Single or double semen samples: the dilemma in epidemiological studies on semen quality.

STUDY QUESTION: Is it necessary to collect more than one semen sample from each individual in epidemiological studies? SUMMARY ANSWER: Single semen samples can be used in model construction as long as the model adjusts for major relevant covariates. WHAT IS KNOWN ALREADY: If a series of semen samples are taken from one individual at different times, significant intra-individual variation may exist. STUDY DESIGN, SIZE, DURATION: A population-based cross-sectional study was conducted from 1 December 2000 to 20 November 2002. A total of 1010 volunteers, aged between 20 and 60 years old, were recruited. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 998 subjects were included for statistical analysis. Of these, 332 men provided single semen samples (group 1) and 666 men provided two samples (group 2). Semen parameters, including semen volume, sperm concentration, total sperm number, progressive motility, vitality, and sperm morphology, were analyzed with standardized methods according to the World Health Organization (WHO) laboratory manual for the examination of human semen and sperm-cervical mucus interaction (3rd edition). MAIN RESULTS AND THE ROLE OF CHANCE: Rapidly progressive motility of semen from group 1 was lower than that of group 2, but other parameters were not significantly different. The differences in mean values between the double samples were small on all semen parameters. The correlations between the two ejaculates were high, but the agreements were poor except for sperm vitality and normal morphology. Model selection and validation analysis supported the premise that the regression model from the first samples was applicable for the second samples. The large sample size with extensive quality control provides robust parameter estimation and promises good applicability for model selection and validation. LIMITATIONS, REASONS FOR CAUTION: The results are valid for healthy men in China, not for subfertile or infertile men. WIDER IMPLICATIONS OF THE FINDINGS: The overall semen quality of a given group of healthy men will not vary significantly in the short term. Single semen samples can be used in model building as long as major relevant covariates are considered. Utilizing multiple semen donations may actually cause the samples to be less representative. STUDY FUNDING/COMPETING INTERESTS: This research was supported by a grant from Shanghai Science and Technical Committee (02DJ14053) and a grant from Ministry of Science and Technology, China (9902). All authors have no competing interests.

Exposure to bisphenol A (BPA) in Wistar rats reduces sperm quality with disruption of ERK signal pathway.

Bisphenol A (BPA) is an estrogenic environmental toxin widely used in the production of plastics and ubiquitous human exposure to this chemical has been proposed to be a potential risk to human health. Exposure to BPA can negatively impact sperm quality. However, the mechanism remains largely unknown. The objectives of this study were to assess the role of BPA on sperm quality and explore the possible mechanisms. The Wistar male rats (aged 28 days) were administered BPA by oral gavage for 28 days at dose of 50, 100 and 200 mg/kg/day; meanwhile, the negative control with corn oil (0 mg/kg/day BPA) and positive control with E2 at the dose of 100 µg/kg/day. The sperm density, sperm activity and sperm survival rate were analyzed byCASA system, and the sperm abnormality rate was analyzed by improved Papanicolaou stained. The protein expression levels of Src/p-Src, ERK1/2, p-ERK1/2 and CREB/p-CREB were detected by Western bolt. The results showed that the body weight gain, testes weight, testis coefficient, sperm density, sperm activity, sperm survival rate and protein expression levels of p-ERK1, p-ERK2 and p-CREB decreased, but the sperm abnormality rate increased with increasing BPA concentrations. There were positive correlations between sperm density, sperm activity and sperm survival rate with protein expression levels of p-ERK1, p-ERK2 and p-CREB, and negative correlations between sperm abnormality rate with the protein expression levels of p-ERK1, p-ERK2 and p-CREB. Results from the structural equation model demonstrated that BPA retained a significant negative effect to p-ERK, whereas p-ERK retained a significant positive effect to sperm quality and acted as the mediate variable. This study provides a novel insight regarding the potential role of p-ERK1 and p-ERK2 protein kinase on reproductive toxicity of BPA. The adverse effects of BPA on adult male sperm quality may be through the induction of the disruption of ERK signal pathway. However, additional research is needed to confirm our findings and to further test the suggested potential mechanisms.

