Overview

The first 12 weeks of your pregnancy are the most significant adjustment period. This article covers everything you need to know to navigate the first trimester. Your baby is building organs and structures. You will experience some physical and emotional symptoms of pregnancy. Understanding common first-trimester symptoms can help you cope with some of the uncomfortable side effects of pregnancy. Learn what to expect at your first few prenatal appointments. Find out what to-do items you should work on this trimester. Plus, get tips on your partner’s role and how they can support you.

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The First 12 Weeks

The first trimester of your pregnancy spans the initial twelve weeks. Pregnancy is measured in the weeks leading up to the birth of your baby. Your baby is due at the start of your 40th week of pregnancy. Week one is the week of your last period before you get pregnant. You don’t ovulate and conceive until week three. This calculation uses a formula called Naegele’s rule. While it operates on some assumptions, like a 28-day cycle and ovulation on day 14, it is widely accepted in the medical community. See this episode for the evidence on due dates.

There is much to learn and many decisions to make throughout your pregnancy and parenting journey. The amount of information to consume can be overwhelming, especially in the beginning. Don’t worry. You have plenty of time to get everything figured out. Tuning into this podcast is a great way to start. Luckily, your instincts will kick in, and nature will arm you with tools you probably don’t even know you have yet.

Pregnancy Safety

As soon as you find out you are pregnant, you should be cautious about consuming some foods and exposing yourself to environmental dangers. This includes some obvious things like caffeine, alcohol, cigarettes, and drugs. This episode brings you up to speed on everything you need to know as soon as you find out you are pregnant. 

There is a lack of safety information on medications during pregnancy. The CDC has an initiative called Treating for Two that aims to improve the health of women and babies by identifying the safest treatment options for common conditions before, during, and after pregnancy. Overall, their advice is to talk to your doctor. The risk of miscarriage is the highest in the first trimester. All your baby’s systems are being put into place during this period, which makes the first trimester the most sensitive for development. Please discuss any prescription or over-the-counter medications with your doctor or midwife.

Your Growing Baby

At conception, your baby is a single cell. Your baby starts out looking like a tadpole, but as they grow, they become more human-like in appearance. During the first trimester, your baby’s organs will begin to develop, and some will even start to function. This means the first trimester is when your baby is most vulnerable to anything that might interfere with development.

As your baby grows, they will be busy kicking and stretching and may even have hiccups. It will still be another couple of months before you can feel them moving around. By the end of the first trimester, their heart beats and pumps blood, their facial features will begin to appear, arms and legs will grow longer, fingers and toes will start to form, and they will even have fingernails.

At 12 weeks, your baby weighs about half an ounce, measuring around two and a half inches from crown to rump. Babies in utero are measured from the crown of their head to their bottom since they are folded to fit inside your uterus. Once they are born, the length is measured from head to toe. Your baby is about the size of a lime or a plum at the end of the first trimester.

Common First Trimester Symptoms

Many common symptoms of pregnancy can arise in the first trimester. Everyone experiences pregnancy differently. Although you will not experience every one of these symptoms, having a basic understanding may help you cope with some uncomfortable side effects of being pregnant.

Increase in Hormones

The most significant drivers of change in pregnancy are changes in hormone levels. Once an egg is fertilized, the part that will develop into the placenta starts producing the pregnancy hormone hCG (human chorionic gonadotropin). hCG is the hormone a pregnancy test detects. hCG instructs your ovaries to stop releasing eggs and triggers increased production of estrogen and progesterone. Estrogen and progesterone play a significant role in all aspects of your pregnancy and many symptoms you will experience. Hormones impact more than your physical health and can also affect your mental health by making your moods and emotions swing all over the place.

Physical Changes

While a pregnant belly is a hallmark of being pregnant, you shouldn’t start to show until the end of the first or beginning of the second trimester. It may be sooner if you are expecting twins or if this is not your first pregnancy. You should expect to gain only about 2 to 4 pounds during the first trimester.

