The word prenatal means before birth. Trimester means 3 months. A normal pregnancy is around 10 months and has 3 trimesters.
Your doctor or midwife may talk about your pregnancy in weeks, rather than months or trimesters. The second trimester begins at week 14 and goes through week 28.
Pregnancy care - second trimester
In your second trimester, you will have a prenatal visit every month. The visits may be quick, but they are still important. It is OK to bring your partner or labor coach with you.
Visits during this trimester will be a good time to talk about:
During your visits, your doctor or midwife will:
At the end of each visit, your doctor or midwife will tell you what changes to expect before your next visit. Tell your doctor or midwife if you have any problems or concerns. It is OK to talk about any problems or concerns, even if you do not feel that they are important or related to your pregnancy.
Hemoglobin testing. Measures the amount of red blood cells in your blood. Too few red blood cells can mean that you have anemia. This is a common problem in pregnancy, although easy to fix.
Glucose tolerance testing. Checks for signs of diabetes which can begin during pregnancy. In this test, your doctor or midwife will give you a sweet liquid. An hour later, your blood will be drawn to check your blood sugar levels. If your results are not normal, you will have a longer glucose tolerance test.
Antibody screening. Is done if the mother is Rh-negative. If you are Rh-negative, you may need an injection called RhoGAM around 28 weeks of gestation.
You should have an ultrasound around 20 weeks into your pregnancy. An ultrasound is a simple, painless procedure. A wand that uses sound waves will be placed on your belly. The sound waves will let your doctor or midwife see the baby.
This ultrasound is typically used to assess the baby's anatomy. The heart, kidneys, limbs, and other structures will be visualized.
Ultrasound can detect fetal abnormalities or birth defects about half the time. It is also used to determine the sex of the baby. Before this procedure, consider whether or not you want to know this information, and tell your doctor or midwife and your ultrasound provider your wishes ahead of time.
All women are offered genetic testing to screen for birth defects and genetic problems, such as Down syndrome or brain and spinal column defects.
Women who may be at a higher risk for these problems include:
Most genetic testing is offered and discussed in the first trimester. However, some tests can be performed in the second trimester or are done partly in the first and second trimester.
For the quadruple screen test, blood is drawn from the mother and sent to a lab.
Amniocentesis is a test that is done between 14 and 20 weeks.
Cell-free DNA testing can sometimes be done instead of amniocentesis. Blood drawn from the mother is the only requirement. Cell-free DNA testing is also called "noninvasive prenatal screening".
Contact your doctor or midwife if:
Gregory KD, Ramos DE, Jauniaux ERM. Preconception and prenatal care. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 5.
Hobel CJ, Williams J. Antepartum care. In: Hacker NF, Gambone JC, Hobel CJ, eds. Hacker & Moore's Essentials of Obstetrics and Gynecology. 6th ed. Philadelphia, PA: Elsevier; 2016:chap 7.
Ormandy J. Antenatal and postnatal care. In: Magowan BA, ed. Clinical Obstetrics and Gynaecology. 5th ed. Philadelphia, PA: Elsevier; 2023:chap 23.
Smith RP. Routine prenatal care: second trimester. In: Smith RP, ed. Netter's Obstetrics and Gynecology. 4th ed. Philadelphia, PA: Elsevier; 2024:chap 208.
Williams DE, Pridjian G. Obstetrics. In: Rakel RE, Rakel DP, eds. Textbook of Family Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 20.