An evolutionary genomic approach to identify genes involved in human birth timing.

Coordination of fetal maturation with birth timing is essential for mammalian reproduction. In humans, preterm birth is a disorder of profound global health significance. The signals initiating parturition in humans have remained elusive, due to divergence in physiological mechanisms between humans and model organisms typically studied. Because of relatively large human head size and narrow birth canal cross-sectional area compared to other primates, we hypothesized that genes involved in parturition would display accelerated evolution along the human and/or higher primate phylogenetic lineages to decrease the length of gestation and promote delivery of a smaller fetus that transits the birth canal more readily. Further, we tested whether current variation in such accelerated genes contributes to preterm birth risk. Evidence from allometric scaling of gestational age suggests human gestation has been shortened relative to other primates. Consistent with our hypothesis, many genes involved in reproduction show human acceleration in their coding or adjacent noncoding regions. We screened >8,400 SNPs in 150 human accelerated genes in 165 Finnish preterm and 163 control mothers for association with preterm birth. In this cohort, the most significant association was in FSHR, and 8 of the 10 most significant SNPs were in this gene. Further evidence for association of a linkage disequilibrium block of SNPs in FSHR, rs11686474, rs11680730, rs12473870, and rs1247381 was found in African Americans. By considering human acceleration, we identified a novel gene that may be associated with preterm birth, FSHR. We anticipate other human accelerated genes will similarly be associated with preterm birth risk and elucidate essential pathways for human parturition.

Utility of Repeat Uterine Cavity Evaluation in the Infertility Workup.

Background: Uterine cavity abnormalities contribute to infertility. The purpose of this study was to evaluate the incidence, recurrence rates, and risk factors for uterine cavity abnormalities in women undergoing infertility workup and treatment, focusing on the utility of routinely repeated imaging. Methods: Retrospective cohort study at single academic medical center of 833 infertile women who had uterine cavity evaluations performed at least 9 months apart. Results: Of 833 eligible patients, 664 (79.7%) had normal initial imaging and 169 (20.3%) had abnormal initial imaging. Among the former, 10% had abnormal uterine cavity on repeat saline infusion sonohysterography (SIS); among the latter, 32% had abnormal repeat SIS [Chi-square p < 0.0001, risk ratio 2.30 (95% confidence interval 1.85-2.86)]. On average, 23.1 ± 13.6 months passed between studies. Regardless of initial imaging findings, women with abnormal repeat SIS were older than those with normal repeat SIS, with no difference in time elapsed between studies. There were no associations between repeat imaging outcomes and body mass index, uterine instrumentation, number of treatment cycles, or maximum peak estradiol levels in a single cycle between studies. There was no difference in live birth rate among cycles started within 1 year after repeat SIS across groups. Conclusions: Uterine cavity abnormalities were found in 10% of patients on repeat imaging despite initially normal testing. No risk factors for cavity abnormality on repeat imaging were identified besides age and prior abnormality. It would be prudent to continue performing routine repeat uterine cavity evaluation for women undergoing fertility treatment, particularly if corrective measures had been taken in the past.

Investigation of genetic risk factors for chronic adult diseases for association with preterm birth.

Preterm birth (PTB) is the leading cause of infant mortality. PTB pathophysiology overlaps with those of adult cardiovascular, immune and metabolic disorders (CIMD), with mechanisms including inflammation, immunotolerance, thrombosis, and nutrient metabolism. Whereas many genetic factors for CIMD have been identified, progress in PTB has lagged. We hypothesized that highly validated genetic risk factors for CIMD may also be associated with PTB. We conducted case-control study of four female cohorts with spontaneous PTB (n = 673) versus term (n = 1119). Of 35 SNPs genotyped, there were 13 statistically significant associations (P < 0.05), which were more than expected (binomial test; P = 0.02). In US White (307 cases/342 controls), the G allele of HLA-DQA1 (A/G) rs9272346 was protective for PTB in the initial discovery cohort (P = 0.02; OR = 0.65; 95 % CI 0.46, 0.94). This protective association replicated (P = 0.02; OR = 0.85; 95 % CI 0.75, 0.97) nominally in the Danish Cohort (883 cases, 959 controls), but lost significance upon multiple testing correction. We observed more statistically significant associations than expected, suggesting that chance is an unlikely explanation for one or more of the associations. Particularly, a protective association of the G allele of HLA-DQA1 was found in two independent cohorts, and in previous studies, this same allele was found to protect against type-1-diabetes (meta-analysis P value 5.52 × 10(-219)). Previous investigations have implicated HLA phenotypic variation in recurrent fetal loss and in chronic chorioamnionitis. Given the limited sample size in his study, we suggest larger studies to further investigate possible HLA genetic involvement in PTB.

