The second trimester, weeks 14 to 27: what changes and what to plan

What is your baby doing between 14 and 27 weeks?

Your obstetrician or midwife leads the pregnancy itself. We are the pediatric side, so this guide stays on the baby, what the tests mean, and what to settle before the third trimester. ACOG defines this trimester as 14 weeks 0 days through 27 weeks 6 days.

• Weeks 13 to 16: bones harden, the neck is defined, toenails form, hearing starts to develop, and the lungs begin building the tissue that will exchange oxygen after birth
• Weeks 17 to 20: the part of the brain that controls movement is fully formed, the digestive system is working, and the ears, nose and lips are recognizable on ultrasound
• Weeks 21 to 24: kicks and turns are stronger, the sucking reflex develops, fat forms under the skin, and ridges appear in the hands and feet that later become fingerprints
• Weeks 25 to 28: eyelids open and close, the lungs start making surfactant (the substance that keeps the air sacs open after birth), and loud sounds can make the fetus startle

Most people feel the first movements somewhere in this trimester. ACOG lists it as a second-trimester change without pinning it to a week, and it tends to come later in a first pregnancy. Tracking movement properly starts later, in the third-trimester checklist.

When can your baby hear you?

Pregnancy material often names a single week, and the weeks named do not agree with each other. ACOG describes a process rather than a switch: hearing starts to develop in weeks 13 to 16, and by weeks 25 to 28 a loud sound can make the fetus startle and pull in the arms and legs. Reading, talking and singing are worth doing from mid-trimester, and the reaction you can feel comes near the end of it.

What changes in your body this trimester?

ACOG lists the usual second-trimester changes:

• Appetite increases, and nausea and fatigue often ease
• The abdomen expands, and by the end of the trimester the top of the uterus is near the rib cage
• The skin over the abdomen stretches and can feel tight and itchy, and stretch marks may appear
• The abdomen aches on one side or the other as the ligaments supporting the uterus stretch, which is what round ligament pain is
• Brown patches may appear on the face, the areolas may darken, and the feet and ankles may swell

Heartburn and constipation are the two that cost you sleep. March of Dimes suggests five or six small meals instead of three large ones, more fluid between meals and less with them, two to three hours between the last meal and lying down, and propping your head up at night. ACOG puts the fiber guideline at 25 grams a day, and most people in the United States get about 15. Ask your obstetrician before taking any antacid or laxative.

Bodies change faster than feelings about them do, and that gap is worth saying out loud at a prenatal visit. If low mood, anxiety or a sense of detachment lasts more than two weeks, tell your obstetrician. Postpartum Support International runs a helpline at 1-800-944-4773 that covers pregnancy, not only the weeks after birth.

What happens at the anatomy ultrasound at 18 to 22 weeks?

ACOG recommends at least one standard ultrasound exam, usually at 18 to 22 weeks. It checks physical development, screens for major congenital anomalies, estimates gestational age, and looks at the placenta, the amniotic fluid and the cord. Ask what any finding means before you leave, rather than searching the word later.

Sex is usually seen at this scan: ACOG says that if the fetus is in a good position, it may be possible to tell. A cell-free DNA blood test, which can be done starting at 10 weeks, screens the sex chromosomes and can report it earlier. Whether you find out, and whether you make an occasion of it, is your call.

If the scan does find something, tell us at your prenatal visit. Knowing in advance changes how we schedule the first newborn visit and who else we involve.

What is the glucose test at 24 to 28 weeks?

Every pregnancy is screened for gestational diabetes. ACOG tests early if you have risk factors, and otherwise measures blood sugar between 24 and 28 weeks. CDC gives the same window and notes that gestational diabetes usually develops around the 24th week. A raised screening result leads to a longer glucose tolerance test, and that longer test is what makes or rules out the diagnosis.

