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Second Trimester Guide: Pregnancy Weeks 13 to 27

A second trimester guide for weeks 13 to 27: baby development, anatomy scan, first movements, glucose test and comfort tips for a smoother pregnancy.

  • By Chaitanya Hospital Medical Team
  • 5 min read
A gentle illustration of a baby silhouette in soft purple, symbolising growth in the middle months of pregnancy
In this article10 sections
  1. 01How You May Feel
  2. 02How Your Baby Develops
  3. 03Feeling Your Baby Move
  4. 04Scans and Tests
  5. 05Staying Comfortable
  6. 06Planning Ahead
  7. 07Things to Avoid
  8. 08Myths and Facts
  9. 09When to See a Doctor
  10. 10Talk to a Doctor

The second trimester, weeks 13 to 27, is often called the most comfortable stage of pregnancy. Nausea usually settles, energy returns and you may feel your baby move for the first time.

This guide explains what is happening inside and outside your body, which scans and tests to expect, how to stay comfortable and when to call your doctor. To see which week you are in, try our pregnancy week calculator.

How You May Feel

Cleveland Clinic says morning sickness and first-trimester tiredness often fade, though some women continue to feel unwell or develop new symptoms. Common changes include:

  • Better appetite
  • Bleeding gums and occasional nosebleeds or a blocked nose, caused by hormones
  • A darker line down the belly and darker nipples
  • Stretch marks, swelling of the hands, feet and ankles
  • Round ligament pain, a short sharp twinge at the side of the belly
  • Back pain and leg cramps (see pregnancy back pain and leg cramps relief)
  • A higher chance of urine and yeast infections

How Your Baby Develops

Cleveland Clinic and Womenshealth.gov describe these milestones:

  • **Weeks 13 to 16:** Eyelids, eyebrows, eyelashes, nails and hair appear. The baby can stretch, make faces and suck a thumb. At 16 weeks the baby is about 4 to 5 inches long.
  • **Around week 20:** The baby is about 6 inches long by Womenshealth.gov's measure, can hear and swallow, and is covered in a protective coating called vernix. The NHS describes the baby as about 25.6 cm from head to heel at this point, using a different measure.
  • **Week 24:** About 12 inches long and about 1.5 pounds.
  • **Weeks 26 and 27:** The NHS says the baby's eyes open for the first time, and the baby learns to blink.

Sizes differ by how and when they are measured, so treat these as rough guides.

Feeling Your Baby Move

Cleveland Clinic says first movements, called quickening, are usually felt around 18 to 20 weeks. They feel like flutters or bubbles. Movements may be irregular at first and become more regular closer to week 28. First-time mothers may notice them later.

If you are unsure whether what you feel is the baby, ask your doctor at your next visit. For later pregnancy, read about what to do about reduced baby movements.

Scans and Tests

  • **Anatomy scan:** A detailed ultrasound often around 20 weeks that checks the baby's organs and the placenta. See ultrasound scans by trimester.
  • **Blood tests:** Cleveland Clinic lists a blood count for anaemia, Rh factor and a repeat syphilis screen among routine tests. See anaemia in pregnancy.
  • **Glucose test:** MedlinePlus says most women are screened for gestational diabetes at 24 to 28 weeks, earlier if risk is high. In the two-step method you drink a glucose solution and have blood drawn an hour later. A reading above 140 mg/dL (7.8 mmol/L) leads to a longer follow-up test. Procedures vary between clinics, so follow your doctor's instructions.
  • **Regular visits:** Cleveland Clinic says visits are usually every four weeks unless your pregnancy is high risk.

Our guide to gestational diabetes explains what the results mean.

Staying Comfortable

  • Exercise gently. Cleveland Clinic suggests about 20 minutes a day, with walking and swimming among the safest choices. Ask your doctor first.
  • Sleep on your side and avoid lying flat on your back for long periods.
  • Eat small, balanced meals and drink water. See foods to eat during pregnancy.
  • Do gentle pelvic floor exercises, as the NHS suggests, to reduce leaking.
  • Rub a cramping calf or pull your toes towards your ankle.