Oocyte and embryo cryopreservation before gonadotoxic treatments: Principles of safe ovarian stimulation, a systematic review.

OBJECTIVE: Review the safety of fertility preservation through ovarian stimulation with oocyte or embryo cryopreservation, including cycle and medication options. EVIDENCE REVIEW: A systematic review of peer-reviewed sources revealed 2 applicable randomized control trials and 60 cohort studies as well as 20 additional expert opinions or reviews. RESULTS: The capacity for future family building is important for the majority of reproductive age people, despite life-altering medical or oncologic diagnosis. Modern fertility preservation generates a high rate of oocyte yield while utilizing protocols that can be started at multiple points in the menstrual cycle and suppressing supra-physiologic levels of estrogen. Finally, more than one quarter of fertility preservation patients will return to later utilize fertility services. CONCLUSION: For most patients, fertility preservation can safely be pursued and completed within 2 weeks without affecting disease severity or long-term survival.

Progesterone Inhibits Apoptosis in Fetal Membranes by Altering Expression of Both Pro- and Antiapoptotic Proteins.

OBJECTIVE: Progesterone supplementation prevents preterm birth (PTB) in some high-risk women, but its mechanism of action is unknown. One-third of PTB is associated with preterm premature rupture of membranes (PPROMs). We have previously shown that progesterone inhibits basal and Tumor Necrosis Factor (TNF) α-induced apoptosis in an explant model of human fetal membranes. This study investigates the molecular mechanisms responsible for progesterone-mediated inhibition of apoptosis in fetal membranes. METHODS: Human fetal membranes were collected at elective cesarean at term (no labor, no infection; n = 6), washed, and pretreated with/without progesterone (125 ng/mL) for 24 hours. Thereafter, membranes were treated with/without TNFα (50 ng/mL) and/or progesterone for 48 hours, harvested, and homogenized. Apoptosis was determined by evaluating caspase-3, -8, and -9 activities. Expression of pro- BH3 interacting domain death against, Bc1-2 associated X protein (BID, BAX) and antiapoptotic proteins (X-linked inhibitor of apoptosis protein [XIAP], Bcl-2, FLICE inhibitory protein [FLIP]) were measured by Western blot. RESULTS: TNFα increased apoptosis (measured by caspase-3, -8, and -9 activities) in fetal membranes, and this effect was abrogated by progesterone. Under basal conditions, progesterone suppressed expression of the proapoptotic protein, BID, by 0.45 (0.14)-fold, and increased expression of the antiapoptotic proteins, Bcl-2 and XIAP; no change was seen in BAX or FLIP. In contrast, TNFα increased BID expression by 5.15 (2.92)-fold, which was prevented by pretreatment with progesterone. CONCLUSIONS: Progesterone inhibits apoptosis in fetal membranes by suppressing expression of the proapoptotic protein, BID (for both basal and TNFα-induced apoptosis), and upregulating expression of the antiapoptotic proteins, XIAP and Bcl-2 (under basal conditions only). These data provide a mechanism by which progesterone supplementation may prevent PPROM and PTB in some women at high risk.

Point-of-care viscoelastic testing improves the outcome of pregnancies complicated by severe postpartum hemorrhage.

