A deep learning method for reflective boundary estimation.

Environment estimation is a challenging task in reverberant settings such as the underwater and indoor acoustic domains. The locations of reflective boundaries, for example, can be estimated using acoustic echoes and leveraged for subsequent, more accurate localization and mapping. Current boundary estimation methods are constrained to high signal-to-noise ratios or are customized to specific environments. Existing methods also often require a correct assignment of echoes to boundaries, which is difficult if spurious echoes are detected. To evade these limitations, a convolutional neural network (NN) method is developed for robust two-dimensional boundary estimation, given known emitter and receiver locations. A Hough transform-inspired algorithm is leveraged to transform echo times of arrival into images, which are amenable to multi-resolution regression by NNs. The same architecture is trained on transform images of different resolutions to obtain diverse NNs, deployed sequentially for increasingly refined boundary estimation. A correct echo labeling solution is not required, and the method is robust to reverberation. The proposed method is tested in simulation and for real data from a water tank, where it outperforms state-of-the-art alternatives. These results are encouraging for the future development of data-driven three-dimensional environment estimation with high practical value in underwater acoustic detection and tracking.

An architecture for passive joint localization and structure learning in reverberant environments.

Passive localization and tracking of a mobile emitter, and joint learning of its reverberant three-dimensional (3D) acoustic environment, where critical structural features are unknown, is a key open problem. Unaccounted-for occluders are potentially present, so that the emitter can lose line-of-sight to the receivers, and can only be observed through its reflected raypaths. The locations of reflective boundaries must therefore be jointly estimated with the emitter's position. A multistage global optimization and tracking architecture is developed to solve this problem with a relatively unconstrained model. Each stage of this architecture establishes domain knowledge such as synchronization and initial environment estimation, which are inputs for the following stages of more refined algorithms. This approach is generalizable to different physical scales and modalities and improves on methods that do not exploit the motion of the emitter. In one stage of this architecture, particle swarm optimization is used to simultaneously estimate the environment and the emitter location. In another stage, a Hough transform-inspired boundary localization algorithm is extended to 3D settings, to establish an initial estimate of the environment. The performance of this holistic approach is analyzed and its reliability is demonstrated in a reverberant watertank testbed, which models the shallow-water underwater acoustic setting.

Should pregnant women be screened for SARS-CoV-2 infection? A prospective multicenter cohort study.

OBJECTIVE: Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), ranges from asymptomatic to severe infection. We aimed to compare the prevalence of COVID-19 in asymptomatic pregnant versus nonpregnant women in order to establish recommendations for a COVID-19 screening strategy. METHODS: A prospective multicenter cohort study was conducted. Asymptomatic pregnant or nonpregnant women after March 2020 (the time when COVID-19 was first detected in north Israel) were tested for SARS-CoV-2 using nasopharyngeal reverse transcription polymerase chain reaction test, anti-nucleocapsid IgG, and anti-spike IgG. Diagnosis was made if at least one test result was positive. Pregnant women were tested between 34 and 42 weeks, mostly at birth. RESULTS: Among the 297 participating women, 152 were pregnant and 145 were nonpregnant. The prevalence of asymptomatic COVID-19 was similar between the groups (4 [2.6%] and 8 [5.5%], respectively; P = 0.2). All women with COVID-19 delivered healthy appropriate-for-gestational-age babies without malformations, at term. CONCLUSIONS: The rate of asymptomatic COVID-19 in pregnant women is low and comparable to the rate among nonpregnant women. Pregnancy outcomes are favorable. Future screening programs should consider that one of 25 screened asymptomatic women will be positive.

Perimortem and postmortem sperm acquisition: review of clinical data.