Mifepristone-induced abortion and duration of third stage labour in a subsequent pregnancy.

To evaluate the impact of mifepristone-induced abortion (MA) on the duration of third stage labour in a subsequent pregnancy, an observational cohort study was conducted from 1998 to 2001 at antenatal clinics in Shanghai, Beijing and Chengdu, China. A total of 4925 pregnant women with no history of induced abortion (NA) and 4931 pregnant women with one previous MA were enrolled and followed until delivery. Of these, 5139 women who delivered singletons vaginally were used in the present analyses, including 2614 with NA and 2525 with a history of MA. Maternal characteristics, labour duration and other obstetric and gynaecological information were obtained. The incidence rates of prolonged third stage of labour were 1.55% and 1.49% in NA and MA, respectively. After adjusting for age at delivery, maternal education, maternal occupation, area of residence, duration of gestational, type of delivery and pregnancy-induced hypertension, MA was not associated with the risk of prolonged third stage of labour (odds ratios = 0.92, 95% confidence interval 0.58, 1.44). Subgroup analysis of women with MA showed similar results regardless of gestational age at abortion, woman's age at abortion, subsequent curettage/complications and the interpregnancy interval. In conclusion, the data did not provide evidence that one MA was associated with the risk of prolonged third stage of labour in a subsequent pregnancy in primiparae.

Effects of caesarean section on maternal health in low risk nulliparous women: a prospective matched cohort study in Shanghai, China.

BACKGROUND: Rates of caesarean section are progressively increasing in many parts of the world. As a result of psychosocial factors there has been an increasing tendency for pregnant women without justifiable medical indications for caesarean section to ask for this procedure in China. A critical examination of this issue in relation to maternal outcomes is important. At present there are no clinical trials to help assess the risks and benefits of caesarean section in low risk women. To fill the gap left by trials, this indication-matched cohort study was carried out to examine prospectively the outcomes of caesarean section on women with no absolute obstetric indication compared with similar women who had vaginal delivery. METHODS: An indication-matched cohort study was undertaken to compare maternal outcomes following caesarean section with those undergoing vaginal delivery, in which the two groups were matched for non-absolute indications. 301 nulliparous women with caesarean section were matched successfully with 301 women who delivered vaginally in the Maternal and Children's Hospitals (MCHs) in Shanghai, China. Logistic regression model or binomial regression model was used to estimate the relative risk (RR) directly. Adjusted RRs were calculated adjusting for propensity score and medical indications. RESULTS: The incidence of total complications was 2.2 times higher in the caesarean section group during hospitalization post-partum, compared with the vaginal delivery group (RR = 2.2; 95% CI: 1.1-4.4). The risk of haemorrhage from the start of labour until 2 hours post-partum was significantly higher in the caesarean group (RR = 5.6; 95% CI: 1.2-26.9). The risk of chronic abdominal pain was significantly higher for the caesarean section group (RR = 3.6; 95% CI: 1.2-10.9) than for the vaginal delivery group within 12 months post-partum. The two groups had similar incidences of anaemia and complicating infections such as wound complications or urinary tract infection. CONCLUSIONS: In nulliparous women who were at low risk, caesarean section was associated with a higher rate of post-partum morbidity. Those requesting the surgical procedure with no conventional medical indication, should be advised of the potential risks.

Mifepristone-induced abortion and placental complications in subsequent pregnancy.

