Women’s beliefs about the duration of pregnancy and the earliest gestational age to safely give birth.

Background: American evidence suggests women are not well informed about the optimal duration of pregnancy or the earliest time for safe birth. Similar evidence does not exist in Australia. Aims: To explore pregnant women’s beliefs about the duration of pregnancy and the earliest time for safe birth, and to compare the results with US data. Methods: A cross-sectional survey of pregnant women attending antenatal clinics at four public hospitals in Sydney, Australia, included collection of maternal and pregnancy characteristics, and two questions exploring women’s beliefs about the duration of pregnancy, and the earliest time for safe birth. Responses were grouped as: late preterm (34-36 weeks), early term (37-38 weeks), and full term (39-40 weeks). Results: Of 784 surveyed women, 52% chose 39-40 weeks as the duration of a full term pregnancy, while for the earliest time for safe birth, 10% chose 39-40 weeks and 57% chose 37-38 weeks. Some maternal characteristics were associated with women’s beliefs, including having a medical and/or pregnancy complication, country of birth, level of education, employment status, and attending a tertiary hospital. The associations were different for each question. In comparison with US studies, Australian women were more likely to choose later gestations for both the duration of pregnancy and the earliest time for safe birth. Conclusions: A significant proportion of Australian women believe that full term pregnancy and earliest time for safe birth occur before 39 weeks, suggesting opportunities for antenatal education.The authors would like to thank the women who participated in the survey, and acknowledge the contribution of the research midwives, Jill Milligan, Rachel Reid, Jocelyn Sedgley and Katrina White-Mathews, as well as Dr. Antonia Shand for assisting with participant recruitment. This work was supported by an Australian National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant (1001066). CLR is supported by an NHMRC Senior Research Fellowship (#APP1021025)

Dietary vitamin, mineral and herbal supplement use: a cross-sectional survey of before and during pregnancy use in Sydney, Australia.

AIM: To describe use of dietary vitamin, mineral and herbal supplements before and during pregnancy. METHODS: Pregnant women attending antenatal care at two tertiary Sydney hospitals between January and March 2014 completed an anonymous survey. Information on general maternal and pregnancy characteristics and the use of dietary and herbal supplements, including type, duration, and sources of information was collected. Frequency and contingency tabulations were performed. RESULTS: 612 women agreed to participate (91% response rate). 23 were excluded due to incomplete data. Of 589 women included in the analysis, the mean gestational age at the time of survey was 28.5 weeks (SD 8.3), 55% had no children, and 67% were tertiary educated. Overall 62.9% of women reported taking a multivitamin (MV) and/or folic acid (FA) supplement in the 3 months pre-pregnancy. At the time of the survey 93.8% of women were taking at least one supplement (median 2, range 1-13). During pregnancy 79.1% of women were taking MVs, including 59.2% taking MV only and 19.9% taking MV and FA. The 5 most common supplements outside of a MV were FA (31%), iron (30%), vitamin D (23%), calcium (13%) and fish oil (12%). CONCLUSION: Use of folic acid and MVs and other supplements during and pre-pregnancy is relatively high, although pre-pregnancy FA supplementation rates could still be improved. Further research on the actual dosages and dietary intakes consumed are needed to examine whether pregnant women have adequate intake of nutrients, regardless of supplement use.NHMR

Iron supplement use in pregnancy – are the right women taking the right amount?

Objectives: To examine the prevalence and determinants of iron supplement use and the amount of iron consumed from iron-containing supplements. Methods: A cross-sectional survey was performed in antenatal clinics in two tertiary hospitals in Sydney, Australia between January and March 2014. Results: Of 612 (91% response rate) pregnant women, 589 with complete data were analysed. The overall prevalence of iron-containing supplement use was 88.0%, of which 70.1% was MV only, 7.2% was iron-only and 22.2% was both. Use of iron-containing supplements was associated with increased gestational age, a diagnosis of anaemia or iron deficiency (ID) in the current pregnancy and pre-pregnancy use of an iron-containing supplement. Several risk factors for ID or anaemia such as on-red meat eating and previous miscarriage were not associated with current iron supplement use. About 65% of women diagnosed with ID, and 62.3% of women diagnosed with anaemia were taking an iron-only supplement, with or without a MV. The proportion of women consuming low (<30), preventative (30-99) and treatment (≥100) mg/day doses were 36.8%, 45.4%, and 17.8%, respectively. Only 46.7% of women diagnosed with ID were taking ≥100 mg/day iron from supplements, while 23.3% were taking <30 mg/day. Conclusion: Women are consuming varying doses of iron and some high-risk women are taking inadequate doses of iron to prevent or treat ID or iron deficiency anaemia. Healthcare professionals are best positioned to advise women on iron supplement use in pregnancy and should educate women individually about the type and dose of supplement best suited to their needs.NHMR