PURPOSE: To provide the clinicians with the most comprehensive medical information about sperm acquisition peri/postmortem. METHODS: The review was conducted according to the PRISMA statement. MEDLINE and Cochrane databases were searched up to January 2021. All studies reporting post or perimortem harvesting of sperm with any indication of an outcome, recognition and viability of sperm, and its utilization and treatment outcome were included. Studies that recorded cases but discussed only the ethical or legal issues without any information about the medical details were excluded. RESULTS: Twenty-four studies were included in this review. One hundred forty-eight cases were described; in 113 of them, sperm was retrieved. A variety of techniques for sperm acquisition were used. The data collected are limited and comparing the efficacy of the different approaches is not feasible. The longest time interval described between the death and viable sperm acquisition was 3 days. The sperm quality varies between the studies. One hundred thirty-six mature oocytes were injected with the retrieved sperm; the fertilization rate was 41%. Transfer cycles of 25 embryos and 8 live births are reported in the medical literature. CONCLUSION: The overall low quality and high heterogeneity of the available data impair the ability to draw definitive conclusions. However, it can be stated that sperm acquisition up to at least 3 days postmortem can result in the live birth of healthy offspring. Further studies are needed to clarify the medical questions regarding the best techniques, success rates, and wellbeing of the parties involved.

Progesterone and estrogen levels are associated with live birth rates following artificial cycle frozen embryo transfers.

PURPOSE: Does an association exist between serum progesterone and estradiol levels and live birth rates in artificial cycle frozen embryo transfer (AC-FET)? METHODS: Retrospective cohort study was based on prospectively collected data at a university-affiliated fertility center. Included were all cycles using an artificial endometrial preparation with estradiol hemihydrate (Estrofem, 2 mg/8 h) and vaginal progesterone (Endometrin 100 mg/8 h), autologous oocytes, and cleavage stage embryo transfers. Serum progesterone and estradiol levels were measured 14 days after FET. A total of 921 cycles in 568 patients from to December 2010 to June 2019 were investigated. Live birth was the primary outcome measure. RESULTS: Significant association was found between live birth and progesterone as well as estradiol levels (progesterone 14.65 vs 11.62 ng/ml, p = 0.001; estradiol 355.12 vs 287.67 pg/ml, p = 0.001). A significant difference in live birth rate was found below and above the median progesterone level (10.9 ng/ml, p = 0.007). Lower estradiol level was significantly associated with lower live birth rate (< 188.2 pg/ml 8.3%, > 263.1 pg/ml 16%, p = 0.02). CONCLUSIONS: Serum progesterone and estradiol levels impact live birth rate in AC-FET.

Should the modified natural cycle protocol for frozen embryo transfer be modified? A prospective case series proof of concept study.

OBJECTIVE: Modified natural cycles for frozen embryo transfer utilize an ovulation trigger which assists in embryo transfer scheduling and simplifies cycle monitoring. There have been conflicting results with this protocol and modifications may be sought. We wanted to ascertain whether a modified natural protocol for frozen embryo transfer without triggered ovulation but with luteal progesterone support disconnecting the timing of embryo transfer from the timing of the LH surge can achieve a high pregnancy rate. STUDY DESIGN: Candidates for frozen embryo transfer of 48-h cleavage cell embryos were recruited from May 2016 to April 2018. The patients were monitored for endometrial growth, follicle formation and estradiol, progesterone, and LH hormone levels. After meeting the predetermined criteria, embryo transfer was scheduled. The patients began progesterone treatment 48 h before embryo transfer, regardless of identification of the LH surge if ovulation had not commenced. The predetermined primary outcome was the biochemical pregnancy rate while the secondary outcome included the clinical pregnancy rate and the ongoing pregnancy rate. Patients were monitored to the eighth week of pregnancy, but data was collected from the medical records to provide the live birth rate as well. RESULTS: Fifty-six women were screened. Eleven women declined or did not meet the inclusion criteria. Three had anovulatory cycles and were excluded. Forty-two women were included in the statistical analysis. The implantation rate was 42.9 % [95 %CI 29.3 %-56.4 %). Of the 42 participants, 25 (59.5 %) conceived [95 % CI 44.0 %-75 %]. Two pregnancies ended in first trimester miscarriage leaving 23 (54.7 %) ongoing pregnancies [95 % CI 39.1 %-70.5 %]. One patient experienced a late abortion such that the live birth rate was 22 of 42 patients or 52.4 % [95 % CI 36.4 %-68.0 %]. CONCLUSION: The proposed modified natural protocol which utilizes progesterone luteal support but does not trigger ovulation, maintains a high pregnancy rate while providing flexibility regarding the day of transfer disconnected from the day of the LH surge. This was a prospective, proof of concept study. This protocol may be suitable for smaller or public in-vitro fertility units whose resources are limited and facilities are not available daily. The high pregnancy and live birth rate that we found provides confidence that this protocol can be part of the armament of protocols the clinician may offer to his patients. Larger studies should confirm these findings.

