S. S. H. Suen

Head‐to‐body delivery interval and risk of fetal acidosis and hypoxic ischaemic encephalopathy in shoulder dystocia: a retrospective review

Please cite this paper as: Leung T, Stuart O, Sahota D, Suen S, Lau T, Lao T. Head‐to‐body delivery interval and risk of fetal acidosis and hypoxic ischaemic encephalopathy in shoulder dystocia: a retrospective review. BJOG 2011;118:474–479.

Comparison of perinatal outcomes of shoulder dystocia alleviated by different type and sequence of manoeuvres: a retrospective review

Please cite this paper as: Leung T, Stuart O, Suen S, Sahota D, Lau T, Lao T. Comparison of perinatal outcomes of shoulder dystocia alleviated by different type and sequence of manoeuvres: a retrospective review. BJOG 2011;118:985–990.

Implications of the relationship between maternal age and parity with hepatitis B carrier status in a high endemicity area.

Summary.  This study aimed to examine the prevalence of maternal hepatitis B virus (HBV) infection in the past 10 years and the age‐ and parity‐specific incidences for evidence of control of HBV infection in the female reproductive population. We conducted a retrospective cohort study on 58 736 consecutive pregnant women delivered from July 1998 to June 2008. Maternal HBV status and demographic data were retrieved from a computerized database for analysis by year, age, year of birth and parity. A total of 5788 (10.1%) women had HBV infection, and the annual prevalence was around 10% throughout. When categorized by maternal age into six 5‐year cohorts, the incidence increased from 6.8% in the <20 years cohort to 10.8% in the 20–24 and 25–29 year cohorts, then declined to 9.3% in the ≥40 years cohort (P < 0.001). When categorized by year of birth into 5‐year cohorts, the incidence varied from 9.2% for the 1965–1969 cohort to 11.3% in the 1980–1984 cohort, which then declined to 7.3% in the ≥1985 cohort (P < 0.001). Multiparas had higher incidence when compared with nulliparas overall (10.5%vs 9.6%, P = 0.001), and significantly higher incidences for the 25–29 year (P = 0.009), 30–34 year (P < 0.001) and 35–39 year (P = 0.032) cohorts when analysed by age. In conclusion, the prevalence of maternal HBV infection remained constant at 10% for the past decade. The changes in relation to age and parity suggested that horizontal transmission, probably by sexual contact, had played an important role in maintaining the same prevalence as reported from Hong Kong 20 years ago.

Chronic hepatitis B virus infection and rubella susceptibility in pregnant women.

Summary.  Increased rubella susceptibility has been shown in subjects from the Asian‐Pacific region where chronic hepatitis B virus (HBV) infection is endemic. This study was performed to explore the relationship between chronic HBV infection and rubella susceptibility in the obstetric population. We conducted a retrospective cohort study on 50556 pregnant women delivered in a university obstetric unit from January 1998 to June 2008. The incidence of rubella susceptibility according to maternal HBV carrier status was examined. HBV infection and rubella susceptibility were found in 5105 (10.1%) and 6102 (12.1%) women, respectively. Rubella susceptibility was more common in women with HBV (13.1%vs 12.0%, P = 0.017), even after adjusting for other confounding factors (odds ratio 1.11, 95% confidence interval 1.01–1.21). Advancing age was associated with progressively decreasing odds of rubella susceptibility, from 0.48 at age 20–24 years to 0.34 at age ≥40 years in women without HBV infection, but had no effect in women with hepatitis B. In conclusion, our study is the first to demonstrate an association between chronic HBV infection with rubella susceptibility. Further studies are warranted to confirm whether chronic HBV infection, especially that acquired by vertical transmission, may impair the immune response to rubella vaccine or natural infection throughout the reproductive age.

Maternal HBsAg status and infant size – a Faustian bargain?

Summary.  Information on the impact of maternal hepatitis B virus (HBV) infection on pregnancy outcome is conflicting. Some studies reported an association with increased infant birthweight, which could be interpreted as advantageous to pregnancy. A retrospective study was performed to compare birthweight outcome between 6261 and 55 817 singleton pregnancies in mothers screened positive and negative for hepatitis B surface antigen (HBsAg), respectively. The HBsAg positive women were younger, had higher body mass index (BMI) and incidence of overweight, but less gestational weight gain, and were associated with increased macrosomia (birthweight ≥4000 g) in mothers <35 years (odds ratio, OR, 1.28), BMI ≥25 kg/m2 (OR 1.24), without gestational diabetes mellitus (GDM, OR 1.19), and in male infants (OR 1.18). It was also associated with increased large‐for‐gestational age (LGA, birthweight >90th percentile) infants in nulliparas (OR 1.13), age <35 years (OR 1.12), BMI ≥25 kg/m2 (OR 1.19), with (OR 1.36) and without (OR 1.09) GDM, and in male infants (OR 1.13). When the effects of high BMI, advanced age, GDM, and male infants were controlled for, positive HBsAg was significantly associated with macrosomic (adjusted odds ratio, aOR, 1.15) and LGA (aOR 1.11) infants. In view of the latest findings on the association between high infant birthweight with increased risk of obesity, diabetes mellitus, and various forms of malignancies from childhood to adulthood, further studies are warranted to determine if maternal hepatitis B infection would impact adversely on the long‐term health of the offspring through its effect on increasing birthweight.

