Loss of a pregnancy is a distressing event for the parents involved, and recurrent miscarriages are even more so. It is estimated that at least 30-40% of all conceptions will end within the first 12 weeks of gestation. Up to 50% of the time, the woman doesn’t even realize that she was ever pregnant. The risk of miscarriage increases with the number of previous pregnancy losses. Overall, a chromosome abnormality is identified in the products of conception in approximately 50% to 70% of miscarriages and they account for approximately 50% of fetal loss between the first 8 to 15 weeks of gestation.
Advancing maternal age is associated with an increased risk of miscarriage, which is thought to be due to poor egg quality leading to chromosomal (genetic) abnormalities. Sometimes, the mother or father themselves may have a slight irregularity in their genes, but the offspring could be more severely affected and thus result in miscarriage.
Sometimes, there could be an abnormality in the uterus (the womb) that leads to miscarriage. The miscarriage may be due to poor blood supply to the pregnancy or inflammation. Some women may be born with an irregularly shaped uterus, and some women may develop abnormalities with their uterus over time.
Recurrent pregnancy loss is classically defined as the occurrence of three or more consecutive pregnancy losses; however, the American Society of Reproductive Medicine (ASRM) has recently redefined recurrent pregnancy loss as two or more pregnancy losses. A pregnancy loss is defined as a clinically-recognized pregnancy involuntarily ending before 20 weeks. A clinically-recognized pregnancy means that the pregnancy has been visualized on an ultrasound or that pregnancy tissue was identified after a pregnancy loss.
What Tests are Done for Couples with Recurrent Pregnancy Loss?
Testing that may be done includes chromosome analysis of both partners. Because chromosome abnormalities are relatively rare, a doctor may choose to not perform this test unless other, more common, abnormalities are ruled out. There are several ways to evaluate the uterine cavity, including a/an ultrasound, saline ultrasound, hysterosalpingogram X-ray, MRI (magnetic resonance imaging), and/or hysteroscopy (to look inside the uterus). A saline ultrasound is when fluid is injected into the inside of the uterus so that the physician can see if there are abnormalities with the inside of the uterus, including polyps (growths of the lining of the uterus), fibroids, or scarring. A hysterosalpingogram is an X-ray of the uterus and tubes, and can help a doctor to evaluate not only the inside of the uterus, but also the tubes (whether they are open or not). A hysteroscopy is a minor surgical procedure where a camera is placed through the cervix into the uterus so that the doctor can directly visualize the inside of the uterus. The doctor can also remove polyps and fibroids and can resect a septum or scar tissue, if present.
An MRI may be done to evaluate the location of fibroids and in cases of abnormalities of the shape of a uterus. Antiphospholipid antibodies, particularly anticardiolipin antibody and lupus anticoagulant, will likely be checked. Any woman with a pregnancy loss at or beyond the 10th week of gestation (with a "normal" appearing fetus) or with 3 recurrent losses at any gestational age should be screened, according to the American College of Obstetrics and Gynecology (ACOG). Testing for inherited thrombophilias, or abnormally increased blood clotting, may be recommended in women who have experienced recurrent fetal loss as some studies have shown a benefit of giving medicine to prevent clots in these patients. Thyroid function tests and thyroid antibodies may be checked, along with measurement of prolactin, the hormone responsible for breast milk production.
What Treatment is Available for Recurrent Pregnancy Loss?
The treatment recommendations for patients with recurrent pregnancy loss are based on the underlying cause of recurrent pregnancy loss. If a uterine abnormality is found, surgery may be performed depending on the defect. If antiphospolipid syndrome is diagnosed, certain medications that reduce blood clot formation may be given. If thyroid dysfunction or diabetes is diagnosed, specific medications can be prescribed.
Although recent advances in the last decade have significantly increased the ability to identify and characterize the chromosome abnormalities causing pregnancy loss, several limitations still remain.
With the advent of recent technical advances such as microarray-based comparative genomic hybridization (CGH), the prevalence of genetic abnormalities identified in products of conception or intrauterine fetal demise has increased significantly over conventional chromosome analysis and/or fluorescence in situ hybridization.
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