Ideal lag time from ovulation to oocyte aspiration using a GnRH agonist trigger.

BACKGROUND: In ART, oocyte maturation (M2) and ovulation is stimulated by a hormonal trigger. For maturation to occur, sufficient "lag time" must elapse between the trigger and aspiration, ranging from 32 to 38 hours. Premature aspiration can result in poor yields; late aspiration risks spontaneous ovulation. AIM: Our study examines optimal lag time using a GnRH antagonist protocol and GnRH agonist trigger for ICSI. METHODS AND MATERIALS: We analyzed data from 220 women undergoing GnRH antagonist protocol using a GnRH agonist trigger for ICSI at our clinic between 02/2012-03/2018. Patients were divided into 4 groups based on lag time: 34.00-34.99 hours (n = 32), 35.00-35.99 hours (n = 113), 36.00-36.99 hours (n = 57) and 37.00 h or more (n = 18). Analyses were performed with the Kruskal-Wallis test, Chi-Square, and Spearman's rho correlation. RESULTS: A positive correlation was found for the number of M2 oocytes aspirated and lag time (ρ = 0.138, p = 0.04) and for the total number of oocytes aspirated and lag time, (ρ = 0.174, p = 0.01). No correlation was found between the proportion of M2 oocytes aspirated and lag time (p = 0.217). The third group (36 h) had significantly more M2 oocytes aspirated than the second group (35 h) (12.4 ± 7.1 vs 9.4 ± 6.2; p = 0.039). The four groups did not differ for the proportion of mature M2 oocytes (H = 2.453, p = 0.484). The four groups differed in the frequency of live births per fresh embryos transferred (χ2 = 9.364, p = 0.025). CONCLUSION: Our study identified a positive correlation between lag time and both the number of M2 oocytes and the total number of oocytes aspirated-factors which lead to an increased rate of successful pregnancies. Further research is necessary.

Gonadotropin Releasing Hormone Agonist Final Oocyte Maturation and Human Chorionic Gonadotropin as Exclusive Luteal Support in Normal Responders.

BACKGROUND/AIMS: Gonadotropin releasing hormone (GnRH) agonist triggering results in an endogenous gonadotropin flare. Although it effectively stimulates ovulation, GnRH agonist triggers results in an early luteolysis and requires modification of the luteal support. The current study aims to evaluate GnRH agonist triggering with exclusive human chorionic gonadotropin (hCG) luteal support. METHODS: In this prospective observational study, 56 normogonadotropic-assisted reproductive technology patients, stimulated using a GnRH-antagonist protocol, were studied. Final oocyte maturation was achieved with 0.2 mg triptorelin acetate followed by progesterone free luteal support with human choriogonadotropin (1,500 IU * 2). A control group was selected from a pool of 1,023 normogonadotropic patients who received Choriogonadotropin alfa for final oocyte maturation and progesterone suppositories for luteal support. RESULTS: No significant difference was found for the number of oocytes, oocyte maturation rate, fertilization and implantation rate, clinical pregnancy rate (25 vs. 26.7%) and live birth rate (25 vs. 21.4%). Progesterone levels in conception cycles were significantly higher in the study group than corresponding levels in the control group. CONCLUSION: GnRH agonist triggering with exclusive hCG support may be a valid alternative to hCG triggering with progesterone support. This protocol combines the potential advantages of a physiological trigger with a simple, patient-friendly, luteal support.