BACKGROUND: The aim of the study was to explore the effect of first-trimester mifepristone-induced abortion (MA) on placental complications in subsequent pregnancy. METHODS: Two cohorts of nulliparous pregnant women were recruited in China during early pregnancy, one with a history of one MA and the other with no abortion (NA). Women were followed up until delivery. RESULTS: The incidence proportions of abruptio placenta, placenta previa, placenta accreta and retained placenta in the MA group (4673) and NA group (4690) were, respectively, 0.5 and 0.3, 0.8 and 0.9, 0.5 and 0.5, and 0.7 and 0.8% (all differences non-significant). After adjustment for center, age, education, occupation, residence, income, BMI and type of delivery, the incidence rates of placenta previa, accreta and retained placenta in the MA and NA groups showed no significant differences. The risk of abruptio placenta in women with a MA was nearly double that of women with no abortion, although this apparent increased risk was not statistically significant. Furthermore, this increased risk of abruptio placenta was found only in those with a gestational age >6 weeks at abortion (aOR: 2.46; 95% CI: 1.00-6.04), a curettage after abortion (aOR: 3.00; 95% CI: 1.25-7.20) or a longer inter-pregnancy interval (P-value for trend: 0.022). CONCLUSIONS: Mifepristone-induced abortion itself is not associated with placental complications in subsequent pregnancy, but other factors related to medical abortion-such as a gestational age >6 weeks at abortion, a curettage after abortion, and a longer interpregnancy interval-may increase the risk of abruptio placenta.

Reference values of semen parameters for healthy Chinese men.

AIMS: To establish reference values of semen parameters in a residential, geographic, and age representative sample of healthy Chinese men. METHODS: From a national study of 1,191 healthy Chinese men, semen samples were analyzed from 105 subjects whose wives or partners were pregnant within the 12 months prior to the date when the semen sample was taken. RESULTS: The means, fifth percentiles, and percentages lower than the WHO criteria for semen parameters were, respectively: 75.8 x 10(6)/ml, 17.8 x 10(6)/ml, and 6.7% for sperm concentration; 206.9 x 10(6)/ejection, 26.3 x 10(6)/ejection, and 6.7% for total sperm count; 18.9, 3.0, and 79.1% for rapid progressive motility; 49.1, 25.3, and 52.4% for sperm progressive motility; 73.8, 49.3, and 45.7% for sperm viability, and 49.5, 25.2, and 9.5% for normal morphology. CONCLUSION: The values of semen parameters for Chinese men are lower than the WHO criteria, especially for rapid progressive motility, progressive motility, and sperm viability, and a different standard for Chinese may be needed.

Do reproductive hormones explain the association between body mass index and semen quality?

AIM: To examine whether reproductive hormones play a role in the association between body mass index (BMI) and semen quality. METHODS: Semen quality and testosterone (T), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and estradiol (E(2)) were evaluated in 990 fertile males with age 38.9 +/- 9.7 (mean +/- SD) years recruited from the Chinese general population in 2001 and 2002. RESULTS: Semen quality was reduced among underweight (BMI < 18.5) compared with normal (BMI 18.5-24.9) and overweight (BMI 25.0-29.9), but the associations were independent of reproductive hormones. After adjustment for the potential confounders, underweight men had reductions in sperm concentration (22.4 X 10(6)/mL), total sperm count (52.9 X 10(6)) and percentage of normal sperm forms (6.9%) compared with men with normal BMI. Being underweight may be a risk factor for low sperm concentration (OR: 4.68, 95% confidence intervals [CI]: 2.01-10.91). Otherwise, being overweight may be a protected factor for low sperm concentration (OR: 0.25; 95% CI: 0.08-0.83) and low total sperm count (OR: 0.37, 95% CI: 0.15-0.87). CONCLUSION: Low BMI was associated with reduced semen quality. The associations between BMI and semen quality were found statistically significant even after adjustment for reproductive hormones. Reproductive hormones cannot explain the association between BMI and semen quality.

Do Ureaplasma urealyticum infections in the genital tract affect semen quality?

