Sperm Quality Issues and Miscarriage

Human spermatozoa
Sperm Abnormalities. De Agostini Picture Library / Getty Images

Because the mother is the one whose body carries a pregnancy, many suspected causes of miscarriage have to do with factors present in the mother. But since chromosome problems are the leading cause of miscarriage and half of a developing baby's chromosomes come from the father, you may wonder whether something in the sperm could be the reason for a miscarriage—especially if you've had multiple miscarriages.

Can Problems with Sperm Cause Miscarriages?

The answer is maybe. In the past, researchers have focused on the egg as being the main source of chromosome problems for a number of reasons. One reason is that (usually) only one egg is ovulated each menstrual cycle, but a natural selection takes place among the sperm before fertilization that theoretically should lead to the "fittest" being the ones to reach the egg. In addition, genetic studies on tissue from miscarriages have traced errors in the first stage of maternal meiosis (early development of the egg) as being the most likely source of the abnormalities that cause miscarriages.

But some research over the past decade suggests that this might not always be the case. Some cases of recurrent miscarriages seem to involve the father having a high incidence of abnormal chromosomes in his sperm. There aren't any real estimates for how frequently the sperm is a factor in recurrent miscarriages, and chromosome problems in sperm aren't believed to be a major cause of repeat losses, but it does seem to be a possibility—especially in men whose sperm ​showed abnormal morphology or other markers of low fertility.​

Some physicians may recommend that men undergo tests for sperm quality when no other cause for recurrent miscarriages is found. Sperm quality can sometimes, but not always, be improved with lifestyle changes or medications.

First Trimester Miscarriage

About 3 of 4 miscarriages occur during the first trimester of pregnancy.

Typically, if a woman has a miscarriage during the first trimester, there was a problem with the baby's chromosomes. Chromosomes are blocks of DNA that contain encode all the information needed during development.

With chromosomal problems, something awry happens during conception and an embryo gets the wrong number of chromosomes (too many or too few) thus eventually resulting in miscarriage. Of note, not all babies with the wrong number of chromosomes are miscarried. For example, babies with trisomy 21 have Down's syndrome.

Sometimes, something happens that results in a miscarriage that has nothing to do with chromosomes. For example, if there are problems with the placenta, the risk of miscarriage increases. Remember that the baby needs the placenta to receive the mother's blood.

Here are some other causes of miscarriage during the first trimester:

  • smoking
  • obesity
  • illicit drug use
  • alcohol use

Second Trimester Miscarriage

Although most miscarriages occur during the first trimester, miscarriages also occur during the second trimester.

Here are some reasons why miscarriage occurs during the second trimester:

  • diabetes
  • kidney disease
  • lupus
  • hormone problems
  • infections
  • severe food poisoning
  • weakened cervix
  • fibroids

Please note that these items are merely risk factors. In other words, not every woman with diabetes will experience a miscarriage.

Ultimately, many people who have miscarriages will never know exactly why they had one. Several factors contribute to the risk of miscarriage.


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