[SPERM SELECTION TECHNIQUES: VISUAL ASSESSMENT VERSUS THE BINDING POTENTIAL TO HYALURONIC ACID].

BACKGROUND: The human oocyte is surrounded by hyaluronic acid (HA), which acts as a natural selector. Only spermatozoa expressing HA receptors can reach and fertilize the oocyte. This study aims to compare two sperm selection techniques by correlation to fertilization rates and embryo quality. METHODS: Couples undergoing IVF-ICSI treatment due to mild male infertility were enrolled in a prospective study. According to the randomization, the sperm suspensions were put into a polyvinylpyrrolidone (PVP) droplet or an HA-containing medium droplet (Sperm Slow). In the PVP group motile spermatozoa with the best morphology were selected for injection. From the HA-containing medium those sperm demonstrating vigorous tail beating and an absence of progressive motility as well as good morphology, were selected. Primary outcome measures were fertilization rate and embryo quality. RESULTS: Thirty couples were randomized to the PVP group and 24 to the slow sperm group; 353 oocytes were injected. There was no statistical difference in fertilization or cleavage rate. Furthermore, in the PVP group, the mean number of embryos was higher and the average morphology of the best embryo was superior. CONCLUSIONS: Considering that the HA-based sperm selection technique is more expensive and time consuming, the current study does not support using it as a routine method.

Increased coagulation index as measured by Thromboelastography during ovarian stimulation for in vitro fertilization: Influence of the final oocyte maturation triggering agent.

OBJECTIVE: Thromboelastography (TEG) is a viscoelastic test of hemostasis which allows measurement of the processes of clot initiation, propagation, stabilization, and dissolution in real time. In this study we aimed to evaluate the alterations in coagulation as measured by TEG during In Vitro Fertilization (IVF) stimulation cycles and to investigate whether final oocyte maturation with recombinant hCG (rhCG) versus GnRH agonist results in a different coagulation state. STUDY DESIGN: This is a prospective observational study which included fifty-three normogonadotrophic women. All the patients received an antagonist IVF treatment protocol. Final oocyte maturation was triggered with either rhCG (n = 25) or GnRH agonist (n = 26). Two patients did not complete the study due to poor response. Venous blood was drawn in the early and late follicular phase and on the day of ovum pickup. The TEG parameters assessed were R (time to first clot formation), K (time until the clot reaches a fixed strength), alpha angle (the rate of clot formation), MA (reflects maximum strength of the platelet-fibrin clot), LY30 (percent of clot lysis at 30 min after MA is reached) and the CI (the overall coagulability). RESULTS: The overall coagulation index of the entire study population was significantly increased on the day of ovum pickup as compared to the early follicular phase. This increase in the coagulation index was also significant in a subanalysis of patients triggered with rhCG. Contrarily, there was no significant increase in the coagulation index in the subgroup of patients triggered with GnRH agonist. CONCLUSION: Our results demonstrate a procoagulable state in patients after ovulation induction. Final triggering with GnRH agonist rather than rhCG, might lower this hypercoagulability pattern.

Clinical benefit using sperm hyaluronic acid binding technique in ICSI cycles: a systematic review and meta-analysis.

The human oocyte is surrounded by hyaluronic acid, which acts as a natural selector of spermatozoa. Human sperm that express hyaluronic acid receptors and bind to hyaluronic acid have normal shape, minimal DNA fragmentation and low frequency of chromosomal aneuploidies. Use of hyaluronic acid binding assays in intracytoplasmic sperm injection (ICSI) cycles to improve clinical outcomes has been studied, although none of these studies had sufficient statistical power. In this systematic review and meta-analysis, electronic databases were searched up to June 2015 to identify studies of ICSI cycles in which spermatozoa able to bind hyaluronic acid was selected. The main outcomes were fertilization rate and clinical pregnancy rate. Secondary outcomes included cleavage rate, embryo quality, implantation rate, spontaneous abortion and live birth rate. Seven studies and 1437 cycles were included. Use of hyaluronic acid binding sperm selection technique yielded no improvement in fertilization and pregnancy rates. A meta-analysis of all available studies showed an improvement in embryo quality and implantation rate; an analysis of prospective studies only showed an improvement in embryo quality. Evidence does not support routine use of hyaluronic acid binding assays in all ICSI cycles. Identification of patients that might benefit from this technique needs further study.

