To summarize the clinical characteristics of patient with haploinsufficiency of A20 (HA20) complicated with systemic lupus erythematosus (SLE).

A case of HA20 complicated with SLE (patient 1) was treated in Xi′an Children′s Hospital in June 2019 was selected in the study. The clinical case data of patient 1 were analyzed retrospectively, and the relevant literature of patients with HA20 complicated with SLE in domestic and foreign databases were retrieved in order to summarize the clinical characteristics of the disease. This study was approved by the Ethics Committee of Xi′an Children′s Hospital (Approval No. 20230048). The guardians were informed consent of the diagnosis and treatment of patient 1.

① The patient 1 was a girl, 5 and a half years old, the main manifestations were pustulosis, fever and joint pain, accompanied by oral ulcer, enlarged liver, spleen and lymph nodes, and short stature. She had a history of hepatosplenomegaly and thrombocytopenia. Her laboratory examinations results showed proteinuria, autoimmune hemolytic anemia, decreased of serum complement (C)3, positive antinuclear antibody (1∶1 000), and positive antism antibody. Renal puncture pathological examination showed mild mesangial proliferative lupus nephritis type Ⅱ (LN-Ⅱ). Gene detection showed that the heterozygous variation of TNFAIP3 gene c. 547 (exon4) C>T, which was a pathogenic mutation and came from her father. She was treated with hormone, cyclosporine, cyclophosphamide and mycophenolate mofetil successively. During the treatment, after hormone reduction, rash occurred again, serum C3 decreased and urine protein increased. Up till now, she has no rash and other manifestations, serum C3 decreased slightly and urine protein is negative. She was final diagnosed with HA20, SLE and LN-Ⅱ. ② Literature review results: There were 14 HA20 complicated with SLE patients retrieved (patients 2-15), the analysis of 15 cases including patient 1 showed that: there were 2 males and 13 females, and the age of onset ranges from 2 months to 29 years old, and 12 patients had the damage of kidney, only 2 patients had genital ulcer. The treatments of these 15 cases was as follows, 12 patients were treated with hormone and 10 patients were treated combined with biological agents. After the treatments, the symptoms of most patients could be controlled, and some patients had repeated symptoms.

The incidence rate of HA20 complicated with SLE is low, and its clinical manifestations are not typical. For SLE children with early onset and poor treatment effect, gene detection is conducive to early diagnosis and treatment for patient of the disease.

To investigate the relationship between serum 25-hydroxy vitamin D[25(OH)D] levels at birth and feeding intolerance (FI) within 7 d after birth (hereinafter referred to as early postnatal period) in very low birth weight infants (VLBWI).

A total of 161 VLBWI admitted to the Neonatal Intensive Care Unit (NICU) of the Affiliated Hospital of Xuzhou Medical University from September 2020 to April 2022 were included in this study, retrospective analysis was conducted. According to whether FI occurred in early postnatal period, they were divided into FI group (n=82) and feeding tolerance (FT) group (n=79). Serum 25(OH)D levels of VLBWI at birth were detected in 2 groups, and clinical data of 2 groups were collected. Univariate and multivariate analysis of the influencing factors of FI in early postnatal period in VLBWI in this study were performed by chi-square test and independent sample t test, and multivariate unconditional logistic regression analysis, respectively. This study was approved by the Medical Ethics Committee of the Affiliated Hospital of Xuzhou Medical University (Approval No. XYFY2022-KL044), and all the guardians of the children with the consent and signed informed consents were obtained.

① Results of univariate analysis showed that: the incidence rates of fetal distress, mild asphyxia at birth, mechanical ventilation treatment duration>96 h, delayed timing of initiation of feeds and delayed meconium excretion in FI group were higher than those in FT group; while the level of serum 25(OH)D at birth was lower than that in FT group, and the differences were all statistically significant (P<0.05). ② Multivariate unconditional logistic regression analysis showed that mechanical ventilation treatment duration>96 h (OR=4.483, 95%CI: 1.449-13.865, P=0.009), delayed timing of initiation of feeds (OR=5.908, 95%CI: 1.599-21.823, P=0.008) and delayed meconium excretion (OR=5.248, 95%CI: 1.539-17.898, P=0.008) were all independent risk factors of FI occurrence in early postnatal period in VLBWI. A higher level of serum 25(OH)D at birth (OR=0.474, 95%CI: 0.367-0.614, P<0.001) was a protective factor of FI occurrence in early postnatal period in VLBWI.

