Second Trimester of Pregnancy

Second trimester of pregnancy: weeks 14 through 27

The second trimester begins at week 14 and continues through the end of week 27. During this stage, pregnancy becomes more visible, fetal growth continues rapidly, and you may feel your baby move for the first time.

Some early pregnancy symptoms may improve, although every pregnancy is different. New changes can include a growing bump, round-ligament discomfort, heartburn, constipation, back discomfort and increasingly noticeable fetal movement.

Major clinical milestones include the 18–22 week anatomy scan, prenatal visits around weeks 18 and 24, and gestational-diabetes screening between weeks 24 and 28.

This page gives you the broad picture of trimester 2. Use the week-by-week guide for precise timing and the month guide when you prefer to follow pregnancy by month.

Which weeks and months are in the second trimester?

Trimester 2 covers weeks 14–27. Saudi pregnancy-month mapping does not align perfectly with clinical trimester boundaries.

• Month 4: weeks 14–17.
• Month 5: weeks 18–21.
• Month 6: weeks 22–26.
• Week 27: the start of month 7 in the month guide while still clinically within trimester 2.

This is why LahaLak shows both weeks and months while keeping gestational weeks as the more precise clinical reference.

How does the fetus develop during the second trimester?

Most major structures began forming during trimester 1. The second trimester is increasingly about growth, maturation, coordinated movement and more detailed anatomical development.

Weeks 14–17: rapid growth and increasing movement

Bones, muscles and the nervous system continue developing. Fetal movement becomes increasingly coordinated, although you may not be able to feel it yet.

Weeks 18–22: movement and the anatomy scan

This is one of the most important periods of trimester 2. Fetal movement may become noticeable, while ultrasound can evaluate anatomy in considerably more detail.

Weeks 23–27: stronger movement and continued maturation

Fetal size increases, while the brain, lungs and nervous system continue maturing. Movement often becomes easier to recognize.

This period also includes the routine window for gestational-diabetes screening.

When will you first feel fetal movement?

Saudi Ministry of Health pregnancy guidance notes that women in a first pregnancy may feel fetal movement around 18–20 weeks.

Women who have been pregnant before may notice movement earlier, sometimes around 13–16 weeks.

Early movement can feel like fluttering, bubbles or subtle tapping before becoming stronger and easier to identify.

Timing varies with factors such as placental position, body build and previous pregnancy experience, so avoid comparing your exact timing with someone else's.

Should you count fetal movements yet?

Early movement is not necessarily regular, so there is little value in turning every early movement into a rigid number that creates anxiety.

As pregnancy advances, become familiar with your baby's usual pattern. Once movement is established, a clear reduction or concerning change should prompt contact with your maternity care team.

What is the 18–22 week anatomy scan?

Saudi prenatal guidance schedules the second routine ultrasound between weeks 18 and 22.

It may be called an anatomy scan, anomaly scan or detailed fetal ultrasound.

Its main purpose is not fetal sex determination. It evaluates fetal growth and many important anatomical structures, while also providing information about the placenta and other pregnancy features when relevant.

A reassuring scan is valuable, but no ultrasound can detect every possible fetal condition.

Can fetal sex be seen during the second trimester?

Fetal sex may become easier to visualize around 18–20 weeks, depending on fetal position, gestational age and image quality.

The clinical priority of the anatomy scan remains fetal growth and anatomy rather than sex determination.

The 18-week prenatal visit

In the Saudi primary-care pregnancy pathway, the second core prenatal visit takes place around 18 weeks.

It may include:

• Weight measurement.
• Blood-pressure measurement.
• Assessment of uterine size relative to gestational age.
• Fetal-heart assessment.
• Urine testing.
• Review of pregnancy risk factors.
• Review of iron, calcium or vitamin D needs.
• Planning or completing the 18–22 week anatomy scan.

The 24-week prenatal visit

The next core Saudi prenatal visit is scheduled around 24 weeks.

Weight, blood pressure, uterine growth and fetal heartbeat are reviewed, and fetal movement is discussed.

Depending on your care plan, testing may include CBC, ferritin, urine testing and gestational-diabetes screening.

When is gestational-diabetes screening performed?

Saudi Ministry of Health guidance places routine gestational-diabetes testing between 24 and 28 weeks.

An oral glucose tolerance test or OGTT may be used according to the clinical protocol.

Earlier glucose testing may be appropriate for women with particular risk factors.

Iron and ferritin in the second trimester

Iron requirements rise as pregnancy progresses because maternal blood volume expands and the fetus and placenta continue growing.

CBC and ferritin may be used to identify anemia or low iron stores. Supplement dose should reflect your actual results and clinical needs.

Calcium, vitamin D and other supplements

Saudi prenatal guidance notes that iron, calcium and vitamin D may be prescribed when needed during this period.

Avoid combining several supplements without checking what your prenatal vitamin already contains.

