Calculate Twin Probability

Maternal Age (Years)

Mother's current age in years

Number of Previous Pregnancies 0 (First pregnancy) 1 2 3 4+

Number of previous pregnancies (including miscarriages)

Height (cm)

Mother's height in centimeters (optional)

Pre-pregnancy BMI

Body Mass Index before pregnancy (optional)

Family History (Select all that apply)

Maternal family has twins

Paternal family has twins

Sister has had twins

Mother has had twins

Fertility Factors (Select all that apply)

Fertility treatment (IVF, IUI, etc.)

Taking Clomid or similar medication

Recently stopped birth control

Currently breastfeeding

Ethnicity Caucasian African/African American Hispanic Asian Other

Mother's ethnic background

Calculate Probability Reset

About Twin Pregnancies

Twin pregnancies occur when two embryos develop simultaneously. The probability depends on genetic, environmental, and medical factors.

Risk Categories:

• Low: < 1% probability
• Moderate: 1-3% probability
• High: > 3% probability

Key Factors:

• • Maternal age (35+ increases risk)
• • Family history of twins
• • Fertility treatments
• • Ethnicity (African descent higher)
• • Previous pregnancies
• • Height and BMI

Medical Considerations:

• • Increased prenatal monitoring
• • Higher risk of complications
• • Earlier delivery common
• • Specialized care may be needed