Pictorial Blood Loss Assessment Chart for evaluating heavy menstrual bleeding in Asian women

INTRODUCTION

Heavy menstrual bleeding is a common gynaecological problem, but some women may prefer not to articulate their menstrual problems. The objective of this study was to evaluate the usefulness and acceptability of the Pictorial Blood Loss Assessment Chart (PBAC) as a selfscreening tool in evaluation of menstrual blood loss among Asian women in Hong Kong.

METHODS

This prospective cohort study recruited 206 women from the general gynaecology ward and out-patient clinic: 118 had self-perceived heavy menstrual bleeding and 88 had self-perceived normal menstrual flow. Participants were asked to fill in the PBAC for one menstrual cycle.

RESULTS

Compared with women who had self-perceived normal menstrual flow, women with self-perceived heavy menstrual bleeding had significantly higher total PBAC scores and numbers of flooding episodes, larger clot sizes and numbers, more days of bleeding, and lower haemoglobin levels. Receiver-operating characteristic curve analysis demonstrated good pairwise associations of self-perceived symptoms with PBAC score and haemoglobin level.

CONCLUSIONS

The PBAC can be used to differentiate self-perceived heavy and normal menstrual bleeding in Asian women in Hong Kong. It can also serve as an additional indicator of possible heavy menstrual bleeding to alert women of the need to seek early medical attention.

Maternal ABO and rhesus blood group phenotypes and hepatitis B surface antigen carriage

In view of a persistently high prevalence of hepatitis B surface antigen (HBsAg) carriage in our obstetric population, we examined the association between HBsAg carriage with maternal ABO and rhesus (Rh) blood group phenotypes determined at routine antenatal screening. In a retrospective study, the antenatal screening results of women booked for confinement between 1998 and 2011 in our hospital were examined for the relationship between HBsAg carriage with the ABO and rhesus blood groups, taking into account also the effects of advanced maternal age (≥ 35 years) and parity status (nulliparous or multiparous), and year of birth before or following the availability of the hepatitis B vaccine (1984). HBsAg carriage was found in 9.9%, 9.6%, 9.1% and 10.2% (P = 0.037) for group-A (n = 20 581 or 26.1%), -B (n = 20 744 or 26.4%), -AB (n = 5138 or 6.5%) and -O (n = 32 242 or 41.0%) among the 78705 women in the study cohort. Rhesus negativity was found in 0.6%, and HBsAg carriage was 12.3% and 9.8%, respectively, for the Rh-negative and Rh-positive women (P = 0.071). Carriage rate between group-O and non-O was influenced by nulliparity, age ≥ 35 years and Rh-positive status. Regression analysis indicated that group-B (P = 0.044, aOR = 1.062, 95% CI 1.002-1.127) and group-AB (P = 0.016, aOR = 1.134, 95% CI 1.024-1.256) were associated with HBsAg carriage. Blood groups-B and -AB are associated with increased hepatitis B virus (HBV) infection in our population, and further studies are warranted to elucidate the implications of this on the sequelae of HBV infection.

Does gestational diabetes mellitus affect respiratory outcome in late-preterm infants?

BACKGROUND

Both gestational diabetes mellitus (GDM) and late-preterm delivery at 34-36 weeks' gestation are independently associated with neonatal respiratory complications, but it is unknown whether their combination increases further its risk. We therefore appraised the independent effect of GDM on the respiratory outcome of late-preterm infants.

METHODS

In a retrospective cohort study, respiratory outcome of 911 infants delivered at 34-36 weeks' gestation between 1 January 2009 and 30 August 2012 from mothers with GDM (study group, n=130) was compared with infants delivered at the same gestation by mothers without GDM (control group, n=781).

RESULTS

The study group had significantly higher incidence of transient tachypnoea of newborn (TTN, p=0.02) and air leak (p=0.012), and required more respiratory support, including oxygen, continuous positive airway pressure (CPAP), mechanical ventilation and neonatal intensive care, with a longer length of hospital stay, but not duration on respiratory support. On logistic regression analysis, GDM is an independent risk factor for TTN (aOR=1.5, 95% C.I.1.0-2.4), CPAP (aOR=2.37, 95% C.I. 1.05-4.89), mechanical ventilation (aOR=4.02 95% C.I. 1.57-10.32) and neonatal intensive care (aOR 1.83, 95% C.I. 1.05-3.87).

CONCLUSIONS

Our results demonstrated an independent effect of GDM on the risk of severe respiratory complications in late-preterm infants. Additional close monitoring and timely intervention are necessary in the management of these infants.

Diagnostic accuracy of the BACs-on-Beads™ assay versus karyotyping for prenatal detection of chromosomal abnormalities: a retrospective consecutive case series

OBJECTIVE

To evaluate the diagnostic performance of the BACs-on-Beads(™) (BoBs(™)) assay for prenatal detection of chromosomal abnormalities.

DESIGN

Retrospective study.

SETTING

Tertiary prenatal diagnosis centre.

POPULATION

Women referred for prenatal diagnosis.

METHODS

We retrieved 2153 archived DNA samples collected between January 2010 and August 2011 for the BoBs(™) assay. These samples had previously been tested by quantitative fluorescence polymerase chain reaction (QF-PCR) and karyotyping. In the BoBs(™) assay a sample was defined as normal disomic when the ratio of the fluorescence intensities in a chromosome locus lay within the threshold (mean ratio ± 2SD), and as deleted or duplicated when the ratio was below the lower threshold (0.6-0.8) or above the upper threshold (1.3-1.4), respectively. The BoBs(™) results were further validated by microarray and compared in a blinded manner with the original QF-PCR and karyotyping results.

MAIN OUTCOME MEASURES

Concordance of any numerical, structural, and submicroscopic chromosomal abnormalities between the methods.

RESULTS

BACs-on-Beads(™) was similar to karyotyping and QF-PCR in detecting trisomy 13, trisomy 18, trisomy 21, and sex chromosomal aneuploidies, and superior to QF-PCR in detecting major structural abnormalities (53.3 versus 13.3%) and mosaicism (28.6 versus 0%) involving chromosomal abnormalities other than the common aneuploidies. BoBs(™) detected six microdeletion syndromes missed by karyotyping and QF-PCR; however, BoBs(™) missed two cases of triploidy identified by QF-PCR. Therefore, the sensitivity of BoBs(™) is 96.7% (95% CI 92.6-98.7%), and its specificity is 100% (95% CI 99.8-100%).

CONCLUSIONS

BACs-on-Beads(™) can replace QF-PCR for triaging in prenatal diagnosis, and gives a better diagnostic yield than current rapid aneuploidy tests.