Study Objective. To compare the clinical outcomes of patients with severe postpartum hemorrhage (PPH) managed with and without the use of Point-of-Care Viscoelastic Testing (PCVT) to direct blood product replacement. Design. A retrospective cohort study of consecutive cases of severe PPH managed at a single tertiary care center between January 1, 2011 and July 31, 2015. Cases included patients managed using PCVT. Controls were patients managed using a standardized massive hemorrhage transfusion protocol, either because PCVT was not yet available or because no PCVT credentialed providers were on site. Setting. Delivery room, postoperative recovery area, intensive care unit. Patients. There were 6,708 cesarean deliveries and 13,641 vaginal births during the study period. Eighty six patients (0.4% of all deliveries) developed severe PPH. Severe PPH occurred in 1% (68/6,708) of cesarean and 0.1% (18/13,641) of vaginal deliveries. Twenty-eight of these 86 patients (32.6%) were managed with PCVT and 58 (67.4%) without PCVT. Interventions. Patients with severe PPH were managed according to a standardized massive transfusion protocol or a PCVT-based protocol to direct blood product replacement. Measurements. PCVT testing was performed using a ROTEM delta device. Results. Patients in the PCVT cohort received significantly fewer transfusions of packed red blood cells, fresh frozen plasma, and platelet concentrates. They also had a significantly lower estimated blood loss, and a significantly lower incidence of cesarean hysterectomy and postoperative ICU admission as compared with patients not managed using PCVT. The length of postpartum hospitalization was also significantly shorter in the PCVT cohort. Among patients who gave birth within 24 hours of admission, the direct cost of hospitalization was 40% lower for patients in the PCVT cohort. Conclusions. PCVT-based goal-directed blood product replacement management was associated with substantial benefits over a standardized massive transfusion protocol both in terms of patient outcomes and cost of care.

Progestin inhibits and thrombin stimulates the plasminogen activator/inhibitor system in term decidual stromal cells: implications for parturition.

OBJECTIVE: Labor is associated with 'decidual activation' with increased proteolysis and extracellular matrix degradation. The balance between plasminogen activator inhibitor-1 (PAI-1) and urokinase (uPA) and tissue-type plasminogen activator (tPA) is an important determinant of proteolytic activity at the maternal-fetal interface. Thrombin released at the time of placental abruption (decidual hemorrhage) is known to promote decidual proteolysis and uterine contractions. This study investigates the separate and interactive effects of steroid hormones and thrombin on PAI-1, uPA, and tPA expression by term decidual cells (DCs). STUDY DESIGN: Term DCs were isolated by enzymatic digestion, purified, and depleted of leukocytes. Cells were treated with estradiol (10(-8) mol [E2]), medroxyprogesterone acetate (10(-7) mol [MPA]), both, or vehicle for 7 days. After 24-hour incubation with or without thrombin (0.1-2.5 U/mL), levels of PAI-1, uPA, and tPA in conditioned supernatant were measured by specific ELISA and Western blotting. Levels of PAI-1 and uPA mRNA were measured by quantitative RT-PCR. RESULTS: In the cultured term DCs, ELISA measurements indicated that basal output of PAI-1 was about 2 logs higher than that of either uPA or tPA (2.5 +/- 0.7 ng/mL per microg protein, 13.4 +/- 6.3 pg/mL per microg protein, and 25.4 +/- 10.8 pg/mL per microg protein, respectively). Although E2 alone did not affect PAI-1 output, MPA and E2+MPA significantly enhanced PAI-1 production (2.5 +/- 0.7 vs 8.2 +/- 2.0 ng/mL per microg protein for E2+MPA [3.3-fold]; P < .01). By contrast, uPA output was inhibited by exposure to MPA (13.4 +/- 6.3 vs 2.6 +/- 1.1 pg/mL per microg protein [0.2-fold]; P < .05), whereas tPA production was not affected by MPA. Thrombin did not significantly affect uPA and tPA production by term DCs. In contrast, in E2+MPA-treated term DCs, thrombin, a hemostatic proinflammatory cytokine, selectively increased PAI-1 output in a dose-dependent fashion, which could be blocked by the selective thrombin inhibitor, hirudin. Western blotting confirmed the effects of MPA and thrombin in elevating secreted levels of PAI-1. Unlike the increase in PAI-1 output elicited by thrombin, term DCs were unresponsive to either of the classic proinflammatory cytokines, TNFalpha or IL-1beta. Corresponding effects on PAI-1 mRNA levels were elicited by MPA and thrombin as seen for PAI-1 protein expression, suggesting that these up-regulatory effects are transcriptionally mediated. CONCLUSION: Progestin enhanced PAI-1 and inhibited uPA expression by term DCs, which may explain in part the pregnancy-prolonging properties of progesterone as a consequence of inhibited proteolytic activity at the maternal-fetal interface. Thrombin augmented PAI-1 expression in the absence of increased uPA or tPA expression by term DCs, suggesting that abruption-associated decidual proteolysis and preterm labor is mediated primarily by thrombin-enhanced matrix metalloproteinase expression rather than an indirect effect on the plasminogen activator/inhibitor system.

