Everything to Expect in the First Trimester of Pregnancy

The first few weeks of pregnancy are filled with new changes, symptoms, and health care appointments. Here's what to expect in the first trimester.

A LGBTQ couple looking at a positive pregnancy test

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The first few weeks of pregnancy can undoubtedly be overwhelming, with so many new life changes, physical symptoms, and those frequent check-ups with a health care provider. First-time parents especially may find the beginning of pregnancy challenging, as they are experiencing uncharted territory for the first time.

Ahead, we'll attempt to de-mystify some of the aspects of early pregnancy. Learn more about what to expect during the first trimester, ranging from symptoms to health concerns and more.

First Trimester Signs and Symptoms

During the first trimester, you will no doubt experience a variety of symptoms that can range from subtle to obvious. Some might be so subtle that you may wonder if they're pregnancy-related; for example, is that fatigue from work or could it be your baby bump? Here are some first-trimester signs and symptoms to know about.

Food Aversions (Or Cravings)

Being repelled by specific tastes and smells is expected in the first trimester. "Your digestion is slowing down, so some formerly appealing foods become intolerable," explains certified nurse-midwife Lisa Kane Low, PhD, RN, a faculty member at the University of Michigan School of Medicine. Ignoring an aversion and forcing yourself to eat may only make you feel sicker, so don't feel you have to eat something just because you think it's good for you.

Cravings are the flip side of aversions: Although the cause is unknown, they may simply be your body's way of telling you to eat what you can stand. Cravings are also extremely common; one study found that 40% of pregnant people experience them. Unless they could be harmful, go ahead and indulge them. If you find yourself craving anything that isn't food, be sure to discuss with a health care provider.

Breast/Chest Changes

Breast/chest tenderness and hypersensitivity are a tell-tale sign of early pregnancy, and around six to eight weeks, you may notice that your breast area is growing larger. "Pregnant people always think of their bellies as the focal point," says Dr. Kane Low, "but usually the first physical symptom they notice is a too-tight bra." In fact, the symptoms of early pregnancy—such as acne, mood swings, cramps, and especially swollen, tender breasts/chest—closely resemble PMS.

Fatigue

Extreme fatigue is very common in the first trimester of pregnancy. "Your metabolic rate—the amount of energy you burn just to exist—is way above normal then," explains Dr. Kane Low. The emotional ups and downs can also take their toll on you.

Fatigue should let up in your second trimester. But if it doesn't, you may be experiencing an iron deficiency—more than 50% of pregnant people are iron-deficient to some degree by week 28, points out Susan Watts, M.D., an obstetrician-gynecologist at Presbyterian Hospital of Dallas.

Weight Gain

While the average weight gain during the first trimester is about 5 pounds, some people actually lose weight because of morning sickness and food aversions. If it happens to you, don't panic: You'll soon see the numbers on the scale climb.

Just remember that pregnancy is not the time to go on a diet, but rather to eat as balanced as you can (some people prefer eating six small meals throughout the day). "Anytime you deprive your body of the nutrients it needs, it has to rob them from someplace else," explains Dr. Kane Low. That means invading emergency stores of calcium or iron, for example.

Nausea

Increased sensitivity to low blood sugar and higher levels of the pregnancy hormones estrogen and Beta HCG can contribute to nausea. The following may help:

  • Eat often. An empty stomach worsens nausea.
  • Sniff lemons or snack on lemon-flavored foods.
  • Drink at least eight glasses of water a day.
  • Try sports beverages, such as Gatorade. They also supply glucose and essential minerals.
  • Have a protein-rich bedtime snack. Protein keeps your stomach feeling full longer, making it easier to face the morning.
  • Move. Exercise diverts blood from your stomach, alleviating nausea.
  • Brush before eating. Toothbrushing stimulates the gag reflex.

First Trimester Tests and Appointments

Throughout your pregnancy, you'll typically have regular check-ins with an OB-GYN, midwife, or health care provider. Some providers may want to see you right away after your positive pregnancy test; others may have you wait until the eight-week mark. Ahead, learn more about the types of tests and appointments you'll likely experience during the first trimester.

Pregnancy Tests

According to a report in the Journal of the American Medical Association, there's a 10% chance that you'll get a false negative reading if you take an at-home pregnancy test on the first day you miss your period. That's because only 90% of pregnancies are detectable that early. A health care provider can confirm your pregnancy with a blood test, if necessary.

Ultrasound

Most obstetricians will perform an ultrasound at your first prenatal visit to confirm your pregnancy and date it. Later, you'll probably have a transabdominal ultrasound (like the ones you see on TV), but the early exam may be performed by inserting a plastic wand into your vagina. (Don't worry—it doesn't hurt.)

Your first ultrasound will help produce your due date. Pregnancy is based on a 40-week (280-day) calendar. To calculate your estimated delivery date on your own, add seven days to the first day of your last menstrual period, then add nine months. Your baby is considered full-term if they arrive anywhere from three weeks before to two weeks after this date.

Chorionic Villus Sampling (CVS)

This diagnostic test for chromosomal disorders such as Down syndrome is usually performed between weeks 10 and 12. Chorionic villus sampling (CVS) can be done earlier than amniocentesis, but unlike amnio, it cannot detect neural-tube defects such as spina bifida.

