Biomedical subjects

Mary D Stephenson

Publications and source records attributed to Mary D Stephenson.

6 recordsLinked to original sources

PubMed2006

Reproductive outcomes in recurrent pregnancy loss associated with a parental carrier of a structural chromosome rearrangement.

BACKGROUND: Reproductive outcome studies of couples with a history of recurrent pregnancy loss (RPL) associated with a maternal or paternal carrier of a structural chromosome rearrangement are limited. Correlation of carrier status and cytogenetics of miscarriage specimens is critical to estimate subsequent pregnancy outcome. METHODS: Couples found to have a structural chromosome rearrangement were followed prospectively in a tertiary academic centre. Descriptive analysis and subsequent pregnancy outcomes were tabulated and compared to historic controls. RESULTS: In 1893 RPL couples, 51 carriers of a structural chromosome rearrangement were identified (2.7%). Overall, this cohort had a total of 273 documented pregnancies. Prior to evaluation, the mean maternal age at the time of delivery or miscarriage was 29.8 years and the live birth rate was 15%. Following evaluation and treatment of concomitant factors, there were 58 monitored pregnancies, with a live birth rate of 71%. Amniocentesis was performed on 22% of the ongoing pregnancies; all were diploid or balanced structural chromosome rearrangements. Thirty-six per cent of the miscarriages were found to have an unbalanced structural chromosome rearrangement. CONCLUSIONS: Following evaluation and management of RPL, the live birth rate for carriers of a structural chromosome rearrangement is highly encouraging at 71%, without the addition of assisted reproductive technology.

Abortion, Habitual↗

PubMed2006

Obstetrical antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease manifested by a thrombotic or obstetrical event in the presence of antiphospholipid antibodies. Obstetrical APS was initially described in the 1950s. Obstetrical features presently include recurrent pre-embryonic and embryonic miscarriage, fetal demise, preeclampsia, intrauterine growth restriction, and possibly placental abruption. Since the first description of obstetrical APS, researchers have unraveled some of the pathophysiology involved in the disease. At present, there are numerous antiphospholipid antibodies that can be measured in human serum, each of which requires evaluation with regard to whether an association with obstetrical events exists. Clinical trials have provided some insight into optimal treatment protocols, but to date, such trials are limited. On the basis of small, randomized trials, live birth rates of approximately 70 to 80% have been reported with the use of low-dose acetylsalicylic acid and heparin. Despite such encouraging results, ongoing pregnancies are fraught with maternal and fetal morbidity. This review will highlight the obstetrical morbidity associated with APS, discuss the limitations of the present criteria for diagnosis, appraise published treatment trials, and summarize directions for future study of obstetrical APS.

Abortion, Habitual↗

PubMed2006

Management of recurrent early pregnancy loss.

Recurrent pregnancy loss is a devastating health problem that affects many couples who are trying to establish a family. Evaluation depends on a number of factors, including the pattern of pregnancy loss, underlying medical disease and life-style issues. A detailed obstetric history, including gestational age at the time of death, ultrasound, pathology and cytogenetic results, is key in the evaluation and management of recurrent pregnancy loss. This complex reproductive disorder requires a multidisciplinary approach since genetic, endocrinologic, anatomic, immunologic, infectious, thrombophilic and iatrogenic factors may require evaluation and management. Monitoring of subsequent pregnancies requires close supportive care.

Abortion, Habitual↗

PubMed2004

Pharmacokinetics of low molecular weight heparin and unfractionated heparin in pregnancy.