Molecular Regulation of Parturition: The Role of the Decidual Clock.

The timing of birth is a critical determinant of perinatal outcome. Despite intensive research, the molecular mechanisms responsible for the onset of labor both at term and preterm remain unclear. It is likely that a "parturition cascade" exists that triggers labor at term, that preterm labor results from mechanisms that either prematurely stimulate or short-circuit this cascade, and that these mechanisms involve the activation of proinflammatory pathways within the uterus. It has long been postulated that the fetoplacental unit is in control of the timing of birth through a "placental clock." We suggest that it is not a placental clock that regulates the timing of birth, but rather a "decidual clock." Here, we review the evidence in support of the endometrium/decidua as the organ primarily responsible for the timing of birth and discuss the molecular mechanisms that prime this decidual clock.

Identification of putative fallopian tube stem cells.

Stem cells are used to repair and regenerate multiple tissues in the adult. We have previously shown that stem cells play a significant role in mediating endometrial repair and tissue regeneration. We hypothesized that the oviduct may possess a similar population of stem cells that contribute to the maintenance of this tissue. Here we identify label-retaining cells (LRCs) in the murine oviduct which indicate the presence of a stem/progenitor cell population in this tissue as well. Two-day-old CD-1 mice were injected intraperitoneally with 5-bromo-2-deoxyuridine (BrdU) or vehicle control. Female animals (n = 36 for each group) were killed at 6 weeks post injection. Reproductive tracts were removed, specimens were embedded in paraffin, and 5-µ sections were prepared. Oviduct was identified by hematoxylin and eosin staining and morphology. Immunofluorescence studies were performed on serial sections tissues (n = 12 per animal) using antibodies against BrdU. Confocal microscopy was used to identify 4',6-diamidino-2-phenylindole (DAPI)- and BrdU-stained nuclei. In the group of mice exposed to BrdU, we identified a population of LRCs in all specimens and not in controls. The putative stem cells are located at the base of each villi, suggesting the location of the stem cell niche. The number of DAPI-stained nuclei divided by the number of LRCs; LRCs constituted 0.5% of all nucleated cells. The oviduct contains a population of progenitor cells, likely used in the repair and regeneration of fallopian tube. Defective or insufficient stem cell reserve may underlie common tubal diseases, including hydrosalpinx and ectopic pregnancy.

Surfactant protein-A (SP-A) selectively inhibits prostaglandin F2alpha (PGF2alpha) production in term decidua: implications for the onset of labor.

