Possible association of folic acid supplementation during pregnancy with reduction of preterm birth: a population-based study

Objective

Periconceptional folic acid or multivitamin supplementation is recommended for prospective pregnant women to prevent neural-tube defects. The question is whether it is worth continuing these supplementations after the first trimester of pregnancy or not. Thus the possible fetal growth promoting and/or preterm birth reducing effect of vitamin supplements in the second and mainly in the third trimester was studied.

Study design

Comparison of birth outcomes of singletons born to primiparous pregnant women with prospectively and medically recorded vitamin supplement in the population-based data set of the Hungarian Case-Control Surveillance of Congenital Abnormalities (HCCSCA), 1980–1996 contained 6293, 169, and 311 primiparae with folic acid alone, multivitamins and folic acid + multivitamin supplementation, respectively, and their data were compared to the data of 7319 pregnant women without folic acid and folic acid-containing multivitamin supplementation as reference.

Results

Mean gestational age was 0.3 week longer and mean birth weight was by 37 g higher in the group of folic acid alone, than in the reference group (39.2 weeks; 3216 g). The rate of preterm births (7.6%) was significantly lower compared with the reference sample (11.8%), but the rate of low birth weight newborns did not show significant reduction. Folic acid alone in the third trimester associated with 0.6 week longer gestational age and a more significant reduction in the rate of preterm births (4.8%).

Conclusions

Minor increase in mean birth weight after high dose of folic acid supplementation during pregnancy would not be expected to result in too large babies; however, the significant reduction in the rate of preterm births may have great public health benefit.     

Worldwide prevalence of adverse pregnancy outcomes associated with in vitro fertilization/intracytoplasmic sperm injection among multiple births: a systematic review and meta-analysis based on cohort studies

Purpose

To perform a systematic review and meta-analysis of reported estimates of adverse pregnancy outcomes among multiple births conceived with in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

Methods

PubMed, Google Scholar, Cochrane Libraries and Chinese databases were searched through May 2016 for cohort studies assessing adverse pregnancy outcomes associated with IVF/ICSI multiple births. Random-effects meta-analyses were used to calculate pooled estimates of adverse pregnancy outcomes and, where appropriate, heterogeneity was explored in group-specific analyses.

Results

Sixty-four studies, with 60,210 IVF/ICSI multiple births and 146,737 spontaneously conceived multiple births, were selected for analysis. Among IVF/ICSI multiple births, the pooled estimates were 51.5% [95% confidence interval (CI): 48.7–54.3] for preterm birth, 12.1% (95% CI: 10.4–14.1) for very preterm birth, 49.8% (95% CI: 47.6–52.0) for low birth weight, 8.4% (95% CI: 7.1–9.9) for very low birth weight, 16.2% (95% CI: 12.9–20.1) for small for gestational age, 3.0% (95% CI: 2.5–3.7) for perinatal mortality and 4.7% (95% CI: 4.0–5.6) for congenital malformations. When the data were restricted to twins, the pooled estimates also showed a high prevalence of adverse outcomes. There was a similar prevalence of poor outcomes among multiple births conceived with IVF/ICSI and naturally (all P?≥?0.0792). Significant differences in different continents, countries, and income groups were found.

Conclusions

The IVF/ICSI multiple pregnancies have a high prevalence of adverse pregnancy outcomes. However, population-wide prospective adverse outcomes registries covering the entire world population for IVF/ICSI pregnancies are needed to determine the exact perinatal prevalence.

     

Global report on preterm birth and stillbirth (2 of 7): discovery science

Background

Normal and abnormal processes of pregnancy and childbirth are poorly understood. This second article in a global report explains what is known about the etiologies of preterm births and stillbirths and identifies critical gaps in knowledge. Two important concepts emerge: the continuum of pregnancy, beginning at implantation and ending with uterine involution following birth; and the multifactorial etiologies of preterm birth and stillbirth. Improved tools and data will enable discovery scientists to identify causal pathways and cost-effective interventions.

Pregnancy and parturition continuum

The biological process of pregnancy and childbirth begins with implantation and, after birth, ends with the return of the uterus to its previous state. The majority of pregnancy is characterized by rapid uterine and fetal growth without contractions. Yet most research has addressed only uterine stimulation (labor) that accounts for <0.5% of pregnancy.