Low serum 25(OH)D level at birth in VLBWI may increase the risk of FI in early postnatal period. Reasonable supplementation of vitamin D in early postnatal period may reduce the incidence of FI in early postnatal period in VLBWI.

To explore the effects of serum adiponectin and placental leucine aminopeptidase (P-LAP) levels on pregnancy outcomes in pregnant women with gestational diabetes mellitus (GDM).

A total of 143 cases of GDM pregnant women admitted to Wuxi Maternity and Child Health Care Hospital, Women's Hospital of Jiangnan University from December 2019 to January 2022 were selected in the study. According to the pregnancy outcome, pregnant women with GDM were divided into good result group (n=115) and poor result group (n=28) by retrospective analysis method. Fasting blood glucose (FPG) and 1 h, 2 h 75 g oral glucose tolerance test (OGTT), glycosylated hemoglobin (HbA1c), serum adiponectin and P-LAP levels were detected in all pregnant women at 24 week of gestation, and were analyzed by independent-samples t test. The influencing factors of pregnancy outcomes in pregnant women with GDM were analyzed by multivariate unconditional logistic regression. Receiver operating characteristic (ROC) curve was used to analyzed predictive value of serum adiponectin and P-LAP levels for pregnancy outcomes in pregnant women with GDM. The procedures followed in this study were in line with ethical standards set by the Ethics Committee of Wuxi Maternity and Child Health Care Hospital, Women's Hospital of Jiangnan University and were approved by the Ethics Committee (Approval No. 2018-003-02). There were no statistical differences in age, body mass index (BMI), gravidity and parity between two groups (P>0.05).

Gestation age at delivery, serum adiponectin and P-LAP levels in poor group of pregnant women with GDM were significantly lower than those in good result group, while proportion of poor control of blood glucose concentration and HbA1c level were significantly higher than those in good result group, and all differences were statistically significant (t=3.89, P<0.001; t=8.22, P<0.001; t=2.57, P=0.025; χ²=101.54, P<0.001; t=3.95, P<0.001). There were no significant differences in FPG, 1 h and 2 h OGTT blood glucose concentration between two groups (P>0.05). Multivariate unconditional logistic regression analysis showed that gestational age at delivery, HbA1c level, serum adiponectin and P-LAP levels, and poor control of blood glucose concentration were all independent influencing factors for pregnancy outcomes in pregnant women with GDM (OR=3.307, 0.216, 3.846, 3.099, 0.552; 95%CI: 1.401-7.806, 0.091-0.509, 1.629-9.079, 1.313-7.315, 0.416-0.783; P=0.017, 0.014, 0.025). ROC curve analysis results showed that area under curve (AUC) of serum adiponectin and P-LAP levels and their combined prediction of pregnancy outcomes in pregnant women with GDM were 0.709 (95%CI: 0.594-0.825, P=0.002), 0.706 (95%CI: 0.584-0.821, P=0.001), and 0.791 (95%CI: 0.679-0.897, P=0.003), respectively.

The decrease in serum adiponectin and P-LAP levels are both independent influencing factors of adverse pregnancy outcomes in pregnant women with GDM, and can be used to predict pregnancy outcomes in pregnant women with GDM.

To investigate the pregnancy outcomes of pregnant women with a history of trial of labor after twice cesarean sections (TOLAC-2) and influencing factors of success of TOLAC-2.

Fifty-three pregnant women with twice prior cesarean sections and voluntarily chose TOLAC-2 in the Leibo County People′s Hospital of Liangshan Yi Autonomous Prefecture from January 2016 to August 2021 were selected as research subjects. They were included into successful group (n=31, succeeded in TOLAC-2) and failed group (n=22, by repeated cesarean section after failure of TOLAC-2) according to the final model of delivery. Maternal length of hospital stay, cost of hospitalization, duration of antibacterial drug therapy, maternal and infant outcomes were compared between two groups with independent-samples t test, Mann-Whitney U test, chi-square test, continuity correction of chi-square test or Fisher′s exact probability test. Maternal factors that contributed to TOLAC-2 failure in failed group were analyzed. The procedures in this study were in accordance with the regulations of the Yibin Second People′s Hospital, and this study was approved by the Ethics Committee (Approval No. 2022-015-01). There were no statistical differences between two groups in general clinical data, such as maternal age, gestational age at delivery, neonatal birth weight of previous delivery, percapita annual income in family and education background (P>0.05).