Breast Changes

Early in your pregnancy, sensitivity, tenderness, and pain are common in your breasts. This can start one to two weeks after conception and, for many women, is one of the first signs of pregnancy. Soreness is caused by hormonal changes, retaining more fluids, and your breasts preparing for lactation. Wear a comfortable and supportive bra that may help if your chest hurts. See this article for an in-depth explanation of the changes you can expect with your breasts during pregnancy.

Fatigue

As your levels of progesterone increase, you may find yourself tired and wiped out. Don’t fight it. If your body is telling you it needs extra rest, listen to it. Pregnancy fatigue is most common in the first and third trimesters. Getting adequate sleep and taking care of your health may help with fatigue. Sometimes, the best thing you can do is relax, rest, nap, or go to bed early.

Morning Sickness

Morning sickness is nausea during pregnancy and can be accompanied by vomiting. This does not just happen in the morning and can be anytime or even all day. Morning sickness affects 60-80% of expecting mothers. This is most common in the first trimester, can start as early as one to two weeks after conception, and usually goes away after 12 weeks or when you begin the second trimester. Hyperemesis gravidarum is a severe morning sickness requiring hospitalization or treatment with IV fluids and affects .3-2% of all pregnancies.

It can be especially tough in the first trimester when you may not tell everyone you are pregnant; you feel sick, miss work, or miss out on social activities. You are going through many physical and emotional changes, and not feeling well can impact your mental health and quality of life. What helps relieve nausea for one expecting mom may not work for you. See this episode for an examination of treatments to find relief. Please check in with your doctor or midwife if you struggle with morning sickness and cannot keep liquids down.

Stuffy Nose and Pregnancy Rhinitis

Your increased circulation in your mucus membranes causes your nose and airway to swell. You may be congested, snoring in your sleep, and even get occasional nosebleeds. This condition is sometimes classified as pregnancy rhinitis. This is an inconvenience, but it will go away on its own eventually.

Frequent Urination

Frequent urination is one of the most common symptoms of pregnancy, especially early on. The pregnancy hormone hCG (the one that caused your pregnancy test to be positive) is causing an increase in blood flow to your pelvic area. This is good for increased sexual pleasure but not so good when running to the bathroom every five minutes. Your kidneys are more efficient at ridding your body of waste, and your growing uterus is beginning to push down on your bladder. All of this adds up to a lot more frequent bathroom breaks.

Constipation

During pregnancy, your body’s increased progesterone production relaxes your smooth muscles, including your digestive tract, which slows down digestion. On the positive side, this gives nutrients more time to be absorbed into your bloodstream and reach your baby. Unfortunately, it can also lead to constipation. Constipation symptoms include difficult or infrequent bowel movements, hard stools, and pain or discomfort in your stomach. Eating high-fiber foods, staying hydrated, and exercising can improve constipation. See this episode for more information on the safety of over-the-counter remedies.

Food Cravings

Many expecting mothers experience different food cravings during pregnancy. There is some speculation that if you crave a particular type of food, your body is trying to balance a nutrient deficiency. For example, if you are craving oranges, you need more vitamin C. Research doesn’t support that theory, and food cravings are likely psychological.

First Trimester Prenatal Appointments

Your doctor or midwife is the cornerstone of your prenatal care and birth experience. This is the expert resource you will work with throughout your pregnancy to make significant decisions. You need to see them as an integral team member and, most importantly, trust and be comfortable with them. If you do not feel supported by your current doctor or midwife, you can change providers. See this article on choosing (or changing) your doctor or midwife.

Your first prenatal visit will be around the eight-week mark. Those weeks leading up to this visit can seem like forever. This episode outlines what you should be doing before your first appointment. The first steps are to confirm your pregnancy and determine your due date. Your doctor or midwife will likely administer a pregnancy test and perform a transvaginal ultrasound. Your due date is determined using a calculation based on your last menstrual period and ultrasound measurements. While a due date is rarely the date your baby will show up, it is a relatively close estimate.

Prenatal appointments are every four weeks from your first appointment through the second trimester. There are routine things that you can expect to happen at each checkup. Your care provider should ask how you feel if you have any questions. It is essential to communicate to make sure you understand everything. Here are five tips to make the most out of every prenatal appointment.

