Genetic influence on parturition in a twin sample: Examination of parental effect on birth timing

Article Outline

• Objective
• Study design
• Results
• Conclusion
• Copyright

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Objective 

Prior twin studies suggest that maternal hereditary factors contribute to preterm birth, but the magnitude of paternal genetic influences is unknown. This study was undertaken to test the hypothesis that paternal, as well maternal, genetics contribute to birth timing.

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Study design 

A database including >19,000 births to monozygotic (MZ) twins, dizygotic (DZ) twins, siblings and parents of twins was created from Dutch twin surveys. Quantitative genetic methods were utilized to examine correlation coefficients(r) and concordance of birth timing (# weeks of variation) in the offspring of twin pairs. The variation in birth timing was calculated by comparing the gestational age of the 1st birth of twin 1 to any birth of twin 2.

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Results 

This study included 273 twin pairs (43 male, 230 female) + 27 male siblings of DZ male pairs. There were 1269 births to these parents. We found a higher correlation of birth timing in MZ than DZ twin mothers (rMZ = 0.31, rDZ = 0.15). This trend was not present for twin fathers (rMZ = 0.08, rDZ = 0.22). The # weeks of variation in birth timing between twin pairs indicate close concordance for both MZ and DZ female pairs compared to male pairs (see table).

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Conclusion 

Our data implicate a strong contribution of maternal genetics to birth timing. In addition, we find that variation in paternal genes contribute little to the timing of birth under normal circumstances.

Birth Timing Correlation