Common second-trimester symptoms

• A more visible pregnancy bump.
• Gradual weight gain.
• Round-ligament discomfort.
• Lower-back discomfort.
• Heartburn and indigestion.
• Constipation and bloating.
• Leg cramps in some women.
• Normal increases in vaginal discharge.
• Skin pigmentation changes.
• The first recognizable fetal movements.

Round-ligament pain

As the uterus grows, the supporting ligaments stretch. This may cause short sharp or pulling discomfort on one or both sides of the lower abdomen, particularly with sudden movement.

Severe or persistent pain, especially with bleeding, fever or other symptoms, should not simply be assumed to be ligament pain.

Back discomfort and sleep

A changing center of gravity can increase strain on the back and pelvis. Appropriate activity, good posture and avoiding prolonged fixed positions can help.

Persistent back pain combined with recurrent contractions, pelvic pressure or a change in vaginal discharge requires assessment for possible preterm labor.

Heartburn and constipation

Pregnancy hormones and the growing uterus can affect digestion. Smaller meals, adequate fluids and gradually increasing dietary fiber may help.

Ask your clinician before regularly using antacids or laxatives during pregnancy.

Nutrition and weight gain

Appetite may improve after early pregnancy nausea settles, but pregnancy does not require eating twice as much food.

Focus on protein, vegetables and fruit, fiber-rich foods, iron sources, calcium, appropriate vitamin D intake and regular hydration.

Healthy weight gain differs according to prepregnancy weight, height and medical factors, so there is no single target that fits every pregnant woman.

Exercise during the second trimester

If your pregnancy is uncomplicated and your clinician has not restricted activity, suitable moderate physical activity can remain part of a healthy pregnancy.

Choose activity appropriate to your previous fitness level, stay hydrated, and avoid overheating or activities with a high risk of falling or trauma.

Sex during the second trimester

In an uncomplicated pregnancy, sex is generally safe unless your clinician advises otherwise.

Restrictions may be advised in situations such as unexplained bleeding, ruptured membranes, certain cases of placenta previa or a significant risk of preterm birth.

What are the warning signs of preterm labor?

Labor beginning before 37 weeks is considered preterm. As you approach the end of trimester 2, it is useful to recognize possible warning symptoms.

• Regular or recurrent contractions.
• New or increasing pelvic pressure.
• Persistent unusual backache.
• A clear change or increase in vaginal discharge.
• Watery or blood-stained discharge.
• Rupture of membranes or suspected amniotic-fluid leakage.

When should you seek prompt medical assessment?

• Vaginal bleeding.
• Fluid leakage or suspected rupture of membranes.
• Sudden or severe swelling of the face or fingers.
• Severe persistent headache.
• Blurred or altered vision.
• Severe lower-abdominal pain.
• Fever or chills.
• A clear reduction in fetal movement once movement is established.
• Pain or burning with urination or markedly reduced urine output.
• Possible preterm-labor symptoms.

Practical second-trimester checklist

1. Continue scheduled prenatal follow-up.
2. Attend the 18-week visit and arrange the 18–22 week anatomy scan.
3. Become familiar with fetal movement as it develops.
4. Attend the 24-week visit and discuss gestational-diabetes screening.
5. Complete OGTT or other glucose testing during weeks 24–28 if included in your plan.
6. Complete CBC, ferritin and urine tests when requested.
7. Use iron, calcium and vitamin D according to your actual needs.
8. Maintain a balanced diet and pregnancy-appropriate activity.
9. Know the warning signs of preterm labor and other pregnancy complications.
10. Prepare to enter trimester 3 at week 28.

Second trimester week by week

• Week 14: the second trimester begins.
• Week 15: continued growth and maternal changes.
• Week 16: some women may notice early movement.
• Week 17: approaching the anatomy-scan stage.
• Week 18: prenatal visit and start of the anatomy-scan window.
• Week 19: movement may become easier to recognize.
• Week 20: approximately the midpoint of pregnancy.
• Week 21: continued growth and movement.
• Week 22: the usual anatomy-scan window closes.
• Week 23: brain, lung and movement development.
• Week 24: prenatal visit and gestational-diabetes screening window.
• Week 25: increasingly recognizable fetal movement.
• Week 26: approaching the end of month 6.
• Week 27: the start of month 7 and the final week of trimester 2.

What happens when you enter the third trimester?

The third trimester begins at week 28.

Prenatal visits gradually become more frequent, while fetal movement, growth, blood pressure and preparation for birth become increasingly important.

If you are Rh negative, your week-28 care plan may include repeat antibody testing and Anti-D immunoglobulin when appropriate.

Medical basis for this guide

This guide follows current Saudi Ministry of Health pregnancy-care guidance, including the 18- and 24-week visits, the 18–22 week anatomy scan, gestational-diabetes screening at 24–28 weeks, fetal movement guidance and pregnancy warning signs.