Impact of neonatal hepatitis B vaccination programme on age-specific prevalence of hepatitis B infection in teenage mothers in Hong Kong

We examined the impact of the neonatal hepatitis B immunization programme, first provided to all neonates born to mothers screened positive for hepatitis B surface antigen (HBsAg) in late 1983, on the age-specific prevalence of HBsAg carriage in teenage mothers managed in 1998–2008. HBsAg carriage was found in 2.5%, 2.7%, 8.8% and 8.0% of mothers aged ≤ 16, 17, 18, and 19 years, respectively (P=0.004), which was also correlated with advancing age (P=0.011). While neither difference nor correlation with age was found in mothers born before 1984, the prevalence of 1.2%, 1.5%, 7.1% and 8.3%, respectively, was significantly different among (P=0.008) and correlated with (P=0.002) age in mothers born 1984 onwards. Regression analysis indicated there was a significantly higher incidence of HBsAg carriage from age 17 onwards (adjusted odds ratio 2.55, 95% confidence interval 1.07–6.10, P=0.035), suggesting that the protective effect of the vaccine declined in late adolescence.

The impact of fetal gender on preterm birth in a southern Chinese population

Objective: This study was conducted to determine whether carrying a singleton male fetus increases the risk of preterm birth (PTB) in Chinese women. Methods: A retrospective cohort study was conducted on women with singleton pregnancies and delivered in our hospital. Maternal characteristics, pregnancy outcome, and incidence of PTB, were compared between women carrying a male versus a female fetus. The independent effect of a male fetus on PTB was examined with multiple logistic regression analysis adjusting for the other confounding factors identified. Results: There were significant differences in maternal and infant characteristics between women with a male versus a female fetus. Despite similar or lower incidences of complications and labor induction, women with a male fetus had increased birth <37 weeks (7.0% versus 6.2%, p < 0.001) and birth at 34–36 weeks (5.15% versus 4.4%, p < 0.001), but not for birth <34 weeks (2.0% versus 1.8%, p = 0.163). Regression analysis confirmed the association between male fetus with birth at 34–36 weeks (aOR 1.11, 95% CI 1.10–1.33) and spontaneous preterm labor (aOR 1.09, 95% CI 1.00–1.19). Conclusions: The results confirmed that carrying a male fetus is an independent risk factor for spontaneous preterm labor and PTB at 34–36 weeks gestation in southern Chinese women.

Correlation between maternal hepatitis B surface antigen carrier status with social, medical and family factors in an endemic area: have we overlooked something?

PurposeHepatitis B virus (HBV) infection is endemic in many countries, but the risk factors for HBV carriage in the obstetric population are unclear.MethodsA survey on 1,580 women attending the antenatal clinic in an endemic region was conducted in order to examine the prevalence of and factors associated with maternal HBV carriage, including socio-demographic, medical, and previous obstetrical and family history, by means of a questionnaire.ResultsThe prevalence of maternal HBV carriage was 9.1%, and 4.8% of women with a history of hepatitis B vaccination were found to be HBV carriers. Factors associated with maternal HBV carriage were residency status (adjusted odds ratio [aOR] 3.65 for immigrants; aOR 7.62 for non-residents), positive family history (aOR 3.72 for infected mother; aOR 5.36 for other family members), no previous vaccination (aOR 4.39) and having previous HBsAg testing (aOR 2.26).ConclusionsThe findings suggest that there was probably an overlooked role of horizontal transmission within the family setting in addition to perinatal transmission in determining the likelihood of HBV infection in our obstetric population. Reconfirmation of hepatitis B status might be necessary among individuals with a history of vaccination to ensure the effectiveness of their immunoprotection.

Breastfeeding initiation: is this influenced by maternal hepatitis B infection?

Objective: To elucidate the effect of hepatitis B virus (HBV) infection on breastfeeding uptake in Chinese mothers in an endemic region. Patients and Methods: A retrospective cohort study on 63 885 consecutive pregnant delivered between January 1997 and June 2008, were extracted from computerized database to examine the relationship between breastfeeding uptake and maternal HBV status, adjusted for demographic factors. Results: A total of 6593 (10.3%) women were hepatitis B surface antigen (HBsAg)-positive, with an annual prevalence of around 10%. In the study period, 29 869 (46.8%) practised breastfeeding, and its prevalence ranged from 35.4 to 54.8% with an increasing trend throughout the years (p < 0.001). HBsAg-positive mothers had a significantly lower rate of breastfeeding (39.2 vs. 47.6% p < 0.001). Multiparas had higher incidence of HBV infection (10.9 vs. 9.8%, p < 0.001) and lower breastfeeding rate (42.2% versus 51.0%, p < 0.001) when compared with primiparas. Among those factors, maternal HBV infection had the strongest negative association with breastfeeding (adjusted odd ratio (aOR) = 0.726, 95% confidence interval (CI): 0.689–0.765). Conclusions: Our results suggested maternal HBV infection was one of the factors for the persistently low breastfeeding rate in Hong Kong over the past decades. To promote breastfeeding, it is necessary to generate definitive data on its safety regarding to mother-to-child transmission (MTCT) of HBV in order to allay the fear and anxiety in HBsAg-positive mothers.