Regional disparities in primary cesarean delivery rates in Japan: the role of obstetrician availability.

Background: The prevalence of cesarean section procedures is on the rise worldwide, necessitating a deeper understanding of the factors driving this trend to mitigate potential adverse consequences associated with unnecessary cesarean section deliveries. Objectives: This study aims to investigate the rate of primary cesarean deliveries (PCD), a potential key indicator of obstetric care quality. Study Design: A national retrospective cohort study was conducted utilizing extensive data from the National Database of Health Insurance Claims and Specific Health Checkups of Japan spanning the years 2012 to 2018. The study examined the temporal trends in PCD rates and the indications for these procedures across different prefectures. Additionally, the study employed the obstetrician disproportionality index, as published by the Ministry of Health, Labour, and Welfare, to assess the influence of obstetrician availability on PCD rates. Results: Throughout the study period from 2012 to 2018, the rate of PCD in Japan remained relatively stable at approximately 14%. The primary indications for PCD in 2018 included labor arrest (18.3%), malpresentation (16.5%), nonreassuring fetal status (6.5%), and macrosomia (6.0%). Substantial regional disparities in PCD rates were observed, ranging from 8.9% to 20.4% among prefectures in 2018. Notably, prefectures categorized in the bottom 10 of the obstetrician disproportionality index exhibited significantly higher PCD rates compared to the top 10 prefectures (P=.0232), with a similar trend noted for PCD due to labor arrest (P=.0288). Furthermore, a negative correlation was identified between the obstetrician disproportionality index and PCD rates at the prefectural level (r=-0.3119, P=.0328). Conclusions: Our study presents a comprehensive analysis of PCD rates in Japan, shedding light on regional disparities and highlighting the notable influence of obstetrician availability on clinical decision-making. This study contributes to the ongoing discourse on the escalating global trend in cesarean sections and the importance of healthcare resource allocation in maternal care.

Uneventful vaginal delivery using epidural anesthesia in patient with exercise induced anaphylaxis: a case report and literature review.

Exercise induced anaphylaxis (EIA) is a rare and potentially life-threatening syndrome characterized by anaphylaxis provoked by exercise. Although vaginal delivery with labor pain is a physical strain for women and a possible trigger for EIA, no consensus exists on the management strategy of delivery in patients with EIA. A 28-year-old primigravida was referred to our hospital because of history of EIA, associated with pruritus, urticaria, and respiratory distress, exacerbated during physical activity. To avoid physical stress, we chose scheduled labor induction with epidural anesthesia, and administered prophylactic intravenous hydrocortisone. She delivered vaginally with no symptoms suggestive of EIA during labor. Since it is quite possible for patients with EIA to develop anaphylaxis during vaginal delivery with labor pain, epidural anesthesia and prophylactic steroid administration may be the most rational approaches for delivery in pregnant women with EIA.

X-ray Pelvimetry Has No Impact on the Outcomes of Trial of Labor after Cesarean Delivery: A Retrospective Single-center Study.

Few studies have examined the relationship between pelvic size and the success or failure of trial of labor after cesarean delivery (TOLAC). Here we aimed to determine whether pelvic size and morphological data obtained from radiography contribute to the first successful TOLAC. This retrospective single-center observational study enrolled pregnant women who underwent TOLAC between 2010 and 2021. The results of X-ray pelvimetry data, including obstetric conjugate (OC), transverse diameter of the pelvic inlet (TD), anteroposterior diameter of the pelvic inlet (APD), shape of the pelvic inlet, and other obstetrical clinical data, were compared between the success and failure groups. Seventy-five patients in successful group after excluding 35 patients with previous successful TOLAC, and 21 patients in failure group were eligible. The failure group had a higher rate of previous cesarean sections due to failed labor trials (p = 0.042) and heavier newborns (p = 0.014). OC, TD, and APD on X-ray pelvimetry did not differ significantly between the two groups nor did the shape of the pelvic inlet affect the success rate for TOLAC. The generalized linear model identified a history of failed trials of labor as a significant predictor of failed TOLAC (odds ratio, 0.26; 95% confidence interval 0.071-0.923; p = 0.037), whereas no pelvimetric parameters were found. Pelvic size and morphological findings have no discernible impact on the outcomes of TOLAC. The universal application of X-ray pelvimetry in all women attempting TOLAC may not have significant clinical relevance.

