Research indicates that both the mother's and father's age significantly influence the risk of miscarriage. If the mother is over 34 years old, her risk of miscarriage doubles. If the father is over 40, the risk increases sevenfold regardless of the mother's age. Studies also reveal that women with a history of miscarriage or low progesterone levels face heightened miscarriage risks.
It is commonly believed that miscarriages after conception are solely attributable to female factors. However, research indicates that many miscarriages, particularly recurrent ones, are also linked to male factors:
1. Chromosomal factors.
Sperm with chromosomal abnormalities are of poor quality. Even if they achieve fertilization and pregnancy, the pregnancy often ends in miscarriage.
2. Immune factors.
The embryo is recognized as a foreign entity by the mother's immune system, potentially triggering rejection. Since half of the embryo's antigens originate from the mother and half from the father, severe immune responses may target paternal antigens, leading to miscarriage.
3. Sperm factors.
Poor-quality or abnormally shaped sperm may still result in pregnancy, but such pregnancies are prone to miscarriage.
Additionally, sexual intercourse during early pregnancy can mechanically stimulate the uterus, while prostaglandins in semen may induce uterine contractions, both potentially triggering miscarriage.
When investigating causes of recurrent miscarriage, if comprehensive examinations of the female partner fail to identify a definitive cause, do not overlook testing the male partner. The causes of recurrent miscarriage in women are multifactorial and not solely attributable to the wife. Clinically, the direct cause of recurrent miscarriage often originates from the husband.
Male Chromosomal Abnormalities Leading to Female Recurrent Miscarriage
Genetics represents one aspect of male factors contributing to recurrent miscarriage. Specifically, male chromosomal abnormalities, such as balanced translocations, can cause miscarriage in the wife.
After fertilization, the sperm and egg fuse, combining the 23 chromosomes from each parent into 23 pairs to form a normal embryo. In cases of chromosomal translocation, this distribution becomes uneven. When abnormal sperm combines with a normal egg, it can result in an abnormal trisomic or monosomic zygote.
Monosomic zygotes often perish during early embryonic development, resulting in miscarriage or stillbirth. Trisomic zygotes also frequently miscarry; even if they survive to birth, the child will invariably be born with congenital deformities, struggle to grow, or develop into a mentally disabled individual.