Etiologies

The etiologies of preterm birth and stillbirth differ by gestational age, genetics, and environmental factors. Approximately 30% of all preterm births are indicated for either maternal or fetal complications, such as maternal illness or fetal growth restriction. Commonly recognized pathways leading to preterm birth occur most often during the gestational ages indicated: (1) inflammation caused by infection (22-32 weeks); (2) decidual hemorrhage caused by uteroplacental thrombosis (early or late preterm birth); (3) stress (32-36 weeks); and (4) uterine overdistention, often caused by multiple fetuses (32-36 weeks). Other contributors include cervical insufficiency, smoking, and systemic infections. Many stillbirths have similar causes and mechanisms. About two-thirds of late fetal deaths occur during the antepartum period; the other third occur during childbirth. Intrapartum asphyxia is a leading cause of stillbirths in low- and middle-income countries.

Recommendations

Utilizing new systems biology tools, opportunities now exist for researchers to investigate various pathways important to normal and abnormal pregnancies. Improved access to quality data and biological specimens are critical to advancing discovery science. Phenotypes, standardized definitions, and uniform criteria for assessing preterm birth and stillbirth outcomes are other immediate research needs.

Conclusion

Preterm birth and stillbirth have multifactorial etiologies. More resources must be directed toward accelerating our understanding of these complex processes, and identifying upstream and cost-effective solutions that will improve these pregnancy outcomes.

     

Birth weight discordancy and adverse perinatal outcomes among twin gestations in the United States: the effect of placental abruption

OBJECTIVE: We evaluated whether the relationship between birth weight discordancy of twins and stillbirth, neonatal deaths, and preterm births was modified by the presence of abruption. STUDY DESIGN: We used the 1995 to 1997 matched multiple birth file for United States twin births (n = 269287). Birth weight discordancy was defined as the ratio of the difference in birth weight of the heavier from the lighter twin to that of the heavier twin and was categorized as <5%, 5% to 9%, 10% to 14%, 15% to 19%, 20% to 29%, 30% to 39%, and >or=40%. We evaluated the risks of stillbirth (>or=20 weeks of gestation), neonatal deaths (within 28 days after birth), and preterm birth (< 32 weeks) in the presence and absence of abruption. Associations between birth weight discordancy and these perinatal outcomes were expressed as adjusted relative risks and were derived from multivariable logistic regression models, based on the method of generalized estimating equations. Risk of these outcomes were derived for each stratum of birth weight discordancy and abruption status, with the <5% birth weight discordancy, nonabruption status labeled as the reference group. All analyses were performed separately for same and different sex twins. RESULTS: A birth weight discordancy of >or=20% among same sex (adjusted relative risk, 1.2; 95% CI, 1.1, 1.4), and >or=40% among different sex twins (relative risk, 2.2; 95% CI, 1.7, 2.8) conferred increased risk for abruption. Among nonabruption births, a birth weight discordancy of >or=15% among same sex and >or=30% among different sex twins increased the risk of stillbirths, neonatal deaths, and preterm births. Among abruption births, however, the risks were increased even in the lowest birth weight discordancy category (<5%). The relative risks of stillbirths and neonatal deaths among abruption births were significantly higher for each birth weight discordancy group, both for same and different sex twins, compared with the reference group. The association between birth weight discordancy and preterm birth was not modified by either the presence or absence of abruption. CONCLUSION: Birth weight discordancy of >or=15% for same sex and >or=30% for different sex confer greatest risk of adverse perinatal outcomes in the absence of abruption. In the presence of placental abruption, these risks are further compounded. The results underscore the need for careful monitoring of twin pregnancies.     

Maternal,Fetal, and Neonatal Outcomes of Elective Fetal Reduction Among Multiple Gestation Pregnancies: A Systematic Review