①Results of one-way analysis of influencing factors of success of trial of labor in successful group and failed group showed that maternal weight gain during pregnancy and body mass index (BMI) before delivery in successful group were (13.4±5.2) kg and (27.0±3.2) kg/m² respectively, which both were significantly lower than those (15.6±5.8) kg, (28.4±3.0) kg/m² in failed group, and both the differences were statistically significant (t=-2.78, -2.91; P=0.006, 0.004). There were no statistical differences between two groups in maternal BMI before pregnancy, history of vaginal delivery, interval time between this delivery and last cesarean delivery, history of postpartum hemorrhage (PPH), ischial intertuberal diameter, method of labor analgesia, incidence of gestational diabetes mellitus, incidence of hypertensive disorder complicating pregnancy and neonatal birth weight (P>0.05). ②Duration of maternal antibacterial drug therapy, length of hospital stay, and hospital costs in successful group were significantly shorter or lower than those in failed group (t=-4.05, -5.71, -8.97; P=0.004, <0.001, <0.001). There were no statistical differences between two groups in maternal and neonatal outcomes, such as incidence of incomplete uterine rupture, complete uterine rupture, PPH, severe PPH, blood transfusion therapy, and intrauterine infection during TOLAC-2, volume of 2 h PPH, volume of 24 h PPH, and neonatal Apgar score 1 min after birth, incidence of neonatal asphyxia, neonatal pathological jaundice, and admission to neonatal intensive care unit (NICU) (P>0.05). ③The top 3 reasons for TOLAC-2 failure in failed group were maternal abandonment of TOLAC-2 midway (10 cases, 45.5%), intrauterine asphyxia (5 cases, 22.7%) and arrested labor (5 cases, 22.7%) in turn.

Weight gain during pregnancy and BMI before delivery are influencing factors of success of trial of labor in TOLAC-2 pregnant women. The success of TOLAC-2 can shorten the length of hospital stay and duration of antibacterial drug therapy in pregnant women with twice prior caesarean sections, reduce cost of hospitalization and do not increase the incidence of serious adverse maternal and neonatal outcomes at the same time.

To explore the relationship between levels of serum chemokines interleukin (IL) -8, interferon-inducible protein (IP) -10, monocyte chemotactic protein (MCP) -1 and the occurrence and development of gestational diabetes mellitus (GDM).

From July 2020 to July 2021, a total of 20 singleton pregnant women diagnosed as GDM in Leshan Maternal and Child Health Hospital were enrolled into GDM group. Meanwhile, other 22 normal pregnant women who underwent prenatal examination in our hospital during same period were enrolled into control group by random number table method. Venous blood was collected from pregnant women in both groups at the 8-12 gestational weeks and 24-28 gestational weeks, and serum levels of IL-8, IP-10 and MCP-1 were detected, and 75 g oral glucose tolerance test (OGTT) was performed at 24-28 gestational weeks. Independent sample t test, Mann-Whitney U test and Wilcoxon signed rank sum test were used to statistically analyze results of the above laboratory tests between two groups. Spearman rank correlation analysis was used to analyze the correlation between serum IL-8 level and glucose concentration of 1, 2 h 75 g OGTT of GDM patients during second trimester. Written informed consent was obtained from all research participants and this study was approved by institutional review board of Leshan Maternal and Child Health Hospital (2021-01-01).

①The age, pre-pregnancy body mass index (BMI) and pre-pregnancy abdominal circumference of pregnant women in GDM group were greater than those in control group, while the gestational age at delivery of pregnant women in GDM group was smaller than that of control group, and all differences were statistically significant (P<0.05). ② The fasting blood glucose and 1 and 2 h 75 g OGTT post-glucose concentrations of pregnant women in GDM group were (5.1±0.8) mmol/L, (9.4±2.2) mmol/L and (9.2±1.9) mmol/L, respectively, which were higher than (4.4±0.3) mmol/L, (7.4±1.3) mmol/L and (6.8±0.9) mmol/L in control group. The differences were statistically significant (t=3.80, 3.67, 5.14, P=0.001, 0.001, <0.001). ③ There were no statistically significant differences in terms of the levels of serum IL-8, IP-10 and MCP-1 during first trimester, and serum IP-10 and MCP-1 levels during second trimester between two groups (P>0.05). However, serum IL-8 level in GDM group was significantly higher than that in control group [37.4 pg/mL (22.1 pg/mL, 117.5 pg/mL) vs 11.1 pg/mL (4.4 pg/mL, 21.9 pg/mL)], with a statistically significant difference (Z=-2.98, P=0.003). The serum IL-8 level of GDM group during first and second trimester gradually increased with the increase of gestational age, and the difference was statistically significant (Z=-2.22, P=0.001). ④The serum IL-8 level in second trimester was positively correlated with the concentration of 2 h after 75 g OGTT administration (r=0.37, P=0.026).