Hyposecretion of cervical MUC5B is related to preterm birth in pregnant women after cervical excisional surgery.

PROBLEM: Excisional surgery for cervical intraepithelial neoplasia is a risk factor for preterm birth in subsequent pregnancies. However, the underlying mechanisms of this association remain unclear. We previously showed that cervical MUC5B, a mucin protein, may be a barrier to ascending pathogens during pregnancy. We thus hypothesized that hyposecretion of cervical MUC5B is associated with preterm birth after cervical excisional surgery. METHOD OF STUDY: This prospective nested case-control study (Study 1) included pregnant women who had previously undergone cervical excisional surgery across 11 hospitals. We used proteomics to compare cervicovaginal fluid at 18-22 weeks of gestation between the preterm and term birth groups. In another case-control analysis (Study 2), we compared MUC5B expression in nonpregnant uterine tissues between 15 women with a history of cervical excisional surgery and 26 women without a history of cervical surgery. RESULTS: The abundance of MUC5B in cervicovaginal fluid was significantly decreased in the preterm birth group (fold change = 0.41, p = .035). Among the 480 quantified proteins, MUC5B had the second highest positive correlation with gestational age at delivery in the combined preterm and term groups. The cervicovaginal microbiome composition was not significantly different between the two groups. Cervical length was not correlated with gestational age at delivery (r = 0.18, p = .079). Histologically, the MUC5B-positive area in the nonpregnant cervix was significantly decreased in women with a history of cervical excisional surgery (0.85-fold, p = .048). The distribution of MUC5B-positive areas in the cervical tissues of 26 women without a history of cervical excisional surgery differed across individuals. CONCLUSIONS: This study suggests that the primary mechanism by which cervical excisional surgery causes preterm birth is the hyposecretion of MUC5B due to loss of the cervical glands.

Shear stress in the intervillous space promotes syncytial formation of iPS cells-derived trophoblasts†.

The intervillous space of human placenta is filled with maternal blood, and villous trophoblasts are constantly exposed to the shear stress generated by maternal blood pressure and flow throughout the entire gestation period. However, the effects of shear stress on villous trophoblasts and their biological significance remain unknown. Here, using our recently established naïve human pluripotent stem cells-derived cytotrophoblast stem cells (nCTs) and a device that can apply arbitrary shear stress to cells, we investigated the impact of shear stress on early-stage trophoblasts. After 72 h of exposure to 10 dyn/cm2 shear stress, nCTs became fused and multinuclear, and mRNA expression of the syncytiotrophoblast (ST) markers, such as glial cell missing 1, endogenous retrovirus group W member 1 envelope, chorionic gonadotropin subunit beta 3, syndecan 1, pregnancy specific beta-1-glycoprotein 3, placental growth factor, and solute carrier family 2 member 1 were significantly upregulated compared to static conditions. Immunohistochemistry showed that shear stress increased fusion index, human chorionic gonadotropin secretion, and human placental lactogen secretion. Increased microvilli formation on the surface of nCTs under flow conditions was detected using scanning electron microscopy. Intracellular cyclic adenosine monophosphate significantly increased under flow conditions. Moreover, transcriptome analysis of nCTs subjected to shear stress revealed that shear stress upregulated ST-specific genes and downregulated CT-specific genes. Collectively, these findings indicate that shear stress promotes the differentiation of nCTs into ST.

Characteristics of pregnancy complicated with type 1 and type 2 diabetes.