ObjectiveTo review the existing literature on fetal and maternal health outcomes following elective pregnancy reduction.Data SourcesMEDLINE, EMBASE, CINAHL, the Cochrane Database of Systematic Reviews, and the Cochrane Controlled Trials Register.Study SelectionStudies involving women pregnant with dichorionic twins, trichorionic triplets, or quadra-chorionic quadruplets who underwent elective fetal reduction of 1 or more fetuses to reduce the risks associated with multiple gestation pregnancies.Data ExtractionThe main fetal health outcomes measured were gestational age at delivery, preterm birth, miscarriage, birth weight, and small for gestational age at delivery. The main maternal health outcomes measured were gestational diabetes, hypertensive disorders of pregnancy, and cesarean delivery.Data SynthesisOf 7678 studies identified, 24 were included (n = 425 dichorionic twin pregnancies, n = 2753 trichorionic triplet pregnancies, and n = 111 quadra-chorionic quadruplet pregnancies). Fifteen studies (62.5%) did not report maternal health outcomes, while every study reported at least 1 fetal health outcome. Fetal reduction was associated with higher gestational age at birth, lower preterm birth, higher birth weight, and lower rates of small for gestational age infants and intrauterine growth restriction. No consistent pattern was observed for miscarriage and neonatal mortality rates. Following fetal reduction, cesarean delivery rates were lower in most studies. There were no appreciable trends with respect to gestational diabetes or hypertensive disorders of pregnancy.ConclusionFetal reduction reliably optimizes gestational age at birth and neonatal birth weight. Miscarriage rates and other adverse procedural outcomes did not increase following transabdominal reduction. Further research on maternal outcomes is needed given a paucity of information in the literature.     

Triplet births in the United States. An epidemic of high-risk pregnancies

OBJECTIVE: To more precisely understand the changes in triplet births in recent years. STUDY DESIGN: Analysis of recent government and medical publications pertaining to triplets. RESULTS: Triplet births are at much greater risk than singletons of poor birth outcomes. More than 9 of 10 triplet births are born preterm (< 37 completed weeks of gestation) as compared with < 1 of 10 singleton infants. The average weight of a triplet newborn (1,698 g) is one-half that of a singleton newborn (3,358 g). The infant death rate for triplet and other higher-order multiple births is 12 times higher than that for singletons (93.7 as compared with 7.8 infant deaths per 1,000 live births). CONCLUSION: Based on their frequency of preterm birth, low birth weight and infant death rate, it is appropriate to characterize all triplet pregnancies as high risk.     

Pregnancy complications and delivery outcomes in pregnant women with severe migraine

Objective

The objective was to study the possible association among maternal migraine during pregnancy, pregnancy complications, and the delivery outcomes: sex ratio, gestational age/birth weight and preterm birth/low birth weight.

Study design

The population-based large data set of newborn infants without any defects of the Hungarian Case–Control Surveillance System of Congenital Abnormalities, 1980–1996 was analyzed.

Results

Out of 38,151 newborn infants, 713 (1.9%) had mothers who had severe migraine during pregnancy; 68% were medically recorded. Pregnant women with severe migraine had a higher prevalence of preeclampsia and severe nausea/vomiting, but a lower occurrence of threatened abortion and preterm delivery. However, mean gestational age and birth weight, as well as the proportion of low birth weight and preterm births, were similar in newborn infants born to mothers with or without migraine.

Conclusion

Severe maternal migraine and its related drug treatment may increase the occurrence of preeclampsia and severe nausea/vomiting during pregnancy, but is not associated with unfavorable delivery outcomes.     

Use of the combined first-trimester screen result and low PAPP-A to predict risk of adverse fetal outcomes

OBJECTIVES: To investigate associations between combined first-trimester screen result, pregnancy associated plasma protein-A (PAPP-A) level and adverse fetal outcomes in women. METHODS: Pregnancy outcomes for 10,273 women participating in a community based first-trimester screening (FTS) programme in Western Australia were ascertained by record linkage to birth and birth defect databases. A first-trimester risk cut-off of > or = 1 in 300 defined screen positive women. RESULTS: Screen positive pregnancies were more likely to have Down syndrome and birth defects (chromosomal or nonchromosomal) than screen negative pregnancies. When birth defects were excluded, screen positive pregnancies were at increased risk of pregnancy loss, low birth weight and preterm birth. Pregnancies with low PAPP-A (< or =0.3 multiples of the median (MoM)) had higher risk of chromosomal abnormality, birth defect, preterm birth, low birth weight, or pregnancy loss, compared to those with PAPP-A > 0.3 MoM. In pregnancies without birth defects, low PAPP-A was a stronger predictor of preterm birth, low birth weight or pregnancy loss than a screen positive result. CONCLUSIONS: Women with positive screen or low PAPP-A were at increased risk for some adverse fetal outcomes. The sensitivity of these parameters was insufficient to support primary screening, but increased surveillance during pregnancy may be appropriate.     

