Week 5 of Your Pregnancy

A look at your body, your baby, and more

While you’ve only just learned that you are pregnant, you’re already about one month in (week 5 of your 40-week journey, to be exact). The reason: Most healthcare providers count pregnancy from the first day of your last period. Your embryo is hard to see on an ultrasound right now, but that doesn't mean that you aren't feeling its presence by way of symptoms such as fatigue, breast tenderness, and nausea.

week 5 pregnancy highlights
Illustration by Verywell

Your Trimester: First trimester

Weeks to Go: 35

You This Week 

Nary a month along, you likely haven’t gained any pregnancy weight yet. (Most women put on a barely noticeable 1 to 4.5 pounds by the conclusion of the first trimester.) However, chances are you have noticed that you’re much more tired than usual. In fact, fatigue is considered a universal symptom this early in pregnancy. The culprit is (in part) the hormones human chorionic gonadotropin (hCG) and progesterone.

The most fascinating thing about your newly amplified fatigue is that pregnant women don’t actually require additional sleep. “It’s a myth,” says Allison Hill, M.D., a private practice OB-GYN in Los Angeles. “Instead, you were likely sleep-deprived to begin with. It’s just that now your body is ruled by hCG, a hormone that won’t let you get away with it anymore.”

At the same time, at 5 weeks pregnant, some women may notice a cramping sensation (also described as the feeling of being full) in their uterus. This is normal.

Your Baby This Week

At about 5 weeks, baby’s gestational sac, which will grow to be the placenta, can often be seen on a transvaginal ultrasound. Here, the ultrasound wand will be placed inside your vagina, not on top of your belly. The sack can actually be detected before the embryo. But just because the embryo is hard to see—it’s crown-to-rump length (CRL) is just 0.118 inches—doesn’t mean there’s not a lot happening.

At this time, the embryo begins to lengthen and take on the appearance of a tadpole thanks, in part, to the development of the all-important neural tube that runs from the top to the bottom of the embryo. (This tube will grow to become the spinal cord and brain.) There’s even a tiny blip at the center of the embryo that will soon develop into baby’s heart.

Right now, most of your baby’s organs—like the heart, stomach, and liver—are starting to take shape. And the same goes for baby’s digestive, circulatory, and nervous systems.

At Your Doctor’s Office

If you learn you are pregnant anytime between August and February, consult your healthcare professional about getting a flu shot. The CDC notes that it is not only safe but recommended that pregnant women get the influenza vaccination during any trimester to protect themselves and their babies from flu.

However, not all vaccines are advisable during your first trimester. Right now, your embryo is most vulnerable to viruses, so you should not get any live-virus vaccinations, like the measles, mumps, rubella (MMR) vaccine or the varicella (chickenpox) vaccine.

Upcoming Doctor’s Visits

While you’re likely hyper-focussed on scheduling—and going to—your first prenatal appointment, there’s another doctor’s visit you should be considering now as well: The dentist. In fact, the American Dental Association, the American Congress of Obstetricians and Gynecologists, and the American Academy of Pediatrics all encourage women to see the dentist while pregnant.

The reason: The very same hormonal changes that bring about nausea and breast tenderness can cause gum inflammation (pregnancy gingivitis). If ignored, pregnancy gingivitis may lead to the serious gum infection periodontitis, which increases the chance of preterm birth.

Taking Care

While you should focus on eating whole foods, as opposed to processed, packaged ones, there are still some specific options that should be avoided during your pregnancy. The big-hitters include the following, as they can contain bacteria that can be dangerous to a developing fetus.

  • Unpasteurized cheeses, such as Brie and feta
  • Raw meats; pâté; deli meats (unless heated)
  • Smoked seafood (unless cooked in a casserole or canned); fish containing high levels of mercury, like swordfish, tilefish, shark, and mackerel

But shying away from all fish is not a wise move, since salmon, sardines, anchovies, and herring are all rich in omega-3 fatty acids, which contribute to baby’s brain health and development. Tuna is also brimming with brain-building omegas, but there can be a mercury concern, since some tunas are loaded with the toxin and others aren’t. For instance, canned light tuna (including skipjack) is considered the healthiest tuna choice by the FDA. Albacore (or white) tuna and yellowfin tuna are still OK, but bigeye tuna should be avoided. In the end, it’s safe to stick to 2 to 3 servings of canned light tuna or 1 serving of Albacore tuna a week.

Beyond tuna, there are other foods and beverages that are commonly considered dangerous, but are actually perfectly fine if consumed properly. These include:

  • Shellfish, such as shrimp and lobster
  • Eggs (unless raw)
  • Sushi-grade fish (unless made from a high-mercury seafood)

A moderate amount of caffeine—200 mg to 300 mg, or one or two 8-ounce cups of coffee—is also perfectly safe, as are herbal teas.

There’s also no need to avoid foods associated with allergies, like nuts, milk, and wheat, unless you are actually allergic. Not eating these during your pregnancy does not shield your baby from developing allergies—it actually does the opposite. Moreover, A 2014 report in JAMA Pediatrics noted that consuming peanuts during pregnancy actually increases allergen tolerance and lowers risk of a childhood food allergy.

Special Considerations

It’s important that pregnant women avoid travel to areas in the United States and worldwide where there’s a risk of contracting the Zika virus. The virus and resulting fever have been connected to several birth defects, including microcephaly, where babies develop smaller-than-normal heads and possible brain damage.

Zika is spread by Aedes mosquitoes and through sexual contact with an infected party. Because there is no vaccine and no cure, it’s very important to check the CDC’s Travel Health Notices to see the most current areas where the Zika virus is spreading. If you must travel to an area where Zika risk is high, talk to your doctor first. Learn how to properly prevent mosquito bites and protect yourself when engaging in sexual activity.

For Partners

Exercise is important during your first trimester and throughout pregnancy. In fact, an American College of Obstetrics and Gynecology report notes that most pregnant women should participate in moderate exercise for 20 to 30 minutes, most days.

“Even though exercise has been shown to help with nausea by releasing natural endorphins, some women feel too fatigued to do it,” says Dr. Hill. The solution: Start an after-dinner or early-morning walk routine with your partner. Research shows that couples feel more satisfied in their relationship when they participate in an enjoyable physical activity together. Plus, it will give you both a chance to de-stress. Finally, if you start a healthy and relationship-strengthening habit now, you’re more likely to stick with it after the baby is born.

Verywell Checklist 

  • Make a dental appointment.
  • Schedule a flu shot, if needed.
  • Continue taking prenatal vitamins.
  • Buy more fresh, whole foods when grocery shopping.
  • Buy comfortable walking shoes. (Weight gain, swelling, and other pregnancy changes can result in foot pain, so supportive sneakers are important.)

Last Week: Week 4

Coming Up: Week 6

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