Serum IL-8 may play an important role in the occurrence and development of GDM, while serum IP-10 and MCP-1 levels during first and second trimester are not related to the occurrence of GDM.

To investigate the birth situation and relative influencing factors of small for gestational age (SGA) infants in Beijing in the past 10 years.

A total of 117 499 SGA infants borned in Beijing from January 2011 to December 2020 in "Beijing Neonatal Disease Screening and Management System" were selected as the research objects and a retrospective analysis was carried out. The incidence of SGA infants among premature, full-term and post-term infants were compared by chi-square test. The incidence of SGA infants in live births in the past 10 years was compared by trend chi-square test. Gestational age and birth weight (BW) of SGA infants in the past ten years were compared by trend test of variance analysis. Ordered multi-classification logistic regression analysis was used to analyze the influencing factors of gestational age (premature, full-term and post-term) of SGA infants. Influencing factors of the occurrence of severe SGA in SGA infants in Beijing was performed using multivariate unconditional logistic regression analysis. The procedures followed in this study were approved by the Ethics Committee of Beijing Obstetrics and Gynecology Hospital, Capital Medical University (Approval No. 2022-KY-091-01).

①From 2011 to 2020, the incidence of SGA infants among live births in Beijing was 5.4%, the ratio of male to female SGA infants was 1.12∶1. The incidence of SGA among preterm infants was 8.2% (10 512/128 749), which were higher than that among term infants [5.2% (106 789/2 056 719)] and post-term infants [6.9% (198/2 868)], respectively, and the differences were statistically significant (χ²=2 107.78, 17.04; both with P<0.001); ②There was significant difference of overall comparison of SGA incidence in live births in the past 10 years from 2011 to 2020 (χ²=122.13, P<0.001), but no linear trend (χ²_trend=0.06, P=0.805). The gestational age and BW of SGA infants in the past 10 years showed a linear trend of decreasing with increasing of years. ③Compared to being full-term SGA infants after birth: the probability of multiple and male fetuses being preterm SGA (PT-SGA) infants after birth were 1.520 times (OR=1/0.658) and 2.261 times (OR=2.261) as much as single and female fetuses. The probability of fetus of female and born in winter being post-term SGA infants after birth were 3.021 times (OR=1/0.331) and 1.618 times (OR=1/0.618) as much as fetus of male and born in autumn.④Multiple fetus (OR=1.340, 95%CI: 1.285-1.400, P<0.001), male fetus (OR=1.267, 95%CI: 1.232-1.302, P<0.001), mother was registered in other citys (OR=1.052, 95%CI: 1.023-1.082, P<0.001), and preterm birth (OR=1.532, 95%CI: 1.464-1.602, P<0.001), were all independent risk factors for the development of severe SGA in SGA infants in Beijing from 2011 to 2020.

In 10 years, the incidence of SGA in live births in Beijing is lower than that in developed countries and our country. Attention should be paid to the management of risk factors of BW and gestational age of newborns in order to improve the quality of life of SGA infants.

To explore clinical characteristics, diagnosis and treatment results of a child with mild Gitelman syndrome (GS), and review related literature, so as to provide reference for clinical diagnosis of children with GS.

One girl (patient-1) with mild GS who visited People′s Hospital of Wuchuan County on August 25, 2021 was selected as research subject. Her clinical data were retrospectively analyzed, including medical history, clinical manifestations, laboratory tests and genetic test results, treatment and follow-up results. Literature of children aged 0 to 18 years with a confirmed diagnosis of GS caused by SLC12A3 gene mutations were retrieved with " Gitelman syndrome" " child" and " SLC12A3" etc. as keywords in CNKI, Wanfang service platform and PubMed database, and the search time was set from January 2018 to December 2022. The initial clinical manifestations of children with GS were summarized. The procedure followed in this study was in accordance with regulations of the Ethics Committee of People′s Hospital of Wuchuan County, and was reviewed and approved by the Ethics Committee (Approval No.02-2022).