Tip: Keep a small notebook for questions and baby movements. It makes antenatal visits shorter and calmer.

Planning Ahead

The middle months are also a good time to prepare. The NHS suggests considering antenatal classes, which are useful even if you have children already, and asking about vaccines such as the whooping cough vaccine. It also recommends talking to your workplace about lighter duties or time for appointments, and starting to think about contraception and family planning after the birth. Having these conversations now leaves more time for the baby's arrival later. Our guide to vaccines during pregnancy explains the common ones.

If you have any long-term condition such as thyroid disease or high blood pressure, this is a good moment to review your medicines and tests with your doctor. Read our article on thyroid problems in pregnancy if this applies to you.

Things to Avoid

  • Raw or undercooked meat, unpasteurised dairy, high-mercury fish and deli meats
  • Alcohol, smoking and recreational drugs
  • Hot tubs and saunas
  • Contact sports and activities with a risk of falls
  • Cleaning cat litter, because of the risk of toxoplasmosis

Myths and Facts

  • **Myth:** The baby is safe from everything now. **Fact:** Warning signs still matter, so keep all visits.
  • **Myth:** Swelling is always harmless. **Fact:** Sudden or extreme swelling with other symptoms can point to preeclampsia. See preeclampsia warning signs.
  • **Myth:** You should eat for two. **Fact:** The NHS says you do not need extra calories until the third trimester.
When to be cautious: Womenshealth.gov says itching together with nausea, vomiting, jaundice or tiredness can signal a serious liver problem. Do not wait. Call your doctor the same day.

When to See a Doctor

Contact your doctor straight away if you have:

  • Unusual or severe cramping or tummy pain
  • Vaginal bleeding
  • Fluid leaking from the vagina
  • Regular contractions, more than four an hour, according to Cleveland Clinic
  • Worsening breathlessness
  • Sudden or extreme swelling or fast weight gain
  • Severe headache or vision changes

For urgent help, see our emergency page.

Talk to a Doctor

The middle months are a good time to settle your care plan, birth preferences and questions. Book an appointment or call +91 944 103 0587. Learn about antenatal check-ups or see the third trimester guide for what comes next.

This article is for general awareness and is not a substitute for a doctor's advice.

References

This article was written in our own words from the following public health sources.

Educational content

Please note. This article is for general awareness and is not a substitute for a doctor’s advice, diagnosis or treatment. If you are worried about your health, or in an emergency, call +91 944 103 0587 or visit the hospital.

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Questions readers ask

When will I first feel my baby move?

Cleveland Clinic says first movements, called quickening, are usually felt around 18 to 20 weeks and feel like flutters. They can be later in a first pregnancy and are often irregular at first.

What is the anatomy scan and when is it done?

It is a detailed ultrasound, often around 20 weeks, that checks the baby's limbs, brain, heart and other organs, as well as the placenta. The NHS says you may have it around week 20.

Do I have to fast for the glucose test?

MedlinePlus says the first step of the two-step test needs no preparation: you drink a glucose solution and have blood taken an hour later. A longer follow-up test, if needed, requires fasting, so follow your clinic's instructions.

Is the second trimester really the easiest?

Many people feel better as nausea and extreme tiredness ease, which is why it is called the most comfortable trimester. But new symptoms such as round ligament pain, swelling and leg cramps can appear.

Can I exercise in the second trimester?

Cleveland Clinic suggests about 20 minutes a day, with walking and swimming among the safest options, after checking with your provider. The NHS suggests aiming for 150 minutes a week, starting small.

Which vaccine is advised in this trimester?

The NHS says the whooping cough vaccine is usually offered around week 20 and can be given from week 16 to week 32. Vaccine schedules differ by country, so ask your doctor what applies in India.

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