A miscarriage, which is also referred to as a spontaneous abortion, is the loss of pregnancy usually before 24 weeks. The majority of miscarriages occur within the first 12 weeks of fetal gestation. After the 12th week of pregnancy, the chances of a miscarriage drop to below 10% but miscarriages in the second trimester, while rare and unexpected, do happen.
Miscarriage or stillbirth
The second trimester of the pregnancy is officially noted as beginning in the 12th week of pregnancy and lasting until the 20th week. Any loss of the fetus occurring between these weeks would be considered a second-trimester miscarriage. After the 20th week, the loss of a pregnancy is termed as a stillbirth.
Causes of second-trimester miscarriage
The most common reason for any miscarriage is chromosome problems in the fetus. These problems often occur during the first trimester and may go undetected until the miscarriage occurs in the 2nd trimester of the pregnancy. In some cases, the fetus may have self-aborted in the first trimester, but was “missed” during normal screenings or doctor’s appointments.
Other causes for a second-trimester miscarriage include severe trauma to the abdomen, incompetent cervix, infections of the pelvic cavity or another part of the body, heart defects of the fetus, thrombophilia disorders, placental abruption, and placenta previa.
Symptoms of second-trimester miscarriage
The symptoms of a first and second-trimester miscarriage are often the same. Vaginal bleeding, abdominal cramping, and the passing of clots are often associated with the loss of a fetus. In some cases, the bleeding may occur internally leading to pain in the shoulder area of the body and bloating of the stomach area.
The incompetent cervix
Late pregnancy miscarriage may be attributed to an incompetent cervix. When the pregnancy begins, the cervix softens and is plugged shut in order to keep the baby firmly in the uterus. In the case of an incompetent cervix, the cervix will begin to dilate within the second trimester. When the dilation goes undetected the baby can pass through the cervix resulting in the miscarriage of the fetus.
Pregnancy after a second-trimester miscarriage
Women who experience a second-trimester miscarriage can go on to carry a full-term infant after the miscarriage occurs. During the pregnancy following a second-trimester miscarriage, the doctor will watch the pregnancy more closely in order to detect any changes that may be occurring between the 12th and 20th weeks.
In the case of an incompetent cervix, frequent pelvic examinations may establish the strength of the cervix well into the third trimester of the pregnancy, up to the date of birth.
Miscarriages occur in at least 30-40% of all known pregnancies. The majority of these miscarriages happen within the first few weeks after egg fertilization. In the rare case of a second-trimester miscarriage, medical attention should be sought immediately and future pregnancies will be noted as high risk.