①Patient-1 was a girl of 11 years and 8 months old who admitted to case collected hospital with " recurrent abdominal pain and low serum K⁺ concentration for 7⁺ years". Her condition began at age of 4, with abdominal pain as primary clinical manifestation, combined or non-combined with diarrhea. There was no abdominal distention, occasional mild fatigue, without symptoms of limb convulsions, numbness, excessive sweating, increased thirst, polyuria, or enuresis, and with long-term hypokalemia. Physical examination at admission showed that abdomen was soft with no palpable masses throughout. The results of relevant auxiliary examinations at admission showed low serum K⁺ concentration which was 3.13 mmol/L, while serum Mg²⁺, Ca²⁺, Na⁺, and Cl^- concentrations were normal, and result of renal ultrasound was also normal. Her condition was recurrent, without a clear cause for low serum blood K⁺ concentration, and treatment effect on serum K⁺ concentration by potassium supplementation was poor. Her result of genetic testing showed SLC12A3 gene compound heterozygous mutations: c.1000C>T(p.Arg334Trp) and c. 1034C>T(p.Ser345Phe), inherited from her father and mother, respectively. Based on her clinical manifestations and genetic testing results, she was diagnosed as GS. After oral treatment by potassium chloride (KCl), spironolactone and enalapril, her gastrointestinal symptoms disappeared and serum K⁺ concentration recovered to normal level when followed up to May 2022. ②Literature review results: a total of 26 pieces of relevant research literature involving 58 cases of GS children were retrieved. Among them, 6 children initially presented with gastrointestinal symptoms at the onset of GS, 2 cases were initially admitted with other conditions and were later diagnosed with GS through result of genetic testing. Initial symptoms in the other 48 cases included low serum K⁺ concentrations, short stature, infections, fatigue, muscle pain, seizures, and hyperthyroidism.

So far, there are few literature has been reported on GS children with slightly low serum K⁺ concentration whose main symptoms were gastrointestinal discomfort. Due to their atypical clinical manifestations, they are prone to be missed diagnosis and misdiagnosis. Genetic testing serves as a crucial method for confirming diagnosis of children with GS. Early diagnosis and treatment can improve their quality of life.

To explore the causes of heart rate variability (HRV) in elderly pregnant women and its influence on their perinatal outcomes.

From June 2020 to May 2022, a total of 70 elderly pregnant women and 70 non-elderly pregnant women in the same period who visited Shanghai First Maternity and Infant Hospital were selected in this study, and were respectively enrolled in study group and control group. Statistical methods such as independent samples t-test and chi-square test were used to statistically analyze the following indicators of pregnant women between two groups: HRV, HRV analysis metrics [standard deviation of normal-to-normal intervals (SDNN), five-minute R-R interval means (SDANN), root mean square of successive difference (RMSSD), percentage of normal to normal intervals differing by more than 50 ms (PNN50)], echocardiography indicators [left atrium end-systolic diameter (LAD), left ventricular end-diastolic diameter (LVDD), inter-ventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), right ventricular end-diastolic diameter (RVDD), left ventricular ejection fraction (LVEF), early mitral inflow velocity (E), late mitral inflow velocity (A), diastolic velocity during early diastolic filling (Em), late diastolic velocity during atrial contraction (Am)], adverse pregnancy outcomes (miscarriage, stillbirth, preterm labor, cesarean section delivery and postpartum hemorrhage, etc.), neonatal abnormalities (neonatal asphyxia, low birth weight, etc.). This study received ethics approval from the Ethics Committee of Shanghai First Maternity and Infant Hospital (20200305). Written informed consent was obtained from all the participants.

①There were no significant differences in gestational age, pre-pregnancy body mass index (BMI) and parity between two groups (P>0.05), but there was significant difference in gestational age between two groups (P<0.05). ②The SDNN [(103.7±10.4) ms], SDANN [(110.6±10.6) ms], RMSSD [(24.7±5.4) ms], PNN50 [(15.5±3.3)%], and delta index (35.6±6.8) of pregnant women in control group were higher than those of study group (93.6±9.5) ms, (99.7±9.7) ms, (19.7±3.6) ms, (11.7±3.1)%, and 27.7±6.5, and the differences were statistically (t=6.02, 6.35, 6.48, 7.08, 7.03; P<0.05). In addition, the HRV of pregnant women in study group (17.8%, 16/70) was higher than that of control group (5.6%, 5/70) and the difference was statistically significant (χ²=6.52, P=0.011). ③ The LAD [(33.6±2.2) mm], LVDD [(47.8±2.4) mm], A [(84.0±8.0) cm/s], and Am [(11.7±3.1) cm/s] in study group were greater than those of control group (31.7±2.6) mm, (45.4±2.6) mm, (62.7±6.4) cm/s, (9.6±2.7) cm/s, and the differences were statistically significant (t=4.66, 5.38, 17.38, 4.26, all P<0.0, 01), and there were no statistically significant differences when comparing the IVST, LVPWT, RVDD, and LVEF between two groups (P>0.05). ④Pearson correlation analysis showed that SDNN, STANN, RMSSD, PNN50 and triangle index were negatively correlated with LAD, LVDD, A and Am, respectively (P<0.05), and positively correlated with E and Em, respectively (P<0.05). ⑤ The incidence of adverse pregnancy outcomes (61.4%, 43/70)]and neonatal abnormality (22.9%, 16/70) in study group were higher than those in control group (22.9%, 16/70) and (4.3%, 3/70), and the differences between two groups were statistically significant (χ²=30.51, 10.29, all P<0.001).