OBJECTIVE: Diabetes in pregnancy is a major risk factor for adverse perinatal outcomes such as congenital anomalies, hypertensive disorders of pregnancy (HDP), and macrosomia. For the mechanism of onset of type 1 and type 2 diabetes are different, we focused on the difference in perinatal outcomes between the type 1 and type 2 diabetes groups. MATERIALS AND METHODS: We retrospectively reviewed 22 pregnancies with type 1 diabetes and 15 pregnancies with type 2 diabetes, who were managed in our single center, with regard to maternal diabetes conditions during pregnancy and neonatal birthweight and blood glucose level. Furthermore, we checked the effect of continuous glucose monitoring and continuous subcutaneous insulin injection in pregnancies with type 1 diabetes. RESULTS: Type 1 diabetes in pregnancy was less controllable and increased neonatal birth weight and neonatal hypoglycemia within 2 h after birth after neonatal care unit admission. Continuous glucose monitoring and continuous subcutaneous insulin injection that are convenient to use, had a similar effect in the management of type 1 diabetes during pregnancy, compared with conventional diabetes treatment. In contrast, maternal BMI and HDP were increased in women with type 2 diabetes. CONCLUSION: In the management of pregnancy with diabetes, we should pay attention to the difference in pregnancy prognosis between type 1 and type 2 diabetes.

The prognosis of neonatal respiratory status within three years after birth in chronic abruption-oligohydramnios sequence.

AIM: Chronic abruption-oligohydramnios sequence (CAOS), which is characterized by vaginal bleeding and oligohydramnios, adversely affects the lungs of fetuses due to bloody amniotic fluid and oligohydramnios. The criteria for termination of pregnancy remain controversial. This study aimed to examine respiratory function in infants within 3 years after birth and risk factors for respiratory prognosis, and to clarify the management of CAOS. METHODS: This study is a case series of patients with CAOS managed at our institution between 2010 and 2020. The clinical data of the patients and their infants within 3 years after birth were reviewed. The amniotic fluid volume was measured using the maximum vertical pocket (MVP). RESULTS: Six of 17 neonates (35.3%) used inhaled nitric oxide (iNO) to improve oxygenation. Women with longer periods of MVP <1 cm delivered more neonates using iNO; however, periods of MVP <2 cm were not associated with iNO use. Almost half of the infants required home oxygen therapy when discharged, regardless of amniotic fluid volume. At 18 months corrected age, only one child needed respiratory support, and the others discontinued. Two neonates, both born at 23 weeks of gestational age, died within 1 month after birth because of extremely preterm birth. CONCLUSIONS: The amniotic fluid volume could predict the use of iNO in neonates, but it did not affect the child's respiratory function after the newborn period. Almost all children born to women with CAOS can improve their respiratory function as they grow up.

Evolutionary histories of breast cancer and related clones.

Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development1-3. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.

Residual amniotic fluid volume predicts the sealing of preterm prelabor rupture of fetal membranes in the pre- and periviable period.

OBJECTIVE: Preterm prelabor rupture of fetal membranes (pPROM) is a leading cause of preterm birth. When pPROM occurs around the pre- and periviable period, the perinatal outcome is unfavorable. However, there have been a few cases in which the leakage of amniotic fluid ceases and the ruptured fetal membranes are spontaneously sealed. MATERIALS AND METHODS: The prognosis of 38 cases of pPROM at less than 27 weeks of gestation in Kyoto University Hospital were studied. The clinical factors related to the sealing of fetal membranes were investigated. RESULTS: Spontaneous sealing was confirmed in five patients (13%), and sealing occurred within 14 days of pPROM. Women in the no sealing group delivered at 26.3 ± 0.5 weeks of gestation, whereas women in the sealing group delivered at term at 38.8 ± 0.4 weeks (p < 0.0001). The maximum vertical pocket (MVP) of amniotic fluid at the time of pPROM diagnosis was 2.2 ± 0.3 cm in the no sealing group and 3.8 ± 0.5 cm in the sealing group (p = 0.043). All cases of sealing occurred when the MVP at diagnosis was more than 2 cm, and there were no cases of sealing if the MVP at diagnosis was less than 2 cm. In addition, the value of C-reactive protein at ROM was less than 0.4 mg/dL in all cases in the sealing group. CONCLUSION: The residual volume of sterile amniotic fluid at the onset of pPROM may predict the possibility of fetal membrane sealing.

High-grade vaginal intraepithelial neoplasia after hysterectomy for high-grade cervical intraepithelial neoplasia: Is hysterectomy a "definitive" treatment compared to conization?