UNLABELLED: To investigate the relationship between Ureaplasma urealyticum (UU) infection and semen quality. METHODS: From 2001 to 2003, 346 eligible patients aged 20-45 years were invited from two hospitals in Shanghai, China, to participate in an investigation which included questionnaires about general and reproductive health, an external genital tract examination, UU culture and semen analysis. Multiple linear regression models were used to examine whether UU had a significant effect on semen quality after adjustment for confounding factors. RESULTS: Findings suggested that UU infection was associated with higher semen viscosity and lower semen pH value. Sperm concentration was lower in UU positive subjects than that in UU negative subjects (54.04 X 10(6)/mL vs.70.58 X 10(6)/mL). However, UU did not significantly affect other semen quality indexes. CONCLUSION: UU infection of the male genital tract could negatively influence semen quality.

[Association between endogenous hormones, hormone receptors and cervical cancer].

OBJECTIVE: To explore the relationship between the levels of estrogen (E2) and progestogen (P), expression of estrogen receptor (ER) and progesterone receptor (PR) and cervical cancer. METHODS: A case-control study with hospital and community controls was employed. The levels of serum estrogen and progesterone were detected by enzyme linked immunosorbent assay (ELISA) for 141 cervical cancer cases, 137 uterine myoma patients as controls and 129 health women as controls. ER and PR were measured by immunohistochemistry sABC in cervix tissues from patients with cervical cancer and uterus myoma as well. RESULTS: The levels of estrogen (47.49 ng/mL) and progesterone (2.34 pg/mL) in cases were significantly higher than those in both control groups. The association between estrogen and cervical cancer was significant both before and after menopause-adjusted, with over 89% of attributable risk percentage (ARP), and showed a dose-response relation. Using the lowest value of 2 pg/ml in follicular phase as cut off point for progesterone, there were no statistically significant difference between cases and controls, and neither in progesterone nor in premenopausal. The expressions of ER and PR in cases were lower than those in controls, even after being menopause-adjusted. CONCLUSION: The high level of endogenous estrogen and progestogen might increase the risk of cervical cancer. Compared with progestogen, estrogen showed a higher risk that was not influenced by menopause. In some sense, ER and PR may exert certain protective effect on progressing of cervical carcinogenesis.

[Prospective observational study on the effects of caesarean section on breastfeeding].

OBJECTIVE: To study the effects of caesarean section on breastfeeding. METHODS: Six hundred and two [301 cases was caesarean section (caesarean section group) and 301 cases was vaginal delivery (vaginal delivery group)] nulliparas were interviewed face-to-face at antepartum and postpartum in an indication-matched prospective study. RESULTS: There was a significantly lower postpartum prolactin (PRL) level in the caesarean section group (8.48 nmol/L, 95% CI: 7.80 - 9.21 nmol/L) compared with vaginal delivery group (9.61 nmol/L, 95% CI: 8.99 - 10.26 nmol/L) during 6 - 24 hours in the daytime after delivery. The median time of breastfeeding initiation was 12 hours and 2 hours after birth for caesarean section and vaginal delivery groups respectively. Caesarean section was an important hazard for a shorter duration of breastfeeding (RR = 1.21; 95% CI: 1.10 - 1.33) within one year after childbirth. CONCLUSIONS: Caesarean section is associated with significantly lower postpartum PRL, which is in line with the longer breastfeeding initiation and lower rate of successful breastfeeding. Necessary measures including promoting the secretion of postpartum PRL such as early contact, early sucking and analgesic method should be taken to improve the successful breastfeeding rate.

[Relationship between contraceptive use behavior and related knowledge and cognition among vocational high school students].