Maternal hepatitis B surface antigen status and incidence of pre-eclampsia

The relationship between chronic hepatitis B virus (HBV) infection with atherosclerosis and cardiovascular disorders remains unclear, and the impact of maternal HBV infection on the development of pregnancy-induced hypertension (PIH) and pre-eclampsia (PE) is also controversial. This retrospective cohort study was conducted to examine the relationship between maternal hepatitis B surface antigen (HBsAg) status with PIH and PE in singleton pregnancies that delivered at 24 weeks of gestation and beyond. Among the 86 537 cases in the cohort, 10% were HBsAg positive, and overall 2.0% had PIH, of whom 56.3% developed PE. HBsAg-positive women had higher weight and body mass index (BMI), but lower incidences of advanced age, nulliparity, PIH (1.6% vs 2.0%, P = 0.007) and PE (0.8% vs 1.1%, P = 0.005). On multiple logistic regression analysis adjusting for the effects of nulliparity, advanced age, high BMI, and underlying renal, cardiac and autoimmune diseases, HBsAg carriage was associated with significantly reduced incidence of PIH (aOR 0.79, 95% CI 0.66-0.95) and PE (aOR 0.71, 95% CI 0.56-0.91). Our results indicate that maternal HBsAg carriage is independently associated with reduced PE. As chronic HBV infection alters the immune response of the individual, our observation could be related to enhanced maternal immunotolerance of the foetus and hence a reduction in the incidence of PE. The implications of our findings on the long-term health outcome of the infected women, from cardiovascular morbidity to malignancies, warrant further studies.

Relationship between age and prevalence of hepatitis B infection in first-year university students in Hong Kong

PURPOSE

To determine the effect of age on the prevalence of hepatitis B virus (HBV) infection during a routine screening programme of first-year students enrolled in Health Sciences Studies at the Chinese University of Hong Kong from 2001 to 2009.

METHODS

In a retrospective cohort study, data on the hepatitis B surface antigen (HBsAg) status was retrieved from the University Health Service and analysed according to the age of the student at testing and year of birth.

RESULTS

Of the 2,688 students enrolled in the study group, 79 (2.9 %) tested positive for HBsAg. The prevalence increased significantly from 0.9, 2.3, 4.3 to 5.5 % for those tested at age ≤ 18, 19, 20 and ≥ 21 years, respectively (p < 0.001). On logistic regression analysis, taking age ≤ 18 years and year of birth before 1983 (before the availability of HBV vaccination) as the reference group, HBV infection increased progressively with age, with an adjusted odds ratio of 3.36 [95 % confidence interval (CI) 1.01-11.23], 6.04 (95 % CI 1.74-20.98) and 11.61 (95 % CI 3.20-42.13) for age 19, 20 and ≥ 21 years, respectively. There was no significant change in the odds ratio after adjustment for the year of birth before and after introduction of the vaccination programme.

CONCLUSION

Among the university students enrolled in our study, the overall prevalence of HBV infection before and after the introduction of HBV vaccination was lower than the 10 % found in the general population. There was, however, a significant progressive increase with age at testing from ≤ 18 to ≥ 21 years, suggesting a previously overlooked contribution of horizontal transmission to the high prevalence of HBV infection found in our adult population.

Maternal HBsAg status and infant size--a Faustian bargain?

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/m(2) (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/m(2) (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.

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

PURPOSE

Hepatitis B virus (HBV) infection is endemic in many countries, but the risk factors for HBV carriage in the obstetric population are unclear.

METHODS

A 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.

RESULTS

The 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).

CONCLUSIONS

The 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.

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

OBJECTIVE

To examine the association between head-to-body delivery interval (HBDI) and cord arterial pH and base excess (BE), and the risk of development of hypoxic ischaemic encephalopathy (HIE).

DESIGN

Retrospective review.

SETTING

A university hospital.

POPULATION

Pregnancies complicated with shoulder dystocia during the period 1995-2009.

METHODS

Cases were identified from a search of the hospital electronic delivery records. Cord arterial pH and BE, and the incidence of HIE and perinatal death, were retrieved from medical records and correlated with HBDI, birth weight, mode of delivery and presence of nonreassuring fetal heart rate pattern and maternal diabetes using univariate analysis, followed by multivariate analysis.

MAIN OUTCOME MEASURES

Any association between cord pH and HBDI.

RESULTS

Of the 200 cases identified, the mean (standard deviation) HBDI was 2.5 minutes (1.5 minutes). Both HBDI and the presence of nonreassuring fetal heart rate pattern were independent factors for pH, and HBDI was the only significant factor for BE. Arterial pH dropped at a rate of 0.011 per minute [95% confidence interval (95% CI), 0.017-0.004; P = 0.002] with HBDI. The mode of delivery, birth weight and maternal diabetes did not affect blood gas levels. The respective risks of severe acidosis (pH < 7) and HIE with HBDI of <5 minutes were 0.5% and 0.5% versus 5.9% and 23.5% with HBDI ≥ 5 minutes.

CONCLUSIONS

Cord arterial pH drops with HBDI during shoulder dystocia, but the risk of acidosis or HIE is very low with HBDI < 5 minutes.

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

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 > or =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 > or =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.

Iron supplement in pregnancy and development of gestational diabetes--a randomised placebo-controlled trial

OBJECTIVE

To test the hypothesis that iron supplement from early pregnancy would increase the risk of gestational diabetes mellitus (GDM).

DESIGN

Randomised placebo-controlled trial.

SETTING

A university teaching hospital in Hong Kong.

POPULATION

One thousand one hundred sixty-four women with singleton pregnancy at less than 16 weeks of gestation with haemoglobin (Hb) level between 8 and 14 g/dl and no pre-existing diabetes or haemoglobinopathies.

METHODS

Women were randomly allocated to receive 60 mg of iron supplement daily (n= 565) or placebo (n= 599). Oral glucose tolerance tests (OGTTs) were performed at 28 and 36 weeks. Women were followed up until delivery.

OUTCOME MEASURES

The primary outcome was development of GDM at 28 weeks. The secondary outcomes were 2-hour post-OGTT glucose levels, development of GDM at 36 weeks and delivery and infant outcomes.

RESULTS

There was no significant difference in the incidence of GDM in the iron supplement and placebo groups at 28 weeks (OR: 1.04, 95% confidence interval [CI]: 0.7-1.53 at 90% power) or 36 weeks. Maternal Hb and ferritin levels were higher in the iron supplement group at delivery (P < 0.001 and P= 0.003, respectively). Elective caesarean section rate was lower in the iron supplement group (OR: 0.58, 95% CI: 0.37-0.89). Infant birthweight was heavier (P= 0.001), and there were fewer small-for-gestational-age babies in the iron supplement group (OR: 0.46, 95% CI: 0.24-0.85).

CONCLUSION

Iron supplement from early pregnancy does not increase the risk of GDM. It may have benefits in terms of pregnancy outcomes.

