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First Trimester: What to Expect When You’re Expecting

Positive pregnancy test in foreground that’s being held by a happy woman who is embracing her partner.

You’re pregnant - congratulations! As you course through a range of emotions, you’ll likely wonder what will start happening to your body now that you’re sharing it with someone else. In this three-part series, we’ll explore each trimester and expand on some commonly asked questions about each stage of pregnancy. Let’s start at the beginning with what to expect during your first trimester

The First Trimester: Fetal Development

The first trimester is considered to be the first week of pregnancy until the end of week 12. The 1st trimester is the most crucial to your child’s development. This is the stage during which your baby’s structure, body and organs develop. Your baby will be changing from a fertilized cell, to an embryo that plants itself in your uterine wall, to a bundle of developing limbs and complex systems.

1st Trimester Fetal Growth Benchmarks

After eight weeks, the embryo is referred to as a fetus. Other major first trimester milestones include the formation of muscles, the production of white blood cells, and the development of vocal chords. At this stage, the fetus is usually 1.5 inches long and all major organs and systems have formed.

During the first trimester, the fetus is most susceptible to damage from alcohol, drugs, certain medicines, and other substances.

First Trimester To-Do’s

Cut out overly-processed foods, cheeses, alcohol, and other harmful substances. Start taking a prenatal vitamin. This extra boost of vitamins and minerals has been shown to greatly reduce the risk of neural tube defects.

Choose a practitioner you can trust and schedule a prenatal appointment at your OBGYN. Keep an open dialogue with your doctor and voice any questions or concerns you have. At your first prenatal visit, you will undergo a physical exam and various health screenings that will assess you and your baby’s health. Be prepared to go in-depth with maternal and paternal family medical history, as well as personal gynecological and obstetrical history including past pregnancies, miscarriages, menstruation, etc.

The First Trimester: Your New Body

First-time mom-to-be? The moment you saw the positive sign on your pregnancy test, you probably wondered when your body would start changing. Continue reading to learn about common first trimester symptoms and potentially harmful symptoms that you should talk to your doctor about.


It’s natural for the mammary glands to enlarge, which causes the breasts to swell and become tender. This is the body’s response in preparation of breast-feeding. Areolas will grow larger and darken. They may also become covered with small, white bumps called Montgomery’s tubercles.

Mood Swings

Your body is going through major physical changes that impact your hormone levels. Because of this, it is common for women to experience mood swings – similar to those that can occur before menstruation.


During early pregnancy, it is normal to feel exhausted. Your body is producing higher levels of progesterone– which affects your sleep pattern and energy level. Rest as much as you can during the first few weeks of pregnancy. A healthy diet and light exercise might increase your energy levels.

Weight & Morning Sickness

What surprises most first-time moms, is that you likely won’t get a baby bump in the first trimester. Most women gain only a few pounds within the first 12 weeks of pregnancy.

The reason most women don’t put on weight in the first trimester is mostly due to morning sickness. It’s difficult to increase caloric intake with a roulette-style appetite. Certain tastes or scents that you used to love could easily make your stomach turn.

Despite the name, it’s normal to experience morning sickness symptoms throughout the day and night. A decrease in appetite paired with the fact that you’ll be skipping high-calorie items like alcohol and cheese, will likely keep the baby bump away – at least until after the first trimester.

Symptoms to Be Aware Of

With so many changes happening in your body, you may be wondering what’s normal – and more importantly, what isn’t. The first trimester is when most miscarriages occur. That said, it’s important to be aware of risk factors and symptoms that warrant a call to your OBGYN.

Talk to Your OBGYN

Not every woman experiences the same symptoms of pregnancy, but one thing is certain – you should talk to your OBGYN during your first trimester. Learning about your body and addressing your lifestyle habits could have a profound impact on the health and life of your baby.

If you have more questions about pregnancy or are ready to make your prenatal appointment, contact the office of Dr. Christopher Quinsey in Lake Mary, Florida. Dr. Quinsey has served thousands of women in the Central Florida community and is one of the highest-rated OBGYNs in Orlando.

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*This blog is for general informational purposes only. Christopher K. Quinsey MD, P.A. does not distribute medical advice through this blog. As such, this blog does not constitute a patient-client relationship between the reader and Christopher K. Quinsey MD, P.A.

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