[IS ANTI-THROMBOTIC PROPHYLAXIS WARRANTED IN FERTILITY AND IN-VITRO FERTILIZATION TREATMENTS?]

INTRODUCTION: Assisted reproductive technology (ART) treatments are potential risk factors for thromboembolism (TE) due to excessive estrogen levels. Recently, several studies have shed new light on this matter. AIMS: To review the literature to assess the risk for TE during ART and to establish guidelines regarding thrombophylaxis. METHODS: A search was conducted of PubMed, Medline, Cochrane and clinicaltrials.gov. The search terms were fertility, assisted reproductive technology, IVF, thromboembolism, thrombosis and anticoagulation. Case reports and reviews were excluded. RESULTS: Three cohort studies and one cross-sectional study were included; one examined the effect of ART on TE risk after cycles not resulting in pregnancy. The others evaluated TE risk if pregnancy was achieved. The rate of TE for 75,141 cycles not resulting in pregnancy was not higher than controls in the general population. The three studies which compared TE risk when pregnancies were achieved found that ART increased the risk for TE primarily during the first trimester. If ovarian hyperstimulation syndrome (OHSS) was present the risk increased further. The risk for TE after frozen embryo replacement cycles was not increased. CONCLUSIONS: ART posed a risk factor for TE during pregnancy, but not during ovarian stimulation or in cycles not resulting in pregnancy. Thrombophylaxis is not indicated for all women undergoing ART. Women with OHSS should be given thrombophylaxis during the acute episode and throughout the first trimester. Caution is advised for patients with combined risk factors and treatment should be individualized. Guidelines for thromboprophylaxis are provided.

A randomized trial comparing time intervals from HCG trigger to intrauterine insemination for cycles utilizing GnRH antagonists.

Intrauterine insemination (IUI) during ovarian stimulation cycles is typically performed 36 hours after human chorionic gonadotropin (hCG) injection. We hypothesized that adjusting the time interval to IUI to better coincide with ovulation may increase pregnancy rates. Patients undergoing induction of ovulation utilizing gonadotropins and gonadotropin releasing hormone (GnRH) antagonists and IUI were divided to three groups based on the time from hCG injection to IUI: 36, 42, and 48 hours. Primary outcome was defined as the clinical pregnancy rate. Secondary outcomes comprised additional parameters including multifetal pregnancy rate. A total of 92 patients completed the study. Baseline parameters were similar between the groups. The clinical pregnancy rate in the three groups was 20%, 38%, and 24%, respectively. While the 42 hour time interval had a higher numerical pregnancy rate, the pregnancy rates did not differ statistically among the study groups. The multifetal pregnancy rate did not differ among the three groups as well. A larger study is necessary to ascertain if a 42 hour time interval can indeed improve pregnancy rates.

Lag time from ovulation trigger to oocyte aspiration and oocyte maturity in assisted reproductive technology cycles: a retrospective study.

