Pregnancy Week By Week

1 Week Pregnant

Surprise! One week pregnant is actually not pregnant at all. Say what?!

Most OBs count pregnancy starting from the first day of your last period. That's because ovulation and conception are really tough to pinpoint, but the physical signs of menstruation are much easier to spot. So in doctor speak, 1 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.

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.

1 Week Pregnant Symptoms

At 1 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.
  • Bloating. 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.
  • Headache. 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.

1 Week Pregnant Belly

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 six 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.

1 Week Pregnant 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 Checklist at 1 Week Pregnant

Reminders for the week:

Medical content was reviewed February 2020 by Sara Twogood, MD, an ob-gyn at Cedars Sinai Medical Center in Los Angeles and author of Ladypartsblog.com.

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