Global report on preterm birth and stillbirth (3 of 7): evidence for effectiveness of interventions

Introduction

Interventions directed toward mothers before and during pregnancy and childbirth may help reduce preterm births and stillbirths. Survival of preterm newborns may also be improved with interventions given during these times or soon after birth. This comprehensive review assesses existing interventions for low- and middle-income countries (LMICs).

Methods

Approximately 2,000 intervention studies were systematically evaluated through December 31, 2008. They addressed preterm birth or low birth weight; stillbirth or perinatal mortality; and management of preterm newborns. Out of 82 identified interventions, 49 were relevant to LMICs and had reasonable amounts of evidence, and therefore selected for in-depth reviews. Each was classified and assessed by the quality of available evidence and its potential to treat or prevent preterm birth and stillbirth. Impacts on other maternal, fetal, newborn or child health outcomes were also considered. Assessments were based on an adaptation of the Grades of Recommendation Assessment, Development and Evaluation criteria.

Results

Most interventions require additional research to improve the quality of evidence. Others had little evidence of benefit and should be discontinued. The following are supported by moderate- to high-quality evidence and strongly recommended for LMICs:? Two interventions prevent preterm births—smoking cessation and progesterone? Eight interventions prevent stillbirths—balanced protein energy supplementation, screening and treatment of syphilis, intermittant presumptive treatment for malaria during pregnancy, insecticide-treated mosquito nets, birth preparedness, emergency obstetric care, cesarean section for breech presentation, and elective induction for post-term delivery? Eleven interventions improve survival of preterm newborns—prophylactic steroids in preterm labor, antibiotics for PROM, vitamin K supplementation at delivery, case management of neonatal sepsis and pneumonia, delayed cord clamping, room air (vs. 100% oxygen) for resuscitation, hospital-based kangaroo mother care, early breastfeeding, thermal care, and surfactant therapy and application of continued distending pressure to the lungs for respiratory distress syndrome

Conclusion

The research paradigm for discovery science and intervention development must be balanced to address prevention as well as improve morbidity and mortality in all settings. This review also reveals significant gaps in current knowledge of interventions spanning the continuum of maternal and fetal outcomes, and the critical need to generate further high-quality evidence for promising interventions.

     

Cervical pessary in the prevention of preterm births in multiple pregnancies with a short cervix: PRISMA compliant systematic review and meta-analysis

Background: Preterm births occur frequently in multiple pregnancies with a short cervix. The cervical pessary is a potential intervention for prevention of preterm births.

Objective: To assess the effectiveness of cervical pessary in the prevention of preterm births in multiple pregnancies with a short cervix (<25?mm).

Search strategy: Major databases from 2006 to 20th November 2016 were searched for relevant terms.

Selection criteria: We included randomized controlled trials that assessed the effectiveness of cervical pessary on pregnancy outcomes in multiple pregnancies with a short cervix.

Data collection and analysis: Risk ratio was used as the summary measure with random effects model. We assessed heterogeneity between studies using the I² index. Quality assessment was done based on Cochrane Handbook Method.

Main results: Pooled data showed no benefit of using cervical pessary in the prevention of preterm births, birth weights less than 1500?g, less than 2500?g, adverse neonatal events and fetal/neonatal deaths in twin pregnancies with a short cervix.

Conclusion: We are unable to show benefit of using cervical pessary in preventing preterm births in twin pregnancies with a short cervix. However, as cervical pessary is a reasonable intervention, there is a need for more randomized controlled trials in this area.     

Modelling the potential impact of population-wide periconceptional folate/multivitamin supplementation on multiple births

Objective To develop a model of the impact of population-wide periconceptional folate supplementation on neural tube defects and twin births.
Design A hypothetical cohort of 100,000 pregnancies ≥20 weeks, plus terminations of pregnancy after prenatal diagnosis before 20 weeks.
Methods Application of pooled data on the relative risks for neural tube defects and twins following periconceptional folate from meta-analysis of the randomised trials.
Main outcome measures 1. Pregnancies with a neural tube defect (i.e. terminations of pregnancy, perinatal deaths, and surviving infants); 2. twin births (i.e. preterm births, perinatal deaths, postneonatal deaths, birth defects, cerebral palsy); 3. numbers needed to treat.
Results The change in neural tube defects would be 75 fewer terminations (95% CI -47, -90), 30 fewer perinatal deaths (95% CI 18, -35), and 13 fewer surviving infants with a neural tube defect (95% CI –8, -16). The change in twinning would be an additional 572 twin confinements (95% CI –100, +1587), among whom there would be 63 very preterm twin confinements (95% CI –11, +174), 54 perinatal and postneonatal deaths (95% CI –9, +149), 48 surviving twins with a birth defect (95% CI –8, +133), and nine with cerebral palsy (95% CI –2, +26). The numbers needed to treat for the prevention of one pregnancy with a neural tube defect is 847, for the birth of one additional set of twins is 175, for the birth of one additional set of very preterm twins is 1587, and for the birth of an additional twin with any of the following outcomes (perinatal death, postneonatal death, survival with a birth defect, or survival with cerebral palsy) is 901.
Conclusions Monitoring rates of neural tube defects and twinning is essential as supplementation or fortification with folate is implemented.     

