TimeDateStack WEEK 27
Second Trimester • 6 months

27 Weeks Pregnant: Baby Size, Symptoms & Due Date Milestones

Comprehensive gestational timeline analysis, fetal growth metrics, anatomical development, and personalized due date milestones for week 27.

Gestational Classification
At 27 weeks pregnant, you are in your Second Trimester

Equivalent to 6 months • 189 calendar days of gestation completed

Overall Gestational Progress 67.5% of 40 Weeks (189 of 280 Days)
Days Pregnant
189 Days
Exact duration
Days Until Due Date
91 Days
13.0 weeks left
Trimester Stage
2nd Trimester
Weeks 14 – 27
Fetal Size Category
Cauliflower
36.6 cm

Baby Development at 27 Weeks Pregnant

Baby Size Comparison
Cauliflower

Fruit / Vegetable Analogy

Estimated Length
36.6 cm

Crown to Heel (Total Length)

Estimated Weight
875 g

Fetal Weight Standard

Week 27 is the final week of the second trimester! The fetal brain is developing intricate surface wrinkles (gyri and sulci) to dramatically increase cortical surface area for billions of neurons.

The baby's sleep and wake cycles are regular and predictable. The lungs are continuing to produce essential surfactant, and the baby's taste preferences are expanding as they swallow amniotic fluid daily.

Personalized Due Date Recalculator

Input your last menstrual period (LMP) to verify your exact week, remaining days, and estimated delivery date.

Real-Time Engine
Recalculated Due Date
Select your LMP date
Days Remaining
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Current Gestation
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Disclaimer: Computational estimates are based on standard clinical algorithms (e.g., Naegele's rule) for educational and planning purposes only. They do not constitute formal medical evaluation, diagnosis, or clinical obstetrics advice.

Maternal Symptoms & Clinical Guidance at Week 27

Common Physical Symptoms

  • Leg cramps and restless legs when settling in for the night
  • Hemorrhoids and sluggish digestion
  • Shortness of breath as the uterus presses on the diaphragm
  • Anticipation and emotional excitement about entering the third trimester

Clinical Action Items

  • Celebrate completing the Second Trimester!
  • Complete your 28-week routine prenatal bloodwork (Rh antibody screen & hemoglobin)
  • Receive your Rhogam injection if your blood type is Rh-negative
  • Schedule your Tdap vaccination to pass whooping cough immunity to your baby

Clinical Biostatistics of Gestational Age & Naegele's Rule Derivation

In clinical obstetrics, pregnancy duration is measured not from the moment of biological conception, but from the first day of the last normal menstrual period (LMP). This standard accounts for the biological reality that the exact time of ovulation and fertilization typically occurs approximately 14 days after menses onset:

Naegele's Rule Mathematical Formula

// Standard 28-day cycle formula:

EDD = LMP + 1 Year - 3 Months + 7 Days

// Exact equivalent calendar day addition:

EDD = LMP + 280 Calendar Days (40 Weeks)

// Cycle length adjustment formula:

EDD_adj = EDD + (Cycle_Length - 28 Days)

Trimester Subdivision & Biological Milestones
First Trimester Weeks 1 – 13 (Days 1 – 91)
Second Trimester Weeks 14 – 27 (Days 92 – 189)
Third Trimester Weeks 28 – 40+ (Days 190 – 280+)

Gestational Age vs. Embryonic Conceptional Age

Healthcare providers distinguish between gestational age (menstrual age) and embryonic/fetal age (conceptional age). Because the first two weeks of gestational age represent pre-ovulatory follicular development, an ultrasound or clinical report indicating 27 weeks gestational age corresponds to an embryo or fetus that has biologically developed for approximately two weeks fewer than the designated gestational count (conceptional age ≈ gestational age − 14 days).

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Frequently Asked Questions About 27 Weeks Pregnant

Yes. Week 27 marks the completion of the Second Trimester. Week 28 begins the final, critical home stretch: the Third Trimester.