CONTEXT: Labor is characterized by "decidual activation" with production of inflammatory mediators. Recent data suggest that surfactant protein-A (SP-A) may be critical to the onset of labor in mice. Whether this is also true in humans is unclear. OBJECTIVES: The aim was to investigate: 1) the expression of SP-A at the maternal-fetal interface; 2) the effect of SP-A on the production of inflammatory mediators by human decidua; and 3) the association between single nucleotide polymorphisms in maternal SP-A genes and spontaneous preterm birth. RESEARCH DESIGN AND METHODS: In situ expression of SP-A was investigated by immunohistochemistry and quantitative RT-PCR. Term decidual stromal cells were isolated, purified, and treated with/without SP-A (1-100 µg/ml), IL-1ß, and/or thrombin. Levels of inflammatory mediators [IL-6, IL-8, TNFα, matrix metalloproteinase-3, monocyte chemotactic protein-1, IL-1ß, PGE(2), prostaglandin F(2α) (PGF(2α))] and angiogenic factors (soluble fms-like tyrosine kinase-1, vascular endothelial growth factor) were measured in conditioned supernatant by ELISA and corrected for protein content. The effect of SP-A on eicosanoid gene expression was measured by quantitative RT-PCR. RESULTS: SP-A localized to endometrium/decidua. High-dose SP-A (100 µg/ml) inhibited PGF(2α) by term decidual stromal cells without affecting the production of other inflammatory mediators, and this effect occurred at a posttranscriptional level. Decidual SP-A expression decreased significantly with labor. Single nucleotide polymorphisms in the SP-A genes do not appear to be associated with preterm birth. CONCLUSIONS: SP-A is produced by human endometrium/decidua, where it significantly and selectively inhibits PGF(2α) production. Its expression decreases with labor. These novel observations suggest that decidual SP-A likely plays a critical role in regulating prostaglandin production within the uterus, culminating at term in decidual activation and the onset of labor.

Intra-amniotic infection upregulates neutrophil gelatinase-associated lipocalin (NGAL) expression at the maternal-fetal interface at term: implications for infection-related preterm birth.

OBJECTIVE: Neutrophil gelatinase-associated lipocalin (NGAL) is a ubiquitous lipocalin that serves as a critical component of innate immunity and a transport shuttle for numerous substances (retinoids, arachidonic acid, prostaglandins, fatty acids, steroids, iron, and MMPs). Despite the well-documented association between intra-amniotic infection/inflammation (IAI) and preterm birth, NGAL expression in the uterus has not previously been examined. This study investigates NGAL expression at the maternal-fetal interface in vivo and in vitro. METHODS: Neutrophil gelatinase-associated lipocalin expression in term placenta with/without IAI was examined by immunohistochemistry. Trophoblast and decidual stromal cells were retrieved from elective cesarean, purified, and depleted of leukocytes. On days 1 (cytotrophoblast cells) and 4 (syncytiotrophoblast), cells were stimulated with/without interleukin 1ß (IL-1ß; 1 ng/mL), tumor necrosis factor α (TNF-α; 1 ng/mL), or lipopolysaccharide (LPS; 1 µg/mL). Neutrophil gelatinase-associated lipocalin messenger RNA (mRNA) and protein expression were measured by immunocytochemistry/Western blot and RT-qPCR, respectively. RESULTS: Under basal conditions, NGAL is expressed in trophoblast, but not decidua. Trophoblast NGAL is significantly upregulated in tissues with evidence of IAI vs controls. NGAL expression was increased after stimulation with all 3 pro-inflammatory mediators in day 1 (cytotrophoblast) but not day 4 cells (syncytiotrophoblast). IL-1ß and TNF-α (not LPS) upregulated NGAL gene expression in cytotrophoblast (not syncytiotrophoblast) cells. CONCLUSIONS: Intra-amniotic infection/inflammation is associated with increased expression of NGAL in trophoblast tissues in vivo. IL-1ß, TNF-α, and LPS stimulated NGAL in cytotrophoblast cells (not syncytiotrophoblast and decidua) in vitro. These data suggest that, in keeping with its role as a mediator of innate immunity, NGAL may have a central role to play in IAI-induced preterm birth.

Role of GnRH-GnRH receptor signaling at the maternal-fetal interface.