OBJECTIVE: Little pharmacokinetic data are available for either low molecular weight heparins (LMWHs) or unfractionated heparins (UFHs) in pregnancy. The objectives of this study were to determine whether differences exist in the pharmacokinetics of dalteparin and UFH before and during the first, second, and third trimesters of pregnancy in women with the antiphospholipid antibody syndrome (APS). Adjustments in our dosing protocol would be made if differences existed. METHODS: Women with APS who were contemplating pregnancy were randomized to dalteparin 2500 U, 2500 U, 5000 U, and 7500 U daily, or UFH 5000 U, 5000 U, 7500 U, and 10,000 U every 12 hours, prior to pregnancy and the first, second, and third trimesters, respectively. Serial plasma concentrations of heparin were measured during 4 blood sampling days by determining anti-factor Xa activity. RESULTS: Fifteen (n = 9 receiving dalteparin and n = 6 receiving UFH) completed all four sampling periods. For dalteparin, significant differences (P <.05) were detected, using area under the curve (AUC), between pre-pregnancy versus third trimester, first versus second trimester, first versus third trimester, and second versus third trimester. No significant differences were detected in the UFH group. CONCLUSION: In APS, our original dosing protocol of dalteparin yielded significant differences (P <.05) in drug exposure throughout pregnancy. Based on these results, we recommend a prophylactic dalteparin dosing regimen of 2500 U every 24 hours pre-pregnancy (and for 6 weeks postpartum), and 5000 U every 24 hours during the first, second, and third trimesters. Due to lack of significant differences in AUC throughout pregnancy for UFH, we recommend continuing with our original dosing protocol.

Adult↗

PubMed2004

Treatment of antiphospholipid antibody syndrome (APS) in pregnancy: a randomized pilot trial comparing low molecular weight heparin to unfractionated heparin.

OBJECTIVE: To compare low molecular weight heparin (LMWH), specifically dalteparin, to unfractionated heparin (UFH) for the treatment of antiphospholipid antibody syndrome (APS) in pregnancy. METHODS: In a tertiary referral centre, 28 women met the 1999 International Consensus Criteria for APS, based on their obstetrical history and APS serology. The women were randomized, using a random numbers table with blocks of 12, to receive either prophylactic dosing of dalteparin or UFH starting either preconceptionally or early in pregnancy. All women also received low-dose acetylsalicylic acid, started preconceptionally. The primary outcome was a live birth. The secondary outcomes were maternal and fetal complications. RESULTS: Of the 14 women who received the LMWH, dalteparin, and the 14 women who received UFH, 1 woman in each group did not conceive. Nine of the 13 women (69%) given dalteparin had a successful pregnancy (95% confidence interval [CI], 39-91%), compared to 4 out of the 13 women (31%) in the UFH group (95% CI, 9-61%). Nine women in total had spinal or epidural anaesthesia, and there were no complications overall. CONCLUSION: Dalteparin may be an effective alternative to UFH for treatment of APS in pregnancy. A multicentre randomized trial is needed to determine benefit-to-risk ratios for the use of dalteparin and UFH to treat this high-risk obstetrical condition. Pharmacokinetic and pharmacodynamic studies are also recommended to maximize therapeutic response and minimize toxicity.

Adult↗

PubMed2002

Effect of pregnancy on bone mineral density in healthy women.

Despite numerous studies and case reports of changes in bone mineral density (BMD) during pregnancy, the postpartum, and lactation, controversy exists regarding the time course of BMD changes and recovery to baseline levels. The degree to which pregnancy affects BMD long-term remains unclear. Several influencing factors, including breast-feeding, length of amenorrhea after pregnancy, and parity, have been studied with respect to changes in BMD in healthy women. We conducted the first systematic review of its kind on this topic and evaluated the 23 identified citations according to the U.S. Preventive Services Task Force rating scale. Six studies qualified as Level II-2, 12 were Level II-3, and 5 were Level III. There seems to be good evidence that calcium is mobilized from the maternal skeleton to that of the developing fetus during pregnancy. However, the eventual return of BMD to prepregnancy values suggests that maternal bone loss may not be permanent. Results from the studies that specifically evaluated the effect of lactation on BMD were varied, ranging from a decrease in BMD to no change. Of the studies that evaluated the effect of parity on BMD, none found an association linking a greater number of pregnancies to greater decreases in BMD. Pregnancy-associated osteoporosis seems to be uncommon, based on the limited published reports. Overall, no long-term adverse clinical effects have been noted in healthy women who had at least one ongoing pregnancy, despite the good evidence that some bone loss does occur soon after delivery. Additional longitudinal studies need to be undertaken to provide more definitive information on the effects of pregnancy on BMD and risk of osteoporosis later in life.

Bone Density↗