Association between sleep quality, hypertensive disorders of pregnancy, and sleep-disordered breathing in pregnant women with and without obesity: An observational cross-sectional study.

AIM: To elucidate whether pregnancy and obesity are associated with poor sleep quality, and to investigate if sleep quality is associated with hypertensive disorders of pregnancy in pregnant women with obesity. METHODS: This observational cross-sectional study examined 15 obese pregnant women (body mass index ≥30 kg/m2 ) (p-Ob group), 15 nonobese pregnant women (p-nOb group), and 30 nonobese nonpregnant women (n-Pr group), using home recording devices to monitor sleep-disordered breathing (SDB): respiratory disturbance index, oxygen saturation, and sleep stage and quality. These variables were compared among the groups. Moreover, obese women with and without hypertensive disorders of pregnancy were compared. RESULTS: Significant differences in respiratory disturbance index (median: 10.3 [p-Ob], 7.1 [p-nOb], 3.5 [n-Pr]) and oxygen saturation (95.1%, 96.5%, and 96.6%) were observed among the groups. Seven participants in the p-Ob group experienced hypertensive disorders of pregnancy with SDB before or after sleep examination. Particularly, those who developed hypertensive disorders of pregnancy before sleep examination showed a lower delta power throughout the night than those without this condition. CONCLUSION: Pregnant women had poor sleep quality; those with obesity had higher frequency of SDB with worsened respiratory conditions that might cause complications. Our findings suggest that the development of hypertensive disorders of pregnancy in some obese pregnant women might be associated with insufficient delta power. Focusing on delta power may reflect subtle changes in sleep quality that occur in pregnant women. Future longitudinal studies with larger sample sizes are required to confirm these findings and investigate causality.

Impact of maternal dyslipidemia on infant neurodevelopment: The Japan Environment and Children's Study.

BACKGROUND: Various genetic and environmental influences have been studied for developmental disorders; however, the precise cause remains unknown. This study assessed the impact of maternal serum total cholesterol (TC) level in early pregnancy on early childhood neurodevelopment. METHODS: The fixed data of 31,797 singleton births from a large national birth cohort study that commenced in 2011 were used to identify developmental disorders as estimated by Ages and Stages Questionnaire, third edition (ASQ-3) scores of less than -2 standard deviations at 12 months of age. Multiple logistic regression analysis was employed to search for correlations between possibility of developmental disorders and maternal TC levels in early pregnancy classified into 4 groups based on quartile (Q1-Q4) values. RESULTS: After controlling for potential confounding factors in 27,836 participants who ultimately underwent multivariate analysis, we observed that elevated TC levels were significantly associated with a higher risk of screen positive status for communication (Q4: adjusted odds ratio [aOR] 1.20, 95% confidence interval [CI] 1.05-1.37) and gross motor (aOR 1.13, 95% CI 1.03-1.25) ASQ-3 domain scores. CONCLUSION: This large nationwide survey revealed a possible deleterious effect of hypercholesterolemia in early pregnancy on infant neurodevelopment and age-appropriate skill acquisition at 12 months age.

Insufficient maternal gestational weight gain and infant neurodevelopment at 12 months of age: the Japan Environment and Children's Study.

Abnormal maternal gestational weight gain (GWG) increases the risk of obstetric-related complications. This investigation examined the impact of GWG on infant neurodevelopmental abnormalities at 12 months of age using the data of a nationwide Japanese cohort study. Questionnaire data were obtained from the ongoing Japan Environment and Children's Study cohort study. Maternal GWG was subdivided as below, within, or above the reference values of the Institution of Medicine pregnancy weight guidelines. The Ages and Stages Questionnaire, third edition (ASQ-3) is a parent-reported developmental screening instrument for children across five domains: communication, gross motor, fine motor, problem-solving, and personal-social. Multiple logistic regression analysis was employed to identify correlations between GWG and developmental delay defined as ASQ-3 scores of less than two standard deviations below the mean. A total of 30,694 mothers with singleton live births and partners who completed the questionnaire were analyzed. The prevalence of mothers below, within, and above the GWG guidelines was 60.4% (18,527), 32.1% (9850), and 7.5% (2317), respectively. We recorded 10,943 infants (35.7%) who were outliers in at least one ASQ-3 domain. After controlling for covariates, GWG below established guidelines was associated with a significantly higher risk of developmental delay for the communication (odds ratio [OR] 1.21, 95% confidence interval [CI] 1.09-1.34), gross motor (OR 1.14, 95% CI 1.05-1.24), fine motor (OR 1.13, 95% CI 1.04-1.24), problem-solving (OR 1.09, 95% CI 1.01-1.18), and personal-social (OR 1.15, 95% CI 1.07-1.24) domains.Conclusion: This large survey revealed a possible deleterious effect of insufficient maternal GWG on infant neurodevelopment.Trial registration: The Japan Environment and Children's Study (JECS) was registered in the UMIN Clinical Trials Registry on January 15, 2018 (number UMIN000030786). What is Known: • Inappropriate maternal gestational weight gain may cause obstetric complications and adverse birth outcomes. • Excess maternal weight gain may result in gestational diabetes, hypertension, eclampsia, caesarean delivery, and macrosomia, while insufficient maternal weight gain has been associated with pre-term birth and small for gestational age. What is New: • This study provides important information on a possible adverse effect of insufficient maternal gestational weight gain on offspring neurodevelopment at 12 months of age. • Our findings indicate a need to reconsider the optimal body mass index and gestational weight gain for women desiring pregnancy.