Women's views about the timing of birth

Background: Estimated date of birth (EDB) is used to guide clinical management of women during pregnancy and birth, although its imprecision is recognised. Alternatives to the EDB have been suggested for use with women however their attitudes to timing of birth information have not been examined. Aims: To explore women’s expectations of giving birth on or near their EDB, and their attitudes to alternative estimates for timing of birth. Methods: A survey of pregnant women attending four public hospitals in Sydney, Australia, between July and December 2012. Results: Among 769 surveyed women, 42% expected to birth before their due date, 16% after the due date, 15% within a day or so of the due date, and 27% had no expectations. Nulliparous women were more likely to expect to give birth before their due date. Women in the earlier stages of pregnancy were more likely to have no expectations or to expect to birth before the EDB while women in later pregnancy were more likely to expect birth after their due date. For timing of birth information, only 30% of women preferred an EDB; the remainder favoured other options. Conclusions: Most women understood the EDB is imprecise. The majority of women expressed a preference for timing of birth information in a format other than an EDB. In support of woman-centred care, it may be helpful to ask each woman how she would like to receive estimated timing of birth information.NHMR

Maternal body weight and first trimester screening for chromosomal anomalies

Prenatal risk ratios for Down syndrome adjust for maternal weight because maternal serum 2 biomarker levels decrease with increasing maternal weight. This is accomplished by converting 3 serum biomarker values into a multiple of the expected median (MOM) for women of the same 4 gestational age. Weight is frequently not recorded and the impact of using MOMs not adjusted for 5 weight for calculating risk ratios is unknown. The aim of this study is to examine the effect of 6 missing weight on first trimester Down syndrome risk ratios by comparing risk ratios calculated 7 using weight-unadjusted-and –adjusted MOMs. Findings at the population level indicate that the 8 impact of not adjusting for maternal weight on first trimester screening results for chromosomal 9 anomalies would lead to under-identification of 84 per 10,000 pregnancies.NHMR

Methods of classification for women undergoing induction of labour: a systematic review and novel classification system

Background: The lack of reproducible methods for classifying women having an induction of labour (IOL) has led to controversies regarding the association of IOL and health outcomes for mother and baby. Objectives: To identify research papers that describe a methodology for classifying women having an IOL, and to evaluate the utility of these methods of classification for clinical, research and surveillance purposes. Search strategy: We conducted electronic searches in CINAHL, EMBASE and WEB of KNOWLEDGE from database inception until Oct 2013 and searched reference lists. Selection criteria: Two reviewers independently assessed eligibility. Studies had to describe a method for classifying women with an IOL using a minimum of two categories, regardless of whether or not this was the main purpose of the study. Data collection: Data were extracted on study characteristics, quality and results. Pre-specified criteria were used to evaluate the utility of these methods of classification for IOL. Main results: Seven studies met the inclusion criteria. All studies categorised women according to the presence or absence of a medical indication for IOL. Uncertainties and/or deficiencies were identified across all methods of classification related to the criteria of total inclusivity, reproducibility, clinical utility, implementability and data availability limiting their usefulness. Conclusion: Current methods of classifying women with an IOL are inadequate for clinical, research and surveillance purposes. Limitations with classification systems based on medical indications suggest that an alternative method of classification is required for women having IOL

Predicting date of birth: the best time to date a pregnancy?

Objective: To compare the estimated date of birth calculations from last menstrual period (LMP) and ultrasounds at varying gestations (<70, 70-106, 110-140, 141-196 and 200-276) against the actual date of birth (DOB). Methods: This cohort study in a single local health district, Australia included 18,708 women with spontaneous labor who gave birth to a single live born infant without major anomalies between 2007 and 2011. Data were sourced from a computerized population birth database. The outcome of interest was duration of pregnancy expressed as total days, and the difference between actual DOB and estimated date of birth by dating method. Results: Only 5% of births occurred on the estimated date of birth regardless of the timing of the estimate. Approximately 66% of births occurred +/-7 days of the estimated date of birth, and there was little difference between ultrasound gestational week bands. The 110-140 weeks of gestation ultrasound performed as well if not better than ultrasounds conducted at other gestations. Maternal factors such as ethnicity and smoking status during pregnancy influenced duration of pregnancy; however, their explanatory power was too low to support incorporating these characteristics in dating estimations. Conclusion: An early dating scan (10 weeks or earlier) is unnecessary if LMP is reliable.Australian National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant (#APP1001066), Sydney Medical School Summer Research Scholarship, NHMRC Senior Research Fellowship (#APP1021025)