OBJECTIVE: To study the relationship between contraceptive use behaviors and related knowledge and cognition among vocational high school students. METHODS: A computer-administrated anonymous cross-sectional survey was conducted among grade one students from three vocational high schools in a district of Shanghai. Based on Health Belief Model, four cognition indexes including perceived benefits, barriers, sex behavior related risks and self-efficacy were applied. RESULTS: Among 1612 respondents, the students who had sexual experience accounted for 7.01% (113/1612). At first sex, 56.64% (64/113) of respondents reported contraceptives use; and the methods most reported were condom (58.70%, 27/46) and oral contraceptive (27.78%, 5/18) respectively for male and female. Most reasons for non-use were feeling shy to buy it (26.53%, 13/49) and the opposite sex's unwillingness to use (18.37%, 9/49). Among those who had experienced sex, 68.35% (54/79) and 68.42% (52/76) of respondents thought withdrawal and rhythm were effective methods. Only 23.26% (10/43) of subjects who had ever used condom could gain the full score of knowledge on how to use condom. A few respondents (22.86%, 24/105) who had sex experience knew that "If a person is infected with STD, he/she may not have noticeable symptoms". And 40.63% (26/64) of respondents who had not use contraceptive at first sex considered that "Infrequent intercourse cannot cause a girl pregnant even she has experienced her menstruation". The level of perceived risks was lowest among four cognition indexes. Contraceptive related knowledge and cognition may contribute to respondents' contraceptive use behaviors at first sex, and only related cognition contribute to contraceptive use behaviors at recent sex. CONCLUSION: It should be urgent to improve contraception knowledge and cognition among vocational high school students and provide youth-friendly contraceptive services.

Does exposure to computers affect the routine parameters of semen quality?

AIM: To assess whether exposure to computers harms the semen quality of healthy young men. METHODS: A total of 178 subjects were recruited from two maternity and children healthcare centers in Shanghai, 91 with a history of exposure to computers (i.e., exposure for 20 h or more per week in the last 2 years) and 87 persons to act as control (no or little exposure to computers). Data on the history of exposure to computers and other characteristics were obtained by means of a structured questionnaire interview. Semen samples were collected by masturbation in the place where the semen samples were analyzed. RESULTS: No differences in the distribution of the semen parameters (semen volume, sperm density, percentage of progressive sperm, sperm viability and percentage of normal form sperm) were found between the exposed group and the control group. Exposure to computers was not found to be a risk factor for inferior semen quality after adjusting for potential confounders, including abstinence days, testicle size, occupation, history of exposure to toxic substances. CONCLUSION: The present study did not find that healthy men exposed to computers had inferior semen quality.

Male hormonal contraception: suppression of spermatogenesis by injectable testosterone undecanoate alone or with levonorgestrel implants in chinese men.

Monthly injections of testosterone undecanoate (TU) act as a male contraceptive by reversibly suppressing spermatogenesis to azoospermia or severe oligoazoospermia in 95% of Chinese men. In 5% of Chinese men, however, monthly TU administered alone fails to suppress spermatogenesis into contraceptive ranges, or sperm "rebound," leading to occurrences of pregnancy during treatment. Since combinations of progestins and androgens are associated with greater degrees of sperm suppression in white men, we hypothesized that the combination of TU and the progestin levonorgestrel (LNG) would result in improved spermatogenic suppression in Chinese men. Sixty-two healthy Chinese men were randomly assigned to one of the following 3 regimens: group I (n = 21) received 4 LNG rods (75 mg each), which were followed 4 weeks later by 500 mg of TU by intra-muscular (IM) injection every 8 weeks for 24 weeks; group II (n = 20) received 4 LNG implants, which were followed 4 weeks later by 1000 mg of TU by IM injection every 8 weeks for 24 weeks; and group III (n = 21) received TU 1000 mg by IM injection every 8 weeks for 24 weeks. Sperm counts, serum testosterone (T), luteinizing hormone, follicle-stimulating hormone, and LNG were measured every 2 weeks before, during, and after treatment. During treatment, group II demonstrated a trend toward a greater attainment of azoospermia than groups I and III (90% vs 62% [group I] vs 67% [group III]; P =.09). Attainments of either azoospermia or oligozoospermia (sperm density, <3 x 10(6)/mL) were 95%, 100%, and 86% for groups I, II, and III, respectively (P >.05 for comparisons between groups). Spermatogenesis in all subjects returned to the normal range after the implants were removed. No serious adverse events and no significant changes in serum chemistry occurred during the study. These results demonstrate that the combination of IM injections of high-dose TU every 2 months and LNG implants is associated with marked suppression of spermatogenesis in Chinese men. The combination of high-dose TU every 2 months and LNG implants is a promising candidate for future large-scale efficacy studies of hormonal male contraception in Chinese men.