Comfort evaluation of maternity support garments in a wear trial

This study aims to evaluate the wear comfort of eight commercially available maternity support garments. The thermophysiological, sensory/tactile and movement comfort were assessed in a wear trial using a 19-item questionnaire. Fourteen pregnant Chinese women aged 32.3 +/- 4.2 years were recruited from a local obstetric clinic. The results show that the tested garments generally provided greater sensory comfort than thermophysiological comfort. The thermophysiological comfort was mainly influenced by the fibre contents and breathability. Significant linear relationships were found between material appearance and hand feel (r = 0.86, p < 0.001), and between non-itchiness and no red mark (r = 0.78, p < 0.001). Movement comfort was influenced by the garment type and style features. Overall, the soft, good-fit, cotton/elastane maternity brief was perceived as the best product. The findings of comfort needs in pregnant women and the effects of various garment attributes would be helpful for the development of maternity support garment design criteria that are required to satisfy critical ergonomic needs. Low back pain during pregnancy is a common and significant health problem. A maternity support garment is regarded as a convenient and safe device to stabilise the lumbar spine so as to relieve pain. However, patient compliance is likely to be affected by discomfort and inconvenience. The results of this study provide guidance for the optimal design of maternity support clothing.

Rapid aneuploidy testing (knowing less) versus traditional karyotyping (knowing more) for advanced maternal age: what would be missed, who should decide?

OBJECTIVES

The application of rapid aneuploidy testing as a stand-alone approach in prenatal diagnosis is much debated. The major criticism of this targeted approach is that it will not detect other chromosomal abnormalities that will be picked up by traditional karyotyping. This study aimed to study the nature of such chromosomal abnormalities and whether parents would choose to terminate affected pregnancies.

DESIGN

Retrospective study on a cytogenetic database.

SETTING

Eight public hospitals in Hong Kong.

PARTICIPANTS

The karyotype results of 19 517 amniotic fluid cultures performed for advanced maternal age (>or=35 years) from 1997 to 2002 were classified according to whether they were detectable by rapid aneuploidy testing. The outcomes of pregnancies with abnormal karyotypes were reviewed from patient records.

RESULTS

In all, 333 (1.7%) amniotic fluid cultures yielded abnormal karyotypes; 175 (52.6%) of these were detected by rapid aneuploidy testing, and included trisomy 21 (n=94, 28.2%), trisomy 18 or 13 (n=21, 6.3%), and sex chromosome abnormalities (n=60, 18.0%). The other 158 (47.4%) chromosomal abnormalities were not detectable by rapid aneuploidy testing, of which 63 (18.9%) were regarded to be of potential clinical significance and 95 (28.5%) of no clinical significance. Pregnancy outcomes in 327/333 (98.2%) of these patients were retrieved. In total, 143 (42.9%) of these pregnancies were terminated: 93/94 (98.9%) for trisomy 21, 20/21 (95.2%) for trisomy 18 or 13, 19/60 (31.7%) for sex chromosome abnormalities, and 11/63 (17.5%) for other chromosomal abnormalities with potential clinical significance. There were no terminations in the 95 pregnancies in which karyotyping results were regarded to be of no clinical significance.

CONCLUSIONS

'Knowing less' by the rapid aneuploidy stand-alone testing could miss about half of all chromosomal abnormalities detectable by amniocentesis performed for advanced maternal age. Findings from two fifths of the latter were of potential clinical significance, and the parents chose to terminate one out of six of the corresponding pregnancies. If both techniques are available, parents could have enhanced autonomy to choose.

Continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries after the study period: Was this the Hawthorne effect?

BACKGROUND

The incidence of birth trauma and birth asphyxia related to instrumental deliveries in our obstetric unit was high (2.8%) in 1998-1999. A study was performed in 2000 to identify the risk factors. Unexpectedly, the incidence (0.6%) was reduced significantly during the study period. We attributed this phenomenon to the famous Hawthorne effect (tendency to improve performance because of awareness of being studied).

OBJECTIVES

The objectives were to study whether there is a continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries in the post-study period (2001-2003) and to investigate the presence of underlying confounding factors apart from the Hawthorne effect.

METHOD

To compare the hospital obstetric statistics among the pre-study period (1998-1999), the study period (2000) and the post-study period (2001-2003), in particular the incidence of birth trauma and birth asphyxia related to instrumental deliveries, the instrumental delivery rate, the overall Caesarean section rate, the Caesarean section rate for no progress of labour, the incidence of failed instrumental delivery, the incidence of attempted instrumental delivery in the operating theatre, and incidence of direct second-stage Caesarean sections.

RESULTS

The incidence of birth trauma and birth asphyxia related to instrumental deliveries (0.6%) during the study period (2000) was significantly lower than that (2.8%) during the pre-study period (1998-1999; RR 0.27, 95% CI 0.11-0.70). This phenomenon continued into the post-study period (2001-2003) when the incidence of 1.0% was similarly lower than that in the pre-study period (RR 0.35, 95% CI 0.20-0.64). The instrumental delivery rate decreased further in the post-study period (13.5%) compared with those in the study (16.6%) and pre-study (19.5%) periods (RR 0.81, 95% CI 0.75-0.89 and RR 0.69, 95% CI 0.65-0.74, respectively). There was a marked increase in the direct second-stage Caesarean section rate in the post-study period (7.1%) compared to those in the study (0.4%) and pre-study (0.7%) periods (RR 15.9, 95% CI 5.05-49.73 and RR 9.77, 95% CI 5.28-18.08, respectively).

CONCLUSION

A change in obstetric practice was identified that may explain the continued reduction in the incidence of birth trauma and birth asphyxia related to instrumental deliveries in the post-study period.

Recurrent pneumothorax in pregnancy: what should we do after placing an intercostal drain

Recurrent pneumothorax is rare during pregnancy. We describe a Chinese woman, with a history of spontaneous pneumothorax managed with an intercostal drain, who developed a recurrent pneumothorax during her 32nd week of pregnancy. There is no consensus on management in this situation. We review the literature and discuss different management approaches. Thirty-six cases of antepartum pneumothorax have been reported in 31 case reports. An intercostal drain only (n=11) or surgeries (thoracotomy, n=9; or video-assisted thoracoscopy, n=2) were common treatment options with no surgical complications reported. Twenty-two (61%) patients progressed to a normal vaginal delivery, while the rest required forceps delivery (22%) or Caesarean section (14%). No single treatment option outweighed the others. There were no maternal or foetal complications reported in those who underwent antepartum surgical intervention. Surgical management of recurrent pneumothorax during pregnancy is well tolerated.

The use of fetal Doppler cerebroplacental blood flow and amniotic fluid volume measurement in the surveillance of postdated pregnancies

BACKGROUND

This prospective observational study aims at determining the distribution of fetal cerebro-placental Doppler indices and amniotic fluid volume in a homogenous group of uncomplicated postdated pregnancies at 41 weeks. The correlation with incidence of passage of thick meconium-stained liquor in labor was analyzed to decide which parameter would be useful in the surveillance of postdated pregnancies.

METHODS

The amniotic fluid volume, middle cerebral artery pulsatility index, umbilical artery pulsatility index, and cerebroplacental ratio were measured and distribution determined in 118 well-dated singleton pregnancies admitted for routine induction of labor at 41 weeks. The 10th centile and the 90th centile in each Doppler parameter and amniotic fluid volume were chosen to divide each parameter into three centile groups. The prevalence of thick meconium-stained liquor in labor in different Doppler and amniotic fluid volume centile groups was compared using Chi-square test for trend with P < 0.05 taken as statistically significant.