OBJECTIVE: To study the correlation between the lag time from ovulation trigger to oocyte aspiration and the proportion of metaphase II (MII) mature oocytes aspirated. DESIGN: Retrospective study. SETTING: Fertility and IVF center in an academic regional hospital. PATIENT(S): A total of 511 women undergoing IVF-intracytoplasmic sperm injection at our center, with at least one oocyte available for maturity determination. INTERVENTION(S): Data were retrieved from patient electronic databases and files. Demographic data, hormone treatments and ovarian response, and the time of ovulation trigger and oocyte aspiration were recorded. MAIN OUTCOME MEASURE(S): The primary outcome was the proportion of MII mature oocytes relative to the total number of oocytes aspirated and allocated to intracytoplasmic sperm injection. Pregnancy rates and clinical pregnancy rates were secondary outcomes. RESULT(S): There were fewer MII mature oocytes when the lag time between oocyte trigger and aspiration was between 33.45 hours and 34.45 hours. The proportion of MII oocytes seems to increase up to a 35-hour lag time and then stabilizes up to 38 hours. Pregnancy and clinical pregnancy rates did not differ among the different time groups studied. CONCLUSION(S): Oocyte aspiration should be scheduled at least 35 hours after ovulation trigger. Oocytes can be aspirated in a 3-hour window of time between 35 and 38 hours without compromising results. Further research should elucidate whether even longer lag times will improve the proportion of MII mature oocytes.

Rescue intracytoplasmic sperm injection: a systematic review.

OBJECTIVE: To assess the feasibility, efficacy, and safety of rescue intracytoplasmic sperm injection (ICSI) in cases of fertilization failure, using a scientific literature search. DESIGN: Systematic review. SETTING: Centers for reproductive care. PATIENT(S): Infertility patients with total or partial fertilization failure during an IVF cycle. INTERVENTION(S): An electronic literature search was performed in PubMed from 1992 through May 2013. The search was then expanded by using listed references from selected articles. MAIN OUTCOME MEASURE(S): Pregnancy rate. The secondary outcome measures were fertilization rate, normal fertilization rate, cleavage rate, birth rate, and malformation rate. RESULT(S): Thirty-eight studies including 1,863 patients were included. The pooled pregnancy rate was 14.4%; 194 babies were delivered. CONCLUSION(S): Rescue ICSI can result in the delivery of a healthy newborn, although the pregnancy rates are low. The clinical evidence did not indicate an elevated rate of malformations, although the data are limited and incomplete.

Haptoglobin phenotypes and in vitro fertilization treatment outcomes.

The haptoglobin (Hp) protein has been implicated in various aspects of reproduction. One possible mechanism is through its effect on angiogenesis. Angiogenesis plays a major role in follicle production. The Hp insertion polymorphism results in the production of Hp proteins denoted Hp 1-1, 2-1, and 2-2, with markedly different angiogenic activities. We sought to determine if the number of oocytes aspirated during in vitro fertilization is related to the Hp type and to compare clinical data and treatment outcomes. We conducted a prospective non-interventional study in an academic in vitro fertilization center serving northern Israel. All patients undergoing in vitro fertilization who agreed to have their haptoglobin phenotype and clinical data evaluated anonymously were included. The main outcome measure was the number of oocytes harvested from each aspiration. The groups did not differ regarding ethnicity or BMI, though women with the Hp1-1 phenotype had a longer duration of infertility (p = 0.037) and a higher gonadotropin requirement (p = 0.024) to achieve the same treatment outcome. Women with mechanical factor infertility were more likely (p = 0.042) to have the Hp 1-1/2-1 phenotypes than the Hp2-2 phenotype. There were no differences in the number of oocytes aspirated or the pregnancy rate. In summary, we could not establish a correlation between Hp phenotype and oocyte number or IVF outcomes though the Hp2-2 phenotype may be protective against mechanical factor infertility. Further studies with a larger sample size, particularly concerning the Hp1-1 phenotype, are required in order to extend these results.

The effect of progesterone on gelatinase expression in the decidua and fetal membranes before and after contractions.

OBJECTIVE: This study was aimed to explore the effect of progesterone on gelatinase expression in the decidua and fetal membranes before and after contractions. STUDY DESIGN: Zymography was conducted for matrix metalloproteinase (MMP) secretion. Semiquantitative reverse transcriptase-polymerase chain reaction was performed to examine MMP2 transcripts, and the effect of progesterone on MMP2 promoter activity was determined with the use of luciferase activity. RESULTS: Progesterone decreased pro-MMP2 secretion, expression, and promoter activity in decidua before contractions began. The effect of progesterone was reversed completely by mifepristone (RU486). Progesterone failed to inhibit MMP2 expression in the amnion and chorion before contractions began. After contractions, progesterone failed to inhibit MMP2 expression in both the decidua and fetal membranes. CONCLUSION: MMP2 expression is inhibited by progesterone only in the decidua and only before contractions begin.