Response of the microbiome-gut-brain axis in Drosophila to amino acid deficit.

A balanced intake of macronutrients-protein, carbohydrate and fat-is essential for the well-being of organisms. An adequate calorific intake but with insufficient protein consumption can lead to several ailments, including kwashiorkor1. Taste receptors (T1R1-T1R3)2 can detect amino acids in the environment, and cellular sensors (Gcn2 and Tor)3 monitor the levels of amino acids in the cell. When deprived of dietary protein, animals select a food source that contains a greater proportion of protein or essential amino acids (EAAs)4. This suggests that food selection is geared towards achieving the target amount of a particular macronutrient with assistance of the EAA-specific hunger-driven response, which is poorly understood. Here we show in Drosophila that a microbiome-gut-brain axis detects a deficit of EAAs and stimulates a compensatory appetite for EAAs. We found that the neuropeptide CNMamide (CNMa)5 was highly induced in enterocytes of the anterior midgut during protein deprivation. Silencing of the CNMa-CNMa receptor axis blocked the EAA-specific hunger-driven response in deprived flies. Furthermore, gnotobiotic flies bearing an EAA-producing symbiotic microbiome exhibited a reduced appetite for EAAs. By contrast, gnotobiotic flies with a mutant microbiome that did not produce leucine or other EAAs showed higher expression of CNMa and a greater compensatory appetite for EAAs. We propose that gut enterocytes sense the levels of diet- and microbiome-derived EAAs and communicate the EAA-deprived condition to the brain through CNMa.

Maternal alcohol consumption and risk of offspring with congenital malformation: the Japan Environment and Children's Study.

BACKGROUND: The association between fetal exposure to alcohol and congenital structural disorders remains inconclusive. The present study searched for relationships between maternal alcohol consumption during pregnancy and the risk of congenital malformations. METHODS: We evaluated the fixed dataset of a large national birth cohort study including 73,595 mothers with a singleton live birth. Information regarding the alcohol consumption of mothers was obtained from self-reported questionnaires. Physicians assessed for 6 major congenital malformations (congenital heart defects [CHDs], male genital abnormalities, limb defects, cleft lip and/or cleft palate [orofacial clefts (OFC)], severe brain abnormalities, and gastrointestinal obstructions) up to 1 month after birth. Multiple logistic regression analysis was performed to identify associations between maternal alcohol consumption during pregnancy and each malformation. RESULTS: The prevalence of maternal drinking in early pregnancy and until the second/third trimester was 46.6% and 2.8%, respectively. The onset of CHD was inversely associated with mothers who quit drinking during early pregnancy (OR 0.85, 95% CI 0.74-0.98). There was no remarkable impact of maternal drinking habit status on the other congenital malformations after adjustment for covariates. CONCLUSIONS: Maternal alcohol consumption during pregnancy, even in early pregnancy, displayed no significant adverse impact on congenital malformations of interest. IMPACT: This large-scale Japanese cohort study revealed that no teratogenic associations were found between maternal retrospective reports of periconceptional alcohol consumption and congenital malformations after adjustment for covariates. This is the first nationwide birth cohort study in Japan to assess the effect of maternal alcohol consumption during pregnancy on major congenital malformations. Our finding indicated that maternal low-to-moderate alcohol consumption during pregnancy, even in early pregnancy, displayed no significant adverse impact on congenital heart defects, male genital abnormalities, limb defects, orofacial clefts, severe brain abnormalities, or gastrointestinal obstructions.

