Repeated multiple maternities in triplet families

Area of Science:

• Human Genetics
• Reproductive Biology
• Biostatistics

Background:

• Previous research has explored genetic and environmental influences on human multiple maternities.
• Understanding the patterns of multiple births is crucial for reproductive health and population studies.

Purpose of the Study:

• To analyze the frequencies of multiple maternities within sibships containing triplets.
• To evaluate the triplet birth rate using the Hellin transformation.
• To compare the influence of maternal versus paternal factors on multiple maternities.

Main Methods:

• Analysis of multiple maternity frequencies in sibships with triplets.
• Application of the Hellin transformation for triplet rate evaluation.
• Comparison of observed frequencies with population-based expectations.

Main Results:

• Observed frequencies of repeated multiple maternities in sibships exceeded population expectations.
• The excess was more pronounced for triplet maternities compared to twin maternities.
• The transformed triplet rate demonstrated results comparable to the twinning rate.
• Maternal factors showed a stronger influence on multiple maternity frequencies than paternal factors.

Conclusions:

• Family-specific factors significantly increase the likelihood of repeated multiple births.
• Triplet rates, when transformed, align with twinning rate patterns.
• Maternal genetic and/or environmental influences play a more substantial role in determining multiple maternities than paternal ones.