OBJECTIVE: To investigate the expression and function of GnRH and GnRH receptor (GnRHR) subtypes at the maternal-fetal interface. DESIGN: In vitro experiments using freshly isolated human trophoblast cells, decidual stromal cells (DSCs), and immortalized cell lines. SETTING: University teaching hospital. PATIENT(S): Placenta-fetal membranes from term deliveries. INTERVENTION(S): Human trophoblast and DSCs were isolated, purified, and cultured. MAIN OUTCOME MEASURE(S): Expression of GnRH-I, GnRH-II, and GnRHR-I mRNA and protein in human trophoblast cell lines and tissues were evaluated by reverse-transcription polymerase chain reaction and Western blot. The effect of GnRH-I and -II on the production of select cytokines (hCG, interleukin [IL] 8, IL-6, matrix metalloproteinase 3, monocyte chemoattractant protein 1, vascular endothelial growth factor, soluble Fms-like tyrosine kinase 1, urokinase-type plasminogen activator, and plasminogen activator inhibitor 1) were measured by ELISA and normalized for protein content. RESULT(S): GnRH-I, GnRH-II, and GnRHR-I mRNA and protein were identified in trophoblasts and decidua. GnRH-I and -II stimulated hCG production by trophoblast and trophoblast-derived cell lines in a dose-dependent fashion (e.g., 2.8-fold, from 2.5 ± 0.5 to 7.0 ± 0.4 ng/mg protein per 24 h, for 1,000 nmol/L GnRH-I and 2.4-fold, from 2.5 ± 0.5 to 6.1 ± 0.6 ng/mg protein per 24 h, for 1,000 nmol/L GnRH-II) without affecting the production of other cytokines. CONCLUSION(S): Trophoblasts and decidua express GnRH-I, GnRH-II, and GnRHR-I mRNA and protein. GnRH-I and -II selectively stimulate hCG production by trophoblast cells without altering the production of select cytokines by trophoblasts or decidua. The role of GnRH-GnRHR signaling at the maternal-fetal interface therefore appears to be limited to the regulation of trophoblast hCG production.

Primate-specific evolution of noncoding element insertion into PLA2G4C and human preterm birth.

BACKGROUND: The onset of birth in humans, like other apes, differs from non-primate mammals in its endocrine physiology. We hypothesize that higher primate-specific gene evolution may lead to these differences and target genes involved in human preterm birth, an area of global health significance. METHODS: We performed a comparative genomics screen of highly conserved noncoding elements and identified PLA2G4C, a phospholipase A isoform involved in prostaglandin biosynthesis as human accelerated. To examine whether this gene demonstrating primate-specific evolution was associated with birth timing, we genotyped and analyzed 8 common single nucleotide polymorphisms (SNPs) in PLA2G4C in US Hispanic (n = 73 preterm, 292 control), US White (n = 147 preterm, 157 control) and US Black (n = 79 preterm, 166 control) mothers. RESULTS: Detailed structural and phylogenic analysis of PLA2G4C suggested a short genomic element within the gene duplicated from a paralogous highly conserved element on chromosome 1 specifically in primates. SNPs rs8110925 and rs2307276 in US Hispanics and rs11564620 in US Whites were significant after correcting for multiple tests (p < 0.006). Additionally, rs11564620 (Thr360Pro) was associated with increased metabolite levels of the prostaglandin thromboxane in healthy individuals (p = 0.02), suggesting this variant may affect PLA2G4C activity. CONCLUSIONS: Our findings suggest that variation in PLA2G4C may influence preterm birth risk by increasing levels of prostaglandins, which are known to regulate labor.

Intra-amniotic infection upregulates decidual cell vascular endothelial growth factor (VEGF) and neuropilin-1 and -2 expression: implications for infection-related preterm birth.