Association between pesticide usage during pregnancy and neonatal hyperbilirubinemia requiring treatment: the Japan Environment and Children's Study.

BACKGROUND: Maternal exposure to pesticides during pregnancy may cause oxidative hemolysis leading to neonatal hyperbilirubinemia. This investigation examined for associations between maternal use of pesticides or repellents during pregnancy and neonatal hyperbilirubinemia requiring phototherapy. METHODS: We used the dataset from the Japan Environment and Children's Study, a large national birth cohort study registered from January 31, 2011 to March 31, 2014. The fixed data of 61,751 live births were used to evaluate the presence of neonatal hyperbilirubinemia and potential confounding factors. We employed multiple logistic regression analysis to identify correlations between the frequency of maternal pesticide or repellent use during pregnancy and clinically relevant neonatal hyperbilirubinemia. RESULTS: After controlling for confounding factors, there were significant associations between neonatal hyperbilirubinemia necessitating phototherapy and the frequent use of indoor insecticide spray (OR 1.21, 95% CI 1.05-1.38). For spray- or lotion-type insect repellents, an opposite relationship was observed (more than a few times a week: OR 0.70, 95% CI 0.61-0.81, up to a few times a month: OR 0.84, 95% CI 0.78-0.91). CONCLUSION: The frequent use of indoor insecticide spray during pregnancy showed an increased risk of neonatal hyperbilirubinemia requiring phototherapy, which was absent for spray- or lotion-type insect repellents. IMPACT: The frequent use of indoor insecticide spray during pregnancy showed an increased risk of neonatal hyperbilirubinemia requiring phototherapy, which was absent for spray- or lotion-type insect repellents. This is the first study examining the effects of maternal exposure to pesticides or repellents on clinically relevant neonatal hyperbilirubinemia using a dataset from a nationwide birth cohort study. This large-scale Japanese cohort study revealed that the frequent use of indoor insecticide spray during pregnancy may increase the risk of neonatal hyperbilirubinemia requiring treatment.

Maternal Exposure to Housing Renovation During Pregnancy and Risk of Offspring with Congenital Malformation: The Japan Environment and Children's Study.

There have been no large, nationwide, birth cohort studies in Japan examining the effects of house renovation during pregnancy on congenital abnormality. This study examined the impact of (1) prenatal exposure to house renovation and (2) maternal occupational exposure to organic solvents and/or formaldehyde on the incidence of congenital abnormality. The fixed data of 67,503 singleton births from a large national birth cohort study that commenced in 2011 were used to evaluate the presence of congenital abnormalities and potential confounding factors. We employed multiple logistic regression analysis to search for correlations between maternal exposure to house renovation or organic solvents and/or formaldehyde during pregnancy and such congenital abnormalities as congenital heart disease, cleft lip and/or palate, male genital abnormality, limb defect, and gastrointestinal obstruction. After controlling for potential confounding factors, we observed that house renovation was significantly associated with male genital abnormality (OR 1.81, 95% CI 1.03-3.17, P = 0.04) when stratified by congenital abnormality, with no other remarkable relations to house renovation or occupational use of organic solvents and/or formaldehyde during pregnancy. There were also significant correlations for maternal BMI before pregnancy, history of ovulation induction through medication, maternal diabetes mellitus/gestational diabetes mellitus, and hypertensive disorder of pregnancy with an increased risk of congenital abnormality. In conclusion, this large nationwide survey provides important information on a possible association of house renovation during pregnancy with congenital male genital abnormality which needs confirmation in future studies.

Alcohol Consumption During Pregnancy and Risk of Placental Abnormality: The Japan Environment and Children's Study.

There have been no large nationwide birth cohort studies examining for the effects of maternal alcohol use during pregnancy on placental abnormality. This study searched for associations between alcohol consumption and the placental abnormalities of placenta previa, placental abruption, and placenta accreta using the fixed dataset of a large national birth cohort study commencing in 2011 that included 80,020 mothers with a singleton pregnancy. The presence of placental abnormalities and potential confounding factors were recorded, and multiple logistic regression analysis was employed to search for correlations between maternal alcohol consumption during pregnancy and placental abnormalities. The overall rate of prenatal drinking until the second/third trimester was 2.7% (2,112). The prevalence of placenta previa, placental abruption, and placenta accreta was 0.58% (467), 0.43% (342), and 0.20% (160), respectively. After controlling for potential confounding factors, maternal alcohol use during pregnancy was significantly associated with the development of placenta accreta (OR 3.10, 95%CI 1.69-5.44). In conclusion, this large nationwide survey revealed an association between maternal drinking during pregnancy and placenta accreta, which may lead to excessive bleeding during delivery.