RESULTS

The prevalence of thick meconium-stained liquor in labor was significantly inversely correlated with the middle cerebral artery pulsatility index (P = 0.008), with significant difference across different middle cerebral artery pulsatility index centile groups (P = 0.02). There was no significant difference in the prevalence of thick meconium-stained liquor in labor or oligohydramnios across different umbilical artery pulsatility index centile groups. Neither was there significant difference in the prevalence of thick meconium-stained liquor in labor and oligohydramnios across different cerebroplacental ratio and amniotic fluid volume centile groups. Logistic regression using the 10th centile of middle cerebral artery pulsatility index confirmed that it was a significant independent predicting factor for risk of thick meconium-stained liquor in labor with adjusted odds ratio (95th CI) of 6.14 (1.6-24.1).

CONCLUSION

Middle cerebral artery pulsatility index is better than amniotic fluid volume or umbilical artery pulsatility index in predicting the risk of thick meconium-stained liquor in labor in uncomplicated postdated pregnancy at 41 weeks.

Unexpected intrauterine death following resolution of hydrops fetalis after betamethasone treatment in a fetus with a large cystic adenomatoid malformation of the lung

Without intervention, the development of hydrops fetalis secondary to cystic adenomatoid malformation of the lung (CAML) implies a 100% mortality rate. Conversely, four CAML cases with in-utero resolution of hydrops fetalis after prenatal betamethasone therapy with good clinical outcome have been reported in the literature. The mechanism is speculated to be the effect of corticosteroid in improving lung maturation. Here we present another CAML case with resolution of hydrops fetalis after prenatal betamethasone therapy but which was followed by later intrauterine death. We speculate that the resolution of the CAML lesion itself may be more important in determining the clinical outcome than the resolution of hydrops. The association between prenatal betamethasone therapy and resolution of hydrops may be related to a different mechanism other than improvement of lung maturation.

Relationship between cerebroplacental Doppler ratio and birth weight in postdates pregnancies

OBJECTIVES

To explore the relationship between cerebroplacental Doppler impedance index and birth weight in postdates pregnancies, and to evaluate the use of a combination of Doppler parameters and ultrasound biometry in the prediction of large-for-gestational age (LGA) fetuses at 41 weeks of gestation.

METHODS

The pulsatility indices of the umbilical (UA-PI) and middle cerebral (MCA-PI) arteries, the cerebroplacental pulsatility index ratio (CPR) and the estimated fetal weight (EFW) were obtained in a cohort of 181 ultrasound-dated pregnancies at 41 weeks' gestation, 2 days before induction of delivery. A regression equation was established and the correlation between umbilical artery impedance and different birth-weight centile groups was determined. A receiver-operating characteristics (ROC) curve was used to compare prediction of LGA fetuses using biometry alone with that using biometry and UA-PI.

RESULTS

UA-PI was inversely related to EFW (Spearson's correlation coefficient rho = -0.28, P < 0.001). Logistic regression showed an independent contribution of UA-PI to the birth-weight estimation (birth weight = 1356.8 - 232.0 x UA-PI + 0.65 x EFW). On ROC curve analysis, the prediction of LGA with the regression equation was comparable to that using ultrasound biometry alone.

CONCLUSION

UA-PI was inversely correlated to EFW, but the combination of ultrasound biometry and UA-PI compared with biometry alone showed similar prediction of LGA fetuses in postdates pregnancies. Further prospective trials on larger populations or groups with a higher prevalence of LGA fetuses would be needed to validate the use of the new formula.

Doppler study of the umbilical and fetal middle cerebral arteries in women with gestational diabetes mellitus

OBJECTIVE

To investigate the correlation between Doppler parameters in the umbilical and fetal middle cerebral arteries and pregnancy outcome in women with gestational diabetes mellitus (GDM).

METHODS

A prospective study was performed on 169 singleton GDM pregnancies in a university teaching hospital from January to December 2002. Umbilical artery (UA) pulsatility index (PI) and middle cerebral artery (MCA) PI and peak systolic velocity (Vmax) were measured every 4 weeks until delivery from the time of diagnosis of GDM. The pregnancy outcome was obtained from the hospital database. Using linear or quadratic regression, lines of best fit were drawn to compare the Doppler measurements between the two groups with normal and abnormal pregnancy outcomes.

RESULTS

One hundred and thirty-eight women with known pregnancy outcome completed the study. A total of 305 Doppler examinations were performed with one to four examinations for each woman. Thirty-eight women (27.5%) had one or more abnormal pregnancy outcomes: placental abruption, pre-eclampsia, preterm delivery, small-for-gestational age (SGA) infants, low Apgar scores, neonatal jaundice requiring treatment, sepsis, birth trauma, meconium aspiration syndrome, respiratory and neurological complications. There was extensive overlap of the UA-PI, MCA-PI and MCA-Vmax measurements between the two groups.

CONCLUSION

A Doppler study of the UA-PI, MCA-PI and MCA-Vmax was not useful in the prediction of abnormal pregnancy outcome in GDM.

Nutritional intake and placental size in gestational diabetic pregnancies--a preliminary observation

A disproportionately large placenta may represent an adaptive response to adverse intrauterine conditions. Both maternal nutritional intake and presence of gestational diabetes (GDM) have been found to affect relative placental growth. As dietary modification is part of the standard management in GDM women, the observed increase in placental size in these women may be partly due to dietary modification. In this study, we set out to examine the relationship between dietary intake and placental size in GDM pregnancies. Food diaries for five consecutive days for 52 women diagnosed with GDM were obtained to assess their nutritional intake in terms of total calories, carbohydrate, protein and fat. Spearman's correlations were calculated for nutritional intake and various factors that may correlate with placental weight. There was a significant inverse relationship (P=0.021) between placental weight and protein intake. No correlations with the other two nutritional components could be demonstrated. Maternal nutritional intake was not correlated with infant birthweight. It is possible that dietary modulations improve GDM pregnancy outcome, not only by improving glycaemic controls but also by affecting placental growth by altering the proportion of protein intake.

Does maternal glucose intolerance affect the length of gestation in singleton pregnancies?

OBJECTIVE

This study determined whether maternal glucose tolerance has a progressive effect on the length of gestation in singleton pregnancies and whether there is an increasing tendency towards spontaneous preterm birth with increasing glucose intolerance.

METHODS

A total of 2,168 consecutive Chinese women with singleton pregnancies who underwent the 75-g oral glucose tolerance test (OGTT) over a 24-month period were categorized by their OGTT 2-hour value (mmol/L) into the following six groups: 5.9 or less, 6.0-6.9, 7.0-7.9, 8.0-8.9, 9.0-10.9, and 11.0 or greater mmol/L. Women with a 2-hour glucose value of 8.0 or more mmol/L were considered to have gestational diabetes mellitus (GDM) and received diet treatment. Women who eventually required insulin were excluded from the final analysis. The mean gestational age, birth weight, incidence of preterm birth, large for gestational age (LGA, birth weight > 90th percentile), and macrosomic (birth weight > or = 4.0 kg) infants were compared among the six groups.