Unexplained antepartum fetal deaths: what are the determinants?

Objective The objective was to assess fetal, antenatal, and pregnancy determinants of unexplained antepartum fetal death.Methods This is a hospital-based cohort study of 34,394 births weighing 500 g or more from January 1995 to December 2002. Unexplained fetal deaths were defined as fetal deaths occurring before labor, without evidence of significant fetal, maternal or placental pathology.Results Ninety-eight unexplained antepartum fetal deaths accounted for 27.2% of 360 total fetal deaths. Two-thirds of these deaths occurred after 36 weeks gestation. The following factors are independently associated with unexplained fetal deaths: primiparity (OR 1.74; 95% CI 1.21, 2.86); parity of five or more (OR 1.19; 95% CI 1.26, 3.26); low socioeconomic status (OR 1.22; 95% CI 1.14, 2.86); maternal age 40 years or more (OR 3.62; 95% CI 1.22, 4.52); maternal age of 18 years or less (OR 1.79; 95% CI 0.82, 2.89); maternal prepregnancy weight greater than 70 kg (OR 2.20; 95% CI 1.85, 3.68); fewer than three antenatal visits in women whose fetuses died at 31 weeks or more (OR 1.11; 95% CI 1.08, 2.48); birth weight ratio (defined as ratio of birth weight to mean birth weight for gestational age) between 0.85 and 0.94 (OR 1.77; 95% CI 1.28, 4.18) or over 1.45 (OR 2.92; 95% CI 1.75, 3.21); trimester of first antenatal visit. Previous fetal death, previous abortion, cigarette smoking, fetal sex, low maternal weight, fetal-to-placenta weight, and post date pregnancy were not significantly associated with unexplained fetal deaths.Conclusion Several factors were identified that are associated with an increased risk of unexplained fetal deaths.     

Obstetric outcomes in women with end-stage renal failure requiring renal dialysis.

OBJECTIVE: To study obstetric outcomes in women with end-stage renal failure undergoing chronic renal dialysis. METHODS: A retrospective review of the database from the High-Risk Pregnancy Clinic at Singapore General Hospital, Singapore. RESULTS: From 1995 to 2004, 7 women treated with chronic renal dialysis had a total of 11 pregnancies. There were 2 pregnancy losses at previable gestation ages and 9 live births. Median gestational age at delivery was 31 weeks, and mean birth weight was 1390 g. Seven newborns had a low birth weight and 5 required neonatal intensive care. Severe hypertension occurred in 4 women for a total of 7 pregnancies. Other complications included polyhydramnios (n=2), preterm prelabor rupture of membranes (n=2), obstetric cholestasis (n=2), postpartum hemorrhage (n=1), thrombosis of the arteriovenous fistula (n=2), postpartum peritonitis (n=1), and fetal anomaly (n=1). There were no maternal deaths. CONCLUSION: Such pregnancies are high-risk, particularly because of maternal hypertension and prematurity. They should be managed by multidisciplinary teams, and prepregnancy counseling should not be neglected.     

