The first trimester, weeks 1 to 13: what happens and what to do

Who is looking after me right now?

Your obstetrician or midwife leads the pregnancy itself. They set your due date and order the blood work and ultrasounds. They also manage any complication. We are a pediatric practice, so our part begins once your baby is born. Call them as soon as a home test is positive. Most offices see you for the first time between 8 and 10 weeks.

What is happening with the baby, month by month?

Pregnancy is counted from the first day of your last period, so weeks 1 and 2 happen before conception.

• Month 1, weeks 1 to 4. The egg is fertilized around week 3 and implants in the lining of the uterus. The placenta and the amniotic sac begin to form. By the end of week 4 the embryo is smaller than a poppy seed, and many notice nothing yet except a missed period.
• Month 2, weeks 5 to 8. This is the month the organs form. The heart begins forming around weeks 5 to 6, and cardiac activity is usually visible on an ultrasound around 6 weeks. The brain, spinal cord, lungs, kidneys and liver all start now, and arm and leg buds appear. By week 8 the embryo is about the size of a raspberry.
• Month 3, weeks 9 to 13. At week 9 the embryo is called a fetus. The heart now has four chambers, tooth buds form under the gums, and the fingers can bend. By week 12 the kidneys are making urine and the baby is about 2 inches long. At 13 weeks fingerprints are forming.

Why am I so nauseated and so tired?

Nausea and vomiting of pregnancy usually start before 9 weeks and are gone by about 14 weeks, though for some people they last longer. It happens at any hour, not only in the morning, and strong smells are a common trigger. ACOG says it rarely harms the baby, but it is worth treating, because it can take over your day.

• Eat something small every two hours, and keep crackers by the bed
• Dry, bland food goes down best when nothing else will: toast, plain rice, potatoes
• Sip fluids between meals rather than with them
• Ginger tea, ginger chews or ginger capsules help some people
• Vitamin B6 is a first-line treatment, often with doxylamine; ask your obstetrician for the dose
• Avoid the smells that set you off, including cooking and perfume

Tiredness in the first trimester is real, and it is not something to push through. Sleep when the chance comes. A pillow between your knees makes side-sleeping easier, and a small protein snack before bed helps if nausea wakes you. If vomiting keeps you from holding fluids down for a day, call your obstetrician. Severe vomiting, called hyperemesis gravidarum, is treated rather than endured.

What should I eat, and what should I avoid?

Folic acid and iron do two different jobs, and they get mixed up often.

• Folic acid, 400 mcg every day. CDC advises starting at least a month before pregnancy and continuing through early pregnancy. It lowers the risk of neural tube defects such as spina bifida and anencephaly. Folate in food comes from leafy greens, broccoli, asparagus, oranges, beans and fortified cereals.
• Iron, to prevent anemia. Iron builds the extra red blood cells you need in pregnancy, and low iron leaves you tired and short of breath. It comes from lean red meat, poultry, fish, lentils, beans, tofu, spinach and fortified cereals. Vitamin C at the same meal helps you absorb the iron from plants.
• A prenatal vitamin covers both, along with vitamin D and iodine. Take it at whatever time of day you can keep it down.

Some foods carry an infection risk: raw or undercooked meat, fish and eggs; unpasteurized milk, soft cheese and juice; and deli meat unless it is heated until steaming. There is no known safe amount of alcohol in pregnancy, at any stage.

Fish is worth keeping. FDA and EPA advise 8 to 12 ounces a week of fish that is lower in mercury. Their Best Choices list includes salmon, sardines, shrimp, cod, tilapia and canned light tuna, which includes skipjack. Limit albacore or white tuna and yellowfin to one 4 ounce serving a week. Avoid bigeye tuna, swordfish, shark, king mackerel, marlin, orange roughy and Gulf of Mexico tilefish.

Caffeine under 200 mg a day, about one 12 ounce cup of coffee, does not appear to raise the risk of miscarriage or preterm birth, so you do not have to quit. Count the tea, soda, energy drinks and chocolate in that total. If you are cutting back on soda, water is the swap, and whole fruit is better than fruit juice because the fiber comes with it. Georgia WIC covers pregnant women and provides food benefits and a dietitian.

What happens at the first prenatal visits?

The first visit is the longest, often an hour or more.

• Your due date, calculated from your last period and confirmed by an early ultrasound
• Blood tests for blood type and Rh factor, anemia, immunity to rubella, hepatitis B, HIV and syphilis
• A urine test, blood pressure, weight and height
• A pelvic exam and a Pap test if you are due for one
• A review of every medicine and supplement you take
• A prenatal vitamin with folic acid

After that, checkups are every four weeks until 28 weeks, every two weeks until 36 weeks, then weekly.

Which tests are offered for the baby in the first trimester?

All of these are offered, not required.

• Cell-free DNA screening, a blood test from about 10 weeks. It screens for Down syndrome and other chromosome conditions, and it can also report the baby’s sex, though that is not its purpose.
• First-trimester screening at 10 to 13 weeks, a blood test combined with a nuchal translucency ultrasound that measures a space at the back of the baby’s neck.
• Diagnostic tests if a screen comes back high risk: chorionic villus sampling at 10 to 13 weeks, or amniocentesis later.
• The anatomy ultrasound at 18 to 22 weeks, which checks how the organs have formed and usually shows the baby’s sex.

Is it normal to feel this up and down?

Yes. Hormone shifts, broken sleep and the size of the news all land in the same few weeks. Feeling excited one hour and frightened the next is ordinary, and so is taking a while to feel attached.

Depression and anxiety are among the most common problems in pregnancy, and they are treatable. Tell your obstetrician if any of this lasts more than two weeks: sadness or anger that arrives without warning, losing interest in things you used to enjoy, trouble finishing ordinary tasks, or upsetting thoughts that will not go away. Screening for this is routine at prenatal visits, and asking early is easier than waiting.

Two numbers to keep: the Postpartum Support International helpline, 1-800-944-4773, which covers pregnancy as well as after birth, and the National Maternal Mental Health Hotline, 1-833-852-6262, staffed 24 hours a day in English and Spanish.

What if the pregnancy ends early?

Between 10 and 20 of every 100 known pregnancies end in miscarriage, and about 8 in 10 of those happen before the 12th week. Most early pregnancy losses happen in the first 13 weeks. More than half are caused by a chromosome problem in the embryo, something set at conception and outside anyone’s control. Working, exercising, having sex, lifting a toddler and a bad night of sleep do not cause miscarriage.

Call your obstetrician for bleeding or spotting, cramping, pain in your belly or back, or pregnancy symptoms that stop suddenly. Plenty of people bleed in early pregnancy and go on to a healthy birth, so the call is for checking. If you do lose a pregnancy, the grief is real whatever week it was. Ask your obstetrician about follow-up care and about trying again, and know that the Postpartum Support International helpline covers loss as well.

When do we come into it?

Not yet, and that is fine. Families usually start choosing a pediatrician around 28 weeks, because the hospital asks for a name before you go home. From about 28 weeks we offer a free prenatal meet-and-greet: you sit down with Dr. Viswanadham, see the office and ask whatever you want. Sign up whenever you are ready, and our third-trimester checklist covers the rest.