Intra-amniotic infection/inflammation (IAI) is a major cause of preterm birth, but the mechanisms responsible are not well understood. This study investigates the effects of IAI on vascular endothelial growth factor (VEGF) as well as VEGF receptor (Flt1, KDR2) and coreceptor (neuropilin-1 and -2) messenger RNA (mRNA) and protein expression at the maternal-fetal interface, both in vitro and in vivo. Decidual stromal cells (DSCs) were isolated from term placentae, purified, and treated with 10(-8) mol/L estradiol (E(2)), 10( -7) mol/L medroxyprogesterone acetate (MPA), both, or vehicle for 7 days. Vascular endothelial growth factor expression in cultured DSCs increased in response to stimulation with interleukin 1 beta (IL-1 beta; 0.01-10 ng/mL)--but not tumor necrosis factor alpha (TNF-alpha; 1 ng/mL)--in a concentration-dependent fashion irrespective of the hormonal milieu. This effect appears to be mediated at the level of gene transcription because stimulation with IL-1 beta (but not TNF-alpha) increased expression of VEGF mRNA as measured by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR); a similar increase was seen in neuropilin-1/-2 (but not Flt1 and KDR2) mRNA. Immunohistochemical studies confirmed these observations in vivo. Immunostaining for VEGF and neuropilin-1/-2 (but not Flt1 or KDR2) was increased in serial tissue sections of decidua from women with clinical and histological evidence of IAI versus noninfected controls, and in cultured term DSCs exposed to IL-1 beta. The novel observations that IL-1 beta stimulates VEGF and neuropilin-1/-2 mRNA and protein expression in term DSCs in vitro along with confirmatory in vivo data using immunohistochemistry provide a mechanism by which IAI can alter vascular permeability, thereby facilitating leukocyte trafficking and increasing the risk of abruption, both of which are associated with preterm birth.

Postterm pregnancy: how can we improve outcomes?

UNLABELLED: Postterm pregnancy is defined as one which has progressed to 42 0/7 weeks or beyond. The most common reason to be diagnosed with a postterm pregnancy is inaccurate pregnancy dating, but it is also associated with obesity, nulliparity, and a prior history of postterm pregnancy. The rate of postterm pregnancy appears to be decreasing whether due to improved pregnancy dating or an increase in induction of labor. Postterm pregnancy is associated with both maternal and neonatal morbidity and fetal and neonatal mortality; similarly pregnancies beyond 41 weeks' gestation are associated with increases in these perinatal complications. Prevention of postterm pregnancies may include stripping or sweeping the membranes and unprotected coitus. Management of such pregnancies may include induction of labor and fetal antenatal monitoring. Individual patient management should involve careful counseling regarding the risks and benefits of each of the components of care. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader should be able to recall the increasing risks of poor outcomes associated with prolonged pregnancy, demonstrate knowledge regarding gestational dating and use of cervical ripening agents in their care of pregnant women, and use evidence-based information when counseling their term patients regarding postterm pregnancy management.

Single nucleotide polymorphisms in the human progesterone receptor gene and spontaneous preterm birth.

Progesterone supplementation can prevent preterm birth in some high-risk women. Progesterone binds to progesterone receptor (PR) and modulates the expression of target genes. This study investigates the association between single nucleotide polymorphisms (SNPs) in the PR gene and spontaneous preterm birth. DNA was extracted from consecutive patients with preterm birth (n = 78) and term controls (n = 415), and genotyping was performed for 3 PR SNPs (+331[G>A], + 770[C>T], +660[G>T]) using Sequenom matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Data were analyzed by chi(2) test and logistic regression analysis. Multivariate analysis showed no association between maternal carriage of minor + 331T, +770T, and/or +660T alleles and preterm birth when controlled for maternal age, ethnicity, gravidity, parity, prior preterm birth, route of delivery, or neonatal outcome. Carriage of +770T and +660T (but not +331T) was associated with preterm birth in women with a body mass index <18.5 kg/m(2) (relative risk, 10.8; 95% confidence interval, 1.4-82.6; P = .02). Maternal carriage of minor alleles of +331(G>A), +770(C>T), and +660(G> T) SNPs in the PR gene is not associated with spontaneous preterm birth.

Prolonged pregnancy: when should we intervene?

The timely onset of labor and birth is an important determinant of perinatal outcome. Prolonged (postterm) pregnancy--defined as delivery at or beyond 42 weeks' gestation--complicates 10% of all gestations and is associated with increased risks to both fetus (stillbirth, macrosomia, birth injury, meconium aspiration syndrome) and mother (cesarean delivery, severe perineal injury, postpartum hemorrhage). The risk of routine induction of labor (failed induction leading to cesarean delivery) in the era of cervical ripening is lower than previously reported. For these reasons, the authors favor a policy of routine induction of labor for low-risk pregnancies at 41 weeks' gestation.