Elder pregnant women have significantly reduced HRV, mainly because of left ventricular diastolic dysfunction, resulting in reduced cardiac reserve function. Lower HRV will increase the risk of adverse pregnancy outcomes and adverse neonatal outcomes.

To explore the changes in risk factors related to stillbirth, and provide basis for evaluating and optimizing the prevention and control measures of stillbirth.

A total of 652 stillborn fetuses (all from singleton pregnancies) were selected in this study from 2008 to 2021 at West China Second University Hospital of Sichuan University, one of the regional centers for perinatal medicine in China. A retrospective analysis was conducted, and the 652 cases of stillbirth were divided into two groups based on the year of occurrence: the early-stage group (n=447, total number of in-patient deliveries of fetuses in our hospitals from 2008-2014 was 55 508) and the late-stage group (n=205, total number of inpatient deliveries of fetuses in our hospitals from 2015-2021 is 96 982). The procedures followed in this study were in accordance with the revised 2013 Declaration of Helsinki by the World Medical Association.

From 2008 to 2021, the average incidence rate of stillbirths in this study was 0.428%, with 0.805% in the early-stage group and 0.211% in the late-stage group. The late-stage group′s proportion of factors contributing to stillbirths, from highest to lowest, was maternal factors (61.46%), umbilical cord factors (20.98%), placental factors (20.49%), fetal factors (15.61%), and unknown causes (8.29%). ① Maternal factors: The main maternal factors associated with stillbirths were maternal cardiovascular diseases, diabetes, intrahepatic cholestasis of pregnancy, and thyroid diseases. The gestational week of stillbirths was mainly between 31 and 34^{+ 6} weeks. The proportion of stillbirths associated with thyroid disease in the late-stage pregnancies significantly increased compared to the early-stage group (χ²=28.83, P<0.001). ② Umbilical cord factors: The late-stage group′s umbilical cord factors contributing to stillbirths, from highest to lowest, were cord torsion (17.56%), cord entanglement (1.95%), and cord prolapse (0.49%). The gestational week of stillbirths was mainly between 32 and 33^{+ 6} weeks. The proportion of cord torsion significantly increased in the late-stage group compared to the early-stage group (χ²=8.62, P=0.003), while the proportion of cord prolapse significantly decreased (χ²=8.46, P=0.004). ③ Placental factors: The late-stage group′s placental factors associated with stillbirths, from highest to lowest, were placenta previa (7.80%) and placental abruption (4.39%). The gestational week of stillbirths was mainly between 31 and 33^{+ 6} weeks. The proportion of stillbirths associated with placenta previa significantly increased in the late-stage group compared to the early-stage group (χ²=4.20, P=0.041). ④ Fetal factors: Abnormal fetal development (11.20%) was the most common fetal factor. The gestational age of stillbirths was mainly between 31 and 33^{+ 6} weeks. ⑤ Unknown causes: The proportion of stillbirths with unknown causes significantly decreased in the late-stage group compared to the early-stage group (χ²=5.94, P=0.015), and the occurrence of stillbirths was mainly between 29 and 33^{+ 6} weeks of gestation.

Strengthening the management of etiological spectrum diseases associated with stillbirths, especially focusing on key diseases, and enhancing maternal and fetal healthcare interventions are crucial in preventing and controlling pathological progression caused by relevant factors leading to fetal demise. Monitoring fetal intrauterine growth and intrauterine conditions, particularly during critical risk periods, enables timely detection of adverse intrauterine conditions in the fetus. Establishing efficient referral systems and green channels for intrauterine transportation of high-risk pregnancies, along with timely and proactive termination of pregnancies, play a vital role in reducing the stillbirth rate in China. These measures are of paramount importance.