RESULTS

The incidence of preterm birth correlated significantly with increasing glucose intolerance. On further analysis, incidence of spontaneous birth before 37 weeks in the lowest to the highest 2-hour value groups was as follows: 5.5%, 2.6%, 3.7%, 4.9%, 8.5%, and 10.3% (P =.015) and that before 32 weeks went from 0.4%, 0.3%, 0.8%, 0.4%, 2.2%, to 3.4% (P =.018), respectively. There was no significant difference in the incidence of LGA or macrosomic infants. Regression analysis confirmed that the OGTT 2-hour glucose value was an independent determinant of gestational length.

CONCLUSION

Gestational glucose intolerance affects gestation length and incidence of preterm birth, which should be considered a confounding factor in the analysis of the neonatal outcome of GDM pregnancies.

Successful outcome after serial amnioreductions in triplet fetofetal transfusion syndrome

BACKGROUND

Triplet fetofetal transfusion is an extremely rare complication with high perinatal mortality. Its rarity does not allow any prospective randomized study on various interventional methods to be conducted.

CASE

We report one case of triplet fetofetal transfusion syndrome with survival of all three fetuses. Two were donor fetuses, and one was the recipient fetus. Serial amnioreductions were performed at 22, 24, and 26 weeks' gestation to relieve symptomatic polyhydramnios. Premature rupture of membranes occurred at 27 weeks and cesarean delivery was performed. All three babies were discharged home by 4 months of age, and all had normal neurological development when assessed at 6 months of age.

CONCLUSION

The option of serial amnioreduction, with the anticipation and preparation for delivery at around 28 weeks, should be seriously considered when triplet fetofetal transfusion syndrome is encountered.

The effect of pregnancy on thyroid nodule formation

Epidemiology data have revealed a higher prevalence of nodular goiters in women than men in both iodine-sufficient and iodine-deficient areas. Increased prevalence of thyroid nodules has also been reported in women with higher gravidity. However, the association between pregnancy and thyroid nodule formation has never been studied. The aim of our study was to evaluate the incidence of thyroid nodules during pregnancy and determine whether pregnancy will induce thyroid nodule formation. Two hundred twenty-one healthy southern Chinese women in the first trimester of their pregnancy were studied prospectively. Thyroid ultrasonography, thyroid function tests, and urinary iodine excretion were measured at first, second, and third trimesters of pregnancy as well as 6 wk and 3 months postpartum. Thyroid nodules (>2 mm in any dimension on ultrasonography) were detected in 34 (15.3%) subjects at first trimester, with 12 (5.4%) subjects having more than one nodule. Eight subjects had clinically palpable nodules. Women with thyroid nodules were older (P < 0.01) and had higher gravidity (P < 0.02) than those women without thyroid nodules. The volume of the single/dominant nodules increased from 60 (14--344) mm(3), median (interquartile range) at first trimester to 65 (26-472) mm(3) at third trimester (P < 0.02). These nodules remained enlarged at 103 (25-461) mm(3) 6 wk postpartum (P < 0.005) and 73 (22-344) mm(3) at 3 months postpartum (P < 0.05). Patients with thyroid nodules had lower serum TSH values (P < 0.03) and higher Tg levels (P < 0.05) throughout pregnancy. Appearance of new nodules was detected in 25 (11.3%) women as pregnancy advanced so that by 3 months postpartum, the incidence of thyroid nodular disease was 24.4% (P < 0.02 vs. first trimester). Compared with those with no detectable nodules throughout pregnancy, subjects with new nodule formation had higher urinary iodine excretion from second trimester onward (P all < 0.05). However, no difference could be detected in their TSH and Tg levels throughout pregnancy. Fine-needle aspiration on nodules greater than 5 mm in any dimension after delivery (n = 21) confirmed the majority having histological features consistent with nodular hyperplasia. No thyroid malignancy was detected. In conclusion, pregnancy is associated with an increase in the size of preexisting thyroid nodules as well as new thyroid nodule formation. This may predispose to multinodular goiter in later life.

Implications of a high placental ratio in pregnancies with appropriate-for-gestational age neonates

OBJECTIVE

To determine the relationship between the placental weight to birth weight ratio (placental ratio) with maternal pre-pregnancy weight, gestational weight gain, and neonatal outcome in non-diabetic pregnancies resulting in appropriate-for-gestational age (AGA) infants.

METHODS

A retrospective study was performed on 593 patients with singleton pregnancies, normal results in the 75-gram oral glucose tolerance test and who delivered AGA newborns within a 1-year period. The patients were categorized into high placental ratio (> mean +1 SD based on previous data, n = 113 or 19.1%) and normal ratio groups for the comparison of maternal and neonatal anthropometric parameters.

RESULTS

The high placental ratio group had a higher pre-pregnancy weight, body mass index, placental weight, and incidence of low Apgar score, but decreased absolute and percentage gestational weight gain, gestational age, and birth weight. After controlling for pre-pregnancy weight and gestational age, only the correlation between placental weight and percent weight gain remained significant.

CONCLUSION

Our finding suggests that a high placental ratio can identify AGA newborns who are disproportionately small relative to maternal size, and may reflect some form of fetal growth impairment.

Mild iodine deficiency and thyroid disorders in Hong Kong

OBJECTIVES

To review evidence of iodine deficiency and clinical thyroid disorders in Hong Kong.

DATA SOURCES

Publications on local dietary iodine intake, the iodine content of local food items, and clinical thyroid problems in the Hong Kong population.

DATA EXTRACTION

Data was extracted and evaluated independently by the authors.

DATA SYNTHESIS

Iodine is an essential nutrient. Iodine deficiency can lead to goitre, hypothyroidism, mental deficiency, and impaired growth. It is now appreciated that determination of goitre incidence in children alone may grossly underestimate the problem of iodine deficiency in a population. In total, the evidence indicates that iodine deficiency exists in Hong Kong, leading to clinical problems of transient neonatal hypothyroidism, goitrogenesis, and thyroid disorders in pregnant women and neonates, as well as thyroid dysfunction in the elderly.

CONCLUSION

A supplementation programme aimed at a relatively uniform iodine intake is recommended to avoid deficient or excessive iodine intake in subpopulations.

Gestational diabetes diagnosed in third trimester pregnancy and pregnancy outcome

BACKGROUND

The clinical significance of gestational diabetes diagnosed in the third trimester is unclear. A prospective observational study was performed on a cohort of women without pre-existing gestational diabetes or other medical disorders to examine the effect of gestational diabetes on pregnancy complications and infant outcome.

METHODS

Four hundred and eighty-nine consecutive women were assessed at 28-30 weeks by random glucose screening and/or a 75 g oral glucose tolerance test. The subsequent management was according to established departmental protocols. The outcome of pregnancy was compared among the groups with negative screening, positive screening but normal glucose tolerance, and gestational diabetes which was controlled with diet therapy.

