Maternal-Fetal Medicine · Patient Education
Managing Hypothyroidism
During Pregnancy
A guide to keeping your thyroid — and your baby — healthy throughout your pregnancy.
ACOG Guideline-Based
SMFM Endorsed
Patient-Safe
Understanding Your Condition
What Is Hypothyroidism?
🦋
Your thyroid gland — a butterfly-shaped gland in your neck — makes hormones that control energy, metabolism, and growth.
Hypothyroidism means your thyroid is underactive and does not produce enough hormone.
Why Thyroid Health Matters
Your Baby Depends on Your Thyroid
During the first trimester, your baby cannot yet make its own thyroid hormone. Your supply is the only source for early brain and nervous system development.
Weeks 1–12
Baby relies entirely on maternal thyroid hormone
Week 5+
Critical window for fetal brain cell formation
Good News
Hypothyroidism Is Treatable
🌟
With the right medication, monitoring, and teamwork, women with hypothyroidism have healthy pregnancies and healthy babies every day.
Proper treatment essentially eliminates the added risk.
Clinical Classification
Types of Thyroid Dysfunction
| Type |
TSH Level |
Free T4 |
Significance |
| Overt Hypothyroidism |
↑ Elevated |
↓ Low |
Requires immediate treatment |
| Subclinical Hypothyroidism |
↑ Elevated |
Normal |
Treatment based on antibody status |
| Isolated Hypothyroxinemia |
Normal |
↓ Low |
Often iodine-related; monitored closely |
Your Treatment Goal
The TSH Target During Pregnancy
< 2.5
mIU/L — Target TSH throughout pregnancy
Every 4 wks
Blood tests during first half of pregnancy
~28 wks
Additional check in the third trimester
TSH = Thyroid-Stimulating Hormone. A simple blood test that tells us how well your thyroid is working.
Your Medication
Levothyroxine — Your Thyroid Hormone
What It Is
A synthetic form of thyroxine (T4)
Identical to what your thyroid naturally makes
Safe to take throughout pregnancy
Safe for breastfeeding
Why Doses Change
Pregnancy raises estrogen levels
Estrogen increases thyroid-binding proteins
More hormone is needed to meet demand
Dose typically rises ~30% in early pregnancy
Action Required
As Soon as You Know You Are Pregnant
📞
Contact us immediately. Do not wait for your first prenatal appointment.
9 pills per week
instead of your usual 7 — take 2 extra doses on any 2 days each week
We will confirm the exact dose adjustment at your first visit.
Monitoring Schedule
Your Monitoring Timeline
✚
Positive Test
Increase dose immediately
4w
Every 4 Weeks
TSH + Free T4 checks through 20 weeks
28
Week 28
Third-trimester thyroid check
🍼
Delivery
Return to pre-pregnancy dose
6w
6 Weeks Postpartum
TSH recheck to confirm euthyroidism
Medication Tips
Taking Your Medication Correctly
-
✔
Take on an empty stomach, 30–60 minutes before breakfast, with a full glass of water.
-
⚠
Wait at least 4 hours before taking iron, calcium, or prenatal vitamins.
-
✔
Bedtime dosing is an option — at least 2 hours after your last meal.
-
⚠
Do not switch brands of levothyroxine without talking to your doctor first.
-
✘
Never stop taking your medication without medical guidance.
Why Treatment Matters
Risks When Hypothyroidism Is Untreated
🤰
For You
Preeclampsia · Placental abruption · Preterm labor · Postpartum hemorrhage
👶
For Your Baby
Miscarriage · Low birth weight · Preterm birth · Perinatal complications
🧠
Brain Development
Untreated overt hypothyroidism is linked to lower IQ scores and learning differences in offspring
Treatment dramatically reduces all of these risks.
A Common Finding
Subclinical Hypothyroidism
TSH is mildly elevated, but free T4 is still normal. This is common — affecting up to 1 in 4 pregnant women.
TPO Antibodies Positive
Treatment with levothyroxine is recommended
Reduces risk of miscarriage and preterm birth
TPO Antibodies Negative
Treatment considered if TSH > 2.5 mIU/L
Decision made together with your care team
Postpartum Care
After Your Baby Is Born
💊
Dose Reduction
Return to your pre-pregnancy levothyroxine dose immediately after delivery.
🩸
TSH Recheck
Blood test at 6 weeks postpartum to confirm your levels are back to normal.
⚠️
Watch For
Postpartum thyroiditis — mood changes, fatigue, or palpitations. Tell us right away.
Your Voice Matters
Questions to Ask Your Doctor
What is my current TSH level, and what is the goal during my pregnancy?
When exactly should I increase my dose after a positive pregnancy test?
Can I take my prenatal vitamin and thyroid medication at the same time?
When will my next thyroid blood test be scheduled?
Summary
Key Reminders
- ✔Tell us as soon as you know you are pregnant — or if you are planning to conceive.
- ✔Increase your levothyroxine dose immediately upon a positive pregnancy test.
- ✔Attend all prenatal appointments and blood tests as scheduled.
- ⚠Take your medication correctly — timing and spacing from supplements matter.
- ✘Never stop your thyroid medication without speaking to your doctor first.
We Are Here for You
You Can Have a Healthy Pregnancy
🤝
With proper management, hypothyroidism should not prevent you from having a healthy pregnancy and a healthy baby.
We are your partners in this journey.
Atlanta Perinatal Associates
DoctorsWhoCode.blog
OpenMFM.org · Dr. Chukwuma Onyeije, MFM