You will have to step on a scale at every appointment. The average woman gains weight between 25 to 35 pounds throughout your pregnancy. This is based on being average weight before getting pregnant. Weight gain is not linear, and you should only expect to gain 2-4 pounds in the first trimester. You can also expect to have your blood pressure taken at each visit and usually give a urine sample several times during pregnancy.

Checking on Your Baby

In addition to checking your health, your care provider will check the baby’s health by listening to your baby’s heartbeat. In the first trimester, your provider detects your baby’s heartbeat with an ultrasound or Doppler. A Doppler is a handheld ultrasound device that amplifies the noises from your womb. Do not panic if your practitioner cannot pick up the sound of your baby’s heartbeat yet. Depending on your baby’s position and where your placenta is, it can be more challenging to hear a heartbeat early on.

Prenatal Tests

Your doctor or midwife will offer or suggest several prenatal tests during your pregnancy. You may feel like you are continually waiting for the result of some test to come back so you can be assured that your baby is healthy. Most tests are routine, and you have a high probability of everything returning normal.

Screening vs. Diagnostic Tests

It is crucial to understand the difference between screening and diagnostic tests. A screening test gives you the likelihood of a condition and may signal that additional testing is needed. You would need a diagnostic test to diagnose anything. It can be devastating to get screening results back, showing your baby is at a higher risk for anything. Please understand that you don’t know anything for sure until you have a diagnostic test.

Invasive vs. Noninvasive Tests

You can further classify tests as noninvasive or invasive. Noninvasive tests do not pose a risk to you or your baby. These typically use a urine or blood sample from you. If you are anxious about needles, you may not consider a test drawing your blood noninvasive. Let your doctor or midwife know if having blood drawn makes you uneasy. You can ask for someone with a lot of experience taking blood so you do not have a first-day intern sticking you with a needle.

First Trimester Screen

The first-trimester screen is a noninvasive test that combines a blood test for the mom with an ultrasound evaluation of the baby. This test is between 10 and 13 weeks, six days, and can identify risk for specific chromosomal abnormalities, including Trisomy-21 (Down syndrome) and Trisomy-18. The ultrasound portion of the test looks at nuchal translucency. Fluid collects at the back of your baby’s neck, and many babies with Down’s syndrome have an increased amount.

A study published in the New England Journal of Medicine states the combined accuracy rate for the screen to detect chromosomal abnormalities is approximately 85%, with a false positive rate of 5%. That means out of every 100 babies affected by the abnormalities the screen tests for, it will identify around 85. Approximately 5% of all normal pregnancies will receive a positive or abnormal level. It is crucial to remember that a positive result does not equate to having an abnormality; it indicates that you may want to discuss further testing with your care provider.

Integrated Screening

Results from a first-trimester screen can also be combined with a quad screen test in the second trimester in an integrated screening test. Combining results from both tests has a higher detection rate for Down syndrome than either of the two tests alone.

Cell-free DNA or NIPT (Noninvasive Prenatal Test)

You can take a cell-free DNA (cfDNA) test as early as ten weeks. This test uses a blood sample to look for fragments of your baby’s DNA floating in your bloodstream. A cfDNA test can detect many more chromosome abnormalities than the traditional screen tests, plus the sex of your baby and their Rh factor.

Your care provider may offer a cell-free DNA test if you are at a higher risk of having a baby with a chromosomal abnormality. The accuracy of this screening test varies. In a high-risk population of 10,000 pregnancies, 324 cases of Down syndrome would be detected, with nine missed and 31 false-positive results. These numbers change significantly in a low-risk population. In a hypothetical low-risk population of 100,000 pregnancies, we would expect 417 cases of Down syndrome detected, with 94 false-positive results. Since the test is less accurate for low-risk mothers, the Society for Maternal Fetal Medicine and the American College of Obstetricians and Gynecologists does not recommend this test for low-risk women.

