First Trimester Overview

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First trimester: you, your baby, your appointments.

The first three months of your pregnancy can be a whirlwind. Learning that you’re pregnant can bring on a wide range of emotions, made all the more dramatic by fluctuating hormone levels. These mood swings are normal and will likely level off over the next few months.

You don’t look pregnant yet, but it may be showing itself in subtle ways, like changes in your complexion and darker nipples. You probably feel tired much of the time, but that fatigue should start to taper off in your second trimester. You may also notice breast tenderness, more frequent urination, and changes in appetite or food preferences.

Morning sickness is typically at its peak in the first trimester, although some women have it throughout their pregnancy. It can range from no nausea at all to severe vomiting, and can strike day or night. Once again, hormones are to blame. Here are a few steps you can take to keep the nausea at bay:

  • Eat a few dry crackers before getting up in the morning.
  • Eat several small meals throughout the day instead of three larger ones.
  • Avoid rich, spicy, and fried foods, as well as odors you find offensive (which may be things that never bothered you before).
  • Go for walks in the fresh air.

As soon as you find out you’re pregnant, you should call your doctor or midwife’s office and schedule your first prenatal appointment. You’ll also want to talk to your provider right away if you’ve taken any medications early in your pregnancy or think you’ve exposed the fetus to a hazardous substance. Most providers won’t have you come in until about your eighth week of pregnancy. However, you should be seen earlier if you had problems with a prior pregnancy, have a current medical condition, or have any of these symptoms:

  • Vaginal bleeding or abnormal discharge
  • Abdominal pain
  • Severe vomiting
  • Diarrhea that lasts longer than 24 hours
  • A burning sensation while urinating
  • A fever higher than 101 degrees Fahrenheit

At this point you’ll probably see your provider once a month or so for the next several months, and your appointments will include a check of your weight, blood pressure and urine. Toward the end of your first trimester, your provider will gently push on your belly and use a tape measure to estimate the size of your uterus, and you can probably hear baby’s heartbeat at about 12 weeks.

The end of your first trimester is also the time for a variety of tests. You’ll have a blood test to determine your blood type and Rh factor, and to check for anemia and immunity to German measles. You may also have a Pap smear to check for cervical cancer, and tests for STDs like gonorrhea, syphilis, chlamydia and HIV. Some screening tests that check for possible problems with the baby are also performed in the first trimester. 

As for your baby, at the six-week mark she is one-inch long and her brain, nervous system, heart, and lungs are beginning to form. She even has tiny buds that will become arms and legs. By the end of the first trimester, she’ll be about six inches long and weigh about four ounces. Her internal organs will be developing, and her fingers and toes will be completely formed. She’ll be moving around, but will still be too small for you to feel her.

View first trimester checklist