Sawtooth fetal heart rate pattern associated with a favorable neurological outcome in an infant: a case report.

BACKGROUND: The sawtooth fetal heart rate pattern is rare, and has been reported as a possible indicator of neurological sequelae in newborns. However, we observed this fetal heart rate pattern in an infant with normal neurological function. CASE PRESENTATION: A 29-year-old primigravida Japanese woman presented to our hospital at 40 weeks and 1 day of gestation with marked vaginal bleeding. Since admission, fetal heart rate tracing consistently demonstrated a sawtooth-like pattern. There were 3-4 oscillations per minute, and their amplitude was 30-40 beats per minute. An emergency cesarean section was performed because of non-reassuring fetal status. Evidence of placental abruption was not observed. The newborn was a male weighing 2936 g, with an Apgar score of 1 and 3 at 1 minute and 5 minutes, respectively. The infant received brain cooling, but was discharged uneventfully. A follow-up examination at age 3 years demonstrated no developmental restriction. CONCLUSION: Although the Apgar score of the newborn was low, the infant had no neurological sequelae. Thus, the sawtooth fetal heart rate pattern may not be linked to in utero irreversible fetal central nervous system injury.

Infant Suffocation Incidents Related to Co-Sleeping or Breastfeeding in the Side-Lying Position in Japan.

Co-sleeping and breastfeeding in the side-lying position have recently been pointed out as risk factors for suffocation in sleeping infants; however, there is no actual report on an "incident." "Incident" is defined as a tense or sobering experience without a consequential fatal suffocation accident. It is important to understand infant suffocation incidents to prevent accidents during co-sleeping and breastfeeding in the side-lying position. We investigated factors and frequency of infant suffocation incidents associated with co-sleeping and breastfeeding in the side-lying position using a self-administered questionnaire survey of 895 mothers during their infant's 1-, 4-, or 10-month health checkups. Co-sleeping and breastfeeding in the side-lying position were practiced by 28.3% and 56.0% of mothers, respectively; thus, 84.3% of the mothers surveyed were practicing either co-sleeping or breastfeeding in the side-lying position. Of those who received guidance from a medical professional, 36.1% practiced only co-sleeping while 60.1% practiced only side-lying breastfeeding. In the co-sleeping group, 10.6% had faced infant suffocation incidents, while 13.2% in the breastfeeding in the side-lying position group had faced similar incidents. Regarding factors associated with suffocation incidents while co-sleeping, the frequency of occurrence was significantly more in mothers of 1-month and 4-month-old infants compared with those of 10-month-old infants. Of mothers who faced suffocation incidents while breastfeeding in the side-lying position, 45% also had faced similar incidents while co-sleeping. These results demonstrate the importance of thoroughly educating mothers about the risks associated with co-sleeping and breastfeeding in the side-lying position for preventing infant suffocation.

Correction: Nationwide survey for current clinical status of amniocentesis and maternal serum marker test in Japan.

Since the publication of this paper, the authors noticed that Yosuke Fujii was assigned to the incorrect affiliation. The affiliation information is provided correctly, above.

Regulation of neuroblast proliferation by surface glia in the Drosophila larval brain.

Despite the importance of precisely regulating stem cell division, the molecular basis for this control is still elusive. Here, we show that surface glia in the developing Drosophila brain play essential roles in regulating the proliferation of neural stem cells, neuroblasts (NBs). We found that two classes of extracellular factors, Dally-like (Dlp), a heparan sulfate proteoglycan, and Glass bottom boat (Gbb), a BMP homologue, are required for proper NB proliferation. Interestingly, Dlp expressed in perineural glia (PG), the most outer layer of the surface glia, is responsible for NB proliferation. Consistent with this finding, functional ablation of PG using a dominant-negative form of dynamin showed that PG has an instructive role in regulating NB proliferation. Gbb acts not only as an autocrine proliferation factor in NBs but also as a paracrine survival signal in the PG. We propose that bidirectional communication between NBs and glia through TGF-ß signaling influences mutual development of these two cell types. We also discuss the possibility that PG and NBs communicate via direct membrane contact or transcytotic transport of membrane components. Thus, our study shows that the surface glia acts not only as a simple structural insulator but also a dynamic regulator of brain development.