RESULTS

Women with gestational diabetes (n=67 or 13.7%) had significantly increased maternal age, pre-pregnancy weight and body mass index, hemoglobin levels at booking and at 36-38 weeks, and incidences of parity >1, pre-eclampsia, and female infants, while the gestational age was shorter and there was no significant difference in the birthweight outcome or neonatal morbidity.

CONCLUSIONS

Despite diet treatment, gestational diabetes diagnosed in the last trimester is associated with increased risk of pre-eclampsia and shorter length of gestation, and this is likely to reflect a pathological process rather than the physiological effect of pregnancy on maternal glucose tolerance.

Perinatal morbidity and placental size in gestational impaired glucose tolerance

OBJECTIVE

The clinical significance of large placentas in diabetic pregnancies is not known. A retrospective study was performed to determine whether a disproportionately large placenta, as represented by a high ratio of placental weight to birth weight (placental ratio), in pregnancies complicated by the World Health Organization category of impaired glucose tolerance (IGT), was associated with perinatal morbidity.

METHODS

We categorized 1472 consecutive singleton pregnancies with gestational IGT as having a high placental ratio (> 0.2095 or mean plus one standard deviation of the value established for appropriate-for-gestational age infants from nondiabetic pregnancies in a previous study) or a normal ratio. Maternal characteristics and glycemic parameters, infant birth weight and neonatal complications, and placental weight were compared between these two groups.

RESULTS

A high placental ratio was found in 400 (27.2%) pregnancies. This group had similar maternal anthropometric and glycemic parameters, except for a slightly higher prepregnancy body mass index and fasting glucose level in the oral glucose tolerance test. The high placental ratio was from increased placental weight rather than the decreased birth weight. The neonates had increased incidence of low 1-minute Apgar score, treatment for neonatal jaundice and infection, and respiratory complications. After adjusting for the effects of preterm birth and vaginal delivery, a high ratio was still associated with low Apgar score, respiratory complications, and treatment for infection.

CONCLUSIONS

The placental ratio in pregnancies complicated by IGT was unrelated to maternal characteristics or glycemic status, but a high ratio was associated with increased perinatal morbidity.

Preterm birth unrelated to maternal height in Asian women with singleton gestations

OBJECTIVE

To determine whether maternal height has a significant effect on the length of gestation or the incidence of preterm birth in Asian women with singleton gestations.

METHODS

We retrospectively studied a cohort of consecutive adult Asian women with singleton gestations who delivered in a 2-year period, to determine the relationship between maternal height, expressed in quartiles, and the mean gestational age and incidence of preterm birth.

RESULTS

Of the 9819 deliveries during that period, 449 were excluded from analysis because of multiple gestation, maternal age less than 20 years, or incomplete data because of no antenatal care in our hospital. The 25th, 50th, and 75th percentile values of maternal height were 152, 156, and 160 cm, respectively. Significant differences were found in the maternal age, weight and body mass index (BMI), birth weight, and birth weight as a percentage of maternal weight, among the four quartiles, but the trend for age, BMI, and birth weight percentage was opposite to that of maternal weight and birth weight. However, there was no significant difference in the mean gestational age or incidence of preterm birth at less than 28, 28-31, or 32-36 weeks' gestation. There was no difference in the incidence of pregnancies beyond 41 weeks' gestation.

CONCLUSION

Maternal stature does not have a significant influence on the mean gestational age or incidence of preterm birth in adult Asian women with singleton gestations.

Maternal mean arterial pressure and oral glucose tolerance test results. Relationship in normotensive women

OBJECTIVE

To examine the relationship between oral glucose tolerance test (OGTT) results and maternal mean arterial pressure (MAP) throughout pregnancy in normotensive women.

STUDY DESIGN

A retrospective study was performed on 84 pregnant women with normal and abnormal antenatal OGTT results who delivered in a 12-month period to determine the changes in MAP and its relationships with the OGTT values.

RESULTS

MAP was increased from 28 weeks until delivery in gestational diabetics (n = 50) as compared with controls (n = 34). The OGTT fasting glucose value significantly correlated with MAP at 32 and 36 weeks, while the 2-hour glucose value correlated with MAP at 24 weeks and from 32 weeks until predelivery. Only the 2-hour glucose values from 32 weeks until delivery correlated with MAP when body mass index was controlled for.

CONCLUSION

Progressive glucose intolerance is associated with an upward shift in blood pressure in the third trimester of pregnancy in normotensive women. Blood pressure changes below the diagnostic threshold for hypertensive disorders of pregnancy may help to identify women at increased risk of gestational diabetes mellitus.

alpha-Thalassaemia trait and gestational diabetes mellitus in Hong Kong

AIMS/HYPOTHESIS

The purpose of this study was to examine the association between maternal alpha-thalassaemia trait and the occurrence of gestational diabetes mellitus in at-risk Chinese women in Hong Kong.

METHODS

From 3320 pregnant women who had delivered in our hospital and undergone the oral glucose tolerance test for various risk factors over a three-year period, 163 with alpha-thalassaemia trait were identified (study group). The control group consisted of 163 women chosen from the next patient that was matched for maternal age and parity, following each index case. Comparison was made in the incidence of gestational diabetes mellitus defined by the World Health Organisation criteria, obstetric complications, and perinatal outcome.

RESULTS

The incidence of gestational diabetes mellitus was higher in the study group (62.0 % vs 14.7 %, p < 0.0001) which had a higher pre-pregnancy body mass index and lower haemoglobin concentrations. Although more patients in the study group had risk factors (41.7 % vs 26.4 %, p = 0.003), there was no difference in the pregnancy outcome or perinatal complications. Among the gestational diabetic women, those with alpha-thalassaemia trait were considerably younger and their infants had lower body mass index but there was no significant difference in the outcome. On multiple logistic regression analysis, the alpha-thalassaemia trait remained an important factor in the diagnosis of gestational diabetes (OR 11.74, 95 % CI 6.37-21.63).

CONCLUSION/INTERPRETATION

Among women at risk of gestational diabetes, the presence of the alpha-thalassaemia trait is an additional risk factor for gestational diabetes mellitus.

Expression of vascular endothelial growth factor in third-trimester placentas is not increased in growth-restricted fetuses

OBJECTIVE

Vascular endothelial growth factor (VEGF) is considered the growth factor that stimulates vasculogenesis and angiogenesis. Recent studies have demonstrated its role in regulating placental growth and invasion. Its expression can be upregulated by hypoxia. Intrauterine growth restriction (IUGR) is thought to be associated with inadequate placental perfusion, which might result from a failure in the development of the villous vascular network. Our present study was undertaken to examine the relationship between VEGF expression and IUGR in pregnancies with preserved umbilical artery end-diastolic flow.

METHODS

VEGF Expression was determined by immunohistochemical analysis of placentas from 17 pregnancies with normal infant birth weight and 17 pregnancies complicated by IUGR.