Effects of a community-based sex education and reproductive health service program on contraceptive use of unmarried youths in Shanghai.

PURPOSE: To evaluate the effectiveness of a youth-friendly intervention in promoting one safe sex behavior-contraception and condom use among unmarried young people aged 15-24 years in Shanghai, China. METHODS: The study was conducted in two towns of a suburban area of Shanghai (one as the intervention and the other as the control), with comparable socio-cultural-economic and demographic characteristics. The intervention intended to build awareness and offer counseling and services related to sexuality and reproduction among unmarried youths, in addition to the routine program activities, which were exclusively provided in the control site. Baseline surveys were conducted in both sites before the implementation of the intervention, and similar surveys were conducted in both sites 20 months after the intervention had been initiated to test the feasibility and effectiveness of the intervention. In total, 1220 unmarried young people from the intervention site and 1007 from the control site, including 1304 out-of-school youths and 923 high school students, were recruited, and about 92% of them were successfully followed up. Four main measures were examined (i.e., ever contraceptive use, current regular contraceptive use, ever condom use, and contraceptive use at onset of sexual intercourse-if it occurred during the course of the intervention). The reasons for nonuse of contraceptives, the status of joint decision on contraception and the first method used were also assessed. Data were analyzed using Logistic regression models with dichotomous measures of contraceptive use and Generalized Estimating Equations (GEEs) with repeated measures. RESULTS: At baseline, there was no statistical difference in contraceptive use between the intervention and control groups. After intervention, the proportions reporting regular contraceptive use and condom use in the intervention group were much higher than that in the control group (p <.001). A group x time interaction effect (p <.0001) was found for regular contraceptive use and ever condom use. Logistic regression analysis with dichotomous measures of contraceptive use and GEEs with repeated measures showed similar results. The regular contraceptive use and ever condom use were correlated with subject's occupation and family economic status, respectively. After adjusting for demographic factors, the subjects from the intervention group were 14.58 (OR) times as likely to use contraceptives at onset of intercourse as those from the control group (95%CI: 8.55-24.87, p <.0001). Similar results were found for both females and males. CONCLUSIONS: A multifaceted intervention program that provided information and skills, as well as counseling and services, appears to have positive influences on contraceptive practice and condom use among unmarried young females and males in suburban Shanghai.

Cloning, Expression and Antibody Production of the Disintegrin Domain of Human Fertilin beta.

A cDNA for the disintegrin domain (hf279) was isolated by PCR from human testis cDNAs. DNA sequencing indicated that hf279 cDNA encoded 93 amino acid residues, and it was identical with the reported sequence of fertilin beta. An expression plasmid, pGEX hf279, was constructed by inserting hf279 cDNA into plasmid pGEX-4T-2 containing gst gene. The expression plasmid was introduced into E.coli BL21(DE3) cells and a substantial amount of soluble fused protein GST-HF93 was obtained by the expression strain HF93/BL21 induced with IPTG. SDS-PAGE analysis revealed that the GST-HF93 fusion protein had an apparent molecular weight of 38 kD and accumulated up to 50% of bacterial soluble proteins. The fusion protein was purified by glutathione S-transferase (GST) Sepharose 4B column (purity 90%) and digested by thrombin to obtain the purified HF93 peptide (purity 80%). Polyclonal antibodies were obtained from the serum of miceimmunized with purified HF93 which was isolated by GST Sepharose 4B column and SDS-PAGE. ELISA and Western blot analysis showed its specificity to HF93. Therefore this antibody can be used in further studies on the function of HF93.