The tendency to repeat gestational age and birth weight in successive births

A study was conducted in Norway on all 454,358 single births which occurred during the 1967-73 period. The results confirm and strengthen earlier findings regarding the tendency to repeat low-birth-weight and small- or large-for-gestational age deliveries in later births. Data collected from the Medical Birth Registry included information on birth weight, length of gestation, mothers' health during pregnancy, and complications and interventions during labor and delivery. A contour level graph was prepared to illustrate the joint distribution of gestational age and birth weight. Relative risks were calculated for each type of birth. These risks were correlated with actual outcome of subsequent births. The tendency to repeat birth weight in later births was greatest for mothers of heavy infants. The tendency to repeat gestational age in subsequent births, however, was greatest for mothers with preterm infants. Delivery of prior preterm births carried a lower risk than delivery of prior low-weight births. These tendencies were unaffected by the sex of the offspring or the birth order. The pattern of repeating similar gestational age and birth weight subsequently could not be accounted for by a tendency to repeat medical complications which predispose toward such outcomes. Such environmental factors as smoking or socioeconomic status were not believed to be relevant in the study results. The study demonstrates a cumulative risk for 3rd and later pregnancies.     

Prävention der Frühgeburt

Background

In recent years an improvement for the prevention of preterm birth has been achieved in evidence-based strategies by the use of progesterone with a proven prolongation of pregnancy and there is also an optimistic perspective for the use of vaginal pessaries; however, both interventions are only valid for singleton pregnancies. The most effective prevention of preterm birth was by reduction of multiple pregnancies in assisted reproductive techniques as well as the avoidance of elective deliveries in late preterm birth in 34 (0/7) to 36 (6/7) weeks of gestation.

Results

Prolongation of pregnancy by progesterone is achieved by the ability to modulate inflammatory mechanisms in cervical and myometrial tissue. Several studies showed a prolongation of pregnancy as well as improvement of perinatal outcome both in pregnancies after previous preterm births as well as in pregnancies with shortened cervix as assessed by sonography.

Discussion

The results on the indications for using cerclage for prevention of preterm birth are controversial. It is unclear where a cut-off for cervical length should be fixed for performing a cerclage to achieve a benefit. There are currently no relevant studies comparing the two methods of progesterone administration and cervical cerclage and no investigations on the combination of both methods. There is increasing discussion on whether routine sonographic assessment of cervical length should be carried out in all pregnancies including those women without previous preterm births.

Conclusion

Promising results have been obtained in a study assessing prolongation of pregnancy by prophylactic screening and treating vaginal infections; however, a meta-analysis failed to show any improvement in pregnancy duration. For more than half a century vaginal pessaries have been used to treat cervical incompetence. A recently conducted well-designed study using the Arabin pessary showed promising results both in prolonging pregnancy and improving perinatal outcome. The results of upcoming studies should be awaited before guideline recommendations for pessary use can be given.     

292例早产的临床因素分析

目的分析与人工早产和自然早产有关的危险因素.方法选取我院1993年1月至1999年7月间分娩的早产292例,将早产分为自然早产(250例)和人工早产(42例),分别与同期分娩的足月对照组295例相比,进行早产的临床因素分析.结果孕期母亲未作产前检查、胎膜早破、多胎、产前出血、中重度妊高征、内科合并症、胎儿畸形等均与早产有关;人工早产者产前检查率最低,剖宫产率最高,并主要与产前出血、中重度妊高征、多胎有关;自然早产者产前检查率低于足月对照组,其主要与胎膜早破、不明原因早产有关.结论孕期多种因素与早产有关;且自然早产和人工早产具有不同的危险因素.     

Born Too Soon: Care before and between pregnancy to prevent preterm births: from evidence to action

Providing care to adolescent girls and women before and between pregnancies improves their own health and wellbeing, as well as pregnancy and newborn outcomes, and can also reduce the rates of preterm birth. This paper has reviewed the evidence based interventions and services for preventing preterm births; reported the findings from research priority exercise; and prescribed actions for taking this call further. Certain factors in the preconception period have been shown to increase the risk for prematurity and, therefore, preconception care services for all women of reproductive age should address these risk factors through preventing adolescent pregnancy, preventing unintended pregnancies, promoting optimal birth spacing, optimizing pre-pregnancy weight and nutritional status (including a folic acid containing multivitamin supplement, and ensuring that all adolescent girls have received complete vaccination. Preconception care must also address risk factors that may be applicable to only some women. These include screening for and management of chronic diseases, especially diabetes; sexually-transmitted infections; tobacco and smoke exposure; mental health disorders, notably depression; and intimate partner violence. The approach to research in preconception care to prevent preterm births should include a cycle of development and delivery research that evaluates how best to scale up coverage of existing, evidence-based interventions, epidemiologic research that assesses the impact of implementing these interventions, and discovery science that better elucidates the complex causal pathway of preterm birth and helps to develop new screening and intervention tools. In addition to research, policy and financial investment is crucial to increasing opportunities to implement preconception care, and rates of prematurity should be included as a tracking indicator in global and national maternal child health assessments.