RESULTS

We found no significant differences in the expression of VEGF in villous syncytiotrophoblasts and intermediate trophoblasts in maternal decidua between IUGR and normal pregnancies. However, in both groups there was a strong correlation in the expression of VEGF with villous syncytiotrophoblasts and intermediate trophoblasts. In normal and IUGR pregnancies the infants' Apgar scores at birth were significantly correlated with VEGF staining in both syncytiotrophoblasts and intermediate trophoblasts (P < .05). A strong correlation also was found between cord hematocrit and VEGF staining in villous syncytiotrophoblasts (P < .05), but VEGF staining in intermediate trophoblasts was not correlated with cord hemoglobin or hematocrit.

CONCLUSIONS

Our results suggest that VEGF acts in an autocrine and paracrine fashion in both normal and IUGR placentas, and its expression can have an effect on the well being of the infant at birth.

Gestational diabetes mellitus in the last trimester - a feature of maternal iron excess?

AIM

To determine whether non-anaemic women with gestational diabetes mellitus (GDM) diagnosed in third trimester pregnancy have evidence of increased iron stores compared with matched non-diabetic controls.

METHODS

In a prospective study, women who had antenatal booking before 20 weeks' gestation and without anaemia or diabetes mellitus were recruited at the time of the oral glucose tolerance test (OGTT) at 28-31 weeks' gestation for the study of serum ferritin, iron and transferrin concentrations. The results were blinded to the managing obstetricians. After delivery, the records were reviewed. The cases diagnosed as GDM were compared with a control group (two controls for each index case matched for parity) selected at random from the at-risk but nondiabetic cases.

RESULTS

GDM was diagnosed in 97 of the 401 women recruited. Compared with the 194 controls, there was no difference in the weight, body mass index, booking and third trimester haemoglobin, or third trimester red cell indices, but concentrations of serum ferritin, iron, transferrin saturation, and the post-natal haemoglobin were significantly higher. On multiple regression analysis, maternal BMI and the log-transformed ferritin concentration remained significant determinants of the OGTT 2-h glucose value.

CONCLUSION

The results suggest an association between increased iron stores and glucose intolerance at the third trimester in non-anaemic women. The role of iron excess in the pathogenesis of GDM needs to be examined.

Goitrogenesis during pregnancy and neonatal hypothyroxinaemia in a borderline iodine sufficient area

OBJECTIVE

Severe iodine deficiency disorders (IDDs) may have been eradicated in many parts of the world, but milder forms still exist and may escape detection. We evaluated the impact of pregnancy on the maternal and fetal thyroid axis in Hong Kong, a coastal city in southern China with borderline iodine intake.

DESIGN

A prospective study performed in a maternity hospital.

PATIENTS

Two hundred and thirty pregnant women were prospectively studied and their neonates assessed at birth.

MEASUREMENTS

Urine iodine concentration, thyroid function tests and thyroid volume (TV) by ultrasound were determined in the mothers during pregnancy and up to 3 months postpartum and in the neonates.

RESULTS

Increased urinary iodine concentration was seen from first trimester onwards and the proportion of women having urine iodine concentration of < 0.4 micromol/l decreased from 11.3% in the first trimester to 4.7% in the third trimester. There was progressive reduction in circulating fT4 and fT3 concentrations and free thyroxine index (FTI) with increasing gestation and the percentage of women having subnormal levels at term were 53.2%, 61.1% and 4.8%, respectively. The serum TSH concentration during pregnancy doubled towards term. In the first trimester, multiparous women had significantly larger TV than the nulliparous women (P < 0.001). By the third trimester, TV had increased by 30% (range 3-230%) so that the goitre incidence was 14.1%, 21.8%, 25.9% during the three trimesters of pregnancy, and 24.3% and 21.9% at 6 weeks and 3 months postpartum (ANOVA, P < 0.05). The change in thyroid volume during pregnancy correlated positively with the change in thyroglobulin (r = 0.225, P < 0.002) and negatively with urinary iodine concentration (r = - 0.149, P < 0.02). Fourteen women with excessive thyroidal stimulation in the second trimester (defined as those with thyroglobulin (Tg) concentrations in the highest tertile and FTI in the lowest tertile) were found to have lower urine iodine concentrations and larger TV (both P < 0.005) throughout pregnancy, and their neonates had higher cord TSH (P < 0.05), Tg (P < 0.05) and slightly larger TV (P = 0.06) as compared to the findings in 216 pregnant women without evidence of thyroid stimulation. Seven neonates (50%) born to these women had subnormal fT4 levels at birth.

CONCLUSION

In a borderline iodine sufficient area, pregnancy posed an important stress resulting in higher rates of maternal goitrogenesis as well as neonatal hypothyroxinaemia and hyperthyro- trophinaemia. An adequate iodization program is necessary to eliminate iodine deficiency disorders during pregnancy.

Placental ratio and anemia in third-trimester pregnancy

OBJECTIVE

To perform a prospective, observational study in a tertiary center to determine whether anemia (hemoglobin level < 10 g/dL) developing in the third trimester was associated with an increased placental weight/birth weight ratio (placental ratio) and whether the placental ratio correlated with the hemoglobin level at different periods and with other factors, such as gestational age and parity.

STUDY DESIGN

A total of 476 nonanemic women with low-risk singleton pregnancies were recruited at their 28-30-week antenatal visit over a three-month period. Excluded from the final analysis were 20 women who delivered elsewhere and 19 found to be carriers of thalassemia traits due to their low mean cell volume. All women received standard obstetric care, and ferrous sulphate was prescribed for those who developed anemia.

RESULTS

Anemia developed in 45 (10.3%) of the remaining 437 women. This group had significantly decreased red cell indices, gestational age (38.3 +/- 2.0 vs. 39.2 +/- 1.3 weeks, P = .004) and birth weight (3,082 +/- 416 vs. 3,220 +/- 411 g, P = .035) but no difference in placental weight (609 +/- 102 vs. 594 +/- 108 g), so the placental ratio was increased as compared with that in the control group (0.196 +/- 0.026 vs. 0.185 +/- 0.026, P = .002). Multiple regression analysis confirmed that the placental ratio correlated only with the last hemoglobin level (P = .041).

CONCLUSION

Our results indicate that placental size increased relative to infant size in pregnancies complicated by anemia, but whether this phenomenon reflected actual placental hypertrophy or failure of fetal growth to keep up with placental growth remains to be determined.

Third trimester iron status and pregnancy outcome in non-anaemic women; pregnancy unfavourably affected by maternal iron excess

A prospective observational study was performed on 488 women with haemoglobin >/=10 g/dl at booking to examine the relationship between serum ferritin concentration quartiles at 28-30 weeks gestation with maternal characteristics, pregnancy complications and infant outcome. While there was no difference in the maternal characteristics or gestational age, the infant size decreased significantly and progressively from the lowest to the highest quartile. Despite a significant difference in the incidence of multiparous women, there was no difference in the incidence of most complications except for prelabour rupture of the membranes and infant admission to the neonatal unit. Compared with the other three quartiles, the highest quartile was associated with increased risk for preterm delivery and neonatal asphyxia, while the lowest quartile was associated with decreased risk of pre-eclampsia, prelabour rupture of the membranes, and infant admission to the neonatal unit. Overall, ferritin quartiles were correlated with other parameters of iron status and red cell indices, and ferritin concentration was inversely correlated with infant birthweight. Our findings suggested that maternal ferritin concentration is primarily a reflection of maternal iron status, and a high level is associated with unfavourable outcome. The rationale of routine iron supplementation in non-anaemic women needs to be re-examined.