AIM: We investigated the frequency of early recurrence of vaginal intraepithelial neoplasia grade 2/3 (VaIN 2/3) (within 2 years) after hysterectomy for cervical intraepithelial neoplasia grade 3 (CIN3). The characteristics of the clinicopathological factors common to them were explored including different surgical methods. METHODS: As a retrospective observational study, a total of 647 CIN3 patients were divided into a conization and hysterectomy group (C group, n = 492; H group, n = 155), and HSIL (CIN2/3 or VaIN2/3) recurrence within 2 years after surgery was evaluated. A stratified analyses was performed. Surgical methods were divided into trans-abdominal, trans-vaginal, and laparoscopic. RESULTS: The recurrence of VaIN3 was detected in four cases (2.6%) in the H group, which was similar to that of CIN2/3 in the C group, 12 out of 491 patients (2.4%). The patients who developed VaIN3 were significantly older than those who did not (median, VaIN3: 71.0; VaIN1 and less: 48.0; p < 0.0001). All VaIN3 cases were detected within 5 months, although majority of cases were negative in the margin (3/4 cases; margin negative). The method of hysterectomy was not related to the VaIN3 recurrence. CONCLUSION: For CIN3 patients for whom hysterectomy is the main treatment, VaIN3 can develop in 2.6% within very shortly after operation even if surgical margin was negative. The elder the age, the higher the risk of early recurrence could be. Laparoscopic surgery is considered to be acceptable methods of hysterectomy.

Laparoscopic resection for pedunculated focal nodular hyperplasia of the liver during pregnancy.

Focal nodular hyperplasia (FNH) is the second most common intrahepatic benign mass lesion; however, extremely rarely, FNH grows in an exophytic manner. It is unclear whether pedunculated FNH can be managed in the same way as intrahepatic FNH. A 35-year-old female presented with right upper quadrant pain, and dynamic enhanced computed tomography revealed an exophytic hyperdense mass lesion originating from the liver, suggesting a pedunculated FNH. Shortly thereafter, she conceived. Since there was a history of acute abdomen, as well as the possibility of torsion of the mass or sudden massive bleeding during pregnancy, laparoscopic resection was performed at 17 weeks of gestation. Her postoperative and pregnancy course was uneventful, and she delivered a baby by cesarean section at 41 weeks of gestation. Our case suggests that pedunculated FNH, unlike typical intrahepatic FNH, may be better managed by laparoscopic surgery during pregnancy, resulting in favorable maternal and fetal outcomes.

A case of solitary lymph node recurrence 9 years after initial treatment for advanced premenopausal endometrioid endometrial cancer; clinical usefulness of hormonal replacement therapy.

There is no consensus on the use of hormone replacement therapy (HRT) after treatment of advanced corpus cancer. We report a case of advanced corpus cancer at a young age, in which HRT was initiated 7 years after surgery, and regional lymph node recurrence was later detected. The patient was 35 years old at the time of initial treatment in X year, when she was diagnosed with stageIIIC2 corpus cancer and underwent a hysterectomy with bilateral salpingo-oophorectomy and a retroperitoneal lymphadenectomy. HRT was started at X + 7 years, and at X + 9 years, a 25 × 12-mm-sized mass was found in the hilum of the right kidney. A laparoscopic resection revealed regional lymph node recurrence of the corpus cancer. A retrospective study further revealed that a tumor measuring 12 × 3 mm was found at X + 3 years and grew to 18 × 7 mm in X + 6 years, just before the start of the HRT. We hypothesize that HRT did not induce tumor recurrence; instead, it allowed for long-term follow-up and early diagnosis.

Obstetric pelvimetry by three-dimensional computed tomography in non-pregnant Japanese women: a retrospective single-center study.

