I am pregnant at around 28 weeks; what are Braxton‑Hicks contractions and when should I seek medical evaluation if I experience them?

When to Expect and Evaluate Braxton-Hicks Contractions at 28 Weeks

Braxton-Hicks contractions are normal, irregular uterine contractions that typically intensify in the third trimester and should prompt immediate medical evaluation if they become regular, painful, or fail to subside with rest, as these features may indicate preterm labor rather than benign physiologic activity. 1

What Are Braxton-Hicks Contractions?

Braxton-Hicks contractions represent coordinated uterine activity that increases progressively as pregnancy advances toward delivery. 2 At 28 weeks gestation, you are entering the period when these contractions become more noticeable and frequent. 1

Key Distinguishing Features of Normal Braxton-Hicks:

• Irregular timing and pattern – they do not occur at predictable intervals 1
• Uncomfortable but not painful – they cause tightening sensation rather than true pain 1
• Subside completely with rest – stopping activity makes them disappear 1
• No progressive increase in intensity or frequency over time 1
• May become more intense with physical activity but resolve when you stop moving 1

When to Seek Immediate Medical Evaluation

You must contact your healthcare provider immediately if you experience any of the following warning signs: 1, 3

Red Flags Requiring Urgent Assessment:

• Regular, rhythmic contractions occurring at predictable intervals 1
• Painful contractions that are more than just uncomfortable tightening 1
• Contractions that persist despite rest and position changes 1
• Progressive increase in frequency or intensity over 1-2 hours 3
• More than 4-6 contractions per hour 3
• Any vaginal bleeding or fluid leakage accompanying contractions 4
• Pelvic pressure or low back pain with contractions 3

Critical caveat: The term "Braxton-Hicks" can create false reassurance and delay recognition of preterm labor. 3 Do not dismiss regular or painful contractions as "just Braxton-Hicks" without medical evaluation, as early detection of preterm labor is essential for preventing preterm birth. 3

Physiologic Impact on You and Your Baby

Maternal Effects:

Braxton-Hicks contractions can temporarily reduce blood flow to the placenta during each contraction. 5 In women with normal placental function, this brief reduction is well-tolerated. 5 However, frequent contractions may cause cumulative effects on uterine blood flow. 6

Fetal Effects:

Research demonstrates that when mothers perceive Braxton-Hicks contractions, fetuses show: 6

• Slightly higher baseline heart rate (135 vs 128 bpm) 6
• Reduced heart rate variability 6
• Fewer accelerations on monitoring 6
• Temporary decreases in fetal brain and liver oxygenation during contractions 7

These changes are typically transient and benign in healthy pregnancies. 6, 7

Activity Modifications at 28 Weeks

You should continue normal daily activities and moderate exercise unless you have specific contraindications. 4 However, if you notice increased Braxton-Hicks contractions during physical activity:

• Stop the activity immediately and rest 1
• Change to left lateral position to optimize blood flow 8
• Hydrate adequately as dehydration can trigger contractions 1
• Resume activity only after contractions completely resolve 1

Specific High-Risk Conditions Requiring Activity Restriction:

If you have any of these conditions, you should avoid moderate-to-vigorous physical activity and maintain only activities of daily living: 4, 1

• Cervical insufficiency 1
• Placenta previa diagnosed after 28 weeks 4
• Active preterm labor 1
• Severe pre-eclampsia 1

Practical Management Algorithm

Follow this decision tree when experiencing uterine contractions:

1. Note the pattern: Are contractions regular or irregular? 1

   • Irregular → Likely Braxton-Hicks, proceed to step 2
   • Regular (every 10-15 minutes or less) → Call provider immediately 1, 3

2. Assess pain level: Uncomfortable tightening or true pain? 1

   • Uncomfortable only → Proceed to step 3
   • Painful → Call provider immediately 1

3. Rest and hydrate: Stop activity, lie on left side, drink water 1, 8

   • Contractions stop within 30-60 minutes → Likely benign Braxton-Hicks 1
   • Contractions persist or worsen → Call provider immediately 1

4. Monitor frequency: Count contractions for one hour 3

   • Less than 4-6 per hour → Likely benign 3
   • More than 4-6 per hour → Call provider immediately 3

Never dismiss your concerns or delay seeking evaluation when something feels different or wrong. 3 Early preterm labor can present subtly, and prompt medical assessment is always preferable to waiting. 3