For many people food and activity keep blood sugar in range, and some need medicine. ACOG suggests 30 minutes of moderate aerobic activity at least 5 days a week, plus a 10 to 15 minute walk after each meal.

Diabetes you had before pregnancy, type 1 or type 2, is managed more closely. ACOG reports birth defects in 6 to 12 percent of those pregnancies, and a higher chance of a very large baby. Babies born after either kind of diabetes can have low blood sugar, breathing trouble or jaundice in the first days, so the hospital checks blood sugar after birth and we watch feeding and jaundice at the first visit. Tell us at the prenatal visit if this applies to you.

What should you eat, and how do you read a food label?

• Caffeine: ACOG puts moderate intake at less than 200 mg a day, about one 12-ounce cup of coffee. Tea, chocolate, soft drinks and energy drinks count towards it.
• Fish: the FDA advises 8 to 12 ounces a week during pregnancy, which is 2 to 3 servings from its "Best Choices" list at 4 ounces a serving. Avoid king mackerel, marlin, orange roughy, shark, swordfish, Gulf of Mexico tilefish and bigeye tuna.
• Fiber: 25 grams a day, from fruit, vegetables, beans, whole grains and bran.
• Labels: read the serving size first, because every number on the label refers to it. On the percent Daily Value column, 5% or less is low and 20% or more is high.
• Sugar: the label lists Added Sugars separately from Total Sugars, so the sugar in milk and fruit is not counted as added. That line is more useful than sorting sweeteners into natural and artificial.

How should you sleep, travel and work now?

ACOG says side sleeping is likely best in the second and third trimesters, because lying on your back can compress a major vein carrying blood to the uterus and leave you dizzy. Bend one or both knees, put a pillow between them and another under your belly. If you wake on your back, turn to one side.

ACOG calls mid-pregnancy, 14 to 28 weeks, the easiest time to travel. Any trip of 4 hours or more, by car, train, bus or plane, doubles the risk of a blood clot, so walk and stretch at intervals. Wear the seat belt low on your hip bones, below your belly. Airlines and cruise lines set their own cutoff dates and may ask for a note with your due date.

ACOG recommends at least 150 minutes of moderate aerobic activity a week, and says to avoid standing still for long stretches, lying flat on your back, contact sports, hot yoga and scuba diving. If your job involves long standing, heavy lifting or night shifts, ask your obstetrician what to change. To lift at home, squat with your knees bent and your back straight, and wear low-heeled shoes with arch support.

How do you choose a pediatrician?

The AAP suggests interviewing pediatricians in the final months of pregnancy. Worth asking:

• How soon after birth does the pediatrician see the baby, and at which hospitals
• Office hours, including weekends and holidays, and how you reach someone after hours
• Who covers when your pediatrician is away
• How you ask a routine question, and whether there is secure electronic messaging
• Whether your insurance plan is accepted

The AAP recommends visiting a pediatrician during the third trimester, covering car seats, the crib, feeding, which vaccines the people around the baby need, and screening for postpartum depression. We offer a free prenatal meet-and-greet, usually booked from about 28 weeks: sign up here. We go through the first visit, feeding, and how to reach us at night, which is set out on after-hours.

Families on Georgia Medicaid or PeachCare can name Dare2Care Pediatrics as the baby’s primary care provider, which is easier to do before the birth than after. The steps are on primary care provider, and the plans we take are on insurance.

What else is worth doing before 28 weeks?

• Book a childbirth class. Ask your obstetrician or the hospital where you plan to deliver which class they run, and book early, because seats fill.
• Ask your obstetrician about Tdap. CDC recommends it in every pregnancy, best between 27 and 36 weeks, so antibodies against whooping cough reach the baby before the baby’s own immunizations start at 2 months. Flu vaccine in season, and RSV vaccine at 32 to 36 weeks in season, work the same way.
• Book the prenatal visit with us, register at the hospital, and buy the car seat you will actually install.
• Work through the third-trimester checklist when you get there.