Repeat miscarriages could be due to faulty sperm

Both partners should be offered tests when a couple experiences repeated pregnancy loss, according to new research.

Also known as recurrent miscarriage, recurrent pregnancy loss, (RPL) is defined as three or more consecutive pregnancy losses before 20 weeks gestation. It is estimated to affect between one and two percent of couples. Women who experience RPL are offered testing, but their male partners are not normally examined.

'Traditionally, doctors have focused attention on women when looking for the causes of recurrent miscarriage. The men's health – and the health of their sperm – wasn't analysed,' said lead author Dr Channa Jayasena of Imperial College London's department of medicine. 'However, this research adds to a growing body of evidence that suggests sperm health dictates the health of a pregnancy.'

The research, published in Clinical Chemistry compared 50 men who were in partnerships affected by RPL with 63 healthy volunteers. Blood tests showed that in the RPL group average testosterone levels were 15 percent lower, and estradiol (a hormone associated with preventing destruction of sperm cells) 16 percent lower than the control group. Both group averages were within the normal range.

The sperm of the men whose partners had lost pregnancies was found to have, on average, lower sperm motility and more abnormal sperm morphology. The sperm were also found to have DNA fragmentation levels twice that of the control group and reactive oxygen species (which can cause cell damage) which was found to be four times higher. 

Dr Zev Williams of Columbia University, New York, who was not involved in the research told Popular Science that this could constitute a plausible explanation for some pregnancy losses: 

'Sperm with fragmented DNA might be able to fertilise an egg and initiate a pregnancy, because they still have the right number of chromosomes to begin the process. Once the male genome is activated, that's when you start seeing problems. Women can get pregnant, and then have pregnancy loss shortly after.'

The authors suggest that both male and female partners should be offered assessment after RPL, and that the standard male tests of sperm count, movement, and morphology are not enough. 

'Not only do men and women need to be tested, but we also need additional tests on DNA fragmentation and reactive oxygen species [for men] to have a more complete view,' said study author Dr Anastasia Dimakopoulou of Imperial College.