Declaration

This article is part of a supplement jointly funded by Save the Children's Saving Newborn Lives programme through a grant from The Bill & Melinda Gates Foundation and March of Dimes Foundation and published in collaboration with the World Health Organization (WHO). The original article was published in PDF format in the WHO Report "Born Too Soon: the global action report on preterm birth (ISBN 978 92 4 150343 30). The article has been reformatted for journal publication and has undergone peer review according to Reproductive Health's standard process for supplements and may feature some variations in content when compared to the original report. This co-publication makes the article available to the community in a full-text format.

     

New-onset hypertension in late pregnancy and fetal growth: different associations between singletons and twins.

OBJECTIVE: To compare the effects of new-onset hypertension (NOH) in late pregnancy on fetal growth in singletons and twins. METHODS: A retrospective cohort study was conducted to evaluate the effect of NOH on fetal growth in 17, 720, 900 singletons and 463, 104 twins born in the United States between 1995 and 2000. RESULTS: NOH was associated with lower mean birth weight in both preterm and term singletons. Increased risk of low birth weight and decreased risk of high birth weight was associated with NOH in preterm and term singletons. NOH was associated with increased risk for small-for-gestational-age (SGA) births and decreased risk for large-for-gestational-age (LGA) births in preterm singletons, whereas it was associated with increased risk of both SGA and LGA births in term singletons. NOH was associated with higher mean birth weight in early preterm twins, and lower mean birth weight in term twins. Decreased risk for low birth weight was found in the NOH group among early preterm twins, and increased risk for low birth weight in term twins. NOH was associated with increased risk of SGA births and decreased risk for large-for-gestational-age (LGA) births in early preterm twins, while increased risk of SGA births in term twins. CONCLUSION: NOH is associated with slower fetal growth in singletons delivered at different gestational ages, but the effect varies in twins depending on gestational age at delivery with faster growth in early preterm twins.     

Physician- and midwife-attended home births Effects of breech,twin, and post-dates outcome data on mortality rates

The effect of attending breech, twin, and post-date pregnancies on home birth outcomes was assessed. The same form was used to collect data on a convenience sample of 4,361 home births attended by apprentice-trained midwives from 1970 to 1985 and 4,107 home births attended by family physicians from 1969 to 1981. Data sets were compared to find 1,000 pairs of pregnant women, one from each group, who were matched for age, sex, socioeconomic status, race, and medical risk. The perinatal mortality rate for the midwife-attended births was 14 per 1,000 (three fetal deaths before labor, six intrapartum fetal deaths, and five neonatal deaths). The perinatal mortality rate for births attended by family physicians was five per 1,000 (one fetal death before labor, two intrapartum fetal deaths, and two neonatal deaths). The difference was statistically significant; however, the differences disappeared when cases involving post-dates, twin, or breech deliveries were eliminated from the sample. Although the data are more than a decade old, they support the premise that outcomes for low-risk home births are comparably good whether attended by physicians or midwives. However, the findings do raise questions about the safety of attending high-risk births at home.     

PHYSICIAN- AND MIDWIFE-ATTENDED HOME BIRTHS: Effects of Breech,Twin, and Post-Dates Outcome Data on Mortality Rates

The effect of attending breech, twin, and post-date pregnancies on home birth outcomes was assessed. The same form was used to collect data on a convenience sample of 4,361 home births attended by apprentice-trained midwives from 1970 to 1985 and 4,107 home births attended by family physicians from 1969 to 1981. Data sets were compared to find 1,000 pairs of pregnant women, one from each group, who were matched for age, sex, socioeconomic status, race, and medical risk. The perinatal mortality rate for the midwife-attended births was 14 per 1,000 (three fetal deaths before labor, six intrapartum fetal deaths, and five neonatal deaths). The perinatal mortality rate for births attended by family physicians was five per 1,000 (one fetal death before labor, two intrapartum fetal deaths, and two neonatal deaths). The difference was statistically significant; however, the differences disappeared when cases involving post-dates, twin, or breech deliveries were eliminated from the sample. Although the data are more than a decade old, they support the premise that outcomes for low-risk home births are comparably good whether attended by physicians or midwives. However, the findings do raise questions about the safety of attending high-risk births at home.