Nationwide survey for current clinical status of amniocentesis and maternal serum marker test in Japan.

Prenatal testing has been provided in Japan over the past several decades. However, it is difficult to assess the clinical status of amniocentesis (AC) and maternal serum markers (MSM) because obstetricians can perform these tests without registration. This study aims to investigate the current clinical status of AC and MSM in Japan. We conducted a questionnaire study that was intended for a total of 5622 Japanese obstetrics/gynecology facilities during October 2013 to January 2014. The response rate was 40.8% (2295/5622). Of the 2295 facilities, 864 performed MSM (37.7%), 619 performed AC (27.0%) and 412 performed both (18.0%). The average number of MSM tests was 2.0 per month (range 0-52), and the average number of AC tests was 2.4 per month (range 0-30). Involvement of genetic professionals, such as clinical geneticists (CGs) and certified genetic counselors (CGCs), contribute to a content-rich explanation and management of difficult issues and lengthened the explanation time. Nevertheless, relatively few facilities employed these specialists (MSM: 96/864 and AC: 128/619). This is the first study to highlight the current clinical status of AC and MSM tests in Japan. Active involvement of CGs and CGCs can provide more appropriate genetic counseling for prenatal tests.

Drosophila SLC5A11 Mediates Hunger by Regulating K(+) Channel Activity.

Hunger is a powerful drive that stimulates food intake. Yet, the mechanism that determines how the energy deficits that result in hunger are represented in the brain and promote feeding is not well understood. We previously described SLC5A11-a sodium/solute co-transporter-like-(or cupcake) in Drosophila melanogaster, which is required for the fly to select a nutritive sugar over a sweeter nonnutritive sugar after periods of food deprivation. SLC5A11 acts on approximately 12 pairs of ellipsoid body (EB) R4 neurons to trigger the selection of nutritive sugars, but the underlying mechanism is not understood. Here, we report that the excitability of SLC5A11-expressing EB R4 neurons increases dramatically during starvation and that this increase is abolished in the SLC5A11 mutation. Artificial activation of SLC5A11-expresssing neurons is sufficient to promote feeding and hunger-driven behaviors; silencing these neurons has the opposite effect. Notably, SLC5A11 transcript levels in the brain increase significantly when flies are starved and decrease shortly after starved flies are refed. Furthermore, expression of SLC5A11 is sufficient for promoting hunger-driven behaviors and enhancing the excitability of SLC5A11-expressing neurons. SLC5A11 inhibits the function of the Drosophila KCNQ potassium channel in a heterologous expression system. Accordingly, a knockdown of dKCNQ expression in SLC5A11-expressing neurons produces hunger-driven behaviors even in fed flies, mimicking the overexpression of SLC5A11. We propose that starvation increases SLC5A11 expression, which enhances the excitability of SLC5A11-expressing neurons by suppressing dKCNQ channels, thereby conferring the hunger state.

Green-to-Red Photoconversion of GCaMP.

Genetically encoded calcium indicators (GECIs) permit imaging intracellular calcium transients. Among GECIs, the GFP-based GCaMPs are the most widely used because of their high sensitivity and rapid response to changes in intracellular calcium concentrations. Here we report that the fluorescence of GCaMPs--including GCaMP3, GCaMP5 and GCaMP6--can be converted from green to red following exposure to blue-green light (450-500 nm). This photoconversion occurs in both insect and mammalian cells and is enhanced in a low oxygen environment. The red fluorescent GCaMPs retained calcium responsiveness, albeit with reduced sensitivity. We identified several amino acid residues in GCaMP important for photoconversion and generated a GCaMP variant with increased photoconversion efficiency in cell culture. This light-induced spectral shift allows the ready labeling of specific, targeted sets of GCaMP-expressing cells for functional imaging in the red channel. Together, these findings indicate the potential for greater utility of existing GCaMP reagents, including transgenic animals.

Guidelines for obstetrical practice in Japan: Japan Society of Obstetrics and Gynecology (JSOG) and Japan Association of Obstetricians and Gynecologists (JAOG) 2014 edition.