Induced abortion and breast cancer: results from a population-based case control study in China.

AIM: To determine whether induced abortion (IA) increases breast cancer (BC) risk. MATERIALS AND METHODS: A population-based case-control study was performed from Dec, 2000 to November, 2004 in Shanghai, China, where IA could be verified through the family planning network and client medical records. Structured questionnaires were completed by 1,517 cases with primary invasive epithelial breast cancer and 1,573 controls frequency- matched to cases for age group. The information was supplemented and verified by the family planning records. Statistical analysis was conducted with SAS 9.0. RESULTS: After adjusting for potential confounders, induced abortions were not found to be associated with breast cancer with OR=0.94 (95%CI= 0.79-1.11). Compared to parous women without induced abortion, parous women with 3 or more times induced abortion (OR=0.66, 95%CI=0.46 to 0.95) and women with 3 or more times induced abortion after the first live birth (OR=0.66, 95%CI =0.45 to 0.97) showed a lower risk of breast cancer, after adjustment for age, level of education, annual income per capita, age at menarche, menopause, parity times, spontaneous abortion, age at first live birth, breast-feeding, oral contraceptives, hormones drug, breast disease, BMI, drinking alcohol, drinking tea, taking vitamin/calcium tablet, physical activity, vocation, history of breast cancer, eating the bean. CONCLUSIONS: The results suggest that a history of induced abortions may not increase the risk of breast cancer.

Effect of interpregnancy interval after a mifepristone-induced abortion on neonatal outcomes in subsequent pregnancy.

BACKGROUND: The study evaluated effects of interpregnancy interval (IPI) on neonatal outcomes after mifepristone-induced abortion in the first pregnancy. STUDY DESIGN: This observational cohort study, conducted from 1998 to 2001 at antenatal clinics in Shanghai, Beijing, and Chengdu, China, included 4682 nulliparous women with one mifepristone-induced abortion in their first pregnancy, who were enrolled and followed up until delivery. We compared neonatal outcomes among women with different IPIs between their mifepristone-induced abortion and subsequent pregnancy. RESULTS: When compared to IPI of 18-24 months, there was an increased risk of the neonate being small for gestational age (SGA) [adjusted odds ratio (aOR): 2.01; 95% confidence interval (CI): 1.04-3.88] when IPI was <6 months; this risk was greater among women without a curettage history after abortion (aOR: 2.49; 95% CI: 1.13-5.50). The associations between IPI and preterm delivery (<37 weeks), low birth weight (<2500 g), mean birth weight and ponderal index were not statistically significant. CONCLUSIONS: The results indicate that an IPI <6 months after one mifepristone-induced abortion in first pregnancy is associated with an increased risk of SGA in the subsequent pregnancy.

[The influence of smoking on the routine parameters of semen quality].

OBJECTIVE: To explore the effect and heaviness of smoking on the routine parameters of semen quality. METHODS: A total of 727 eligible subjects including 421 smokers and 306 nonsmokers were selected in 2004 - 2006 in Hebei, Shanxi, Guizhou, Zhejiang and Shandong provinces. Data on background information, general demographic characteristics, exposure to smoking and related confounding factors were obtained through a questionnaire survey. Semen samples of all the subjects were collected during the period of study. Parameters of semen were examined according to the manual recommended by WHO. RESULTS: Four models from the multiple logistic regression regarding the semen routine parameters were used as the dependent variables to be fitted in descending order respectively, while six confounders including area, age, abstinence time, education level, history of alcohol intake and the exposure to pesticides etc., were adjusted. RESULTS: showed that smoking could affect the sperm viability, with significantly higher proportion of abnormal sperm viability seen in the smoking group (OR = 1.77, 95% CI: 1.12 - 2.80). Proportions regarding the abnormal mobility and morphology of sperms in the smoking group were also significantly higher than in the control group, with OR values as 1.51 (95%CI: 1.00 - 2.27) and 2.55 (95%CI: 1.68 - 3. 88) respectively. The density of sperms was significantly decreased in the smoking groups who smoked more than 20 cigarettes per day (OR = 1.70, 95%CI: 1.05 - 2.76) or the total numbers of cigarette consumption exceeding 150 000 (OR = 1.84, 95% CI: 1.03 - 3.29). CONCLUSION: Smoking showed adverse effects on the quality of semen, especially for heavy or long-term smokers.

