Biomedical subjects
Publications and source records attributed to Johnny S Younis.
Women with complete absence of oocytes during retrieval, as well as those with less than the 10th percentile of the expected number of oocytes retrieved, have clear manifestations of low ovarian reserve. It seems that this occurrence is a gradual biological phenomenon related to the basic pathophysiology of ovarian aging.
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Severe pregnancy complications, primarily severe pre-eclampsia, placental abruption, intrauterine growth restriction (IUGR) and intrauterine fetal death (IUFD) occur in about 1-5% of gestations. This rate is even higher in special medical situations. These pregnancy complications have been shown to increase maternal and fetal morbidity and mortality considerably. Severe pregnancy complications have also been shown to be associated with deficient uteroplacental circulation and are linked with intervillous and spiral vessel thrombosis. Moreover, it has been suggested that these complications could have their basis in a deficient trophoblast invasion in the uterine spiral arteries at a stage much earlier than the clinical manifestations become evident. In the last few years, evidence has accumulated to suggest that severe pregnancy complications could have a common thrombogenic basis associated with inherited and acquired thrombophilia. In this chapter we present a comprehensive update of the aetiology, pathophysiology, clinical manifestations, diagnosis and treatment of these severe pregnancy complications.
Thrombophilia is associated with several complications of pregnancy including first and second trimester fetal loss, intrauterine fetal death, intrauterine growth restriction, preeclampsia, and placental abruption. Few studies have documented thrombotic lesions observed on the pathologic examination of the placenta in women with severe pregnancy complications. Moreover, a significantly higher rate of factor V Leiden and prothrombin G20210A gene mutations have been found in placentas with thrombotic events compared with normal placentas. In addition, clinical studies have been performed, using Doppler ultrasonography, to assess the uterine placental circulation in women with thrombophilia. Doppler studies of the umbilical artery in cases of intrauterine growth retardation have shown a high systolic to diastolic ratio (S/D) ratio, suggesting an increase in the resistance of the placental small vessels. When these placental vessels were examined after delivery, significant differences were found in comparison with placental vessels of normal pregnancies. Most of the Doppler studies of the umbilical and uterine arteries in pregnancies with thrombophilia were performed in women with antiphospholipid antibodies. The other pathologic conditions associated with thrombophilia and complications of pregnancy were published only recently. These few studies have demonstrated abnormal umbilical and uterine arteries blood flow in complicated pregnancies. Finally, few Doppler studies also suggest improved uterine placental circulation when women with thrombophilia received thromboprophylaxis.
OBJECTIVE: To describe the characteristics of thrombophilia in women with idiopathic pregnancy loss. DESIGN: Prospective observational study. SETTING: Tertiary referral center in a teaching academic hospital. PATIENT(S): One hundred forty-five patients with repeated pregnancy loss and 145 matched controls. INTERVENTION(S): Prospective assessment of thrombophilia in patients and controls. MAIN OUTCOME MEASURE(S): Prevalence of activated protein C (APC) resistance, protein C, protein S, and antithrombin III deficiencies, antiphospholipid antibodies, factor V Leiden, factor II G20210A, and MTHFR C677T mutations. RESULT(S): At least one thrombophilic defect was found in 66% of study group patients compared with 28% in control group patients. Combined thrombophilic defects were documented in 21% of women with pregnancy loss compared with 5.5% of control patients. Late pregnancy wastage occurred more frequently in women with thrombophilia compared with women without thrombophilia (160/429 [37%] vs. 39/162 [24%], respectively). APC resistance was documented in 39% of women with pregnancy loss compared with 3% of the control patients. APC resistance without factor V Leiden mutation was documented in 18% of women with pregnancy loss compared with none of the controls. While factor V Leiden mutation was more common in women with pregnancy loss (25% vs. 7.6%), factor II G20210A and homozygosity for MTHFR C677T contributed to pregnancy loss only in the presence of other thrombophilia. CONCLUSION(S): Thrombophilia was found in the majority (66%) of women with idiopathic pregnancy loss. APC resistance with or without factor V Leiden mutation is the most common thrombophilic defect, and combined thrombophilia is a frequent finding in women with pregnancy loss. Thrombophilia is associated with increased frequency of late pregnancy wastage.