Impaired glucose tolerance and pregnancy outcome in Chinese women with high body mass index

To determine if impaired glucose tolerance (IGT) impacts on the outcome of singleton pregnancies in Chinese women with a high (>26 kg/m(2)) body mass index (BMI), a retrospective case-control study was performed on 128 women with IGT and 128 controls with normal oral glucose tolerance test results, who were matched for pre-pregnancy BMI (within 0.1 kg/m(2)) and delivered within the same 3 year period. The IGT group was older, with more multiparae, a higher incidence of previous gestational diabetes mellitus, higher booking haemoglobin and fasting glucose concentrations, but no difference in the pre-pregnancy weight, gestational weight gain, or weight or BMI at delivery. There was no difference in the obstetric complications, mode of delivery, or the gestational age or mean infant birthweight. However, the birthweight ratio (relative to mean birthweight for gestation), incidence of large-for-gestational-age (birthweight >90th percentile) and macrosomic (birthweight > or =4000 g) infants, and treatment for neonatal jaundice, were significantly higher in the IGT group. The results suggest that some of the complications attributed to gestational diabetes mellitus are probably related to maternal weight excess/obesity in the affected subjects, but IGT could still affect infant birthweight outcome despite diet treatment which has normalized gestational weight gain.

Predicting the success of external cephalic version with a scoring system. A prospective, two-phase study

OBJECTIVE

To develop a noninvasive and quantifiable scoring system based on clinical parameters to predict the success of external cephalic version (ECV) in women with breech presentation at term.

STUDY DESIGN

This was a prospective, two-phase, clinical study. Phase 1 was to develop a scoring system from 53 versions with singleton pregnancy in breech presentation at term using a standard protocol with fetal monitoring, ultrasound assessment and tocolysis. Phase 2 was to verify this scoring system by application to 88 versions using the same standard protocol as in phase 1.

RESULTS

The success rates for ECV in phases 1 and 2 were 64.2% and 61.4%, respectively, making the overall success rate 62.4%. The results of phase 1 showed that there were significant differences in the following parameters: head palpable, breech unengagement, symphysisfundal height and uterine relaxation. A scoring system based on these four clinical parameters was developed. When applied to 88 versions in the second phase, the likelihood ratio of successful ECV was > 30 if the version score was > or = 3 and < 1.8 if the version score was < or = 2.

CONCLUSION

Using our scoring system, prediction of successful ECV was possible without ultrasound scan or vaginal examination, and counseling could be given once breech presentation was diagnosed.

Labour characteristics and uterine activity: misoprostol compared with oxytocin in women at term with prelabour rupture of the membranes

OBJECTIVE

To compare the labour pattern and uterine activity of oral misoprostol with oxytocin for labour induction in women presenting with prelabour rupture of membranes at term.

DESIGN

Prospective randomised study.

SETTING

Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong.

PARTICIPANTS

Eighty women presenting with prelabour rupture of membranes at term.

METHODS

The women were randomised to receive either 100 microg misoprostol orally every 4 hours to a maximum of three doses, or intravenous oxytocin infusion according to the hospital protocol. Intrauterine pressure transducers were inserted one hour before induction of labour in both groups of women. We compared the pattern of uterine activity, the induction-to-delivery interval, duration of labour, mode of delivery and neonatal outcome between the two groups.

RESULTS

Both oxytocin and oral misoprostol caused an increase in uterine activity within one hour of labour induction. Peak uterine activity was reached 6-8 h after oral misoprostol, with persistent effects, and 8-10 h after oxytocin, requiring continuous titration of medication. The duration of labour was significantly reduced in nulliparous women, but not in those who were multiparous in the misoprostol group. The induction-to-delivery interval, the mode of delivery and the perinatal outcome were similar for the two groups.

CONCLUSION

Oral misoprostol caused earlier peak uterine activity, compared with oxytocin (6-8 h vs 8-10 h). Oral misoprostol was not only as effective as oxytocin in inducing labour in women at term with prelabour rupture of the membranes, but it reduced significantly the duration of labour in nulliparous women.

Relationship between preterm delivery and maternal height in teenage pregnancies

A retrospective study was performed in 613 singleton pregnancies born to mothers aged < or =19 years over a 4-year period to determine the relationship between maternal height and preterm delivery (<37 weeks). The pregnancies were grouped according to maternal height quartiles for comparison of maternal and infant characteristics, obstetric complications and pregnancy outcome. The incidences of preterm delivery and labour decreased from 17.5% and 15.6% respectively in the lowest quartile, to 8.5% and 7.1% respectively in the highest quartile, without any difference in the risk factors or major complications. In the pregnancies without major complications, which included 73.3% of the cases of preterm labour, the rate of preterm labour was significantly and inversely correlated with the height quartiles. In the newborns, gestational age, birthweight and crown-heel length increased with the higher quartiles, but the ratio between infant crown-heel length and maternal height (height ratio) decreased with the higher quartiles. Unlike birthweight and crown-heel length, the height ratio was not correlated with gestational age. Our findings suggested that the inherent risk of preterm delivery in teenagers was related to their immature physical development at the time of pregnancy, as reflected by the maternal height.

Placental size and large-for-gestational-age infants in women with abnormal glucose tolerance in pregnancy

AIMS

To determine if the placental size is disproportionately increased in the large-for-gestational age infants in pregnancies complicated by impaired glucose tolerance.

METHODS

A retrospective study was performed on 568 consecutive singleton pregnancies complicated by gestational impaired glucose tolerance controlled with diet and who delivered within a 15-month period. The cases were categorized by the infant birthweight percentile into three groups, i.e. small-for-gestational age (< 10th percentile), appropriate-for-gestational age (10th to 90th percentile) and large-for-gestational age (> 90th percentile). Maternal and infant anthropometric data, glycaemic status, and placental weight-to-birthweight ratio were compared among the three groups.

RESULTS

The infant body mass index and placental weight showed a significantly increasing trend from the small-for-gestational age to the large-for-gestational age groups, but there was no significant difference in the placental weight-to-birthweight ratio, values of the oral glucose tolerance test, or haemoglobin A1c among the three groups. On the other hand, the maternal body mass index before pregnancy and at delivery were significantly higher in the large-for-gestational age group. The placental weight, but not the ratio, was significantly correlated with the maternal body mass index before pregnancy and at delivery (P < 0.001).

CONCLUSIONS

The results indicate that the placenta is not disproportionately bigger, and therefore unlikely to be the cause, in large-for-gestational age infants. Maternal size appeared to be the major determinant of birthweight percentile ranking in pregnancies with gestational impaired glucose tolerance.