[The influence of high birth weight on the blood pressure during childhood - a cohort study].

OBJECTIVE: To explore the effects of high birth weight (HBW) on blood pressure (BP) during childhood. METHODS: A total of 1435 couples with high or normal birth weight were selected from a birth cohort who were born between 1993 and 1995 in Wuxi, China and, followed between 2005 and 2007. A questionnaire survey was conducted, with their height, weight and blood pressure measured. RESULTS: The medians of systolic blood pressure (SBP) and diastolic BP (DBP) of HBW group were 100 mm Hg (Q(1)-Q(3): 90 - 110 mm Hg), 64 mm Hg (Q(1)-Q(3): 60 - 70 mm Hg) in the high birth weight group, respectively, while they were 100 mm Hg (Q(1)-Q(3): 90 - 108 mm Hg), 62 mm Hg (Q(1)-Q(3): 60 - 70 mm Hg) in the normal weight group. No statistical significant difference was found between the exposed and unexposed groups. The proportion of elevated BP, including pre-hypertension and hypertension, in exposed group was 13.66%, a bit higher than that (11.57%) of the unexposed group (P = 0.055). The relative risk (RR) of HBW on elevated BP was 1.06 (0.92 - 1.21), after adjusted the following parameters as BMI in childhood, sex, age during the follow-up period, age of mother at delivery, gestational age, type of feeding at infancy, dietary habit as well as the frequencies of exercise during childhood. CONCLUSION: No statistically significant correlation was found between high birth weight and blood pressure of children.

Mifepristone-induced abortion and vaginal bleeding in subsequent pregnancy.

BACKGROUND: The aim of this study is to explore the effect of first-trimester mifepristone-induced abortion on vaginal bleeding in subsequent pregnancy. STUDY DESIGN: This observational cohort study was conducted during 1998-2001 at antenatal clinics in Beijing, Chengdu, and Shanghai, China. The study enrolled 4,931 women with one previous mifepristone-induced abortion, 4,925 women with no history of induced abortion, and 4,800 women with one previous surgical abortion and followed them through pregnancy and childbirth. RESULTS: The rates of vaginal bleeding in pregnant women with a history of medical abortion, no abortion, and surgical abortion were 16.5%, 13.9%, and 17.3%, respectively. The women with medical abortion had a higher risk (adjusted relative risk (aRR)=1.17, 95% confidence interval (CI): 1.07, 1.29) of vaginal bleeding compared with those with no abortion but similar risk to prior surgical abortion. When the correlation between medical abortion and vaginal bleeding was examined by period, increased risk was observed only in the early period (<16 gestational weeks) (aRR=1.25, 95% CI: 1.12, 1.39). The comparison between subgroups of medical abortion and no abortion showed that the observed risks increased particularly in those with abortion at gestational age ≤ 7 weeks (aRR=1.33, 95% CI: 1.18, 1.49), those followed by a postabortion curettage (aRR=1.58, 95% CI: 1.37, 1.84) or complications (aRR=1.99, 95% CI: 1.67, 2.37). There was no difference between women with medical abortion and women with surgical abortion in the occurrence of vaginal bleeding for either period. CONCLUSIONS: One previous mifepristone-induced abortion increased the risk of vaginal bleeding in early gestation period of subsequent pregnancy compared with no abortion, especially if abortion occurred before 7 weeks of gestation and was followed by a curettage or complications.