The matrix metalloproteinases (MMPS) in the decidua and fetal membranes.

The role of the matrix metalloproteinases (MMPs) in the decidua, fetal membranes and amniotic fluid (AF) has been receiving more and more attention. The MMPs are not only important intermediaries in pathological processes leading to preterm labor but it seems that they also play a crucial role in the activation of labor at term. During normal gestation MMP-1, -2, -3, -7 and -9 are found in the amniotic fluid and fetal membranes. MMP-2 and MMP-3 are expressed constitutively while MMP-9 is barely detectable until labor. At labor, while MMP-9 is the major MMP responsible for gelatinolytic activity in the membranes, MMP-2 is dominant in the decidua. MMP-7 (AF) increases with gestation but does not appear to play a major role in labor. The expression of MMPs is attenuated through the expression of relaxins, integrins and extracellular matrix metalloproteinase inducer (EMMPRIN). Spontaneous preterm delivery (PTD) may be a product of preterm labor (PTL), preterm premature rupture of membranes (P-PROM) or placental abruption. Each of these processes may have differing pathways but the presence of an intrinsic inflammatory response with or without infection seems to involve all etiologies. The inflammatory response is mediated with cytokines such as interleukins -1, -6 and -8 and tumor necrosis factor alpha. MMP-3, MMP-7 and MMP-8 appear to be important in these processes. MMP-9, which is the major MMP involved in normal labor, plays an important role in pathological labor as well. Finally, apoptosis seems to play a role in pathological labor, particularly deliveries involving P-PROM. African-American are at greater risk of PTD than white or Hispanic Americans. Environmental differences may not suffice to explain this phenomenon. Genetic polymorphisms of the MMP genes may help explain the greater risk among this population. Finally, manipulating MMPs may have a role in the prevention of PTD. Agents suggested include indomethacin, N-acetylcysteine, progesterone and specific inhibitors of phosphodiesterase 4.

A randomized study of thromboprophylaxis in women with unexplained consecutive recurrent miscarriages.

OBJECTIVE: To compare the effect of aspirin and enoxaparin on live births in women with unexplained recurrent miscarriages, as well as secondary outcomes including birth weight, uterine and umbilical blood flows, and congenital malformations. DESIGN: Multicenter randomized comparative cohort study. SETTING: Four centers including two university hospitals, a peripheral general hospital, and a community health clinic. PATIENT(S): One hundred seven patients were randomized, 104 were available for analysis; 54 were randomized to enoxaparin and 50 to aspirin. INTERVENTION(S): Treatment with enoxaparin or aspirin in subsequent pregnancy. MAIN OUTCOME MEASURE(S): Subsequent live births or miscarriage, and the incidence of obstetric complications. RESULT(S): Both groups had a similar live birth rate (relative risk = 0.92, 95% confidence interval: 0.58-1.46). In primary aborters, live births occurred in 17 of 18 (94%) enoxaparin-treated pregnancies compared to 18 of 22 (81%) aspirin-treated pregnancies. In the aspirin group, two pregnancies were terminated: for tricuspid insufficiency and for hemolysis, elevated liver enzymes, low platelet (HELLP) syndrome. One enoxaparin-treated infant was growth restricted (2,020 g) at 36 weeks. Preeclampsia was found in three aspirin-treated patients. Preterm delivery, placental Doppler blood flow, apgar scores, and mean birth weights were similar in both groups. In the aspirin group, one infant underwent orchidectomy after testicular torsion in utero, and one infant had hypoglycemia and convulsions. CONCLUSION(S): Both regimens were associated with a high live birth rate and few late pregnancy complications.