to skip ahead. If you’ve tested around the time of a missed period, you’re probably actually about four weeks along (congrats!).

In doctor speak, one week pregnant means you’re on your period and not yet pregnant. You won’t actually conceive your baby until week two or three, depending on the length of your cycle.

Baby at Week 1

If you’ve just found out you’re expecting, you might think this is your first week of pregnancy, but you’re probably around 4 weeks pregnant. Yes, already! (Your OB will give you a more accurate estimate when you go in for your first prenatal appointment.) Skip ahead and check out week 4.

How big is baby at 1 week?

Baby is but a glimmer in your eye. Remember you’re not actually pregnant yet—and if you are, you’re more likely about four or five weeks along.

1 week ultrasound

You’re not likely to have a 1 week pregnant ultrasound. But if you’ve been trying for a while to get pregnant and have seen a fertility specialist, you may have had an ultrasound to check for fibroids, to see how many follicles (which grow into eggs) are in your ovaries and/or to gauge the thickness of your uterine lining. If there are any problems, your doctor may prescribe a fertility treatment that can help you conceive. Now, get ready to have some sex. You’ve got a baby to make!


Pregnancy Symptoms at Week 1

At one week pregnant—remember, at this early stage, the symptoms you're experiencing are those typical to your period because you're not actually pregnant. These symptoms may last from three to seven days and can include:

Vaginal bleeding

Your body is shedding the uterine lining, which was plumped up just in case of a pregnancy.

Lower back pain and cramps

To release that lining, your uterus contracts, causing your back and abdomen to ache.


Fluctuating hormones can give you a bloated belly right before and during your period.

Mood swings

Those hormone surges can also cause irritability and wreak havoc on your emotions


Many women complain of menstrual migraines, which are also hormone-related. (Surprise, surprise.) Ice packs, OTC pain relievers and relaxation exercises may help ease the pain.

Your Pregnant Belly at 1 Week

Inside your 1 week belly (remember, you’re not actually pregnant at this point), your body is releasing last month’s uterine lining and starting to form a new one, which (with a bit of luck!) will hold next month’s fertilized egg.

Cool fact: Human eggs are the largest cells in the body. An egg is smaller than a fleck of pepper. Your body will release one (or in rare cases, two) eggs somewhere between day 10 and day 19 of your menstrual cycle—or about 14 days before your next period is expected. It can be fertilized for about 12 to 24 hours after that. Having sex even before then is helpful, since sperm can live in your body for up to five days.

The first signs of pregnancy won’t occur right away—in fact, many women miss their period at week 4 before they begin to feel “different.” But some common early signs of pregnancy in the first weeks after fertilization include breast soreness or tenderness, nausea, fatigue and the frequent urge to pee.

At one week pregnant (aka hoping to be pregnant soon!), you’re probably thinking about how you can prep your body to carry a baby. It’s a good idea to start pregnancy at a healthy weight and free of bad habits such as smoking and drinking. Reduce your caffeine intake to the equivalent of a cup of coffee or two (we’re talking 8 ounce cups—not the Venti!) per day.

The first thing you’ll want to do is start a prenatal vitamin. Prenatal vitamins contain important vitamins and minerals to help support a healthy pregnancy. Second, we want to optimize trying to conceive. You can start by tracking your menstrual cycle and learning your fertile window. You can try using ovulation predictor kits to have a better understanding of when you’re ovulating to time intercourse. Also, make sure to pay attention to your lifestyle habits. Stop smoking and keep alcohol and caffeine to moderate consumption or less!

MD, ob-gyn and reproductive endocrinologist at Spring Fertility

Tips for 1 Week Pregnant

Are you still smoking, drinking and taking in excessive amounts of caffeine? You don’t want to reactively stop doing these things after a positive pregnancy test. You should curb bad habits now before you're expecting.

Consider going for a preconception visit

If you haven’t seen your doctor in a while, you might consider scheduling a visit before you even attempt to get pregnant. It’s a great way to get the ball rolling and have all your pressing questions addressed and answered.

Try to relax

Pregnancy can be stressful. And trying to conceive may be stressful tool. It’s easier said than done, but try not to sweat the small stuff while you’re getting started on this journey.

Getting pregnant isn't always as easy as your high school sex-ed teacher told you. For some of us it takes years. After three years of trying, several IUIs and IVF, we got to meet our beautiful daughter. IVF is a lot to wrap your head around, but the community of support continues to grow—and you're never alone!

Jessica L., mom of one

Please note: The Bump and the materials and information it contains are not intended to, and do not constitute, medical or other health advice or diagnosis and should not be used as such. You should always consult with a qualified physician or health professional about your specific circumstances.


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