OBJECTIVE: While a basic understanding of pelvic size and typology is still important for obstetricians, pelvic measurement data for Japanese women are very scarce. To our best knowledge, no large-scale pelvimetry studies of Japanese women have been made for the past 50 years. This study aimed to investigate the accurate size, particularly the obstetric conjugate (OC) and transverse diameter of the pelvic inlet (TD), of modern Japanese women, using three-dimensional (3D) computed tomography (CT), and to obtain their reference values. METHODS: This retrospective, single-center observational study enrolled Japanese non-pregnant women aged between 20 and 40 years, who underwent pelvic CT examination from 2016 to 2021. CT was performed for various reasons, including acute abdomen, search for cancer metastases, and follow-up of existing disease. However, no cases were taken for pelvic measurements. Pelvimetry was performed retrospectively using a 3D workstation. The OC was measured on a strict lateral view and the TD was measured on an axial-oblique view. Other clinical data, such as age, height, and weight, were also extracted from the medical charts and analyzed. RESULTS: A total of 1,263 patients were enrolled, with the mean age of 32.7 years (standard deviation [SD] 6.2). The mean height, weight, and body mass index were 158.8 cm (SD 5.8), 54.8 kg (SD 11.7), and 21.7 kg/m2 (SD 4.4), respectively. The mean OC length was 127.0 mm (SD 9.5, 95% confidence interval [CI] 126.5-127.5), while the mean TD length was 126.8 mm (SD 7.5, 95% CI 126.4-127.2). Both values were normally distributed. Height was significantly associated with OC (regression coefficient = 0.75 [95% CI 0.66-0.84], p < .001) and TD (regression coefficient = 0.63 [95% CI 0.56-0.70], p < .001). Age showed a weak but statistically significant positive association with TD (regression coefficient = 0.14 [95% CI 0.07-0.20], p < .001) and OC (regression coefficient = -0.10 [95% CI -0.18 to -0.01], p = .026). CONCLUSION: The 3D CT pelvimetry in 1,263 non-pregnant Japanese women of childbearing age revealed the mean OC and TD of 127.0 mm, and 126.8 mm, which were 11.8 mm and 4.3 mm larger, respectively, than those in the survey in 1972. Our data will be referred to in clinical practice as the standard pelvic measurement values for the Japanese population.

ATM mutation in aggressive uterine adenosarcoma in which systemic chemotherapies had remarkable effects.

Uterine adenosarcoma is a rare gynecologic malignancy, and 10-25% of the cases exhibit clinically aggressive behaviors. Although TP53 mutations are frequently identified in high-grade adenosarcomas of the uterus, definitive gene alterations have not been identified in uterine adenosarcomas. Specifically, no reports have described mutations in homologous recombination deficiency-related genes in uterine adenosarcomas. This study presents a case of uterine adenosarcoma without sarcomatous overgrowth but with TP53 mutation that exhibited clinically aggressive behaviors. The patient had an ATM mutation, which is a gene associated with homologous recombination deficiency, and exhibited a good response against platinum-based chemotherapy and possible therapeutic target by poly(ADP-ribose) polymerase inhibitors.

A case of dedifferentiated carcinoma associated with grade 1 endometrioid carcinoma with prominent squamous differentiation at the lower uterine segment.

Locally advanced cervical squamous cell carcinoma is a rare indication for surgery. In this report, we describe the case of a patient with presumed locally advanced cervical squamous cell carcinoma who underwent surgical treatment and was postoperatively diagnosed with endometrial cancer with prominent squamous differentiation. A 41-year-old woman presented with squamous cell carcinoma that was detected via Pap smear and confirmed by histological diagnosis of cervical biopsy. Magnetic resonance imaging showed a bulky cervical mass that spread to the lower uterine segment, vaginal wall, and rectum. The initial diagnosis was cervical cancer stage IVA. The patient underwent neoadjuvant chemotherapy followed by radical hysterectomy with combined rectal resection. Postoperative histopathology revealed a dedifferentiated carcinoma of the uterine corpus with prominent squamous differentiation. Immunohistochemistry of the surgical specimen showed loss of expression of mismatch repair proteins. The patient was informed of the possibility of Lynch syndrome and was recommended genetic counseling.

Placental functional assessment and its relationship to adverse pregnancy outcome: comparison of intravoxel incoherent motion (IVIM) MRI, T2-relaxation time, and umbilical artery Doppler ultrasound.