High maternal serum ferritin in early pregnancy and risk of spontaneous preterm birth

Previous studies have reported inconsistent associations between maternal serum ferritin concentrations and risk of preterm birth. The aim of this study was to examine the association between iron biomarkers, including serum ferritin and risk of total, early and moderate-to-late spontaneous preterm birth (sPTB). This cohort study included women with singleton pregnancies who were attending first-trimester screening in New South Wales, Australia. sPTB births included births 75th percentile (≥43 μg/L) (OR: 1.49, 95% CI: 1.06, 2.10) and >90th percentile (≥68 μg/L) (OR: 1.92, 95% CI: 1.25, 2.96). Increased odds of early and moderate-to late sPTB were associated with ferritin levels >90th (OR: 2.50, 95% CI: 1.32, 4.73) and >75th (OR: 1.56, 95% CI: 1.03, 2.37) percentiles, respectively. No association was found between sPTB, and elevated sTfR levels or iron deficiency. In conclusion, elevated early pregnancy maternal serum ferritin levels are associated with increased risk of sPTB from 34 weeks gestation. The usefulness of early pregnancy ferritin levels in identifying women at risk of sPTB warrants further investigation.NHMR

Iron deficiency in early pregnancy using serum ferritin and soluble transferrin receptor concentrations are associated with pregnancy and birth outcomes.

Background: There are several biomarkers for measuring iron deficiency (ID) in pregnancy, but evidence of their prevalence in association with inflammation and adverse pregnancy outcomes is inconclusive. Objectives: To describe the prevalence and determinants of ID in women in the first trimester of pregnancy and associations with pregnancy and birth outcomes. Design: A record-linkage cohort study of archived serum samples of women attending first trimester screening and birth and hospital data to ascertain maternal characteristics and pregnancy outcomes. Sera were analysed for iron stores (ferritin; μg/L), tissue iron (soluble transferrin receptor, sTfR; nmol/L) and inflammatory (C-reactive protein, CRP; mg/L) biomarkers. Total body iron (TBI) was calculated from serum ferritin and sTfR concentrations. Multivariate logistic regression analyzed risk factors and pregnancy outcomes associated with ID using the definitions: serum ferritin <12 μg/L, TfR ≥21.0 nmol/L and TBI<0 mg/kg. Results: Of 4,420 women, the prevalence of ID based on ferritin, sTfR and TBI was 19.6%, 15.3% and 15.7%, respectively. Risk factors of ID varied depending on which iron parameter was used and included maternal age <25 years, multiparity, socioeconomic disadvantage, high maternal body weight and inflammation. ID was associated with reduced risk of gestational diabetes (GDM) defined using serum ferritin and TBI, but not sTfR and increased risk of large for gestation age (LGA) infants defined using TBI only. Conclusions: Nearly 1 in 5 Australian women begin pregnancy with ID. Evidence suggests excess maternal weight and inflammation play a role in the relationships between ID and GDM and LGA infants.NHMR

High maternal iron status, dietary iron intake and iron supplement use in pregnancy and risk of gestational diabetes mellitus: In-house study and systematic review

Background: High iron measured using dietary and serum biomarkers have been associated with type 2 diabetes; however it is uncertain whether a similar association exists for gestational diabetes mellitus (GDM). Objectives: To conduct a cohort study examining first trimester body iron stores and subsequent risk of GDM and to include these findings in a systematic review of all studies examining the association between maternal iron status, iron intake (dietary and supplemental) and the risk of GDM. Methods: Serum samples for women with first trimester screening were linked to birth and hospital records for data on maternal characteristics and GDM diagnosis. Blood was analysed for ferritin, soluble transferrin receptor (sTfR) and C-reactive protein (CRP). Associations between iron biomarkers and GDM were assessed using multivariate logistic regression. A systematic review and meta-analysis, registered with PROSPERO (CRD42014013663) included all studies published in English from Jan 1995 to March 2014 that examined the association between iron and GDM and included an appropriate comparison group. Results: Of 3, 776 women, 3.4% subsequently developed GDM. Adjusted analyses found increased odds of GDM for ferritin (OR 1.41; 95% CI: 1.11, 1.78) but not for sTfR (OR 1.00, 95% CI: 0.97, 1.03) levels. Two trials of iron supplementation in early pregnancy found no association with GDM. Increased risk of GDM was associated with higher levels of maternal ferritin and serum iron and dietary heme iron intakes. Conclusions: Increased risk of GDM among women with high serum ferritin and iron levels and dietary heme iron intakes warrants further investigation.NHMR