Paternal genes and placenta
The elegant paper of Wind Olesen et al. suggests that the timing of
birth, may in part, be determined by paternal genes. We like to add to
their suggestion: 'very likely through the process of placentation'.
Kloosterman pointed out that the observation that at a longer duration of
pregnancy heavier placentae are born, may indicate that in the presence of
well developed and well functioning placentae pregnancies last longer (1).
In general, placentae of multiparae are heavier than placenta of
primiparae (2). It would be interesting to know whether Wind Olesen et al.
have data on placental weights in their registry, to test the hypothesis
that a change of partner may, to some extent, reduce placentation in the
next pregnancy. If these data are not available, we like to stress the
importance, that we midwives and obstetricians, should document placental weights of
all pregnancies according a standardized method of weighing.
1. Kloosterman GJ. How long growths the human placenta (in Dutch).
Ned T Verlosk 1965; 65: 202-16.
2. Bleker OP et al. A study of birth weight, placental weight and
mortality of twins as compared to singletons. Br J Obstet Gynaecol 1979;
Competing interests: No competing interests