The 'Clinical Guidelines for Obstetrical Practice, 2011 edition' were revised and published as a 2014 edition (in Japanese) in April 2014 by the Japan Society of Obstetrics and Gynecology and the Japan Association of Obstetricians and Gynecologists. The aims of this publication include the determination of current standard care practices for pregnant women in Japan, the widespread use of standard care practices, the enhancement of safety in obstetrical practice, the reduction of burdens associated with medico-legal and medico-economical problems, and a better understanding between pregnant women and maternity-service providers. The number of Clinical Questions and Answers items increased from 87 in the 2011 edition to 104 in the 2014 edition. The Japanese 2014 version included a Discussion, a List of References, and some Tables and Figures following the Answers to the 104 Clinical Questions; these additional sections covered common problems and questions encountered in obstetrical practice, helping Japanese readers to achieve a comprehensive understanding. Each answer with a recommendation level of A, B or C was prepared based principally on 'evidence' or a consensus among Japanese obstetricians in situations where 'evidence' was weak or lacking. Answers with a recommendation level of A or B represent current standard care practices in Japan. All 104 Clinical Questions and Answers items, with the omission of the Discussion, List of References, and Tables and Figures, are presented herein to promote a better understanding among English readers of the current standard care practices for pregnant women in Japan.

Compartmentalized calcium transients trigger dendrite pruning in Drosophila sensory neurons.

Dendrite pruning is critical for sculpting the final connectivity of neural circuits as it removes inappropriate projections, yet how neurons can selectively eliminate unnecessary dendritic branches remains elusive. Here, we show that calcium transients that are compartmentalized in specific dendritic branches act as temporal and spatial cues to trigger pruning in Drosophila sensory neurons. Calcium transients occurred in local dendrites at ~3 hours before branch elimination. In dendritic branches, intrinsic excitability increased locally to activate calcium influx via the voltage-gated calcium channels (VGCCs), and blockade of the VGCC activities impaired pruning. Further genetic analyses suggest that the calcium-activated protease calpain functions downstream of the calcium transients. Our findings reveal the importance of the compartmentalized subdendritic calcium signaling in spatiotemporally selective elimination of dendritic branches.

Placental mesenchymal dysplasia: chronological observation of placental images during gestation and review of the literature.

Placental mesenchymal dysplasia (PMD) is characterized by multiple hypoechoic vesicles which are similar to molar changes in the placenta; however, the process of such morphological changes of PMD during pregnancy has not been fully understood. We performed a review of all PMD cases published in English and identified 49 articles including 110 cases. With regard to the gestational age at which the multicystic pattern was seen, approximately 70% of cases were diagnosed at 13-20 weeks of gestation. Another characteristic feature of PMD is varicose dilation of fetal chorionic vessels. As many as 90% of cases were diagnosed as placenta with dilated fetal chorionic vessels in the third trimester. We also report a case of PMD which was found at 10 weeks of gestation according to ultrasonic molar patterns. Serial observations of the placenta using ultrasound and magnetic resonance imaging revealed that multicystic lesions became smaller after 23 weeks. In contrast, dilated placental vessels on the fetal side became apparent at 38 weeks. The present review highlights that placental vesicular lesions of PMD may precede dilation of fetal chorionic vessels during pregnancy. It also indicates the potential of a gradual reduction in size of PMD's placental vesicular lesions by serial study of placental images.

Predicting the route of delivery in women with low-lying placenta using transvaginal ultrasonography: significance of placental migration and marginal sinus.

BACKGROUND/AIMS: To examine the significance of placental migration and the presence of a placental marginal sinus to predict the eventual route of delivery in low-lying placenta. METHODS: 49 women with a low-lying placenta after 30 weeks' gestation were studied. The distance between the internal os and leading edge of the placenta was measured weekly using transvaginal ultrasonography until 37 weeks' gestation. The relationship between the rate of placental migration, the presence of a placental marginal sinus and the eventual mode of delivery was investigated. RESULTS: Although the cesarean section rate was 56.3% (9/16) in the 'slow' migration (0-2.0 mm/week) group, no patient (0/33) in the 'fast' (>2.0 mm/week) migration group underwent a cesarean section (p < 0.01). The cesarean section rate was 71.4% (5/7) in patients with a placental marginal sinus, significantly greater than the rate of 9.5% (4/42) in patients without a marginal sinus (p < 0.01). CONCLUSION: A decreased rate of placental migration until 37 weeks' gestation and the presence of a placental marginal sinus were associated with subsequent cesarean delivery because of antepartum vaginal bleeding. These parameters may be useful for predicting the route of delivery in women with a low-lying placenta.