hree widely accepted causes of RPL are parental chromosomal abnormalities, antiphospholipid antibody syndrome, and structural uterine abnormalities. First-trimester losses in PL have a signiicantly lower incidence of genetic abnormalities than sporadic miscarriage (Stephenson, 2002; Sullivan, 2004).
The timing of recurrent loss can ofer clues, and in some women, each miscarriage may occur near the same gestational age (Heuser, 2010). Genetic factors usually result in early embryonic losses, whereas autoimmune or uterine anatomical abnormalities more likely cause second-trimester losses (Schust, 2002). Approximately 40 to 50 percent of women have idiopathic RPL (Li, 2002; Stephenson, 1996).
Although these account for only 2 to 4 percent of RPL cases, karyotyping of both parents is considered by many to be essential. Of abnormalities, reciprocal translocations are most common and followed by robertsonian translocations (Fan, 2016). heir genesis and reproductive sequelae are discussed in Chapter 13 (p. 261).
After thorough genetic counseling, couples with an abnormal karyotype can be ofered in vitro fertilization (IVF) followed by preimplantation genetic diagnosis (American Society for Reproductive Medicine, 2012; Society for Assisted Reproductive Technology, 2008). This technique is described in Chapter 14 (p. 295). However, in couples with RPL who are chromosomaly normal, PGD is not currently recommended.
Several genital tract abnormalities have been implicated in RPL and other adverse pregnancy outcomes (Reichman, 2010). According to Devi Wold and colleagues (2006), 15 percent of women with three or more consecutive miscarriages will be found to have a congenital or acquired uterine anomaly.
Of acquired abnormalities, uterine synechiae-Asherman syndrome-usually result from destruction of large areas of endometrium. This can follow uterine curettage, hysteroscopic surgeries, or uterine compression sutures (Conforti, 2013; Rathat, 2011). Characteristic multiple illing defects are seen with hysterosalpingography or saline-infusion sonography. Treatment is hysteroscopic adhesiolysis. In many, this lowers miscarriage rates and improves live birth rates (Yu, 2008).
Uterine leiomyomas are common and may cause miscarriage, especially iflocated near the placental implantation site. That said, data indicating them to be a significant cause ofRPL are not con 77 73 68 62 vincing (Saravelos, 2011). Uterine cavity distortion is apparently 69 64 58 52 not requisite for bad outcomes (Sunkara, 2010). But in women undergoing IVF, pregnancy outcomes are adversely afected by
Data fror Brigham, 1999 submucous but not subserosal or intramural leiomyomas a un,
TABLE 18-5. Clinical and Laboratory Criteria for Diagnosis of Antiphospholipid Antibody Syndromea
Obstetric:
One or more unexplained deaths of a morphologically normal fetus at or beyond 10 weeks,
Severe preeclampsia or placental insufficiency necessitating delivery before 34 weeks,
Vascular: One or more episodes of arterial, venous, r small vessel thrombosis in any tissue or organ
Presence of lupus anticoagulant according to guidelines of the International Society on Thrombosis and Hemostasis,
Medium or high serum levels of IgG or IgM anticardiolipin antibodies,
IgG = immunoglobulin G; igM = immunoglobulin M.