Danish researchers led by Annette Wind Olsen have reported in the British Medical Journal that fathers might be responsible for pregnancies that last longer than 42 weeks or 294 days. The condition of prolonged pregnancies affects around 5% of pregnant mothers. The researchers conducted a study of about 28,000 women between 1980 and 1994. About 21,000 women in the group had a first pregnancy that had lasted longer than 42 weeks and another 7,000 women whose first pregnancy had lasted between 37 and 41 weeks. The data gathered from the participants indicated that those who had had one prolonged pregnancy had a 20% risk of having a second one. If the first pregnancy had lasted for 44 weeks, the risk increased to 30%. However, if the women switched partners between pregnancies, the the risk of a second prolonged pregnancy was reduced to 15% The length of pregnancy differed by more than a week in women who had changed partners, compared with those who had not. In the group of women who had a 'normal' length pregnancy, only 7.7% had a prolonged second pregnancy. The researchers thus suggested that paternal genes may affect the timing of the birth. They also concluded that women who had experienced one prolonged pregnancy were more likely to experience another if they were with the same partner.
The study, which is claimed by the researchers as the first to have made such observations, has not been completely accepted by UK experts who say that there may also be other factors that are responsible for the findings. Professor Andrew Calder, a consultant obstetrician at the University of Edinburgh, claimed that pre eclampsia could be one such factor and that there was also no information as to how many women were induced before they reached 42 weeks.