An examination by the New York Times found these tests perform much worse when looking for less common conditions caused by missing pieces of chromosomes called microdeletions. To evaluate the newer tests, The Times interviewed researchers and combined data from multiple studies to produce the best estimates of how well the five most common microdeletion tests perform. The analysis showed that positive results on those tests are incorrect about 85% of the time. Keep this in mind and get clear with your doctor, midwife, or genetic counselor to ensure you understand the results and the accuracy of the test for any condition that comes up positive. See this episode for more in-depth information on the cell-free DNA or NIPT test.

CVS (Chorionic Villus Sampling)

A chorionic villus sampling is a diagnostic test to determine if a baby has chromosome abnormalities like Down syndrome and genetic disorders like cystic fibrosis. The window for a CVS is short, and you can get this test between 10 to 13 weeks. A CVS involves removing some chorionic villi cells from the placenta at the point where it attaches to the uterine wall. There are two ways samples are collected. The most common method is transcervical, where an ultrasound guides a thin catheter through the cervix to your placenta, and the chorionic villi cells are gently suctioned into the catheter. The other method is a transabdominal approach, where an ultrasound guides a long, thin needle through the abdomen to your placenta. The level of accuracy is high, at 98-99%, but this test does not measure the severity of these disorders.

Miscarriage is the primary risk related to CVS. A systematic review and meta-analysis found the miscarriage rate to be 0.22%. This is the data also referenced by ACOG. There are other possible side effects for the mother following the procedure, including spotting, cramping, and pain at the puncture point. 

Vaccines

Vaccines are a very controversial and complex topic. The choice to get vaccinated is a decision you should make with your doctor or midwife. If you have questions or concerns about any vaccine, please bring them up with your care provider. Vaccines should be given with informed consent, and it is ultimately your decision to get vaccinated.

There are multiple vaccines that the American College of Obstetricians and Gynecologists recommend during pregnancy. Vaccines during pregnancy protect you and allow you to pass antibodies to your baby before they are born. Two vaccines (COVID-19 and influenza) may be available in the first trimester. Some expecting mothers and care providers may avoid vaccines during the first trimester because this period is critical to development.

ACOG states that vaccination for COVID-19 may occur in any trimester, and emphasis should be on vaccine receipt as soon as possible to maximize maternal and fetal health. See this episode for more information on the COVID-19 vaccine during pregnancy.

The timing of the flu vaccine aligns with the flu season, which runs from October through May in the United States. ACOG states that if you are pregnant, it is best to get the vaccine early in the flu season, as soon as the vaccine is available, and you can get the shot any time during your pregnancy. This article examines the evidence on the flu vaccine for the current flu season.

To-Do Items for the First Trimester

The first trimester is a significant adjustment period. You can do some simple things to get your pregnancy off to a healthy start.

Take Care of Your Health

The number one thing you should do in your first trimester is take care of your health. Do not stress out if you are not the healthiest person right now. Many women find out they are pregnant before implementing a healthier lifestyle, and their babies are perfectly healthy. It is never too late, and today is a fantastic day to start.

The first trimester is a good time to evaluate your diet. Your goal should be to eat mostly healthy whole foods. Some episodes examine the evidence on specific aspects of diet like fish, meat, sugar, natural and artificial sweeteners, plant-based diets, and organic foods. It is also critical to drink adequate water and stay hydrated. You should take a high-quality prenatal vitamin, not just a multivitamin. Prenatal vitamins contain more folic acid and iron than standard multivitamins, which is critical for your baby’s growth and development.

Regular exercise during pregnancy can decrease your risk of complications like gestational diabetes, preeclampsia, and cesarean birth, promote healthy weight gain, and ease many common pregnancy symptoms. Whether you are an athlete or are just starting to incorporate exercise, almost any activity can be modified so that you can feel empowered to exercise during your pregnancy. There are more in-depth episodes on specific exercises, including cardio, strength training, and yoga.

The growing body of research on sleep demonstrates the absolute necessity of sleep for every biological function. This includes learning, memory, brain function, mental health, appetite regulation, immune system function, metabolic function, gut microbiome health, and even cardiovascular health. It is well-established in the scientific literature that sleep is critical for all aspects of health, especially during pregnancy. The good news is you can take many evidence-based and straightforward steps to improve the quantity and quality of your sleep.

