Which Asian ethnic groups have a higher incidence of twinning (multiple gestations) due to genetic predisposition?

Twinning Rates Among Asian Ethnic Groups

Japanese, Korean, and Chinese ethnic groups have higher rates of twinning compared to other Asian populations. 1

Ethnic Variation in Twinning Rates Among Asians

The incidence of twinning varies significantly among different Asian ethnic groups, with important distinctions:

• East Asians (Japanese, Korean, Chinese): Evidence suggests these groups have higher susceptibility to twinning compared to other Asian ethnicities 1

• Southeast Asians: Lower twinning rates are observed among Vietnamese, Thai, and Koreans (approximately 6 per 1000 maternities) 2

• South Asians: Indians from India show lower twinning rates compared to those reported from the Indian subcontinent 2

• Cambodians: Have the highest twinning rate among Asian groups at 8.57 per 1000 maternities 2

Comparative Twinning Rates

When standardized for maternal age, twinning rates per 1000 maternities show significant ethnic variation:

• Blacks: 13.20
• Whites: 10.05
• Asians (overall): 7.18 2

Genetic Factors in Twinning

Research indicates that genetic factors play an important role in twinning:

• The Ring Finger Protein 213 (RNF213) gene shows higher prevalence in East Asians, particularly Japanese and Korean populations 1

• Women who are twins themselves have an increased risk of giving birth to twins, suggesting a genetic component 3

• Dizygotic twinning appears to have a maternal genetic influence, with women who are dizygotic twins having a 30% higher risk of having twins themselves 3

Migration and Interethnic Mixing Effects

Twinning rates appear to be modified by both migration and interethnic mixing:

• Chinese, Japanese, and Filipino populations established longer in California show higher twinning rates than more recent Asian immigrants 2

• This suggests environmental factors may interact with genetic predisposition to influence twinning rates

Clinical Implications

Multiple gestations carry significantly higher risks compared to singleton pregnancies:

• Approximately 5-fold increase in fetal death
• 7-fold increase in neonatal death
• Higher risk of preterm delivery, growth restriction, and congenital anomalies 4

Key Takeaways

1. East Asian ethnicities (Japanese, Korean, and Chinese) demonstrate higher twinning rates compared to other Asian groups
2. Genetic factors appear to play a significant role in twinning predisposition
3. Environmental factors and migration can modify twinning rates over time
4. Understanding ethnic variation in twinning rates has important implications for obstetrical care and risk assessment

Healthcare providers should be aware of these ethnic differences when counseling patients about pregnancy risks and planning appropriate monitoring for women of East Asian descent.