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Patient education · Maternal-Fetal Medicine

MTHFR Variants in Pregnancy

What the result means—and what care actually helps

Dr. Chukwuma Onyeije · Maternal-Fetal Medicine

01 · Terminology

Start with the right word

Common finding
C677T / A1298CVariant · not disease
Different condition
Severe deficiencyRare · specialist care
02 · Biology

A pathway, not a prediction

MTHFR helps process folate. A common variant may modestly change enzyme activity, but it does not predict a pregnancy complication.

03 · Evidence

Professional guidance agrees

ACOG
SMFM
Not a clinical thrombophilia
ACMG
ASRM

Do not screen for common MTHFR variants. They are not an inherited thrombophilia and do not independently guide pregnancy treatment.

04 · Clinical utility

Screening and diagnosis differ

05 · Interpretation

Read the report calmly

MTHFR genotypelimited utility
Personal historydrives care
06 · Nutrition

Folic acid still works

People with MTHFR variants process folic acid. Take at least 400 mcg daily before and during pregnancy, unless advised otherwise.

Proven neural-tube protection
07 · Folate forms

Methylfolate is not required

Folic acid

Recommended
No mandatory
switch

5-MTHF

Optional form
08 · Medication

Blood thinners need another reason

MTHFR alone: no aspirin or heparin
Preeclampsia risk: consider aspirin criteria
Prior VTE / APS: use condition-specific guidance
09 · Decision pathway

The clinical algorithm

10 · Recurrent loss

After pregnancy loss

11 · Laboratory context

If homocysteine is already high

Routine testing is unnecessary. If already elevated, investigate nutrition, kidney function, medicines, and other causes with your clinician. Treat the cause—not genotype.

12 · Prenatal care

Pregnancy care usually stays standard

13 · Shared decisions

Four questions for your visit

14 · Communication

Balanced counseling matters

“The result is real. Its predictive power is often overstated.”
15 · Action

Your practical plan

Before you finish

Education, privacy, and your care

Educational information
This presentation does not replace advice from your obstetric or MFM care team.
Your privacy
This presentation does not ask for, collect, or store personal health information.

Medication and supplement decisions should be based on your complete medical and pregnancy history.

Take-home message

MTHFR is information—not a treatment plan.

Use evidence. Treat the person. Protect the pregnancy.

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