Visit the Dentist

Several common oral health conditions can occur in pregnancy. Approximately 40% of pregnant women have some form of periodontal disease. The American College of Obstetricians and Gynecologists recommends that you see a dentist during pregnancy and that cleanings and x-rays are safe. Make dental care a priority and schedule an appointment.

Exploring Your Birth Options

You have options when it comes to everything in your pregnancy. Your primary doctor or midwife and where you plan to give birth greatly influence your choices. The first trimester is a good time to start exploring what type of provider you want to work with and where you want to give birth. The majority of births in the U.S. take place in a hospital. If you are open to it, check out your options to have a home birth or visit a birth center. Even if you want an unmedicated birth, you can have a natural birth in the hospital.

Understand Your Health Insurance

In the United States, the average cost of vaginal birth is nearly $10,000, and the average price for a cesarean section is close to $14,000. Looking at your health insurance to minimize your costs and ensure you are covered is a good idea. You may be eligible for tax-advantaged accounts to pay qualified medical expenses. If you are not in a financial position to obtain insurance or utilize tax-advantaged accounts, you may be able to get assistance with coverage. See this episode on the cost of birth and understanding your insurance.

When to Announce Your Pregnancy

Many expecting parents wait until the 12-week mark to announce their pregnancy. While I don’t want to alarm you, miscarriage is more common than you may realize. Rates of miscarriage are very confusing. The most widely accepted statistic is that 10-15% of clinically recognized pregnancies result in a loss. The rate of miscarriage decreases the further you are in your pregnancy and drops significantly by week 12 or the end of the first trimester. A chromosomal abnormality is the most common cause of a miscarriage in the first trimester. These abnormalities result from a damaged sperm or egg or a problem with the embryo during the division process.

It is common to have some anxiety about the possibility of miscarrying. Especially early on, you may have some signs or symptoms of pregnancy, but you don’t look pregnant and can’t feel your baby moving or kicking. Talk about announcing your pregnancy with your partner and get on the same page about when to share the news.

Your Partner

Some mothers have babies without the luxury of a partner. If the two of you can navigate this together, you are fortunate. The entire process of having and raising a baby is exponentially more difficult alone. If you don’t have a romantic partner or a co-parent, I encourage you to lean on friends and family so you are not going through this phase of your life without support.

As soon as there is a positive pregnancy test, there are many things partners and dads can do to support mom. Partners can support eating healthy whole foods by cooking meals at home or grabbing healthier options when you eat out. Your partner can let you sleep in or encourage you to go to bed earlier if you are tired. If you need support to be active, an invitation from your partner to go on a walk or encourage you to do something active together can be helpful. It can be even more challenging if you have difficulty with healthy habits and your partner is not supportive and encouraging. 

All kinds of symptoms can pop up during pregnancy. You can mitigate some of these symptoms with remedies. Unfortunately, some conditions are out of your control and will persist until your baby is born. Your partner may not be experiencing the same things you are, but they can empathize with you. Sometimes, it is nice to know that someone is by your side, even if they cannot relate and don’t have any solutions.

If your partner can attend your doctor or midwife appointments, please encourage them to accompany you. You can expect to have around 14 appointments throughout your entire pregnancy. Your partner should prioritize being there in person or virtually for all of them. Or at least as many as they can. This allows your partner to be included, have input in major medical decisions, ask questions, and hear everything firsthand. If any complications come up throughout prenatal care or you get some unfavorable test results back, those appointments can be challenging to go through alone. Having your partner by your side can be a fantastic source of support. One of the more essential appointments for your partner to attend is the first appointment, when a doctor or midwife confirms the pregnancy and sets expectations. 

Make the Most of Your First Trimester

Your first trimester is the shortest, especially when you consider you don’t even get pregnant until week three and probably do not know you are pregnant until week four or five. Pregnancy and raising a baby can come with many uncomfortable symptoms and a rollercoaster of emotions. If you struggle with conditions like morning sickness, hang in there and know this will improve. While the amount of information to consume about pregnancy and birth can be overwhelming, don’t forget to have some appreciation for everything your body is going through to build a human.

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