In addition, says Donald R. Mattison, MD, senior adviser to the directors of the National Institute of Child Health and Human Development and Center for Research for Mothers and Children, the miscarriage risk is slightly higher with CVS—around 1% vs. less than 1% for amnio.

First Trimester Health Concerns

The beginning of pregnancy can be very exciting, but it also may bring about some health concerns and worries. Ahead are some of the common topics you might have on your mind.

Prenantal Vitamins

Most health care providers will recommend a daily prenatal multivitamin with 400 micrograms of folic acid for people trying to conceive, and one with 600 micrograms when pregnant. "Folic acid goes a long way toward preventing serious neural-tube defects of the brain and spinal cord," explains Dr. Mattison. Spina bifida is perhaps the most well-known of these problems.

Avoid over-the-counter prenatal vitamins that contain herbals or "natural" products; they are not as strictly regulated. If the vitamins upset your stomach, iron is probably the culprit. Ask your doctor about taking folic acid alone until your morning sickness passes. In the meantime, eat lots of folate and iron-rich foods, such as beans, spinach, and raisins.

Genetic Counseling

If you're at risk of having a baby with an inherited disorder, genetic counseling can help you and your partner decide whether to undergo further testing. These tests can determine if either of you is a carrier and see if your fetus is affected. Age and personal/family medical history are just a few factors to consider when deciding on testing.

Infections

You may be surprised—and concerned—if a health care provider prescribes antibiotics to treat a condition such as a simple gum or bladder infection. But infection anywhere in the body may lead to preterm labor. If you have further concerns about antibiotics or infections, be sure to discuss with an OB-GYN or health care provider.

Miscarriage

10% to 20% of all pregnancies result in miscarriage, and most miscarriages occur in the first trimester. Many blame themselves when it happens, but no evidence exists that emotional stress, physical activity, or sex causes it. Call a health care provider immediately if you begin spotting, bleeding, or cramping while pregnant.

If you miscarry and need help coping, ask a health care provider to recommend a support group; alternatively, you can find one online. It's important to remember that a miscarriage is not your fault, and you are also not alone.

Before the first trimester is over, visit your company's human resources department to find out how much maternity leave you'll have and whether it will be paid, unpaid, or a combination of both. "You also need to think about your work environment, including chemical exposures, stress, and physical demands," says Dr. Kane Low. Try to avoid heavy lifting or standing for long stretches at a time.

Stress-related risks—such as demanding deadlines, long commutes, and grueling hours—are less tangible but shouldn't be ignored. Put your feet up on a footstool several times daily, ask for help, and delegate, if possible.

Although leaking urine shouldn't be an issue this trimester, it's never too soon to start strengthening your pelvic floor muscles. Contract and relax them throughout the day, as though you're stopping and starting the urine flow (called a Kegel).

Pregnant people generally start taking childbirth preparation courses, such as Bradley or Lamaze classes, during the second trimester, but classes fill up quickly. Research the options in your area (your doctor or midwife and local hospitals probably have lists), and sign up early. While you're at it, look into breastfeeding and newborn care classes, hospital tours, and, if needed, big sibling classes.

While some people feel sexy when they're pregnant and enjoy not having to fuss with birth control, others don't want to do anything in bed but sleep. If you've lost your libido, don't fret; you'll probably find it in the second trimester, which many call the honeymoon period of pregnancy.

You probably won't look pregnant until after your fourth month, when your uterus outgrows the pelvic cavity, but that doesn't mean you'll be able to wear your clothes comfortably until then. Increased estrogen levels promote fat storage in several places, including the waistline.

Deciding when and with whom to share your news is a very personal decision, but there are a few things to consider. Keeping your pregnancy a secret will give you and your partner time to absorb the idea privately before others know. While some people wait until the risk of miscarriage drops markedly (at 14 weeks), others spill the beans right away because they'd tell their friends anyway if they miscarried. Telling co-workers is trickier.

You may find that your employer expects the news to be followed by the details of your maternity leave, but you may not have decided yet when to return to work—if ever.

Things to Avoid During Your First Trimester

Expecting a baby undoubtedly brings upon some lifestyle changes. You may want to avoid or limit some of the following things in the first trimester to increase the odds of a healthy pregnancy:

  • Alcohol, cigarettes, illicit drugs
  • Unheated deli meats, soft-cooked or raw eggs, raw or undercooked meats, raw sprouts
  • Handling cat litter or gardening without gloves
  • Herbal supplements and teas
  • Hot tubs and saunas
  • King mackerel, shark, swordfish, and tilefish; raw oysters, mussels, and other mollusks
  • Oil-based paints, lead, mercury (found in some latex paints), chemical solvents, oven-cleaning products, and dry-cleaning chemicals
  • Over-the-counter and prescription medicines not approved by your doctor
  • Soft cheeses, such as brie and feta; unpasteurized milk and juice
  • Unnecessary X-rays
  • More than 200 mg of caffeine daily

If you find yourself with lingering questions or concerns about your pregnancy, be sure to reach out to an OB-GYN, midwife, or health care provider.

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Sources
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