BACKGROUND: Early identification of placental insufficiency can lead to appropriate treatment selections and can improve neonates' outcomes. Possible contributions of magnetic resonance imaging (MRI) have been suggested. PURPOSE: To evaluate the prognostic capabilities of placental intravoxel incoherent motion (IVIM) parameters and T2-relaxation time, and their correlation with fetal growth and adverse outcomes, comparing umbilical artery (UmA) pulsatility index (PI). MATERIAL AND METHODS: A total of 68 singleton pregnancies at 24-40 weeks of gestation underwent placental MRI and were reviewed retrospectively. UmA-PI was measured using Doppler ultrasound by obstetricians. IVIM parameters (Dfast, Dslow, and f) were calculated with a Bayesian model fitting. First, the associations between gestational age (GA) with placental IVIM parameters, T2-relaxation time, and placental thickness (PT) were evaluated. Second, IVIM parameters, T2 value (Z-score), PT (Z-score), and UmA-PI (Z-score) were compared between ( 1) those delivering small for gestational age (SGA) and appropriate for gestational age (AGA) neonates, ( 2) emergency cesarean section (ECS), and non-ECS, and ( 3) preterm birth and full-term birth. RESULTS: Low birth weight was observed in 15/68 cases (22%). GA was significantly associated only with T2-relaxation time and PT. SGA was significantly associated with T2 value (Z-score), f, and UmA-PI (Z-score). In the ECS groups, T2 value (Z-score), f, and Dfast were significantly lower than those in non-ECS groups. All IVIM parameters and T2 values (Z-score) showed significantly lower scores in the preterm birth group. CONCLUSION: Placental f and T2 value (Z-score) had significant associations with low birth weight and clinical adverse outcomes and could be potential imaging biomarkers of placental insufficiency.

Nivolumab for malignant transformation of ovarian mature cystic teratoma.

Mature cystic teratoma of the ovary (MCT) occasionally undergoes malignant transformation (MT) that is resistant to chemotherapy and has a poor prognosis. We experienced a case of clinically aggressive MCT-MT that invades surrounding organs and tissues. Although tumor was resected entirely, a rapid tumor recurrence occurred during postoperative chemotherapy (paclitaxel + ifosfamide + cisplatin). The results of comprehensive genomic profiling test performed early in the postoperative period showed a high tumor mutational burden of 23 mutations/Mb. Treatment with nivolumab monotherapy has promptly been initiated and has been very successful for more than one year.

A Case of a Patient with Adhesive Small Bowel Obstruction in Pregnancy after Extensive Myomectomy for Diffuse Uterine Leiomyomatosis.

Background: Diffuse uterine leiomyomatosis is a rare disease in which countless, poorly defined, and small nodules are present in most parts of the uterine myometrium. It frequently occurs in fertile women and causes infertility. A deep, median, longitudinal incision of the uterine corpus with the opening of the endometrial cavity, "extensive myomectomy," is required to restore fertility. However, myomectomy may also be a risk factor for perinatal complications. We present a rare case of adhesive small bowel obstruction after extensive myomectomy for diffuse uterine leiomyomatosis. Case: A 37-year-old primigravida presented with sharp epigastric pain and vomiting at 21-week gestation. The patient had a history of extensive myomectomy for diffuse uterine leiomyomatosis. Abdominal radiography revealed moderate air fluid levels in the small intestine, and the patient was diagnosed with adhesive small bowel obstruction. The patient was also diagnosed with placenta previa. Bowel rest with intestinal tube was continued until delivery. Cesarean section was performed at 32-week gestation due to (i) prolonged fasting and total parenteral nutrition for conservative treatment and (ii) fear of sudden massive bleeding from placenta previa. Because the ileum was strongly adherent to the uterine scar from the previous myomectomy, adhesiolysis and enterectomy were performed. The placenta was uncomplicatedly delivered and the hemorrhage was well-controlled. Conclusions: Pregnancy with a history with extensive myomectomy for diffuse uterine leiomyomatosis should be carefully monitored because of the occasional occurrence of adhesive small intestine obstruction during pregnancy.